Archived No start - what else besides VP44

[d2500]

I've been running a comp, and haven't had any probs until now.



While under moderate acceleration, I watched my oil pressure gauge drop down to 0. So in a bit of panic, I shut the engine off, and pulled off to the side.



Then, when I tried to start the truck back up - nothing!



So after getting pulled back to the in-laws house (where I'm visiting from 1000 miles away), I started to try and diagnose:



First, checked the fuel pressure pre and post filter, and both seem fine - when the lift pump kicks on, it goes up to 15, and eventually drops off after the pump shuts off.



Then, being scarred ****less that it's the VP44, I started cracking the injector lines only to find that fuel IS indeen pulsing to the injectors.



Doesn't this mean that the VP44 is ok? What else could keep the truck from starting? I may have a bad oil pressure sending unit - would the ECM prevent the the truck from starting if it thought there was no oil?



HELP!!!!

 

[Bob Wagner]

if its an 00 or newer check for codes

 

[d2500]

no codes

It's a 98. 5, but there's no codes (checked with ODBII scanner)...

 

[d2500]

injector pressure?

I noticed that when I crack the injector lines, I only get a trickle - it pulses, but not anywhere near the 17000 psi that I've seen mentioned here.



Where is that pressure generated? VP44? What else can I do to troubleshoot?



Thanks in advance!!!!

 

[TGRISH]

I HAVE A 96 3500, CUMMINS AND I HAD A FUEL PRESSURE RETURN HOSE THAT THAT HAD AN AIR LEAK AND IT DID THE SAME AS YOU SAY YOUR RIG DOES IF THE HOSE IS LEAKING IT NEEDS TO BE CHANGE I HAD IT DONE AT THE DEALER AND IT COST ME $174. 50 INCLUDING PARTS.

 

[MCummings]

The VP44 throws real bad temper tantrums when you take the load away real fast when working 'em real hard.



Keep Cranking. It will take much longer than a normal injector swap. Be sure to crank with the fuel pedal on the floor. I went from 2,700RPM WOT, 40PSI boost, then pushed the clutch in, went to idle, and the motor died. I cranked for about 90 seconds untill the truck started firing,, first on one cylinder, I let go of the key, and the tach showed about 200RPM, hammering away, only one cylinder, with smoke rings coming from my stacks, WOT,, that went on for about 5 seconds, the motor died again, I continued cranking (by this time my batteries were wearing down) and finally it started firing off a few more cylinders, once I got 2-3 cylinders firing, and the RPM picked up above 1,500RPM, I was off like a rocket. (I was late to pick up my G/F in the first place). Being in the middle of the intersection this whole time, When the truck finally fired off, it was 3,00RPM, riding the clutch, then burning rubber to go pick my G/F up.



The lack of Oil Pressure will not keep the truck from starting.



I'd say to keep on cranking, or to take the truck out to a deserted road, and let the clutch out in 2nd, or 3rd gear, and get the RPM up to about 1,500RPM, and the truck should fire right off.



My $. 02

Merrick

 

[CstlEng]

Merrick is usually (always) right as far as I am concerned... but I will add my . 02 anyway.



You should have more than a trickle coming out of those injector lines. If the high pressure side is behaving properly and you loosen one of the lines, you should come back to the house after your truck starts with a strong enough aroma of #2 fuel eminating from your clothes to cause problems with family members who don't share our affinity for deisel soaked clothes. Try cranking with the fuel lines cracked for a couple minutes as suggested, and you should notice a change at some point from dripping and sputtering to pumping and flowing (noticable stream of fuel flowing down the flat of the cylinder head beneath the injector line connections). Tighten one by one at this point and you should gain one running cylinder at a time.



While cranking for that long, look at the oil pressure and see if it comes up. The truck will start/run with 0 oil pressure as Merrick says. This could be a problem in your case (so happy the truck starts, you run it for a while before remembering why you shut it down at speed in the 1st place )



Important caution note for those reading the thread that may not be aware of the danger of high pressure fuel injection (to ones body, not the cylinder). While there is not a huge amount of fuel coming out of the injector lines, the fuel that is present is under VERY high pressure (as mentioned up to 17,000 PSI depending on model year). It is this pressure that will atomize the fuel from the cracked injector line enough to squirt it everywhere. There is more of a problem with a pinhole leak in the line than a loosened injector line compression fitting, but the danger does exist if the opening is small enough to keep the pressure up. If you were to cover such a small opening with your finger (to feel for a suspected leak, for example) the fuel will be injected into your finger, actually penetrating the skin. This might not sound serious, but it is quite dangerous, and it does occur. So check for those small leaks with a peice of cardboard and keep those digits.

 

[R.E. Miller]

Just because I am no real newbie to working on ISB's, I'll add this. Remove the breather tube assembly, and remove the injection pump gear nut and check the key way. NOOOOOOOO, I have not misaligned one yet, BUUUUT, it has been done, and NOOOOO, I am not trying to make anyone feel dumb, it is just that I have seen many dumb things, and I try to pass them along It really is easier than one might think to mess this up, especially in applications like chance, and frieghtliner chassis... ... those who work on those know what a horror show is :--)

Hope this helps,

Russell

 

[RobertMiller1]

injector pump

I would be real concerned with the orignal case of trouble that caused you to shut the engine down. The sudden loss of oil pressure in a running engine is extremely worrisome.



What you described sounds like fuel delivery is just fine. VP44, lift pump are working. The implused trickles are a good sign.



I have cracked the lines pre-injectors on other high pressure diesels (robert bosch pumps) and a trickle is normal. It is getting fuel to the injector, that is the important part. The impulse in firing order is of such short duration and small volume, that a much bigger hole or cracked line just doesn't have that kind of spray.



* Constantly cranking on the starter for long periods of time is also not recommended. (see handbook)



* Sometimes a starter just never will do it. You can crank till hell freezes over or until your starter motor overheats.

* Check the fuel cut fuse and/or relay (if so equiped)

 

[d2500]

Thanks to everyone for the replies.



Unfortunately, it was indeed the injector pump that went kaput!



In retrospect, I now believe that I did not loose oil pressure until the pump died, and so did the engine. As mine is an automatic, the vehicle kept rolling and I, upon seeing no oil pressure, turned off the key.



FYI, once I installed a new pump, the high pressure lines pre-injectors, began to shoot strong streams at every cylinder, and the truck fired up very quickly.



Thanks again to everyone for the help!

 

[CstlEng]

Sorry it was your pump, glad you are running again.



Did you get any fuel from the healthy 44 on you, like I always seem to? I am always so happy that the truck is back up and running, that don't seem to mind that smell anymore, in fact I think I have started to like it I was amazed how much fuel came out of the HP lines when I saw it the first time. .

 

[d2500]

Once the air is purged out of the lines, you definately know when the vp44 is working

 

[MCummings]

What did you do with your old VP44?



CstlEng, thanks for the kind words. I appreciate them.





Merrick

 

[d2500]

Just sitting on my work-bench.



I hope to find the time to take it apart, and maybe rebuild it (if I can find the parts).

 

[MCummings]

Last I checked, there was no rebuild for them (not for consumers).



If you want to let it go. let me know, I'd be interested in testing it on my truck.



Merrick

 

[d2500]

Testing?