97 hard start suddenly

[MrMarty51]

And it now is fixed ?

 

[royunion]

And it now is fixed ?

Nope. The fuel shutoff solenoid arrived Sunday, but before I tackle that - on a Van a major job - I am going to try a new PMD.

I normally keep a spare new one or working repaired spare, but the last time I ordered transistors they all arrived testing bad except two from yes, China. I complained via ebay and he refunded my money, and said keep them.

They are Motorola made in Mexico which China buys to make PMD units. My guess is that they tested bad and sold them on eBay.


I thought I would check the PMD calibration resistor and when it took it off to remove the resistor, it just fell out. The friction teeth in the resistor were gone and a few fell out with it. That was a number 7 and I had a number 9 spare so I tried it and no start.

For nothing else to do I had two PMD waiting for new transistors I just never out in - one a Grey stanadyne and other a black Chinese unit.

The transistors were in two rows of five and I forgot which end I put the two good ones on so I just two in the Stanadyne unit and the next two in the Chinese unit. In hindsight I should have put two from each in ineach. Transistors are now 7 to 10 dollars each so repairing them now longer makes sense.

Anyway I put the Stanadyne unit on and standing outside the van cranked it and it started immediately, but died. I tried cranking again but the batteries were too low. It never started it again however.

OK got out the generator and charger starter. Pulled the generator recoil start and it broke. Rope went in and out with no engage of the engine.

I am at my lady friend's apartment on the street where she cannot run an extension cord - against apartment rules.

So four ten mm bolts later - that was too easy, it is off and in my hand and the two broken pieces of course they phenolic plastic.

JB Weld to the rescue, and the design was such I could pool up the JB Weld so of it to reinforce the broken part once hard.

Overnight next day, it is working again, but I can see it has been wobbling riding on the catch prongs. Put it on but it only would catch for half a revolution pull. A common thing on those generators, such that replacement recoil start cover assemblies are available for $10 to $12 delivered. So I ordered one.

OK so looking like the PMD might be the culprit. Most PMD fail due to low fuel pressure causing heat from the switching function they play for pulse width modulation on the fuel solenoid as the throttle. Mine never even get warm.

The last PMD I replaced was with a new one two years ago that failed immediately and I put the old one back on. Then to be "safe" I ordered another new one and put the new one on. I figured I would replace the transistors in the Chinese one working fine just to be safe and that is when I got the junk transistors - after I had taken out two perfectly good ones - well actually one was bad.

The Chinese unit that failed immediately went in the trash.

So the generator has a 14 mm nut on the end, so I could not find my 3/8 screw gun adapter, and took a 3/4 to 3/8 male socket adapter and drove a 12 or 13 bolt into the 3/4 end, chunked it in my drill and used a 6 point socket to "electric start" the generator from the battery power left using the inverter. The batteries were reading 11.9 volts and I had maybe one good burst with the drill before the inverter would go into fault mode. One Goid burst is all it took and the generator started immediately.

I may cut a hole in the old cover and leave it "electric start" by gutting the old recoil and putting it back on. It serves as a fan shroud to air cool the cylinder.

Took a long time to get a charge back into the batteries, but you know it is bad when you know a one second burst of starting fluid is all it takes to start the engine relatively quickly and quietly. I went to get the fuel shutoff solenoid and (Amazon locker) and now I am waiting on the PMD and relocation kit to arrive.

These ebay sellers, many have started using these "shipping partners" who pick up the item and deliver it to the post office of zip of delivery and sometime they sit on it for two or three days.

The fuel shutoff solenoid was $45 delivered by Amazon, and the PMD is $30 but it is the 6.5 frustration I am tired of.

There are no American made PMD anymore and if China raises the price with this tariff war, or they stop making them then this 6.5 is junk.

I am accelerating the re-cabling adapter for the 5.7 engine harness removal of the 6.5 even faster now to put in the 5.7 vortec.

