1994 Chevy Suburban V8 5.7L Four Wheel Drive Automatic 245000 miles
Engine was running rough at idle and all speeds.
Replaced the fuel filter. Still the same.
Replaced the spark plugs with manufacturer specs, gapped to 0.035", new distributer cap and rotor. Checked the compression - 125 to 145 psi.
Now engine will not start. Battery is fully charged, it cranks over. I see fuel spraying from the injectors into the throtle body; I pulled a spark plug and grounded it. It sparks. I then replaced the ignition coil. Still no good. The check engine light comes on during initial key turn, then goes out, like it is suppose to. Checked the ECM codes. There is no codes. It is clear. What could be wrong?
Can you check the timing?
Check the ignition timing and the valve timing. With this many miles the timing chain could have jumped.
The ignition switch, normally, sends power to the ignition coil, fuel injectors, etc, when it is in the RUN or crank positions, right? What if power (12 volts) were being distributed when the key is in START; but, NOT, when the key is in RUN?
Do you know of the easiest way to check this?
I rotated the engine until timing marks are at TDC. I pull the cap back off and it seams the roter is about 1/3 past ‘number one’, towards ‘number 8’. Is this the problem? I also checked the pick up coil in the distributer. It measured fine on the resistance.
If it was running bad before but still running, and now it isn’t after you tuned it up, first thing would be to go back and check your work. Look for wire off, misplaced, broken, cap not on tight etc. 40 years ago as a kid I put points in my VW and couldn’t get it started. A family friend mechanic came over and found I mis assembled the wire on the distributor and grounded it out.
So if everything was done ok and you have spark and you have fuel pressure, timing chain might certainly be the prob. If it is really bad, you can look into the valve cover through the oil filler while someone is cranking the engine to see if the rocker arms are moving or not. If not you know the chain is the problem for sure. Might have been the problem of bad running in the first place which would make sense. Might be time to have someone look at it.
Check firing order.
Thanks folks for all of your help and suggestions.
It turned out to be the ignition coil pickup on the side of the distributer. From what I understand, this is the electronic version of points in old style distributers. Anyways, $39.95 later, she is up and running. Runs best at 10BTDC instead of TDC. Must be that loose timing chain, I think.
Good thing you don’t have to have ignition timing set “correctly” as some states will fail you for an "incorrectly " set distributor.
That’s why I live in Nevada. No car checks. No smog checks. You can license anything that runs, practicially.