Not fuel or pmd but no start now

[dbrannon79]

I have to admit the extension harness on mine is from the wonderful amazon chineesium warehouse. I have inspected it a few times and hasn't given me any trouble, but I know that one of these days it's gonna bite me in the arse and @WarWagon is gonna sit back, laugh and say "I told ya so" as will everyone else!

 

[Bobburns]

As said - it has run six years with no problems until I replaced the lift pump and did not tighten the inlet to the lift pump enough and let it suck air - for three weeks at that

I also discovered the fuel cap not vented well enough.

Why that new PMD failed I am surprised at but also do not care about. I will put in new transistors - only because I have a couple of new ones already, and switch to a #5 resistor one day and see what happens.

The DS-4 is an enigma wrapped in a dichotomy of feckless-ness. I have measured the draw of the fuel solenoid by going up idle and when the IP is starved for fuel and load is higher and the heat goes up standing still.

I do not know why I have to pull the Ecm (crank) and cig lighter fuse before it will both crank and Inject to start - otherwise it just cranks.

It is running back to how it was previously just fine

 

[WarWagon]

As said - it has run six years with no problems until I replaced the lift pump and did not tighten the inlet to the lift pump enough and let it suck air - for three weeks at that

I also discovered the fuel cap not vented well enough.

Why that new PMD failed I am surprised at but also do not care about. I will put in new transistors - only because I have a couple of new ones already, and switch to a #5 resistor one day and see what happens.

The DS-4 is an enigma wrapped in a dichotomy of feckless-ness. I have measured the draw of the fuel solenoid by going up idle and when the IP is starved for fuel and load is higher and the heat goes up standing still.

I do not know why I have to pull the Ecm (crank) and cig lighter fuse before it will both crank and Inject to start - otherwise it just cranks.

It is running back to how it was previously just fine

You had to pull fuses or you have to pull fuses now? Cleaning grounds esp for the ECM come to mind. On pickups the two or three ground wires are by the trans dipstick passenger side head. Take apart and clean no matter what they look like.

FWIW: the ECM stays "alive" for around 30 seconds after key off. If you turn the key back on before the caps have discharged and the ECM finally shuts off: the SES and STS light are random rather than both going through a standard bulb check. Other side effects may vary.

With a weird failure like you have on the PMD I suggest exchanging it under the warranty. You will not know for sure if your repair fixed anything on a intermittent failure prone part. Simply because you clearly have other problems as well. (This repair to a PMD is something I would and could do myself, but, I warn against bothering because it adds another "unknown" to the problem(s) you already have.)

The fuel solenoid high current draw IMO is the real problem. I would have AAA or other "pre-paid hook program" to tow it home when the IP quits for good. Starving the IP for fuel can damage it and likely your luck ran out on this one sadly.

Are you using anything for additional fuel lube? This may buy the IP some time.

 

[Bobburns]

WarWagon

www.thetruckstop.us

There is no reason to believe any of what you suggest is an issue.

The ecm / crank fuse pull and replace is common of that vintage gm vehicle though with the 6.5 it may crank and not inject.

There is no high current draw to the fuel solenoid. That happens as you say when the IP is starved for fuel I have 16 to 18 psi regulated at the IP and I use R99 or B20 which has adequate lubricity.

There is no intermittent problem - it was simply air in the system which had to be self purged so I expected high rpm but not that long

I bought a lot of spare parts and an IP is one of them

Trying to use a warranty today means nothing but wasted time

 

[dbrannon79]

The ecm / crank fuse pull and replace is common of that vintage gm vehicle though with the 6.5 it may crank and not inject.

This is new news to me! I haven't heard of this being a common thing. owned a few obd1 vehicles and have wrenched on many. usually this kind of an issue points or a faulty ground or a failing PCM/ECM.

 

[Bobburns]

This is new news to me! I haven't heard of this being a common thing. owned a few obd1 vehicles and have wrenched on many. usually this kind of an issue points or a faulty ground or a failing PCM/ECM.

Well it is quite common and you can references to the oddity all over forums on the internet. On various vehicles it presents in different ways - but it is always the crank fuse.

Here is one such thread https://www.s10forum.com/threads/whats-the-crank-fuse-do.462149/

On this 6.5 seven years ago I had a low oil pressure shutdown when an oil cooler hose blew. When I replaced the hose and put in fresh oil it cranked and cranked and would not start. I went to check the crank fuse not blown and put it back in and cranked it and it immediately started - with no gauges working - so I shut it off and checked that fuse - also not blown and put back in and cranked - NO START again. This time I pulled cig lighter and crank and put them back in.

