1998 6.5 shuts off past 170° f

[Will L.]

Search ds4 problems and there will be thousands of threads.
Search db2 problems and see if you can find 10.

 

[JMJNet]

That is because there may be more truck with DS4 than DB2? at least on the consumer market.
Then, most with DB2 post in 6.2 section?

All I have changed in mine was the PMD in terms of IP.
Yes, I put additives like you suggested so that is the same.
I have never tinker with the IP and never fix problem that I never have.
The LP is weakness, I would think that DB2 needs LP also.

I take it that DB2 is more resilient but if I don't have the skill to replace with DB2, how much will it cost me to do so?

Either way, I have to buy a new IP when the IP in there goes bad.

 

[WarWagon]

@JMJNet No, it's because of awful PMD design located in the valley of Heat Hell causing problems all the time. Including bad heatsink contact killing it on the way home from the dealer when brand new.

 

[JMJNet]

@JMJNet No, it's because of awful PMD design located in the valley of Heat Hell causing problems all the time. Including bad heatsink contact killing it on the way home from the dealer when brand new.

We have a work around for that problem now.
However, with Arizona's heat, this truck with DS4 is probably not the best choice of vehicle.

Sorry to see what happened to your 93.

 

[Loganshaw_6]

Update: I took the advice you guys gave and purchased a rebuilt DS4 pump from an authorized stanadyne dealer with a stanadyne PMD. I got the truck running although I do not have the scanner to read timing but should have it later this week so I am unsure of what the timing is. I did run the truck and let it heat up and the higher the ECT temperature got the lower the idle went. It eventually dropped to about 600 RPM and then the engine stalled yeah. I was able to restart and keep the engine running above 1000 RPM anything lower the engine would stall out. Obviously this could be a timing issue considering I do not know where it is set now but I am starting to believe it is not the pump. I will update again once I have the scanner and can see where it is set.

 

[MrMarty51]

Update: I took the advice you guys gave and purchased a rebuilt DS4 pump from an authorized stanadyne dealer with a stanadyne PMD. I got the truck running although I do not have the scanner to read timing but should have it later this week so I am unsure of what the timing is. I did run the truck and let it heat up and the higher the ECT temperature got the lower the idle went. It eventually dropped to about 600 RPM and then the engine stalled yeah. I was able to restart and keep the engine running above 1000 RPM anything lower the engine would stall out. Obviously this could be a timing issue considering I do not know where it is set now but I am starting to believe it is not the pump. I will update again once I have the scanner and can see where it is set.

Did You leave the PMD mounted to the pump ?
If so, I would get that pulled from the pump and remote mounted to behind the front bumper, or, at least remove it from the pump and then try running the engine and see if there is any difference.
is this new PMD the Stanadyne grey box unit. if it is one of the old black box units, those too are very prone to failure.
The grey box unit will require a harness plug adapter to fit the old style black boxes, unless the Stanadyne shop has the harness already made to fit the grey box.

 

[Loganshaw_6]

Did You leave the PMD mounted to the pump ?
If so, I would get that pulled from the pump and remote mounted to behind the front bumper, or, at least remove it from the pump and then try running the engine and see if there is any difference.
is this new PMD the Stanadyne grey box unit. if it is one of the old black box units, those too are very prone to failure.
The grey box unit will require a harness plug adapter to fit the old style black boxes.

Yes it is a new gray pmd. I relocated it to behind the grill. I did realize the extension harness I have did not fit the PMD properly I trimmed the tabs off of the harness extension and it fit. This morning I removed the harness extension and plugged the PMD into the pump directly floating in the engine bay with the heatsink still attached. I'm going to go ahead and trash this extension harness and if I can get it to run properly I will purchase a new one.

 

[WarWagon]

If it very consistently shuts off at 170* and you can get it to start by unplugging the ECT sensor on the thermostat crossover housing, then it's shutting down for the fail-safe mode of TDCO being too far out of spec when it tries to learn. Fix is to mechanically adjust the pump into an acceptable position or repair the fault that's causing the learn to fail (Optic sensor, crank sensor, wiring, etc.)

You can verify if it's too far out of spec by performing a "TIME SET" Command with the proper scan tool. Desired timing will command 0* and Actual Timing will read back to you how many * the pump is advanced from TDC. If this procedure doesn't work, then one of the sensors or wiring is bad and the computer can't determine the crank/cam position relationship.

