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Truck started...rough ass idle (Update)

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chev4life

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Sup guys...truck is running and Scott cruised this morning and got it timed dead on and noticed a miss. So...I was screwing around with it to see if I had a vac leak...sprayed some brake cleaner around and didnt notice any idle change. Soooooo...I checked for codes and it pulled a 42 (ignition control/open/short.component failure)
How can I fix this problem?

...Its running, not perfect but running. The idle is a rouch rough when cold and smooths a bit when hot...but not normal. It also feels as though it has some power loss (my new heads and manifold should have upped it for sure) and when on the freeway it doesnt have enough power to stay at speeds above 70 without downshifting. I am totally at a loss. Any ideas? Sensors bad etc..??
 
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chev4life said:
Sup guys...truck is running and Scott cruised this morning and got it timed dead on and noticed a miss. So...I was screwing around with it to see if I had a vac leak...sprayed some brake cleaner around and didnt notice any idle change. Soooooo...I checked for codes and it pulled a 42 (ignition control/open/short.component failure)
How can I fix this problem?
Click to expand...

I'd get a factory service manual and work through the diagnostic flowcharts ... this where the Chilton's/Hayne's suck.

OTOH, I'd make a GUESS, withotu seeing the truck nor ahving said manual, that your ignition module might need replacing, and/or has a lousy ground connection.

But see what someone who actually understands TBI says first. Maybe Scott'll post up 'cuz he saw the truck.

Least it's starting now, huh? ;)

-- A
 
Did you reconnect the bypass wire (you disconnect to set timing) and after reconnecting it, with the engine off, did you remove the ECM fuse for 10 seconds to clear the codes?

Maybe it's as simple as that?

Search my username as thread creator, and "troubleshooting" in thread subject, and you'll find my link to the GM troubleshooting flow charts, if you need them.
 
It sounds like you have a bad plug wire.

Try spraying soapy water on the wires and look for sparks.
 
I replaced the plugs and it seemed to run fine. I then proceeded to throw in the air cleaner and take it for a drive. When i started it again it was running like crap all over. I dont know what the hell is going on???? I turned all the lights off in the garage and closed the door, ran it...and saw no sparks or anything like that. I did notice that the two wires going into the black plug on the top of the coil looked a little frayed, one you can see the wires...I wraped in elec tape and am unsure if that is causing anything. I really dont want to have to go on a wild ass goose chance but Im lost. The Taylor wires I have are brand new, plugs are now brand new (ngk v-power gapped .045), rotor, cap are new and ignition, pickup coil are 1 month old. The cap is also pretty new. WTF!!!!!?????
 
Would a .035 gap fix this? Chiltons says .045 and I dont have stock stickers anymore.
Update... I was screwing last night around the dist with the engine running to see if I get a reaction, I pressed on the wire going into the msd coil and the engine turned off. Im thinking I need to swap that thing out. Also...to make sure, the shop I got my Taylor wires is nice enough to swap them out for some MSD 8.5's. I will try all this and pray to god.
 
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OH...out of curiosity...is it possible that the way I adjusted my valves could be causing this? I adjusted them as recommended by others... #1 intake full open adjust the #6..etc...then do half turn after tension is gone.
 
Did you replace plug wires?

Did you put plug wires on properly, fully seated and in the correct firing order?

Did you inspec the dizzy cap and rotor and/or replace them

Could have a loose wire or something.

Did you pull plugs to check to see if there is other issues going on?

Double check your timing
 
I had a similar problem a while ago. It was a combination of a bad ignition module and a bad ECM. I would suggest that you take the ignition module off and have it tested at an auto parts store like Advance or Autozone.

Since it might be intermittent and temperature related, I would suggest getting a new module and carrying your current one as a trail spare. Also, check for loose or damaged wiring to the module and computer. This would have the same effect and trip the same codes.
 
It has a new ignition modual, wires, rotor, plugs, and coil. The timing is tits and the firing order is correct. I will check for damaged wires. It isnt throwing any codes...wish it would. Is there any good way to test this stuff?
Oh...I did check to see if all the wires were seated correctly and 1 and 6 were a little loose. I plugged them in nicely and it still does the same thing....could the plugs be toast from the 10 or so miles and some idling Ive done with them loose?
 
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