OH and the last thing, a honey bee decided to investigate the back of my knee, and after I almost started it and got in to try again, it got pinched in my knee bend and proceeded to sting me, to which I reached back there and ended it life and pulled the barb out, but of course now the back of my leg is good a swollen and itching. Oh joy.

 

[dbrannon79]

If you don't mind @royunion please share your repairs done on PMD's, you can do this in another thread if you want to keep this one from getting derailed off it's tracks! I was messing with them and came up with an idea I wanted to test that would have the transistors remote mounted away from the PMD and easily replaceable on failure. was also thinking about using some "overkill" rated transistors to hopefully eliminate the failures.

Problem I was having was being able to get the epoxy gunk out of the way safely without destroying the circuit board in the PMD. some come with soft malleable epoxy but most I have seen have the hardened type that you have to grind and chisel out!

 

[jrsavoie]

If you don't mind @royunion please share your repairs done on PMD's, you can do this in another thread if you want to keep this one from getting derailed off it's tracks! I was messing with them and came up with an idea I wanted to test that would have the transistors remote mounted away from the PMD and easily replaceable on failure. was also thinking about using some "overkill" rated transistors to hopefully eliminate the failures.

Problem I was having was being able to get the epoxy gunk out of the way safely without destroying the circuit board in the PMD. some come with soft malleable epoxy but most I have seen have the hardened type that you have to grind and chisel out!

I've often wondered why, after the pmd issue was identified and the solutions figured out, that nobody came out with something.
There was no reason to maintain the hardware pattern.

 

[royunion]

If you don't mind @royunion please share your repairs done on PMD's, you can do this in another thread if you want to keep this one from getting derailed off it's tracks! I was messing with them and came up with an idea I wanted to test that would have the transistors remote mounted away from the PMD and easily replaceable on failure. was also thinking about using some "overkill" rated transistors to hopefully eliminate the failures.

Problem I was having was being able to get the epoxy gunk out of the way safely without destroying the circuit board in the PMD. some come with soft malleable epoxy but most I have seen have the hardened type that you have to grind and chisel out!

The transistors cost too much now. https://www.amazon.com/MJ15004G-Complementary-Silicon-Power-Transistors/dp/B082S34GBK

I use this kind of iron. https://www.amazon.com/RadioShack-45-Watt-Desoldering-Iron/dp/B007Z7MNEM

I used a harborfreight.com El cheapo dremel style tool kit. https://www.harborfreight.com/07-amp-rotary-tool-kit-80-piece-58999.html

You cannot really relocate the power transistor as it's case is the collector or base. It will fail fast without a heat sink and there is no good way to carry that current to the PMD circuit board.

The best solution is higher pressure fuel pressure which reduces the need for excessive fuel solenoid operation..

I watched a YouTube video of a guy destroy a "customer's" engine not knowing what he was doing. A two part video. The engine was doing runaways and I never saw him deal with fuel pressure. They do that for two reasons, excessive fuel pressure and improperly installed fuel solenoid usually during a rebuild attempt some guys try at home. Usually the sweet spot is around 15 psi, but they will take up to 22 before runaway.

and

and the guy did not know a sick mechanical engine and kept going until he blew it with a rod through the block. Watch the idiot, who frankly gave the owner all the proof to sue him.

The converse is true not enough fuel pressure works those transistors like switches to provide voltage via pulse width modulation to the fuel solenoid for more fuel. They get hot, heat fatigue and fail. We saw guys come into the shop with after market lift pumps for gas vehicles pushing 30 psi with runaway problems and real hard heads. As a stanadyne shop all we could do is put on an oem pump.

With pressures like that it takes very little pulse width modulation to open the throttle wider. That is why mine has a regulator on the fuel line.

I can always put my hand on the PMD heat sink and it is barely warm.

If this PMD failed it is something with how it communicates the starting sequence set of the stepper motor timing and inject command. The transistors have nothing to do with it or it would be cutting out while driving.

Otherwise it is the fuel shutoff solenoid and worst case the CPS.

I cannot get to my fuel shutoff solenoid with taking out the ac compressor and then there is a question if I can unplug it.

