Hey guys, I am currently working on my code 43 issue. I bought a volt meter and am trying to figure out what has failed. I've replaced the knock sensor ( still suspicious of it though as I can't get an ohm on it), I tested the pig tail and got something like 8.5 volts I believe. I'm working on checking the ECM for a loose unit or wire but I could really use help with possible unit numbers for what the knock should display and the pig tail. I am an idiot when it comes to voltmeters and that general physics stuff. Lol

 

Have you checked to make sure the EST wire is connected well?

Have you checked the connector at the ESC module? (It's located driver side firewall between brake booster and fender, where the fuel pump relay is)

 

ECM wiring is good. Not sure what est is. I realized I can't ohm the ks because my voltmeter only goes to 2k ohms lol. Apparently the ks is supposed to read ~4k. I'm not trying to find out how to check wire consistency ( along the blue ks wire)

 

Holy crap, so I found a test light from a neighbor and followed the blue wire all the way from the pug tail to the ECM. Couldnt get it to go on once! Sssssssooooo I'm guessing it's the ECM. Or at least the mcal? The wire I tested is on the biggest of the 3 attachment locations on the ECM. On the left most side.

 

 

Your test light may not light at the ECM because its only a 5 volt signal and I assume your test light is a 12 volt incandesent bulb. And don't use a test light on the ECM's electronics unless it is a LED test light.

And to the best of my knowledge your 91 Z28 would not have an ESC. Its not TBI and you also stated the wire goes to the ECM.

Provided you did not kill your ECM from testing on it with a light,
-Unlpug the Knock sensor and check the wire for 4-6 volts with the ignition on.
over 6 you may be getting a feed off of some other wires (kinda unsual) or a faulty ECM. Under 4 a short or faulty ECM
-Check the resitance of the Knock sensor (yes you can). Sensor terminal to engine block. Should be 3300-4500 ohms.
No, replace the sensor
yes, make sure your MemCal is seated in its socket. If it is then it may need replaced.

 

Well now I feel like a moron. What you said about the test light makes sense. When I first touched the wire the light came on and then went off and it won't come back on. Did I fry my ECM? If I did did the prom go too?

I did follow the wire the whole way back, I was under the impression at the esc was a part of my comp that's why I checked. Regardless...

Now my car won't idle, if imhold the gas down and feather it, the camaro will run. But it will run horribly.. Kinda like my spark wires are mixed up.

I screwed up

 

I'm not doubting - I'm curious - I never did much on a TPI car before.

The TPI cars don't have a ESC module? They still have knock sensor, still have EST wire, still have CC distributor that advances and retards timing same as a TBI. Might be located in a different area underhood, but wouldn't there still be an ESC module somewhere?

 

 

Are you SURE the OP's 91 has an ESC module??? My 89 TPI does but my 89 is not a 91.

 

90-92 TPI have the ESC built into the ECM. Unless I missed something, under the OP's avitar it says "91 Z28" so I assume that is whats being worked on.

 

Going back to your first post you stated you measured volts and got 8.5 which is too high. Now if the wire and all was fine and not picking up anything from any ignition wires or something else that would lead to a faulty ECM.

Maybe try for ***** and grins, disconnecting your battery for a minute or so. Maybe even while its disconnected take out your ECM and make sure the MemCal is in its socket well. Once you have it back together turn the key on and check for voltage again. Either way, 0volts or the original 8.5 is wrong.