I dont want to railroad an awesome thread but I'd like to touch on the topic of fuel cooling via a fuel cooler of some sort.  I just have this crazy premonition that there needs to be a fuel cooler on these trucks.  Given what I recently experienced while towing a very large trailer in 100*+ weather uphill with the engine at 215*-220* and having the throttle do something unexpectedly weird, excessive fuel temps or just plain excessively hot PSG is becoming very likely the culprit of what happened.

 

I'm going to be digging into this topic really heavily and searching for an optimal small radiator to mount somewhere under or in front of the truck.  Possibly with a fan assist too.  There is just too many other trucks/diesel vehicles utilizing a diesel fuel cooler.

 

In saying that, I've wondered if anyone has ever considered trying to cool the PSG itself.  Chip from Bluechip told me around a year ago that Bosch has implemented thicker heat sinks under the PSG but I can’t confirm this and he's not around anymore.....that I know of.  Then I got to thinking about a Peltier Module.....  Why hasn’t this been considered?????  Maybe it couldn’t offset the heat dissipation needed but I think using a $20 Peltier Module and sticking an aluminum bladed computer CPU heat sink to the top of it would have to help.  Here's a video of what this device is if someone doesn’t understand what I'm talking about. https://www.youtube.com/watch?v=9Cuh2msd2lo If someone was so inclined they could install an inline thermostat too so it didn’t run in the winter.

 

Maybe this would be better served in another thread but I think its a topic which needs to be revisited again.....

Before i do much more I think the DDRP is gonna need to go somewhere else.

Mechanical is what I am thinking.

Chris

im quite enjoying my mechanical pump. pressure goes up with the RPM'S.   Just make sure everything is clear bypass valve wise.

excuse my ignorance, im usually really good at acronyms but whats does PSG stand for Pump S? G?   

excuse my ignorance, im usually really good at acronyms but whats does PSG stand for Pump S? G?   

Just hover your cursor over the acronim and it will tell you.

It is the computer on top of the injection pump that takes communicates back & forth with the ECM to decide fuel delivery quantity & timing.

 

Ed

Found out some more information about the PSG.  So far no one can tell me why the PSG fails.  Thats the million dollar mystery question apparently.....  The concept was tossed out there that maybe it pertains to how the older PSG's were manufactured but other than that there's no understanding why one component would be more problematic over another. 

 

In regards to Bosch.....  Bosch is no longer building VP44 housings but are still producing PSG's, which is where these new PSG's are supposedly coming from.  The PSG's also must be synced with the VP in order to function properly which is why the 1/4 million dollar test bench is necessary.  PSG number 029 and 030 are supposed to be an industrial version but only meaning they wont work on the Dodge Cummins VP.  I cant confirm whether or not either of those have Pb solder though.

 

Also something very interesting and potentially useful for some people is that the first 10 digits under the PSG bar code are the model version.  If you have the numbers 0 281 010 890 then you have the most updated PSG available by Bosch, which has been around for at least 5 - 6 years since I have that code and I bought my pump in late 2008.  But if the last digits are 827 then you have the older version PSG which may have been reused on a re-manufactured VP simply because it still worked.  But.....that said, I could still see where someone who just bought a VP could have a 890 PSG which was still reused.

Edited August 18, 201410 yr by KATOOM

You have been doing your homework KATOOM.

My PSG reads (as far as I can tell)  0 281 401 827...it would seem its an original one and the pump itself has no reman numbers on it.

I guess thats not bad for a 99 with 157 k on it.

Regards Chris

Well...I went and did a bit of homework myself. My VP44 died last week with a  P1688 code.

I found very little info about that other than Mike says its the failure of the solder in the electrics of the PSG.

I sort of feel okay with that. I always wonderd how the truck was treated before I got it. Wondered about fuel and heat.

I am carefull with fuel and set the edge to shut off when it cools to 300 degrees.

...Hmmm if its electric, i should send my core to Mike... he has a nasty pump with a gooder PSG than mine.

Regards Chris

I think the million dollar question would be..

After the   transistor  has  become  'desoldered'...     has it (the  transistor)  been  tested afterward  for  faults???   Did it fail,  got hot, THEN melted away? Or are they  perfectly good,   only needing  resoldered?

 

What exactly is  a  transistor?   

A transistor is basically an amplifier taking a smaller signal and turning it into a stronger signal.  There are also transistors which work like on/off switches too, and really.....I have no idea what type of transistor is in the PSG or what its true purpose is in there.  But because transistors are generally amplifiers, this is why some people (including me) feel that there's a reason the transistor fails and potentially that cause is amplification of voltage from some unknown source or reason.  Like maybe the process of starting the engine is very taxing on the PSG transistor while it takes in a large surge of voltage as the ECM instructs the VP to begin the fueling process.  Thus the "starting cycle" we all know about.  Or maybe the the transistor is merely overloaded period.  Maybe there needs to be some kind of capacitor wired in or maybe the VP power supply shouldn't be coming from the ECM but rather from a direct 12 volt source via a relay.  Again.....I dont know but I'm betting someone somewhere knows.