Once I start this creature it idles smoothly at 600 rpm with r99 - r95

I am just going to buy a few now PMD at low prices and expect they are junk

There is a lot of junk transistors out there, some even with aluminum cases

I my opinion it is not worth it you will need to test every transistor before install

OH yes NOT an Amazon Associate here.

 

[royunion]

If you can't link the videos here are the numbers to put behind watch?v=. 9o20wIa_Vjg
and xCklOZQ6INI

 

[dbrannon79]

I will have to watch these vids after work.

One thing that GM never provided in their books nor could I find ant reference of online is the internal schematic or digital blueprint of the PMD it's self. I would love to find more info on the internals and components, just never found anyone who personally worked on them before other than seeing other vids on how to replace that transistor. for me just as a general hobbyist if you have that to share, that would be awesome.

On some electronics I have managed to swap out burned out components with a "heavier duty" one making it last longer than it's expected life. I like to fool around with things like that. I once had a inverter burn out one of it's mosfets rendering it almost useless. Yes they are cheap enough but as a determination I ended up swapping out the internal mosfets with ones that would handle 3 times the power and current, This didn't increase any output wattage but you could tell less heat would build up under load and seemed to work better than when it was new!

Yeah I know I'm rattling on about it, I just wish some of these other aftermarket MFG's would have taken the time to examine the oem design and upgraded them with overkill components making them last longer. then again that would put them out of business if they never failed LOL

 

[royunion]

I will have to watch these vids after work.

One thing that GM never provided in their books nor could I find ant reference of online is the internal schematic or digital blueprint of the PMD it's self. I would love to find more info on the internals and components, just never found anyone who personally worked on them before other than seeing other vids on how to replace that transistor. for me just as a general hobbyist if you have that to share, that would be awesome.

On some electronics I have managed to swap out burned out components with a "heavier duty" one making it last longer than it's expected life. I like to fool around with things like that. I once had a inverter burn out one of it's mosfets rendering it almost useless. Yes they are cheap enough but as a determination I ended up swapping out the internal mosfets with ones that would handle 3 times the power and current, This didn't increase any output wattage but you could tell less heat would build up under load and seemed to work better than when it was new!

Yeah I know I'm rattling on about it, I just wish some of these other aftermarket MFG's would have taken the time to examine the oem design and upgraded them with overkill components making them last longer. then again that would put them out of business if they never failed LOL

GM did not design the PMD Stanadyne did to integrate the rehostat accelerator pedal into the gm ecm and for automatic start functions to control the Stanadyne DS4 IP.

One company popped up with an extreme heavy duty PMD for $350. They disappeared almost instantly.

The issue is simple. Using power transistors as switching transistors to manufacture pulse width modulation to control a solenoid is stupid.
However minimize the use of them with fuel pressure and a spring means the fuel solenoid does not require as much current.

GM did not listen to Stanadyne and put that crap solenoid lift pump on that is not really a pump, and there is the aftermarket solution, an actual positive displacement regulated lift pump.

With all the 6.5 pundits saying a variety of things it was misinformation city.

The biggest is the 5 psi fuel pressure requirement. That is a MINIMUM test figure + -or - 1% regulated for test purposes only on the bench. Even that burns up PMD on the test stand.

DB2 operate best at 5 to 7 psi for a reason.

Forget dreaming of anyone making a better PMD because it would have always been a loosing product. As long as GM put those solenoid lift pumps on that made no reliable regulated pressure, the PMD was always going to fail

I mean look at like this - every fuel injected vehicle has a regulated fuel pressure or unpredictable performance.

 

[dbrannon79]

True, thinking about it that way, yes our 6.5's don't really have a pressure regulator, they all use the fuel pump, 99% of all gassers fuel pumps will push well into 90+ psi if they are deadheaded where ours is constantly pushing it's max where the demands of the engine exceed what it can supply. Give thanks to GM bean counters there.

for me going that route using a pump that can supply good flow and higher pressure, running a pressure regulator to limit it. I would want something else in the line for protection if and when a regulator would fail and send full pressure to the IP. maybe a pressure sensor after the regulator that would shut down the lift pump when pressure was exceeded a given amount. something that would give a warning light that you would have to manually reset so the LP would not turn back on.

