Code 43...NOOOOO

[fasterthanyou925]

Hey there I've been lurking on these forums for years but have never posted. I've had 7 GMT400's ranging from 4.3 long beds to a 92 SCSB that I had a alum head 355 to a couple vortec trucks, but I'm stumped on this one. It's a 95 Tahoe 4WD that I just picked up for going up to Reno/Tahoe and the like for the winter.


Picked her up for 800 bucks, has Colorado plates on it, found some receipts from in December stating that they replaced the fuel tank, lines, filter, and rebuilt the TB with new throttle bushings, regulator, and new ICM. Has 3" exhaust with a cat and a 40 series on it.

When at a stop light it will randomly run like crap (surging) and die if I don't pop her into neutral...put it back in drive and it's fine. Pinned A and B and came back with a TPS code and a Code 43. Replaced the ESC (put a 95 4wd Tahoe PCM in) and it killed the TPS code but the 43 is still there. Tries a CTS and it started running like crap on cold start...go figure. Put a good CTS in (from a running truck) and still runs like crap and on fire up (very rich) then clears up when I pull out of my driveway and get to my stop sign. (Also had an off idle to 1800rpm miss which I finally cured by unplugging the EGR)

Other than the intermittent surging/dying at idle the truck runs awesome, shifts good, ect.

Any ideas?




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[fasterthanyou925]

Put a TPS and the code went away, PCM didn't fix the code 43*****


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[NaturalGasForcedAir]

IAC? maybe

 

[fasterthanyou925]

Possibly, the PO zip tied to the connector to the IAC (connector clip broke)


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[great white]

GM OBD Code 43

Knock Sensor Error

The ECM receives a signal from the Knock sensor based on the amount of engine ping detected. The ECM uses information from this sensor to help calculate fuel delivery and spark timing.

Fault Code Description

43 - Knock sensor error
Symptoms

Engine ping
Lack of power
Common Problems

Faulty Knock sensor
Poor connection at Knock sensor

Also go through your engine bay grounding points and make sure they are good and clean.

An ESC change should not have cleared a tps code. That makes your grounds suspect....

 

[fasterthanyou925]

Great white,
I don't have pinging or lack of power, or any of the symptoms normally associated with a bad KS. It loads up on fire up, goes away then later on in the trip (if it does it at all) she randomly surges at a light then goes back to normal.

-that being said, I checked the KS and wire & connector which seemed fine other than when I twisted the white nipple where the connector plugs in on the KS it spinned in the casing...doesn't seem right to me, any input?




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[fasterthanyou925]

So I replaced the ICM so now no funky fire ups or dying at the stoplights, and the faulty EGR (unplugged it and it fixed my off idle stumble) RUNS GREAT! However, still has the code 43 though...WTF? Seems like every component on top of the motor failed at once...


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[fasterthanyou925]

Also, replaced the KS


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[TylerZ281500]

its your grounds. my 93 did this

 

[fasterthanyou925]

I just replaced all of the engine ground straps + hot wires like a month ago


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