I put the key in and now the key in ignition sounded, the gauges zeroed and I cranked and it immediately started.

So it doesn't mean a bad ground or pcm/ECM failing as seven years later that ECM is still working fine. I do have a spare however.

This was the first and rare occasion GM and Stanadyne tried to computerize essentially the Rotary Injection Pump using essentially a gas ECM. The 94 - 95 OBD-I wiring and ECM is different from the 96-2000 OBD-II ECM. The software IN BOTH was full of GLITCHES - and one such feature was no inject under 200 crank rpm. These circuits cross check each other and every year the firmware changed until the last flash upgrade and wiring in 2000 was the best.

So it may be news to you but that depends on where you look in the real world and tech bullitens

 

[MrMarty51]

This is new news to me! I haven't heard of this being a common thing. owned a few obd1 vehicles and have wrenched on many. usually this kind of an issue points or a faulty ground or a failing PCM/ECM.

I too had done extensive searches on problems with the 6.5 before I bought mine and I found no refrences to having to pull and replace fuses to get one to crank or to run.
I had dealt with a LOT of the 6.5 platforms working for the DOT over here and not once did we ever have to mess with fuses for any reason.

 

[Bobburns]

I too had done extensive searches on problems with the 6.5 before I bought mine and I found no refrences to having to pull and replace fuses to get one to crank or to run.
I had dealt with a LOT of the 6.5 platforms working for the DOT over here and not once did we ever have to mess with fuses for any reason.

This is a disability mini-bus by Braun Mobility with commercial side mount condenser and fan and rear heat and a/c with wheelchair lift. It has custom wiring which may cause or contribute to the issues.

If you have a 2000 6.5 these glitches are gone from yours. From 97 to 98 starting and glow plug wiring changes were made as well as software in the ecm

It cannot just carte Blanche be said because one person has not seen it that it does not exist as an issue

I have low oil lights and a tach and engine hour meter not found from gm. I also have dual heavy-duty alternators with external regulators.

Just as I do not know what 6.5 years say you dealt with at whatever DOT you refer to, similarly what kinds of special circumstances that arose you do not mention.

Just because you have not seen or experienced what I have does not mean it does not happen under the right circumstances as I described. I actually found the pu and replace fuse fix on another forum seven years ago, and it turns out to apply to my 6.5.

As I said, it is running fine again, cool pmd, and the issue was caused by loose lift pump inlet and an insufficiently vented fuel cap. What happened to me is a chronicle of what apparantly can occur as real world actual happenings and what someone else has never seen is not relevant.

 

[Will L.]

Ak diesel driver for the win.
that clear tubing tells a lot of stories and is almost always an instant diagnosis. Thats why most of us keep that on 24/7/365.

 

[Bobburns]

Ak diesel driver for the win.
that clear tubing tells a lot of stories and is almost always an instant diagnosis. Thats why most of us keep that on 24/7/365.

I agree

When I read that suggestion I thought but how could that be??

When I saw that wet inlet and could smell the R99, I knew all I needed to do was tighten that fitting and get it started and keep rpms high enough to clear the air. When the pump ran faster with the loose fuel cap I knew that was helping to hide the issue being clogged.

When I saw my fuel pressure jump up fast and hold I knew it was fixed. I was afraid it was going to be the CPS

What that new pmd did I want to think is because it was defective out of the box

THE END

 

[WarWagon]

Not sure where you are getting no-warranty parts from or did they age out of warranty as NOS spares? Nothing like hauling an alternator around for years till you need it, install it, and then find out it was defective all along.

Step #1 in the GM service manual is check for air in fuel. They snort air you may get a bit of a loss of power surge as a warning, but, more likely it just quits running. Then it's real fun to purge the air out. The kinked fuel line softened by biodiesel saga I went through... and then the internal hose flapper at the inlet to the IP itself.

Yes the ECM issues are discussed on here in depth like the 94-95 linked below. The above key on-off-on in 30 seconds would trigger a ghost APP trouble code in my 1995. Neat watching the APP data change moving the pedal with the key just turned off for the next 30 seconds or so.

Detailed 6.5 ECM info: "Stanadyne DS4 and GM PCM.... yea, quite a piece of work."