I'm just a little anal on trusting a single regulator that if failed could destroy the engine not having a fail-safe in place.

Just curious, I know Ford uses DB2's on some of their trucks, did they also use the same style DS4 type? maybe we can look at how or if they regulated their fuel supply and pressure.

 

[royunion]

True, thinking about it that way, yes our 6.5's don't really have a pressure regulator, they all use the fuel pump, 99% of all gassers fuel pumps will push well into 90+ psi if they are deadheaded where ours is constantly pushing it's max where the demands of the engine exceed what it can supply. Give thanks to GM bean counters there.

for me going that route using a pump that can supply good flow and higher pressure, running a pressure regulator to limit it. I would want something else in the line for protection if and when a regulator would fail and send full pressure to the IP. maybe a pressure sensor after the regulator that would shut down the lift pump when pressure was exceeded a given amount. something that would give a warning light that you would have to manually reset so the LP would not turn back on.

I'm just a little anal on trusting a single regulator that if failed could destroy the engine not having a fail-safe in place.

Just curious, I know Ford uses DB2's on some of their trucks, did they also use the same style DS4 type? maybe we can look at how or if they regulated their fuel supply and pressure.

Simply do not use a diaphragm regulator design that can crack or tear the diaphragm and fail.

Use a pressure plate design that is two discs against one another by spring pressure.

The discs must fail or the spring loose all temper.

Mine has been working for over ten years

Don't use a pump that can push crazy high pressure if the regulator fails.

Put a gauge in the line electrically wired into the cab

 

[Will L.]

No, Ford never went for ds4. Thats when they dumper the idi 7.3 and introduced the 7.3 powerstroke

The pmd issue was learned and been solved for years. Just not everyone knows it yet.
It needs to be on a heat sink with at minimum the thin thermal contact pad, best is arctic silver5. Mount the heat sink on the back side of the front bumper. The equal temps and slower temp changes eliminates 90% of the failures.

The resistor arguments were settled here many many years ago, because I refuse to own ds4/pmd I can’t remember who- but a member here ran without any resistor for years and others copied to verify. It is used for setting it up and only is affect at 50 start intervals and without it the truck will still start and run once it’s been running.

As to which pmd- Leroy Diesel still sells the lifetime warranty ones that he has been selling for years. Ask him if he has had to warranty half a dozen yet….
I been telling people how we dealt with pmd in the fleet with hundreds of 6.5 trucks crushing 100,000 miles per year- was running two. Put a dummy plug in the spare. Both mounted to either two separate heat sinks or one big one. When in question- swap the wire and get on with life. If it is bad- you drive on the old spare while waiting for the lifetime warranty one to be replaced. Next week when its back- run on the lifetime again.

Absolutely the fuel pressure is big- just as big is the lubricants that are required to be added since we no longer have sulfur in the diesel. Original reports of bio fuel being high lubricants was good- but the addition of ethanol/ methanol off sets most of the B-fuels. As to the pressure- I have went from reading it at the fuel filter outlet to saying ONLY metal T connection at the ip inlet fitting because I have seen SO MANY rubber fuel lines between filter & ip and it all looks ok but is being blocked just before the ip. Search pics previously posted by myself and others.

Redoing anything other than running the modern design/built pmd & resistor is a serious waste of time. Understand not having a spare pmd ready to rock is like not having a spare tire. Pre mounted means all testing and swap is just doing some of the work ahead of time and only added cost at that point is $20 for an extra heat sink. Do the math about broke down at night, bad weather, etc especially with family in the rig or God forbid an emergency situation and it isn’t an iq higher than a dog needed to realize it should be a flat requirement to owning the ds4.

