VP44 PSG fuel cooler ideas

[KATOOM]

You'll see in my previous post Mike where I stated that this very question was to continue to arise.....  First off, as you also pointed out, we dont know anything about the ECM construction or materials used.  Most likely it also contains Pb free solder but how its manufactured could be very different from the PSG.  Unless I'm mistaken, the common failure in the PSG is the transistor.  Why that component?????  Is there some high current issue going on here no one knows about?

 

I dont know but I do think its a critical point in making that we have two circuit boards sitting about one foot apart yet only one is prone to problems.   That tells me that either the ECM is built different or isnt subject to the same electrical properties as the PSG.

[Mopar1973Man]

I'm going to reach out on a limb here for that transistor which is most likely for the fueling solenoid on the VP44. As the fuel solenoid has to work harder controlling the fuel pin be it seizure, debris, bad wire tap, etc. I can see the transistor taking a mild beating. Once again I'm using a educated guess here and from what I learned from pulling apart that VP44.

 

Here is the VP44 rotor disassembled and the fuel pin and solenoid.

[rancherman]

we know the  computer  is  culprit  on  most  failures..   has it been  documented  if it's  the  same  component  within the  computer that's failing?    I might of  missed it if already  posted  here...

The next question is,   are  the  computers available  for  joe public  ( NOT JOE 'FARMER'   *mIke*)   to  buy?

[KATOOM]

I dont have any pictures of the PSG transistor but here's a video of someone replacing it. https://www.youtube.com/watch?v=STTNDXWEl38  If you Google around you'll see that for some reason the European crowd points to an overheated transistor as the cause for PSG failure.  Many pictures of it on Google images too.  Hey.....by no means do I think I'm absolutely right.....I'm just looking for answers like everyone else.

Edited August 14, 2014 by KATOOM

[Mopar1973Man]

I dont have any pictures of the PSG transistor but here's a video of someone replacing it. https://www.youtube.com/watch?v=STTNDXWEl38  If you Google around you'll see that for some reason the European crowd points to an overheated transistor as the cause for PSG failure.  Many pictures of it on Google images too.  Hey.....by no means do I think I'm absolutely right.....I'm just looking for answers like everyone else.

 

I'm pretty sure is lower right corner. Correction lower left...

 

[Yankneck696]

OK, I'll have to dig, but I sis find a different chart a while back, whereas the no lead solder goes down to as far as 110*F, depending on the alloy.

The Cummins ECM is NOT produced by an autto manufacturer and has quality solder. It is supplied to Dodge as a unit, therefore Dodge (Auto manufacturer) did not produce it & it may get a pass on the no lead. Bosch & Cummins may also just use different alloys of solder..

 

Ed

[KATOOM]

Thats the one Mike.  But I have to ask.....  What happened to that VP?  Looks like someone dropped it and kicked it all the way home.

[Mopar1973Man]

The owner didn't know what a gear puller was so they used a pair of crow bars and pried it out of the gear. So a wonder member here happen to notice this VP44 that not worth the core being the whole nose is trashed. Which now is the photo shot VP44 for the site. So if anymore pictures are needed I still got it here.

[KATOOM]

I remembered something which happened to me years ago I think is very worth noting on this topic.....  I'd try to find the old thread where I wrote about it back then too but it would just be easier to tell the story again.

 

Back about 5 years ago when heat soak from the hot engine to the cooler VP after shutdown was discovered, of course I was particularly concerned about this new problem so coming home and opening the hood became common ritual during the hotter months.  Then after feeling the VP still continue to heat up quite a bit even with the hood open, I took it a step further and placed a small house fan laying across the engine area and blowing down directly on the VP.  The fan would generally run until some time later in the evening before I'd remember to shut if off.  It "seemed" to help with overall temperature increases of the VP so I continued turning the fan on every time I'd come home for a few months, until..........

 

One day something really odd happened.  I went to start the truck and everything seemed normal.  Key to ON, all according dash lights and dinging noises, and then crank 'er up.  The engine fired as normal BUT within split seconds of initial idle the engine began vibrating ferociously and there was this very loud hissing noise coming from somewhere under the hood.  The dash lights went bazzerk, my (then) electric fuel pressure gauge was reading 0, and it felt like all chaos was taking place.  I was completely and utterly taken by surprise and didnt know what to do but turn the key OFF.  Even more strangely though.....the engine continued to freak out and then shut off on its own.  Granted, I tell the story as if this whole episode took 30 minutes but I'd be surprised if from beginning to end was a total of 30 seconds.  Clearly no time to do anything but be surprised and completely confused.  Certainly no time to open the hood and see what the heck was going on either or try to determine where the hissing noise was coming from since it was obviously related to the shaking motor.

Well I restarted the engine and it was like nothing had ever happened.  It idled away calmly and effortlessly and I drove to work looking at all gauges and waiting for the beast to give some indication but nothing, and nothing for probably a month too.

