I was unable to find a similar situation after searching-

Car: 1991 RS
305 TBI 5 speed
8746 AXKW chip

History
About 2.5 years ago, I had replaced my stock 305 with a 350 TBI and made all required changes (knock sensor, esc module, programming etc.). The car ran great, excellent gas mileage and performance and virtually no knock counts even after hours of driving. That was working so good, I had to get rid of it and cause myself some real problems.

Current
Fast forward to present, I rebuilt the stock 305 purely to stock form so I had something to drive while re-working the 350 to a 383. The only hang-over modifications from the 350 days are MSD 6AL ignition, Prominator (tuning g*dsend, c’mon speedreader!) and 3” cat-back exhaust.

Problem
During and after break-in, I noticed a lot (150-300 knocks per cell) of knock in WinALDL even though I cannot hear or feel any.

* I remembered I neglected to replace the 305 esc module (on firewall driver side). Replaced that with stock GM unit- still knocking.

*While under the car replacing the knock sensor, I noticed the cross-over pipe was close to the starter. Clearanced it, still recording knock.

*Replaced the 305 knock sensor- still knocking.

* I also noticed I was getting prom, est and ecm error flags in WinALDL. I yanked the Prominator-equipped ecm and replaced it with a stock 1228746 with a stock AXKW bin in it. Still knocking, but I no longer have the prom, est and ecm errors.

* The SES light has never come on (it is operational). No codes present.

The bottom line is that the stock 305 should run perfect (or close to it) with the stock chip, but it is getting tons of knock. I am wondering if you guys may have any additional insight to this problem.

Any help appreciated.

Gracias-
S-D

 

That is ALOT of knock. Each cell is actually knock/256. Id say its more likely either some sort of mechanical noise or an open signal wire.

 

D24/7-
That is what I am thinking, but cannot determine why it will not at least set a code.

Just sitting in my driveway, I start it up and the the knock climbs by 5s and 10s every couple seconds- just at idle.
I even checked to see if I had the two sensor connectors on the Passenger Side switch (temp and knock) since they have the same type of connectors. They are on right.

I searched but cannot find- is there a way to test the continuity of the knock sensor wire? I believe the sensor is ohms (100K), but am not sure if I can check the continuity of the knock sensor actual wire to the ecm. Is it sending some set voltage through the knock wire? Not sure how that works.

Any thoughts (anyone)? This one is kicking my butt.

 

More searching reveals a good post from RBob concerning my question above.
S-D