Posted before and asked about a bit ago. http://www.10000cows.com/stanadyne-ds4.htm

www.thetruckstop.us

disability mini-bus by Braun Mobility with commercial side mount condenser and fan and rear heat and a/c with wheelchair lift

There will be lots of changes and additional wires. IMO I would suggest you clean the fuse contacts you suspect trouble with. (That is the blades on the fuses themselves. They are up to 25 years old after all.) Some on here have pulled and cleaned every single fuse and breaker. The frame and body ground straps to the engine are critical to keep in good working order: esp if the lift grounds to the frame. That's a lot of current for a lot of time finding ways around a bad ground strap. You probably already know about batteries working this hard working the lift before or after glow plugs and 10 HP diesel starter drain them.

 

[Rockabillyrat]

If your pulling ECM fuses to make the vehicle run sounds like a ECM issues to me. I have replaced ALOT of ECMs on GMT400s both gas and diesel configurations. Use a head lamp bulb to confirm power and ground to the ECM.

And guys STOP WAISTING TIME pulling grounds off and cleaning them. A simple 5 second voltage drop test with a meter can tell you if the grounds are bad. Almost 20 years as a mechanic and I hardly every see ground issues and I live in NE ohio. The salt capital of the Midwest.

 

[Rockabillyrat]

Also, have you tried communicating with the ECM when its a crank no start? Alot of times that's a great way to catch a bad module. If a scanner wont talk to it while its a crank no start then that points to a ECM or power/ground issue. If pulling the fuse and reinstalling fixes the crank no start and communication is back then that defiantly sounds like a ECM issue to me. If you don't have a scanner then look for the CEL on a KOEO on bulb check. If the CEL doesn't come on when you turn the key then there is a ECM issue because it controls the light. So if the CEL doesn't light up when its a no start, but does light up when it does start I would lean towards a ECM issue.

 

[Will L.]

I would disagree with the ground removing/cleaning.

You and I have had training and have access to a DLRO incase the DMM shows an intermediate reading. But a ton of these guys don’t and have no clue how to diagnose it. Many don’t even have a DMM. If a guy has a rig 15 years old and is having issues- removing the few grounds, cleaning and reinstalling takes maybe 15-20 minutes, can eliminate a lot and is free. Many guys will spend 30 minutes learning to do their first VD test. Then they will forget it because they won’t need that again for years and years. If they get a questionable reading then they are going to spend that original 15-20 minutes anyways.

Unless someone lives where the corrosion is insane enough to make that a problem in a few years, it is a one time thing- maybe twice in the life of the rig.
So long as people don’t think this is something they should do every oil change- no harm imo.

 

[WarWagon]

If your pulling ECM fuses to make the vehicle run sounds like a ECM issues to me. I have replaced ALOT of ECMs on GMT400s both gas and diesel configurations. Use a head lamp bulb to confirm power and ground to the ECM.

And guys STOP WAISTING TIME pulling grounds off and cleaning them. A simple 5 second voltage drop test with a meter can tell you if the grounds are bad. Almost 20 years as a mechanic and I hardly every see ground issues and I live in NE ohio. The salt capital of the Midwest.

A casual look through the forums here have a LOT of fixes from taking apart and cleaning the hidden corrosion on a ground. No, working a meter or locating the proper wire isn't in some of their skill levels. The headlight idea is good at first then figure it's frankly dangerous as someone may mess up the connections and fry something.

People either "Get it" with Trons or they don't. Even then it's still a bit of a black art.

New 2020 GMC Mobility van already went through H E L L over a dammed ground, under warranty, and I live in DRY SALT FREE Arizona. They wound up running a new ground wire when it was all said and done.

The fuses in the 1993 were all showing surface oxide and giving me some trouble as well as some wires and conectors that failed. The pinhole in the dome wire that corroded the wire in one area the driver side door floor area was from 25 years of monsoon rains.

Battery cable corrosion is also looked at and "ignored" from simply not knowing any better.

 

[Rockabillyrat]

A casual look through the forums here have a LOT of fixes from taking apart and cleaning the hidden corrosion on a ground. No, working a meter or locating the proper wire isn't in some of their skill levels. The headlight idea is good at first then figure it's frankly dangerous as someone may mess up the connections and fry something.

People either "Get it" with Trons or they don't. Even then it's still a bit of a black art.

New 2020 GMC Mobility van already went through H E L L over a dammed ground, under warranty, and I live in DRY SALT FREE Arizona. They wound up running a new ground wire when it was all said and done.

The fuses in the 1993 were all showing surface oxide and giving me some trouble as well as some wires and conectors that failed. The pinhole in the dome wire that corroded the wire in one area the driver side door floor area was from 25 years of monsoon rains.

Battery cable corrosion is also looked at and "ignored" from simply not knowing any better.