FTB mod has been done by 1 person who said it was a waste of time that I ever heard of. And when a couple of us offered to drive to him, pay time to put back 5/16 line and record results then swap to 3/8 line (FTB) and bet him $100 if there wasn’t a noticeable difference. Why would I do it? Because I have done so many ds4 & db2 “3/8 conversions” as I called it before hearing the term FTB that I know 100% it has helped every single 6.2 & 6.5 I have ever done it with. Basically it is a no brainer and it ticked me off this guy was swearing it didn’t help and infact was hurting it. Notice that clown never shows up. Several people question it- which I understand. Two people have said it’s illegal- Roy and a guy in Europe. The guy in France had a Hummer, and another Hummer owner met him & showed him his with a FTB. Within a month they both were owned by the one guy and both had FTB. Funny part is, that guy who now owns both is a gubmint employee who oversees the division that oversees their smog requirements for his county (I can’t remember which one). hahaha.

The only thing to really debate in the fuel at this point is which additional lubricants (never use a water emulsifier) and which aftermarket lift pump & filters is worth the investment.
Less water the better- FASS has the best I have found so far. Factory filter (by Stanadyne requirements) is 10 micron nominal. So long as volume and pressure at the ip inlet is met- going smaller is always better.

Which pump- lifetime warranty cost more usually but is like insurance.
If you don’t have a pressure gauge permanently mounted-you are guessing.
The last training books I saw (afaik others here too) that were the Stanadyne training literature said 8-14 psi is proper range for ds4.
I asked before and will again:
The different spec you mentioned: please post pics of the specs and the manual they are in Including the identifier for that literature because there are misprints.

I sell no parts. I sell no services. I get no pay from any vendors (infact they get paid by me- haha). I have busted parts sells guys on multiple sites for misrepresentations. The link posted earlier in this thread for the lift pump-
I HIGHLY QUESTION IT being the best choice. Can’t say it is horrible- but there are cheaper options and there are other options that cost more on day one but have better return on investment imo.

I do have a habit of investing too much in some situations but like my Hummer with db2- it was more economical to just keep replacing the EP 158 by AC Delco, which while toted as the best factory style lift pump- is too low output for the ds4 unless you get one that an individual store will do lifetime warranty because it barely meets bottom spec when new and within a year or so falls below.

So, from a fairly obvious air intrusion problem to maybe fso, to in dash electrical short, firing the parts cannon continues with a pmd & resistor before installing the already purchased fso and still not doing what both Stanadyne say is task #1 of installing clear line in place of the ip return line to examine for air intrusion (bubbles) or other contamination then reading pressure/flow at ip inlet… Am I up to speed?

Again- please show the specifications you mentioned at the beginning of this thread as they are completely incorrect at too low and too high. I stopped by the local Standyne authorized shop to check on his supply of injector shims and had him pull up the numbers- he verified what has been in my book from the 1990s:
8-14psi

 

[royunion]

No, Ford never went for ds4. Thats when they dumper the idi 7.3 and introduced the 7.3 powerstroke

The pmd issue was learned and been solved for years. Just not everyone knows it yet.
It needs to be on a heat sink with at minimum the thin thermal contact pad, best is arctic silver5. Mount the heat sink on the back side of the front bumper. The equal temps and slower temp changes eliminates 90% of the failures.

The resistor arguments were settled here many many years ago, because I refuse to own ds4/pmd I can’t remember who- but a member here ran without any resistor for years and others copied to verify. It is used for setting it up and only is affect at 50 start intervals and without it the truck will still start and run once it’s been running.

As to which pmd- Leroy Diesel still sells the lifetime warranty ones that he has been selling for years. Ask him if he has had to warranty half a dozen yet….
I been telling people how we dealt with pmd in the fleet with hundreds of 6.5 trucks crushing 100,000 miles per year- was running two. Put a dummy plug in the spare. Both mounted to either two separate heat sinks or one big one. When in question- swap the wire and get on with life. If it is bad- you drive on the old spare while waiting for the lifetime warranty one to be replaced. Next week when its back- run on the lifetime again.