Edited August 19, 201410 yr by KATOOM

Could the transistors be getting cooked because of things like high AC voltage from the alternator? I am not sure how the current flows through the PSG but that might explain why Mike's is outlasting a lot of others. He keeps good track of the AC voltage, not to mention everything else.

I think transistor damage is partially AC noise and poor electronics (modules). I still can't see 130*F being a issue for transistor. I've seen amplifiers get quite hot. CPU in a normal every day PC is loaded with thousands transistors. Both AMD and Intel processors will run upwards of 160-180*F on a full load run. So why does a simple single transistor fail in a PSG unit at low temps (not enough to trip the P0168 code). The only other thing is maybe the early years Bosch used margin transistors in the manufacture and they couldn't tolerate the load and POOF! So now they have updated the transistors to to tolerate loads of the VP44 solenoids.

Maybe you're right Mike.  Maybe the updated computers do have better components.....just like the rest of the VP received over the years.  Strangely though, I clearly and without a doubt remember Chip telling me a couple years ago that Bosch upgraded to a larger heatsink for better PSG heat dissipation but when asking other (just as reputable) venders they say they've never heard of that.  So.....who's right?  Well since I've never seen a picture of a VP which doesnt look like any other bazillion VP's I've seen on the internet, I would have to say assume that there's been no heatsink change.

 

But I also agree with you in that there's no reason running temperatures should ever affect the PSG.  Even heat cycle temperatures shouldn't cause a problem since anything I find says that the lowest melting temps for tin solder are around no less than 400* F.....and thats on the cold side since optimal solder gun tips run in the 600*-700* range.

 

I'm beginning to think that the "heat cycle" theory is just that.....a theory.  Potentially bogus too.  Just like the dreaded torn or cracked diaphragm theory which seemingly plagues every VP that lands on the bench of a VP supplier.  Especially if its a warranty item.  A knee-jerk response we still see it floating around forums like its fact too and is the main cause of all VP problems.  Its almost like the FDA is helping Bosch come up with things to tell everyone.....

 

There's a reason the PSG fails.  Is it heat or is it surges of electricity?  It sure would be nice if we could find out.    It only took around 10 years for someone to volunteer a VP core.  Maybe it wont take another decade before someone with some serious electronic skills can figure this out.  Thats not to say Mike isnt an electronic guru either.

Anyone  in here  do  a   p pump conversion... and  have  a spare  VP laying around?

Anyone  in here  do  a   p pump conversion... and  have  a spare  VP laying around?

 

Yea I got a spare VP44 on the shelf ready for tear down. Its a 027 Rev pump so its the newest out.

Yea I got a spare VP44 on the shelf ready for tear down. Its a 027 Rev pump so its the newest out.

 

I know the one I sent back in to get the core charge  would've been perfect...   OEM  2000,      99%  sure it was   PSG   related,      *oh,  If  I only knew  that  saving a  few hundred bucks*     or    "the  burden on  ONE  is  good  for  the benefit of many"  ...  sigh,

 

OK,   so  'transistor'      (transformer-resistor)  correct??

 

It'd  be  REALLY   informative  on how that lil dude    works  in the system...     what's it  doing  at various  stages  of  operation of the engine:   Is it going nuts  when  accelerating,    or  is it  when    it's  holding  max   timing..    or  perhaps    a  start-up   loop.     

Maybe the  dang thing  just  sits  there and  hums,   supplying the  rest of the board  with a constant    type  of current... 

 

So,   a  test mule   (vp)  without an engine to  run it  ( I suppose this is  where  those   high dollar test benches  come in handy)     probably  won't  help much  on   finding  'how'  that transistor  works  within the  system.

 

although,  it'd  sure  be nice to  find  a vp with   desoldered  transistor,     remove it,    and  test it to  find out if it's  still   within it's  parameters...       I'm assuming  they  are  externally marked  (like  a  resistor. "stripes, numbers" )  so  a  person  could look up  the values they are rated at?    

By the end of the month, I will be testing a system to cool the PSG. I will compare internal fuel temps to external laser temps.

Michael, I didn't know you had another pump. I have almost everything I need for the next experiment, except an ECM & pump.

 

Ed

Does anyone know if you can remove the PSG cover and replace the screws and still be able to run the engine?  I know there's an o-ring seal under there which must be held tight but my understanding is that no electronics are ever bathed in diesel.

 

Having the cover off would make it possible to view the circuitry of the PSG while the engine is running.  Not that you'd be able to watch anything as you're cruising down the road but you could certainly try to establish what happens during heat cycles and start up cycles and maybe even detect the temperature of certain portions of the circuit and the transistor.

Some of hte high end multimeters come with a temperature probe. Might help.

Ed

A bit about thermal conductivity...

http://www.matbase.com/material-categories/other-materials/fuels/material-properties-of-diesel.html#properties shows the thermal conductivity of diesel fuel at 0.15 W/m.K

Compare that to air, water & aluminum on this chart... http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

 

Just something to ponder.....

Ed