I don't need to look thought the internet to read about ground issues. Like I said.... almost 20 years as a mechanic and I hardly see issues with grounds. I have real world experience working on trucks and car of all makes and models. Sure some vehicles have ground issues from the factory. There are plenty of TSBs out there that point out the issue and how to fix it. But as far as taking all the grounds off and cleaning them... That hardly seems to ever be the fix. Everyone jumps on cleaning the ground circuit but have no idea how to properly test it. How is its a black art?? its OHMs law, that's grade school stuff!!

A voltage drop test can be done with any cheap meter and is extremely easy to do. Positive lead at the ground wire for the part you are testing and the negative lead on the negative battery cable. Load the system and measure the voltage drop across the ground circuit. Its that easy. Unless you like cleaning grounds for no reason, then sure go for it. I like to work smarter not harder. You can even voltage drop the battery terminals and see if they have a bad connection. Its hands down one of the easiest and best way to test any circuit.

A head lamp bulb is a great way to load test any circuit. I've had plenty of issues where my meter showed 12 volt, but would not light up the bulb. A corroded wire can show 12 volts but cant carry the amperage load to light the bulb. I test EVERY circuit with a bulb before I replace a part. Especially computers!!

 

[WarWagon]

I don't need to look thought the internet to read about ground issues. Like I said.... almost 20 years as a mechanic and I hardly see issues with grounds.

Let me rephrase that: The "it fixed it." when told to clean the grounds is a bad rash over the internet. Typically this is after the shotgun parts approach was used with zero results.

Understand the skill level and limitations of the audience. Bad grounds do exist, as noted, TSB's for bad grounds exist thus "Black Art" for something that should have been designed and built without problems, period. Grade Skool can't fill out a time card on High Skool Graduation and you expect them to know what Ohm's Law is: their first guess will be a new Starbucks Drink. "Six dimes and two quarters" is an answer that saves me time when they can't figure out what to give me with the screen telling them the cash change. Who said I was any good at math.

Last ground issue I fixed was a no-start situation on a generator. It just went click-click-click then "dead silence of nothing". Most would have pulled the starter for a rebuild. I tried it a couple of times just the be sure and then cleaned the battery cable ground.

Same problem after cleaning the ground. The set was used and located near a lake - rusty on lots of things including connections.

I could have gotten out the meter, but, dead battery in it. +45 min to get a new 9V battery. No time to waste on a single item shopping trip. (9V min to solenoid and 11V minimum at starter battery cable connection. Intermittent connection and/or solenoid banging on/off = cheap meter worthless. Need a min/max hold... or starter amp draw test.)

I could have used an IR temp gun to look for hot spots in the cables. No. (IR Camera I do not own to look for hot spots in cables.)

The dead giveaway was sparks coming off the star washer during a crank attempt. Re-assembled in a different order with the battery cable direct to the block and star washer on bolt head it cranked over and started. Bad cleaning job on my part, yes.

Another generator set, the entire set was rust free and clean, on the Neutral-Ground bond looked great from the outside. Normally carries ZERO current. But, if it's bad it can kill you or others.




Corrosion hidden by the nut:




As far as the OP's @Bobburns is concerned it merely takes lots of cranking without cooling the glow plugs off at minimum RPM to get the air out of the injection lines and light the diesel off to start. A single bad battery ground can slow the crank RPM down too much = no start. ECM weirdness can be a bad ground. If they have the tools they can "prove it". Pulling random fuses and trying again while the air is purged from the fuel system is a likely possibility. Clear return line off the IP and injector return lines would "prove it".

 

[dbrannon79]

Something I have learned from a few old timer electricians, all dissimilar metals that carry current will always corrode. some worse than others, but the corrosion always starts at the contact point where the current flows through and spreads from there. in your photo above shows this where the corrosion began in he center area of the ring terminal and would have eventually spread outward if contact was kept and hadn't completely lost connection. in high current areas the resistance from the corrosion causes ground to be pulled from elsewhere (anywhere it can flow through) and the end result is wires melting boards frying and getting electrocuted for some equipment.

Grounds should be a PM check, at least by meter or draw test. that alone can save a person money and time in the long run.

 

[WarWagon]

Charging resistor connection problem both wire terminal and adjustable clamp rust on variable resistor from the same set as the ground problem. It's a known trouble area as it runs hot and it's in the hot air exhaust of the generator section.

Grounds are just a name for another troublesome "connection".

 

[Rockabillyrat]

I never said bad grounds don't happen. I simply said that pulling all the grounds and cleaning them rarely fixes the issue. Its a hail mary when you are out of options. If you learn to TEST grounds properly you can save a lot of time. Its not as hard as you make it out to be.