Absolutely the fuel pressure is big- just as big is the lubricants that are required to be added since we no longer have sulfur in the diesel. Original reports of bio fuel being high lubricants was good- but the addition of ethanol/ methanol off sets most of the B-fuels. As to the pressure- I have went from reading it at the fuel filter outlet to saying ONLY metal T connection at the ip inlet fitting because I have seen SO MANY rubber fuel lines between filter & ip and it all looks ok but is being blocked just before the ip. Search pics previously posted by myself and others.

Redoing anything other than running the modern design/built pmd & resistor is a serious waste of time. Understand not having a spare pmd ready to rock is like not having a spare tire. Pre mounted means all testing and swap is just doing some of the work ahead of time and only added cost at that point is $20 for an extra heat sink. Do the math about broke down at night, bad weather, etc especially with family in the rig or God forbid an emergency situation and it isn’t an iq higher than a dog needed to realize it should be a flat requirement to owning the ds4.

FTB mod has been done by 1 person who said it was a waste of time that I ever heard of. And when a couple of us offered to drive to him, pay time to put back 5/16 line and record results then swap to 3/8 line (FTB) and bet him $100 if there wasn’t a noticeable difference. Why would I do it? Because I have done so many ds4 & db2 “3/8 conversions” as I called it before hearing the term FTB that I know 100% it has helped every single 6.2 & 6.5 I have ever done it with. Basically it is a no brainer and it ticked me off this guy was swearing it didn’t help and infact was hurting it. Notice that clown never shows up. Several people question it- which I understand. Two people have said it’s illegal- Roy and a guy in Europe. The guy in France had a Hummer, and another Hummer owner met him & showed him his with a FTB. Within a month they both were owned by the one guy and both had FTB. Funny part is, that guy who now owns both is a gubmint employee who oversees the division that oversees their smog requirements for his county (I can’t remember which one). hahaha.

The only thing to really debate in the fuel at this point is which additional lubricants (never use a water emulsifier) and which aftermarket lift pump & filters is worth the investment.
Less water the better- FASS has the best I have found so far. Factory filter (by Stanadyne requirements) is 10 micron nominal. So long as volume and pressure at the ip inlet is met- going smaller is always better.

Which pump- lifetime warranty cost more usually but is like insurance.
If you don’t have a pressure gauge permanently mounted-you are guessing.
The last training books I saw (afaik others here too) that were the Stanadyne training literature said 8-14 psi is proper range for ds4.
I asked before and will again:
The different spec you mentioned: please post pics of the specs and the manual they are in Including the identifier for that literature because there are misprints.

I sell no parts. I sell no services. I get no pay from any vendors (infact they get paid by me- haha). I have busted parts sells guys on multiple sites for misrepresentations. The link posted earlier in this thread for the lift pump-
I HIGHLY QUESTION IT being the best choice. Can’t say it is horrible- but there are cheaper options and there are other options that cost more on day one but have better return on investment imo.

I do have a habit of investing too much in some situations but like my Hummer with db2- it was more economical to just keep replacing the EP 158 by AC Delco, which while toted as the best factory style lift pump- is too low output for the ds4 unless you get one that an individual store will do lifetime warranty because it barely meets bottom spec when new and within a year or so falls below.

So, from a fairly obvious air intrusion problem to maybe fso, to in dash electrical short, firing the parts cannon continues with a pmd & resistor before installing the already purchased fso and still not doing what both Stanadyne say is task #1 of installing clear line in place of the ip return line to examine for air intrusion (bubbles) or other contamination then reading pressure/flow at ip inlet… Am I up to speed?

Again- please show the specifications you mentioned at the beginning of this thread as they are completely incorrect at too low and too high. I stopped by the local Standyne authorized shop to check on his supply of injector shims and had him pull up the numbers- he verified what has been in my book from the 1990s:
8-14psi

Ah yes I am familiar with the Stanadyne shop pitch. The shop is not allowed to give information which does not match the GM spec, for example the EP158 PUMP spec is 9.5 to 14 so that is what you tell the customer.