Unplugging the ECT (engine coolant temp sensor) tells the computer the engine is still cold and kicks it out of the learn procedure. The OBD II 6.5 PCM automatically goes into re-learn every 50 warm up cycles. That's what the book says, but it's a bit more random in real life. Same reason many OBDII trucks will go into idle lope randomly from a missing or #9 PMD resistor because the only time the computer actually adjusts the fueling calibration per the resistor is during a TDCO re-learn.

OBD I trucks don't behave like this so this reply only applies to 1996+.

@Loganshaw_6 I believe you misunderstood this post or missed it. Sorry you wasted money on another DS4 instead of getting a scanner first or renting the experience of a shop or dealer that has one. I really don't see where we suggested another pump aside of converting to a DB2 mechanical pump.

 

[Loganshaw_6]

@Loganshaw_6 I believe you misunderstood this post or missed it. Sorry you wasted money on another DS4 instead of getting a scanner first or renting the experience of a shop or dealer that has one. I really don't see where we suggested another pump aside of converting to a DB2 mechanical pump.

I realized my two options were to replace or convert. I figured just replacing the DS4 with a good pump would solve my problem. I'm not sure how long I will keep the truck and I assumed it would last as long as I kept it. I didn't really feel like getting any more into a project of swapping over to a db2 but now I'm thinking that I may have been better off doing that. Unfortunately now I am stuck with this pump. I have access to a Snap-On Solus which tells me all the information I need to get the truck timed with a DS4.

 

[Loganshaw_6]

@Loganshaw_6 I believe you misunderstood this post or missed it. Sorry you wasted money on another DS4 instead of getting a scanner first or renting the experience of a shop or dealer that has one. I really don't see where we suggested another pump aside of converting to a DB2 mechanical pump.

If the truck was a 5-speed with a single thermostat I probably would have been more likely to go the db2 swap route but the thought of having to do with more computers and fabrication rather than it being a direct bolt in kind of steered me away. Not that I'm not capable but this seems to be the easier of the two options.

 

[WarWagon]

Hope the time set gets it resolved for you.

 

[JMJNet]

If I may suggest to create a summary list of what have been done so far includes part replacement, etc.

May be we are missing something. This thread have gone to 4 pages, it is difficult to thumb through everything.

 

[Loganshaw_6]

If I may suggest to create a summary list of what have been done so far includes part replacement, etc.

May be we are missing something. This thread have gone to 4 pages, it is difficult to thumb through everything.

Parts replaced so far on my 1998 c2500:

-Authorized stanadyne dealer reman DS4 pump
with gray PMD
-AC Delco oil pressure switch
-AC Delco ECT sensor (crossover & gauge sensor)
-Napa IAT sensor
-Crank sensor
-Starter
-Air filter
-Fuel filter
-AC Delco lift pump
-2 new batteries
-Used PCM pulled from truck with no MAF or EGR (My truck has both so I unplugged them as they're not needed)
-PMD relocation kit with heatsink but the new PMD does not match my extension harness so PMD is mounted to heat sink in engine bay temporarily

I'll add more if I think of anything I missed.

 

[JMJNet]

Is the Crank Sensor using ACDelco?

 

[Loganshaw_6]

Is the Crank Sensor using ACDelco?

I believe it's either ac delco or Napa I cannot remember

 

[JMJNet]

Yes, the crank sensor is very picky because it has to be somewhat read by the ECM.
So, you may want to make sure that it is NOT Napa.

I read this in the other forum called DieselPro Gremlin remover:
In post #12

No fuel after IP swap

www.dieselplace.com

It is not exactly the same issue but it may eliminate your potential part that cause the issue in your truck.

 

[Loganshaw_6]

Yes, the crank sensor is very picky because it has to be somewhat read by the ECM.
So, you may want to make sure that it is NOT Napa.

I read this in the other forum called DieselPro Gremlin remover:
In post #12

No fuel after IP swap

www.dieselplace.com

It is not exactly the same issue but it may eliminate your potential part that cause the issue in your truck.

I'm going to go ahead and order an AC Delco cps. I did notice today that the truck is smoking while cranking when it doesn't want to start so I guess it is getting fuel which is an improvement.

 

[Loganshaw_6]

Okay for anyone still following, I replaced the CPS with an AC delco today with no different outcome. Tried with the original computer and nothing. Unplugged the ect sensor and the truck ran for over an hour just fine around 800 rpm. Anything lower it starts running rough and stalls. After it stalls it won't start. Once it gets hot it misses crank reference and cam reference but nothing above 1. Does not start with optical sensor unplugged.

 

[ak diesel driver]

Sounds like a wiring issue. I'd get a new harness

 

[Will L.]

Yup. Leaves wiring on the majic komputer box