If he's not real familiar with these trucks like Rick said you may want to get it out of there. A good diesel repair shop would be the way to go if you don't want to troubleshoot it yourself. There is some good help around here like Rick and others if you want to try it yourself otherwise a good reputable diesel shop should be able to get you going.

 

I figured your problem out.


Your wallet is too fat. Your mechanic is just going to keep throwing parts and your money at it until he gets lucky. Did we ever confirm the fuel bowl heater did not short out? Is the crankcase full of oil, if he tops off the HPOP reservoir, does it empty back right after a few seconds of cranking? I'm guessing your mechanic isn't going to want to listen to ideas from a bunch of guys from the internet, so you're either going to have to start asking him some very pointed questions and be ready to say no to his suggestions or pay a whole bunch of money.

Is he going to charge you for the IDM he said you needed that didn't fix your truck? Did he claim the IDM was bad and needed to be replaced anyway, and now it's the HPOP on top of that? Perhaps you'll need new injectors next.

I'd have a heart to heart with the mechanic and if he's really lost and just want's to keep throwing your money at it, call a tow truck and get it out of there.

 

For the money he wants to charge me for the repair and the time it's going to take him to do it, I will be asking some very pointed questions tomorrow!

There is a reason I don't trust many mechanics!! The longer the truck is there, the more I distrust them. I should have known better than to take the truck there. He wanted to soak me $600 to replace a coil pack on my 99 Pontiac Grand Prix a while back. I bought a used one from the junkyard down the road and had it done it 10 minutes. It took me longer to find my Chiltons book to make sure I had the firing order correct. It was sort of a moment of desperation/panic. The truck wouldn't start and this guy is in town. The other mechanic I've had it at is dealing with a BIG legal issue right now and likely wouldn't get to it any faster.

Thanks for the suggestions!! This forum has been a huge help!

I'll post another update tomorrow after I get my questions answered (or I have it towed out).

 

Talked to the shop this morning. He did fill the HPOP resevoir and the truck fired right up, but died about 15 seconds later. While it was running, there was no oil pressure on the gauge.

He did NOT charge me for the IDM. Crankcase is full of oil. I made sure of that before I took it in.

 

Where's that "scratching my head " emicon.
Low pressure pump is no refilling the res . Not a big job ,or real expensive . It could also be a cracked pick up tube(rare) & there is a test for that also. A blown injector o ring can cause this as well (can be verified visually ) but it would have to really bad . Bypass valve in the oil cooler header falling out , but yours should have the clipped in version . There is a check valve for the res also that can stick , I cannot verify if your 96 has one or not

The Illustration below shows the path of the low pressure oil

Pic below shows the location of the check valve

Last pic is the valve ...

 

I've read that the LPOP doesn't just "fail", but fails over time. I wonder if it's been failing and I didn't realize that was the issue.

I had problems getting the truck started a few days before I got absolutely nothing. It cranked, cranked and cranked until the battery died. It initially had started, but died about 10-15 seconds later. It was our first cold snap (17* F) of the season. I jumped it when my wife got home. It wouldn't start until I jumped the GPR terminals. By that time it had reached to the upper 20s. A few days later, when it wouldn't start again, it was another really cold morning.

Now, it won't even start in the shop until the HPOP resevoir is filled. Mechanic says he is going to get started on it later today or tomorrow. I guess I'll find out. I don't have anywhere else to take it (that I trust) at the moment, so I'm going to let him go with this and see where he gets.

When you say not real big or expensive, what would you expect it to take?

 

Rick, I agree but that should be checked out and verified. Have your mechanic pull the oil filter and check for proper placement of that bypass valve. If there is just a hole then you probably found the problem, probably lost it during last oil change.

 

A little info on the LPOP ,,,Here ....

I don't know what they cost , but is a simple job . Again , I have never heard of one failing suddenly Or being an intermittent problem ,I wouldn't go there first ...The symptoms you are describing are what happens to a weak LPOP , but not usually with a synthetic oil

 

Last oil change was almost 10K miles ago (I've been procrastinating alot .. partly due to $$ issues right now). I do alot of highway driving and the thing leaks enough that over half the oil has leaked out and been refilled.

Given that, I would think I'd have seen that by now.