The shop was not, as a stanadyne repair and rebuild shop, not allowed to install anything not oem matching or approved. In short they will not tell you the truth.

I run my pump at 15 psi regulated, which unofficially is Stanadyne's best situation too, but they won't say that because gm has no regulation system for a lift pump.

I said real world I know from putting one on a test stand it takes over 22 psi before they run away possibly.

I guess you need to own and drive a 6.5 with a regulated fuel system to see and feel the difference.

Scribd has the DS4 service manual and anyone can download it and find the operating range spec. Whatever it says it what it says, however there was a revision to match the generally accepted talking points to match the gm lift pump.

The Leroy Diesel lifetime warranty is cute. I can buy five full pmd relocation kits with pmd for that $150.00 price. Uh, no.

I am caught with my pants down, without a spare but maybe it is not the PMD.

I use cpu heat Grease on my pmd install, but they don't get hot enough for the transistors to fail. I am still driving with the no start condition and when the PMD finally arrives I will know. Even the Leroy one looks like the Chinese one, and I know he does not make them. I also know what the Chinese ones wholesale for in quantity.

On the test stand at 5 psi one cannot hold the PMD in your hand. At 15 you can.

Plus for the warranty, the buyer pays shipping both ways.

My 6.5 is running fine, it just has the start problem with the wait on the new PMD to arrive to see if it really is the fuel shut off solenoid

 

[snarl95]

The flight systems pmd is made in the USA. But feel free to buy the chinese ones.

 

[royunion]

The flight systems pmd is made in the USA. But feel free to buy the chinese ones.

Ah yes, "made in the USA" likely always meant "assembled in the USA". The plastic case, the die cast frame and even the circuit board is likely made elsewhere imported and final assembly done here. It is a big investment to make all of that here. But flightsystems does not own the PMD business anymore, Dorman does.

I will continue to use them as they work and I can afford plenty of spares and I only had one fail immediately which is the one I should have immediately replaced with another spare.

Flight Systems is now Dorman. See dieselplace thread "Dorman-pmd. 986042"

One guy said his pmd has lasted 11 years. Mine has too, and the last time I swapped it was actually due a cable gone bad. Then I needlessly destroyed it by going to replace the transistors to freshen it only to find the transistors shipped were junk.

I am closer to this whole thing than most, as the owner of the Stanadyne shop I did work for told me none of the PMD are made in America anymore.

On the flightsystems website nothing is found about pmd anymore.

It is an urban legend at this point. No value in chasing the truth when the Chinese units are probably now the Dorman flightsystems units anyway with a warranty that is more hassle than just having spares. Autozone and Oreillys etc charge enough to eat one or two, and they will check how long before you show up for a replacement.

I do not have an established pmd problem yet.

But, I will continue to use the Chinese units as they work, one for 10 years and the price is right.

 

[Will L.]

I went through training to rebuild the pumps at the stanadyne site when they were the only authorized training center. One of the two engineers who created the ds4 taught the class. I am telling you- the pressure is 8-14 psi according to the engineer who made the thing. Your information is wrong.

And the spec for the EP158- if you look up the big testing that was done comparing all the different in line lift pumps of multiple brands and all-
The testing was done in my shop. The EP158 was the best of that style, thats why it is the one recommended by everyone. If you drive over 10,000 miles in a year- that pump won’t make it the one year maintaining pressure to the 8psi level. Most of them don’t maintain 5 psi for a year.

If you wanna run at 15 psi- you can. I know a guy who lets his gasser v8 run until the oil is not visible on the dipstick then adds so much oil that he is overfilled 2 quarts. Truck has 150,000 miles on it so that proves its smart, right?
No. There are things you do to get the most efficiency and longevity from components.

Just understand when you do pull the engine- you have shown you don’t follow actual specs and there is an obvious problem with aeration which is insane for damage to the pump & rotor so people don’t expect to get 20,000 miles from the ip from you. Jerry rig patch on the filter and still running it means they can’t trust any of the maintenance to care for the engine holds low impressions that the entire engine has low shot at even being a good core. So don’t expect more than a couple hundred bucks for the engine with all its diesel accessories. Honestly the throttle pedal probably holds more value than everything else combined if it is same pedal as the trucks- i never compared if they are or not.

