I have swapped a 92 305 TPI motor into my Wrangler with the help of Painless Wiring's late model TPI wiring harness and anti-VATS chip. Now, the only error code I am getting is code 43. My understanding is that I may need to swap out the 305's stock knock sensor for a 350 one because the Painless stuff is meant for 350's not 305's. The ECM is out of the same 92 Firebird, so it should already match.

Anyone have any ideas? I hate to buy a knock sensor ($30, but still...) just to try something that may have nothing to do with the problem, then get stuck with a useless knock sensor.

I do know that they are two different part numbers for the 305 and the 350.
Thanks in advance!


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90 Wrangler with 305 TPI motor out of 92 Firebird Formula/ SM465 tranny/ Scout Dana44's on 35" BFG's

 

By the way, the motor seems sluggish and seems to want to cut out at times on the highway. May be an unrelated problem, though (I attributed it to the 3.07 gears and 35" tires!)

Would a bad (or mismatched) knock sensor cause this?

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90 Wrangler with 305 TPI motor out of 92 Firebird Formula/ SM465 tranny/ Scout Dana44's on 35" BFG's

 

Try clearing your secondary ignition wires(spark plug and coil) away from your wiring harness. Specifically the wires coming from the esc (electronic spark control) module). It worked for me Unfortunateley after an exhaustive harness check and replacing everything including the ecm.
I too switched a 305TPI to a 350 kept getting code 43, sometimes intermittantly.
I have read that you are supposed to replace the knock sensor and escm so I did but still kept getting 43 code. Try moving your wires first.

 

I've tried moving the wires around to make sure they aren't touching, and that hasn't helped anything. I even tried shielding the knock sensor wire with plastic loom, no dice. I think I may have to bite the bullet and get a new knock sensor.



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90 Wrangler with 305 TPI motor out of 92 Firebird Formula/ SM465 tranny/ Scout Dana44's on 35" BFG's

 

Does anyone know if the knock sensor has to be matched to the prom, or to the ECM for sure? I beleive the prom that I used (Painless Wiring non-VATS prom) is for a 350 (they said they were the same), but the ECM is for a 305.

What is the difference between the two knock sensors? they appear to have the same thread and wiring connection.

 

the ecms are all the same for tpi 305 and 350 they have the same service numbers the only thing that sets the two aapart is the chip which wouldnt give you a code i've been running a 350 ecm with a 305 chip for a while and havent gotten a code at all the esc module might be bad no way t check other than replacing it try the knock sensor as well