Rough, miss-like idle

Can electronic contact cleaner eat copper rtv? Saw someone else using it on here to check for vacuum leaks. I sprayed the IC piping then checked other places, and a few minutes later, the joint to the upper intake plenum started leaking.

I do have a code reader now, but only get 2 digit codes.
 
Can electronic contact cleaner eat copper rtv? Saw someone else using it on here to check for vacuum leaks. I sprayed the IC piping then checked other places, and a few minutes later, the joint to the upper intake plenum started leaking.

Copper RTV spec sheet says this about that:

"Chemical / Solvent Resistance
The product retains effective properties in contact with most shop fluids, automotive fluids, such as motor oil, transmission fluids, alcohol and antifreeze solutions. Note: Not recommended for parts in contact with gasoline."

If the joint was tight to begin with, it should be hard to get -anything- in there, so...

I'd be wary of spraying anything to check for leaks. Small ones the computer will correct faster than you can notice them...big leaks tend to stand out on their own. A smoke test finds them all. You can rent a smoke machine from your local partysRUs, but hey...whatever works.

I do have a code reader now, but only get 2 digit codes.

I think 3-digit codes are found w/late model, but you have a chip/tune, so...

My opinion at this point is you have a combination of vacuum leaks and electrical issues. I'd go after vacuum leaks first. Just remember that vacuum leaks are unlikely to throw CID errors.
 
Messing with the stock IC piping is getting old. I really need a fmic setup, just can't find any upper intake plenums made for it.
 
Copper RTV spec sheet says this about that:

"Chemical / Solvent Resistance
The product retains effective properties in contact with most shop fluids, automotive fluids, such as motor oil, transmission fluids, alcohol and antifreeze solutions. Note: Not recommended for parts in contact with gasoline."

If the joint was tight to begin with, it should be hard to get -anything- in there, so...

I'd be wary of spraying anything to check for leaks. Small ones the computer will correct faster than you can notice them...big leaks tend to stand out on their own. A smoke test finds them all. You can rent a smoke machine from your local partysRUs, but hey...whatever works.



I think 3-digit codes are found w/late model, but you have a chip/tune, so...

My opinion at this point is you have a combination of vacuum leaks and electrical issues. I'd go after vacuum leaks first. Just remember that vacuum leaks are unlikely to throw CID errors.

I get 3 digit codes on my 91 SC. I have several memorized like 214 for cam sensor.

David
 
Well one of the wires on the front harness, the single one with the gray plug, is quite frayed and broken. Not sure if that is the cause of the main issue, but we'll see.
 
Problem solved

After repairing the wire in question, cleaning grounds, resealing any place that could have a possibility of being a vacuum leak, and pretty much checking everything possible... it idles normal once again! So no more bouncy needle or miss-like idle. It was truly interesting to figure out. It had this miss-like idle, just running poorly. But if you gave it gas, it wouldn't show any sign of an issue.
 
-sigh-

Alright, we solved whatever was causing the engine light to come on very randomly. However, the miss has returned but more noticeable. During a drive, it "bucks" enough for me to notice. The A/F gauge also goes crazy when it does it. Fuel pressure shows no change.
 
Alright, we solved whatever was causing the engine light to come on very randomly. However, the miss has returned but more noticeable. During a drive, it "bucks" enough for me to notice. The A/F gauge also goes crazy when it does it. Fuel pressure shows no change.
Unplug the cam sensor. See if the bucking goes away. It may take multiple tries to get it to start.
 
when checking over the crank sensor, i noticed some wires frayed out. After further inspection its the same style wire i mentioned earlier. Just bare wire, like a signal or ground wire, but its not connected to the sensor or rather anything... i checked another crank sensor i had and its the same thing, just cleaner. i feel like its not supposed to look like that, but its just something i noticed.

cranksensor.png
 
The wires that are frayed out on my one sensor are not connected to anything, just like this one pictured. They both confuse me. If its like that from the factory, then that's a silly, if not pointless design. Is it supposed to be a ground?
 
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