chevyuser74
1/2 ton status
i concur
CK5
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91 burb running rough need help ASAP
- Thread starter 80 Chevy K20 4x4
- Start date
i concur
chevyuser74
1/2 ton status
sorry for the backyard shot then, but i just hate know-it-alls, and that is the way u come off to me. I could be wrong about you because i really dont know you.
One more thing (serious question I'm not trying to come off as a punk here, because i really dont know.) does a automotive machinist work on driveability problems?
Apologies accepted. No an Automotive machinist doesn't even work on cars but as a hobby for the last 30 years i have been working on cars and am very knowledgable on the subject. I just happen to have chose a carreer that was on the much cleaner and non knuckle busting side of things. I'm also sorry if any of my replies make me sound like a know it all (because i don't know it all). This being the internet it is hard to know what kind of knowledge someone has just by reading a few post. You can just about ask anyone on here though where they think my knowledge base is given all of my replies to different post on here regarding technical advise.
Thunder
3/4 ton status
Just read this post and dont want to get into a pissing contest but.
.
Re: the drivability problem in the burb....
First clear the codes out of the ECM by disconnecting the neg battery cable for a few minutes.
Take the truck out for a drive and put a load on it.
Then check codes again. If the 42 comes back the pick up coil is most likely the problem. Bucking, hesitation, low power under load, Intermittant CEL, code 42, are common symptoms of a bad pick up coil.
Also you can check the PU coil with a Ohm meeter. Put it across the two wires that come off of it. You should read 500 -1500 ohms. If the readings are out of specs the PU coil is bad. preferably do the test when the engine/ coil is warm.
If it cures your problem or not, at least it will eliminate the pick up coil as the problem.
.Re: the drivability problem in the burb....
First clear the codes out of the ECM by disconnecting the neg battery cable for a few minutes.
Take the truck out for a drive and put a load on it.
Then check codes again. If the 42 comes back the pick up coil is most likely the problem. Bucking, hesitation, low power under load, Intermittant CEL, code 42, are common symptoms of a bad pick up coil.
Also you can check the PU coil with a Ohm meeter. Put it across the two wires that come off of it. You should read 500 -1500 ohms. If the readings are out of specs the PU coil is bad. preferably do the test when the engine/ coil is warm.
If it cures your problem or not, at least it will eliminate the pick up coil as the problem.
IMO (hey lets start pissing! 
) you don't need to disconnectthe battery cable. People forget, or don't know, that pulling the ECM fuse is the way to do this.
At least on mine, it kills the radio presets and clock, which is a pain. But pulling the fuse doesn't take any tools either.
Of course, I've figured out how to remove/install my battery cables by hand so they are tight enough to work correctly, but that's because of the whole alternator/battery situation. My ECM fuse is on the firewall under the hood, and is a heck of a lot easier to remove and reinstall than the battery cable.
Also a good theft preventive measure in high risk areas, or long term storage. Drop a dead ECM fuse in place of a good one, and the truck will go nowhere. There is work around forthat, and no thief is going to spend the time to find the problem.
) you don't need to disconnectthe battery cable. People forget, or don't know, that pulling the ECM fuse is the way to do this. At least on mine, it kills the radio presets and clock, which is a pain. But pulling the fuse doesn't take any tools either.
Of course, I've figured out how to remove/install my battery cables by hand so they are tight enough to work correctly, but that's because of the whole alternator/battery situation. My ECM fuse is on the firewall under the hood, and is a heck of a lot easier to remove and reinstall than the battery cable.
Also a good theft preventive measure in high risk areas, or long term storage. Drop a dead ECM fuse in place of a good one, and the truck will go nowhere. There is work around forthat, and no thief is going to spend the time to find the problem.
Thunder
3/4 ton status
Yeah the problem is With TBi there are 2 fuses. I cant rember which fuse to pull. ECM A or ECM B. 1 does fuel pump. the other does the ECM/clears codes.. Because senility is comong on strong and my memory is a little foggy...I fuggured disconnect the - cable was the best way to assure that things went ok.
But maby you can tell us ..............Which one clears the codes ECmA or ECM B?
BTY i an unzipping my pants...........
You dont want to se me whip it out.
But maby you can tell us ..............Which one clears the codes ECmA or ECM B?
BTY i an unzipping my pants...........
You dont want to se me whip it out.
To be honest with you, on the TBI I don't know. Don't have my wiring manual here to check. It always seemed odd to me that they have two ECM fuses, when only one of them affects the ECM AFAIK.
On TPI, GM was smart enough (or dumb enough) to put the ECM fuse separate of the fuse panel.
I totally understand what you mean about forgetting which it is, not like you should need to pull it very often. If it were me, I'd probably put a dab of paint or something next to the label on the right fuse on the panel.
On TPI, GM was smart enough (or dumb enough) to put the ECM fuse separate of the fuse panel.
I totally understand what you mean about forgetting which it is, not like you should need to pull it very often. If it were me, I'd probably put a dab of paint or something next to the label on the right fuse on the panel.
Just an update and now the burb is fixed.....lol
I checked the pickup coil and it was at 928 ohms, but while I was putting the module and dist cap back on the distributor, I decided to check the firing order of the spark plug wires since we had changed them doing the full tune up. I found that the #5 and #7 wires were swapped around. It should have been 18436572 but it was 18436752, so it was running like a 6 cylinder basically.....LOL
Anyway, it's fixed now and I appreciate all of your help with this.
Thanks,
Doug
I checked the pickup coil and it was at 928 ohms, but while I was putting the module and dist cap back on the distributor, I decided to check the firing order of the spark plug wires since we had changed them doing the full tune up. I found that the #5 and #7 wires were swapped around. It should have been 18436572 but it was 18436752, so it was running like a 6 cylinder basically.....LOL
Anyway, it's fixed now and I appreciate all of your help with this.
Thanks,
Doug
farshot1
Surrender the Booty
Any lifter tap?.....bad lifter? Just a thought
chevyuser74
1/2 ton status
huh wasnt fuel related how bout that?
I honestly don't know how the #5 and #7 plug wires got switched around? Maybe it was because it was like 100+ degrees outside with no breeze and we had been working on the burb for hours and was getting tired from the heat.....I know the chevy firing order just off the top of my head anyway, but I'm glad I decided to double check it again just for the heck of it....= cheap and easy fix......
