1998 Chevy Silverado 4x4 Starts then Dies
 

Hello

I acquired a 1998 Silverado 3 door ½ ton 4x4 5.7l Vortec V8 with approx 224k on it. He said all it needed was a flex plate and it would run fine. Well he was in error, the engine was froze up. After a week of soaking the rings in trans fluid and kerosene I freed it up by hand then turned it over with the starter after putting in a new flex plate. Now here is the problem, it starts then dies starts and dies, and sounds like a rod knock .Here is what has been replaced.

New flex plate

New starter

New fuel filter

New fuel pump relay

New oil pressure switch

New 12v battery

Here is what has been checked.

Drawdown test 60-65lbs holds at 65 then drops to 60 after crank

Check fuel pump was pulled and cleaned, not replaced, can hear at prime

Iac pulled and cleaned

Air cleaner pulled and cleaned (K&N)

Check security light flashes at bulb check, then goes out

Check fuses all good

Checked pulse rate (Noid light) all injectors light up at crank

Checked cap and rotor, not bad, cleaned them up like new

Checked with OBDII scanner, no codes

Still the same thing ,starts and dies after you release the key, it will stay running if you feed it gas from a spray bottle. I am using a newer key.

I am stumped I am an old school wrench poor and would like to get it at least running even if it does have a rod knock, sounds like screeching more than a rod knock. Any help would be appreciated.

Regards :confused:

Anything on the serpentine drive system that's seized causing extreme engine drag? Maybe too much internal engine drag to keep running?

I'd start by figuring out if the injectors are spraying .. this is a vortec engine, right?

This is a 98 Vortec 350 with the spider assembly and poppet valves. A noid light was used to test injectors it flashed at crank on all cylinder's. The serpentine belt was removed to test it, nothing external was causing drag. The engine starts then dies when the key is released. Relearn was done 15min on then off then another 15mi on then off. The passlock system, when key is turned security light flashes 3 times then goes out for bulb check. Tried ths also.

Regards :confused:

What I'm saying is maybe the injectors are plugged up. I mean verify that the're spraying - you've verified that they're getting the injector pulse signal from the computer, but I mean physically pull the spider and pull all the poppets out and crank it and see if they spray.

If you have a scanner handy, maybe check to see if you have your crank signal going to the ECM, and check to see if your spark timing is way out. Do you know that stabbing the distributor on these vortec engines isn't like stabbing an oldschool distributor? Maybe your timing's off because the distributor isn't quite right.