Just completed a new 350 vortec stealth ram build. Previously had a TBI harness I converted to a speed density TPI harness and ran a stock TPI motor with no issues other than a pesky O2 sensor CEL I never really figured out.

Since the new engine build and reinstallation I changed the following........


-Bigger cam
- vortec heads
-Vortec HSR intake
-went from 22# to new 24# injectors from Southbay
-had to switch over to a small cap external coil style dizzy because of clearance issues with the HSR intake
-got a fresh base tune from TP and upgraded from a V6 prom/memcal up to a V8 chip that now allows me to utilize the knock sensor system.


I now have severe overfueling, hard starting,won't idle,revs up but not very steady, and a code 42 and 43. (EST and Knock sensor codes).
Base timing with EST unplugged is set at 6 deg advance. I've been searching forum since yesterday and haven't got a good direction to go yet. I'm running a 1985 5.7 knock sensor and was told by a forum member I should be running a 1989 5.7 knock sensor but I think my issues go far beyond only the knock sensor. I wouldn't think the knock sensor alone could cause all of this. The plugs are so soaked with gas at this point I'll have to take them out and clean them to get it to fire again.

If anyone has any ideas or direction I'd greatly appreciate it.

 

Is it a TPI knock sensor ; not a TBI one ?

Have you done the code 42 and 43 diagnostics ?

http://www.chevythunder.com/est_code_42.htm
http://www.chevythunder.com/maf_esc_module_code_43.htm

 

Knock sensor is out of an 85 5.7 TPI motor that came out of a Corvette.

No I haven't done 42 and 43 diagnostics. Guess I was searching the wrong sections/places. Thank you very much for the helpful links. I'll go through the tests and let you know what I find out. Your awesome!

 

Alright I should have listened better to VincentZ28 in my older thread before assuming there was more to it. You guys were right on the knock sensor, swapped it out with no change then started testing wires. Turns out in addition to the wrong knock sensor, I also had the fan switch wire plugged into the knock sensor and the knock sensor wire plugged into the fan switch sensor on the side of the head. Got it striaghtened out and solved CEL.

Thanks Veetoz!