Another "No-Start Hot" quagmire

[DrDeltic]

'99 VP44 fresh Bosch re-man, lift pump new, 12psi supply pressure @inlet line to VP44
VP44 # 6 & 7 terminals/pins both show 3-3.5 amps when running hot. No Start hot.
pull the VP44 electrical plug and power the unit with 12-volts + & -, starts right up HOT, plug harness back in, cranks and NO START
Cranks at 190 rpm: engine rpm, CKP, CMP, Injection pump, ECM all rpm right there on scan data. No Start.
cold: starts and runs all day. Unless you turn it off. Then no start until cold.
Have NO CODES.
curious!
would like a direction - anyone seen this?

 

[Nigel]

I had a no start hot and had the pump replaced and the reman pump did the same thing. Reman was sent back and the second one was fine. When mine would not start hot I could unplug the temp sensor at the front of the head and the truck would start right up. If I remember correctly the remans were done by Sheid Deisel.

Nigel

 

[JR]

Pin #6 is the ground, how are you seeing voltage there? How many volts are you seeing at pin 7, should be battery voltage there. Also did you check for voltage at both key positions (start and run).

 

[DrDeltic]

JR,
Thank you.
Pin 6 is 0-volts/battery ground
Pin 7 is 12-volts.
I reported amps on both for current flow documentation: good power supply, good ground, enough to deliver required amout for full functionality. Basically just a note for the curious.
Again, thank you.

 

[DrDeltic]

Nigel,
Thank you. Good info. Didn't try it.
I will report tomorrow.
Did you ever run down the reason for the pump electronics failure?
Electronics on both remans are new Bosch.

 

[Nigel]

No I don’t know what failed. I had a shop supply and change the pump so he had Sheid warranty it. A couple of us had tow trucks before I knew about TDR and spent lots of money trying to get the hot start figured out. They always started cold so we thought maybe if we disconnected the temp sensor the truck might think it was cold and sure enough they would start every time. I don’t remember who told us to change the pumps to cure the problem. Then a few years later I had the issue with my pick up and that is the truck with the defective rebuild.

 

[JR]

Did you figure anything out?
Who did you get your VP from? It's been a few years but I talked to a major internet supplier of remans and he told me straight up they bench test the fpcm (ecm on the injection pump) and if they passed a certain criteria they were re used on a reman pump. Meaning you get someone else's used fpcm with unknown hours and heat cycles on your fresh pump. No wonder why the fpcm is still the number one failure point...
There are a few builders putting NEW fpcm on their reman pump but they are few and far between. And you sure aren't going to buy one for a grand like so many list them for.

 

[DrDeltic]

Did you figure anything out?
Who did you get your VP from? It's been a few years but I talked to a major internet supplier of remans and he told me straight up they bench test the fpcm (ecm on the injection pump) and if they passed a certain criteria they were re used on a reman pump. Meaning you get someone else's used fpcm with unknown hours and heat cycles on your fresh pump. No wonder why the fpcm is still the number one failure point...
There are a few builders putting NEW fpcm on their reman pump but they are few and far between. And you sure aren't going to buy one for a grand like so many list them for.

JR
your info appears to true also from my supplier. Bosch has changed their repair order program for those in the re-man business who are authorized to re-build their units with their warranty. Bosch says they can re-use the injection pump electronics 3-times, re-programming each time to match application. But as you note, that unit is expensive.
This supplier always changed them previously because of the logic behind your observations. And they absolutely changed it this time because of this repeat problem. However, they have never seen this particular difficulty persist to this point. This particular VP is Bosch re-man from CZ, according to its tag, fpcm is new.
Just to be clear, the Bosch test-bench and re-programmer is a Bosch-programmed unit that cannot operate the VP at engine operating temperatures! How useful in this scenario!
And as another point of interest, the engine will start hot with the injection electrical plug un-plugged and 6 & 7 supplied voltage/ground directly from the battery as source. I even tried doing this same thing with #7 supplied 12-volts and the connector plugged back in, with and without the temp sensor. NO GO!
The fpcm does something with the info or the ECM does something to prevent the unit from supplying injectors timed fuel.
So with the connector plugged into the VP, no start.
Unplugging the temp sensor at the front of the head did nothing. No start hot.
Fires up perfectly cold and runs all day if you do not shut it off.
Looking more and more like an ECM failure.
Too bad for this customer, he is not spending any more. I don't blame him. And looks like he will be done with Dodge product. He has another Cummins in his Freightliner or he'd be done with Cummins as well.
Your interest and input is appreciated.
william

 

[DrDeltic]

Nigel,
Sorry about the delay.
Unplugging the temp sensor did nothing. Except change the temp reading on the dash guage.
Appreciate your suggestion and efforts.
william

 

[JR]

So it may have been the ECM from the get go? Or was there an issue with the VP? I can understand his frustrations but failures happen on an 18 year old pick up...doesn't matter whose name plate is on the grill. I personally had two VP44 equipped trucks and they were both very reliable. Had them all over the Eastern half of the country towing trailers or a camper. They never left me stranded.
One last thing I can think of if you are still tinkering, what about a cold pack on the ECM when the truck hits the no start when hot routine? A few minutes of that should cool it down enough to know wether or not that's your issue....

 

[DrDeltic]

JR
Probably ECM/PCM problem from the start. Followed the "most likely" route first after consulting with rebuilder and presenting symptoms and data.
I agree with you on your observation about ANY brand at 18-years of service (this one at 240K miles). This one had an ECM replaced under warranty by Dodge (unknown when) as evidenced by hand-written part number on Dodge dealer campaign sticker on the unit. The number written is illegible now so I can't report that part #. I work on all of the brands and find corporate decisions for profitability of the corporation most often is not in line with advertising about how great is great to the customer. This particular customer's frustration is understandable and it was his decision to go for the pump rebuild rather than test more to attempt to confirm or rule out. "Replace with known good unit" is the term used as the last step in most diagnostic flow charts, so that's what was done.