 

[royunion]

I went through training to rebuild the pumps at the stanadyne site when they were the only authorized training center. One of the two engineers who created the ds4 taught the class. I am telling you- the pressure is 8-14 psi according to the engineer who made the thing. Your information is wrong.

And the spec for the EP158- if you look up the big testing that was done comparing all the different in line lift pumps of multiple brands and all-
The testing was done in my shop. The EP158 was the best of that style, thats why it is the one recommended by everyone. If you drive over 10,000 miles in a year- that pump won’t make it the one year maintaining pressure to the 8psi level. Most of them don’t maintain 5 psi for a year.

If you wanna run at 15 psi- you can. I know a guy who lets his gasser v8 run until the oil is not visible on the dipstick then adds so much oil that he is overfilled 2 quarts. Truck has 150,000 miles on it so that proves its smart, right?
No. There are things you do to get the most efficiency and longevity from components.

Just understand when you do pull the engine- you have shown you don’t follow actual specs and there is an obvious problem with aeration which is insane for damage to the pump & rotor so people don’t expect to get 20,000 miles from the ip from you. Jerry rig patch on the filter and still running it means they can’t trust any of the maintenance to care for the engine holds low impressions that the entire engine has low shot at even being a good core. So don’t expect more than a couple hundred bucks for the engine with all its diesel accessories. Honestly the throttle pedal probably holds more value than everything else combined if it is same pedal as the trucks- i never compared if they are or not.

I am perplexed why you are stuck on the 8-14 psi operating range spec to insist anything else is wrong.

You say some engineer told you that. That without proof, is called "hearsay"

But then other authority sources and fact contradict you. For one the DS4 test spec is 5 psi + or - 1%, REGULATED so that contradicts your 8 psi claim

Second the stanadyne-ds4-service-bulletin-sb-500r2-pdf (500r2) at Section Three speaks to a test on the test stand for fuel delivery is to raise the inlet pressure to a "minimum" of 16 psi and check again.

I remember that the DS4 service manual specified the operating range was 5 to 18 psi.

I could have recalled wrong but it could only then be 5 to 16.
But I am fairly sure it was 5 to 18. It really is not important to keep on about it.

This is a revision of the service manual that speaks to the purpose of the return valve is to keep housing pressure between 5 and 14 psi. Other service bulletin speak to how the return valve should be able to waste up to 3 psi and be in spec.

Other diesel 6.5 sites speak to guys getting Hp4601 pumps to run at 18 psi the early ones., now they claim 16 psi max.

Just because you say some engineer told you something does mean he is right or if he knows if he is right of wrong, especially when there is no proof in writing.

Anyone can go download the manual, which is the rebuild procedure.. It is a newer revision, that is missing the "operating range" inlet pressure statement which was on the page with the black and white pictorial of the pump. https://www.scribd.com/document/334125089/Stanadyne-Ds-Pump

The 500r2 service bulletin would not speak to raising the pressure to a MINIMUM of 16 psi if the upper limit might not be 18.

I would not tell someone they are "wrong" without written proof, and not just "hearsay" as proof.

I am not going to pay $150 for an EP158 that won't perform well out of the box even new. I am going to use a true positive displacement pump that can keep 15 psi at idle or wot. There is no problem with aeration in the IP and you can not make a diagnosis there is or was. The DS4 is a self bleeding system with adequate line pressure.

This thread is about why it might be suddenly hard to start, which is now will not start without fluid. I am waiting for a new PMD, which seems to have sent by Amazon as a USPS shipping partner 50 miles in the opposite direction first, and has it appears turned it around. Yet except for the start issue it runs perfect. Otherwise it is likely the Fuel Shutoff Solenoid which is hard to get to on a Van.

As to the rest of your post I have little of any idea what you are talking about. The flippant example about low oil makes no relative sense.