Not understanding what had happened that glorious morning, I continued to follow my normal regiment of popping the hood and placing the small fan cooling the VP.  Then again without notice, one day while starting the truck in the morning before work the whole event happened again.  A complete and exact replication of what took place around a month earlier too but this time I was on guard and ready to take note of everything which was taking place so I could establish what freakish thing was going on.  I watched the dash lights come on, the fuel pressure gauge saying zero, the engine vibrating violently, the hissing emitting from under the drivers side of the engine compartment.  I even tried to get out and open the hood to see what was hissing but I turned the key off in a kneejerk reaction and the engine shut down before I could get a peak under the hood.

 

Now, as unlikely as this sounds.....  The best way I can describe what happened was it truly and honestly felt like the engine was turning backwards and RUNNING!  And because this is not normal, all electronic devices were reacting the only way they could.  But after discussing this with some others and trying to get serious and logical about the situation and what caused it, my only eventual diagnosis was that I was causing the problem by cooling the VP in an non-designed fashion by using the house fan.  Somehow and for some reason the electronics went nuts and the engine went violent for a momentary 30 seconds or so.  The hissing could only have come from the VP as I dont know of any other device under there which would make that noise either.  No matter how I describe it.....it was just crazy and since then I decided not to use the fan anymore and the truck has never repeated the experience.  Coincidence or not, I couldnt say and since there's not a single person out there who's ever had anything similar happen to their truck, I will never fully understand what it was.  The only thing I can contribute to the situation was the VP cooling too rapidly.  Yeah.....sounds stupid right?    Nonetheless, I thought it worth telling the story again since it pertains directly towards cooling the VP after shutdown.

Edited August 15, 2014 by KATOOM

[rancherman]

I had  a  v8 diesel  powered  IH  tractor  that  would  'kick' back and  run backwards.     Good thing nobody was standing in front!....  reverse  WASN'T  reverse

 

Actually,   it wasn't  making enough power to  barely  turn over,      ruff as  a cobb,   sounded more like those  hit and miss   engines..   fire  coming out of the exhaust.. God only knows  what  was  going on in the intake!

 

Besides  the  obvious,  sound, smoke,   it  was carrying  zero OP.   It had  a mechanical  FP  that didn't care what way the motor turned..  so kept on  supplying fuel.

[MnTom]

Most people don't realize that any diesel engine will run backwards. The injector timing is off a bit, but they all are capable of it. The two cycle detroits were notorious for doing just that.

[Mopar1973Man]

@Katoom

 

Exactly. It was running backwards. When you alter sensors by abnormal cooling or heating you can adversely alter timing and other thing causing these weird things to happen. I've seen it on older 2 1/2 ton military trucks fire up and be blowing exhaust out the air filter. Weird sight to see put it in a forward gear and it travels backwards. The good thing you shut it down rapidly because the oil pump is running backwards too so its blowing air bubbles in the oil pan.

[Yankneck696]

I have hears of the 2 1/2 tons & Detroits running backwards, also some ancient Volvo dieseld (Hand crank start), but never a Cummins. Sure it wasn't just the AC powered fan possibly creating noise or leaking AC to the system?

[KATOOM]

When this all happened the house fan was turned off and not on the engine and the hood was closed, so no outside interference from that.  But I'm surprised to hear you all think the engine was actually running backwards.  Being that the VP is electronically controlled, how could it have allowed any level of fueling for that to take place?  After trying to forensic the experience back then, I considered that maybe it was running in the 3 cylinder mode but obviously everything was far from the necessary parameters.  I've never felt the 3 cylinder mode so thats merely a guess of what it would feel like.  I'm not sure.....  It was just WEIRD and it seemed to be connected to the auxiliary fan cooling the VP faster than normal.

[Yankneck696]

3 cyl (Factory) starts normal & ramps up to 1200 RPMs. Then it switches to 3 cyl. I seriously doubt the Cummins was running backwards.

 

Ed

[KATOOM]

Ed, I dont think it was running backwards either.  I think the PSG was freaking out due to being cooled off too fast.....or something related to that.

 

Anyone want to guinea pig their truck by placing a fan blowing on the VP after shutdown like I did?  Maybe your truck will react the same way.

[Mopar1973Man]

You have to remember there is a certain amount of timing effect from fuel temperature. As fuel is warmer it will ignite easier so less timing advancement is needed. But as fuel cools or gets cold then the timing has to advance to give time for the fuel to convert from liquid to vapor in the compression. So its very possible you got excessive timing from overcooling of the VP44 and timing was over advanced and got the engine to run backwards. (Think in theory... )

[CUMMINSDIESELPWR]

those transistors look like they are being thermally disentegrated and failing. possibly incorrect load handling rating for the stock ones?

Edited August 16, 2014 by CUMMINSDIESELPWR

[CUMMINSDIESELPWR]

when mine fails next ill do this replacement, im very good with electronics and micro soldering

Edited August 16, 2014 by CUMMINSDIESELPWR

[KATOOM]

when mine failes next ill do this replacement, im very good with electronics and micro soldering

 

Now that would be revolutionary for these forums.  If it worked too.....