stalled when trying to restart starts cranking normal then acts as if timing way advanced

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Hogg

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What happens if you remove the air intake and drizzle fuel into the throttlebody while cranking? I once used this technique to back a truck with a bad pump into the shop. If the truck fires, you've got some fueling issue somewhere.

If this is a 96+ L31 Vortec 350 the fuel pressure will be over 62-66psi at WOT. These stock pumps will dead head at 100psi. The OEM fuel pressure regulator is located inside the intake plenum therefore is always exposed to manifold vacuum while running

Pull a plug, ground it an see the spark. These engines run 0.060" plug clearances, if the spark is lazy and orangey at all, just wait til it has to fire at 9.4:1 the pressure during the compression stroke. You want a nice bright white/blue spark, these OEM coils are quite good. Same coil is used in the LT1/LT4 engines and that engine redlines at 6400rpm. The 96-98 truck blackbox VCM's have the 6000rpm hardlimit. The rpm coding simply stops at 6000rpm. These CSFI(Centralport Sequential Fuel Injection) was the last distributer based ignition system to be used on production vehicles. The medium duty Vortec L21/LP4 GEN-VI 454 being the first GM bigblock engine to employ Electronic Throttle Control(ETC) and Coil Near Plug(CNP) ignition. Now each cylinder has its own coil. Each coil now only has to fire once for every 8 ignition events.

I've seen coils go out slowly. Throw in a new one, they arent expensive.

96 and 97 were models years of the GMT-400 truck lineup that had yet to use any sort of VATS(Vehicle Anti Theft System).
If the system recognizes an unauthorized ignition attempt, the VATS will disable the fuel injectors for 30 minutes. The GMT's got VATS for MY1998.

With the way you are describing the behaviour, you gotta be off by a tooth. I would go to the extremes of where you are now (loosen hold down and "clock" the distributor and see how it changes what you have now.

Also another low buck test for these trucks to test the fuel system. If you leave the key in the ignition turned to run, then on your back and grab a hold of the crank pulley and turn the engine over. Just go slow and let the compression bleed off. Eventually you'll hear the fuel pump prime itself by running for 2 seconds. IIRC you can get the pump to cycle twice for every single crank rotation.

I seem to remember saying that something plastic was broken? If it was there is the CranKshaft Position(CKP) sensor is housed in that one use only front timing cover.

peace
Hog
 

54vicky

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that is something I thought about just too dam cold right now but will try for sure. as too the person of short stature if he is one of santa's helpers ask him to bring you a box of crayons to occupy you.
Don't doubt your abilities. Where there is a will--there is a way. You can make anything work if you try hard enough. I can make a car run just by having a midget blow gas through a straw directly into the engine if i wanted to.

take all of the plugs out and check spark from each plug, to ground. with all of the plugs out, there should be no binding due to crossfire. everything is saying theres a problem with the distributor or cap.
 

54vicky

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it warmed up a bit today so pulled the plugs with them out it cranked as it should.my son noticed that 1-3-5-7 all had evidence of fuel sprayed out on to manifold 2-4-6-8 there was no sign of fuel spray.would a spider cause a one sided (LvsR)spay pattern? I should add plug four came out with a black (carbon?)build up all others looked as they should with less than a thousand miles I am planning on changing spider if this is a common problem rather than a single cylinder going for a shyt.this may explain the loading up when cranking with coil plugged in
take all of the plugs out and check spark from each plug, to ground. with all of the plugs out, there should be no binding due to crossfire. everything is saying theres a problem with the distributor or cap.
 

cngodfather

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evidence of fuel shows that the fuel is reaching the cylinder. This goes back to your ignition system. Chase the rabbit down the spark rabbit-hole.
 

cngodfather

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Although, you may want to check your oil for gasoline. If your fuel is stuck in the open condition, you will get so much that it could hydrolock your pistons. This could give the symptoms of not wanting to start. I think someone else mentioned this before. If that is the case fuel will pour into your cylinders, leak past your rings, and end up in the oil. This would be very bad for you and the engine. If your oil has gas in it, fix whatever is causing it, and make sure you change the oil before it actually runs.
 

54vicky

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lost my manual years ago computer crash.anyone offhand know the CR for this engine.I have a bad feeling it may be too late on hydraulic info but compression check should show if rods bent lowering the piston in hole
 

texas tough

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the black plug can indicate a leaking injector.. I had a motor with a MERCARB on it, and it would drip after shut down, then on restart, would lock the motor up.
while cranking the motor over with all plugs out and grounded, u should be able to see if the plugs are sparking when they should be, listen for piston suck and blow.. if its firing when it should, then its a fuel problem. I would get a new set of plugs just to be safe. once u put plugs back in, spray down ignition system and look for arcing from wires, distributor, ect.. VERIFY based on what u test and observe, not what u ASSUME to be good or not. then move to the next system... give it fuel give it fire, give it that which it desires!
 
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