Any great mechanics out there?

chevrolet
s-10

#1

I believe I have asked this before, but I’m at my wits end.



I’ve got a 2001 Chevy S10 with a 4.3L V6, and I am having a lot of trouble with it. The truck is extremely hard to start and staggers while driving it down the road. I’ve replaced the fuel pump,filter, plugs, plug wires, distributor and rotor, with no change in performance.



The only other helpful info I can give is that I had to remove the distributor to change the intake gasket recently. I got the ignition out of time when reinstalling the dist, but used my Chiltons book to correct it. The running problem started soon after this incedent.



Thanks for any help.


#2

All the great mechanics appear to be busy. But, you may have the distributor out of time one cog. That would cause a miss fire. Get the crankshaft at TDC, find #1 on the cap and carefully mark the distributor housing at the location of #1 terminal. Remove the cap and compare the location of the rotor and its relative position to the terminal when running. The timing will advance moving the rotor about 15* counter clockwise. And, did you set the timing by the book?


#3

If the problem only started after performing the intake gasket repair and was not present before you worked on it, the problem will be with something you touched when doing the repairs to the intake gasket. Timing for your truck should be at TDC at idle with the electronic advance disconnected, if I remember correctly. If you timed it with the advance hooked up, that will cause driveability and, probably, starting problems.

Another place to look would be your central fuel injection unit. These are somewhat failure prone when they start getting old. You may have bent one of the plastic fuel lines enough when working on it to cause it to start leaking. This will cause these symptoms and an overly rich condition. Performing a fuel pressure test may tell the story, but if the leak is in one of the plastic tubes running to the injector port, the test may not produce anything. Sometimes you have to remove the upper plenum and visually inspect the unit to find the problem. If the timing is set right and the secondary ignition components are in good shape, I would look at the central fuel injection unit.


#4

This truck doesn’t have adjustable timing. The distributor hold down tab has no adjustment aloowable. There is a triangular tab on the distributor housing just under the cap. The crankshaft HAS to be set at TDC, and the rotor MUST point to this tab when the distributor is seated. That way, the computer knows the base timing is correct, and adjusts the timing from there.


#5

Not sure if anybody commented on this yet, but if you changed your intake gaskets you might check for a vacuum leak?


#6

I would hookup a vacuum gauge and do a commpression test
http://www.secondchancegarage.com/public/186.cfm


#7

Sorry for the delay, my internet went down about the time I posted the question.

When I reinstalled the distributor, I set it “by the book”. My manual said to “set the engine to the timing mark on the balancer, on the #1 cyl’s compression stroke. Then install the distributor so that the rotor points to the “6” on the housing.” When set in this position, the engine is on TDC and the rotor is pointed at the #1 post on the distributor. So alls well on this end.

However, my book didn’t mention anything about an “electronic advance” connection. Where can I find this? Can I disconnect it, and reconnect to correct it?

As far as the vaccume and fuel discrepancies, my local parts store scanner gave me a “P0300” code which labeled a vaccum leak or faulty fuel injection as possible causes. Can I check for these without special equipment or disassembly of the engine?

Thanks again for all your input, it’s been helpful.


#8

I’m back again after some replacements and checks.

Checked fuel pressure and it’s O.K.
Replaced the fuel pressure regulator (which was leaking badly).
Double checked plugs and wires, and all are firing.
Compression “seems” good (i dont have a gauge, but it’s not showing the signs of blow-by or leaking heads)

The truck still will not start or run. What else is there?!? I feel like either the spark or the fuel is not occuring at the right time. The timming is “set” right, but with the newer engines, it’s also controlled by the PCM. Same goes for the fuel. It’s getting fuel, but i cant determine if at the right time.

Please help!