Hi all, a new member here with his first desperate post
I did use the search and Google first (For several days).
Vehicle: Suburban, 1998, Vortec 350, not modified.
I have replaced the intake manifold gaskets due to a water leak.
I put everything back together and the engine fired up and ran great, but I got a code about the cam and crank sensor signals being out of sync.
The engine started a bit hard, as if it had too much initial advance. Once started, it ran normal.
So I thought I had the dist one tooth off, affecting initial timing. I know the computer controls actual ign timing and the distributor positioning affects mainly the cam position sensor signal.
So I put the dist back in one tooth different, and it ran worse, real weak. So I pulled the dist again. At this point I cleaned the cap and rotor, heavy corrosion buildup there. Long story short, I modified the rotor to extend the tip a little further to make up for lost metal at the point where sparks erode it.
I put the dist back in in the position where the engine ran ok (but threw the code). No start. Hasn't started since, and I have tried just about every dist position possible.
Other things I have tried or tested:
cleaned and gapped the plugs & dried them
Tested fuel pressure (65 initial when pump primes, then 60 when pump turns off, holding)
I DO get spark at #1 plug. Every time.
Plugs seem a bit wet each time I pull them after trying to start the engine.
The best I get now is low thumping sounds from the muffler, and occasional short burst as if it tried to fire up. Engine turns over great. Shooting carb claner in the intake before or during cranking doesn't make any difference.
I have lined up the TDC mark and the dist rotor with the "8" mark at compression stroke. I know of the dimple at thedriven gear lining up with the paint mark on the dist body, but that is essentially just another way to make sure the rotor will point at the "8" mark. It cannot do anything else, the shaft is solid from teh driven gear to the rotor. Driven gear was never removed. Rotor was, but it can go on only one way.
With a timing light hooked up to #1, the mark on the damper lines up close with the mark on the timing cover. TUrning the dist doesnät change timing. (As it shouldn't, right?)
Cam position sensor gets 11V input voltage and it produces 3-6V output signal (fluctuating as expected) during cranking.
Jan Andersson, Orlando FL