So 1996 z28 lt1 auto(VIN 2G1FP22P0T2115740)...has been sitting at the mechanics for 4 years because he said it needed an engine, after it shut down on the road and would not turn over. Same mechanic had just replaced the front main seal the week before. Well he had a shelter and I didn't have the cash to put a motor in it. So I finally had it brought back home with the intent to clean it up enough to sell. However, when I started looking at stuff, the first thing I did was check the oil....It had 1.5 qt's in it. It's worth noting that the seal is still leaking, now that I've had it started a time or two and it's full on oil, >_<.


Now I had taken the mans word that it needed an engine, based on him starting it to move it inside, and said the engine "sounds horrid, somethings broken internally" . He did confirm it started right up but didn't recommend driving it based on how it sounded. So I of course, topped off the oil and attempted to start it. I had put 5 gallons of fresh premium in it, gave it a couple squirts of it in the intake(removed all plastic) and sure enough it fired right over for 4-5 seconds.

With oil in it, I could not hear anything from the motor that sounded off even remotely, but it's hard to say in 5 seconds. Later I had a friend help out, and was able to keep it going on squirts for a good 15 seconds, but fuel would never catch. Those 15 seconds sounded like pure heaven, beautiful. That was as far as I got at that point, with help. Back to working solo I cracked the fuel filter, nothing but old gas smell, not quite varnish, but not far off.

After checking the fuses, (I still can't find the fuel relay) I saw a thread here about the bypass wire above the pcm on drivers side for pressure testing, and that's easy solo so I gave that a go. I didn't get anything at the rail, no catch trying to start it that way at all and cracking the line at the filter produced no more fuel beyond that bit that came out the first time, I can put a hose on it and blow air back into the tank, so it's not varnished shut.


Does that bypass wire confirm for sure that the pump is dead? Money is tight and I really want to confirm if there's anything else I can do solo before going ahead and replacing that pump, doing the panel cutout..

If so, I've read here that the HP10036 is the correct pump, but parts sites tend to disagree and suggest something about the size of a start solenoid...?

What do you think?

If it matters, there's 131k original on the engine and turning over and short starts on squirts sound great, no hard knocks for sure, but I figure I won't be sure on the internals till I can get it going and give it a little torque.


Am I on the right track?

 

Well I'm not much for electrical stuff but it sure sounds like a pump failure.
131K isn't much on an LT1 short of being seriously abused and or run out of oil it should still be strong.
My '93 Z28 had 222,000 miles on it when I sold it and still ran like a scalded dog.

 

Now that you have run the car pull the dips stick and check for shinny material. I have seen cars before that started sounded ok cold but showed there real colors once it was running for a few minutes or under load. Also if it ran low on oil then the motor can be in the process of ripping itself apart. You may not know that for a few miles.

I am not saying that your motor is bad just there is no way to be 100% sure. I have seen many cars that ran low on oil to the point they made noise. Sometimes they are fine, some times they make it a day and sometime 6 months. I use to tell people "If it it was me" that if I ran low on oil and now the car has dropped more the 10 PSI of oil pressure trade it in ASAP. If you see no drop in pressure and the motor sounds ok it is probably fine. Slight lifter tap I would say is common in any engine that has seen some metal shavings in it.

I once bought a Van from the dealer I worked for. The customer said the motor was blown our used car department agreed. I paid $500 for a rust free conversion van. I swapped out the oil, it was very low and dirty, (more like 3 quarts) When I started it up is sounded like crap. I was just trying to get an idea if I should rebuild or buy a used motor, I was reaching into shut it off and it stated to smooth out, the knocking stopped then the lifter settled down to a slight tap. I drove that van for 2 years and sold it at auction for $1800. I am not sure what the customer had in that motor but I doubt it was real motor oil. It was a company van and I think the driver was just tired of it and put something in there instead of oil so he could get a new one.

 

Lifter noise is very common with the LT1 motors especially on cold start up,a little tapping is normal.