Hello everybody from Italy,

I have a 1988 Pontiac Firebird with the 305 V8 TBI motor (code E). I am getting code 43 (low voltage at electronic spark timing circuit, or functional test failure). I've bought a new ESC module, new knock sensor, new plug wires, new spark plugs and new distributor. I've checked and changed timing and octane fuel, with no results! Continuity in the wiring appears OK.

When the car first starts, it runs great for about 5 minutes, then upon heavy acceleration/hill climbing, there is hesitation, I hear a strange noise from the enigne (probably a detonation) and the SES light comes on (code 43). The car runs bad (hesitation, uneven idle, very sluggish) until I shut off the ignition, wait a few seconds, then restart (then the problem repeats).

I'm becoming crazy! I hope in your help! Thanks!

 

Check your ignition components: plugs, wires, coil and so on.

 

Thanks for fast reply, I'll check tomorrow!

But do u think that the noise from engine before the SES light is normal?

 

That noise could be a misfire, which would explain the hesitation and bogging down.

 

I understand..

 

hey i had a 1989 s10 with a 4.3 with the same probilty it the pick-up coil in the dist checked ign coil module ps do you tachjump around ??????

 

Do u suggest to swap the ignition coil??

 

Garth, the forced knock test is failing. Once the engine temperature is above the proper level the ECM will advance the spark timing to force the engine to detonate. This will be done under heavy load which matches your description.

Try using a lower octane fuel so that the engine will actually detonate and see if that clears up the problem. Also check that the distributor base timing is set correctly.

There are several threads on this where I go into more detail. Should be easy to find by using my name in the authors box along with some key words.

RBob.

 

Hello Rbob,

I've red all your threads about code 43 and I've tried to use a cheaper fuel and tried a lot of base timings from 0 to 12 without any results..

Probably, in order to solve definitively this problem, I can buy a PROM without the code 43 control for my car, but I have to find someone that sell it!

 

WHAT?

 

"hey i had a 1989 s10 with a 4.3 with the same probilty it the pick-up coil in the dist checked ign coil module ps do you tachjump around ??????"

it's a riddle, being a person living in N. Chas SC my self ill explain. This is what he/she was saying.

"Hey, i had a 1989 s10 with a 4.3. It had the same problem as your describing. It turned out to be the pick up coil in the distributor so i suggest to check that. One more thing, does your tach jump around?"

I hope that helps.

 

Thanks! What means "does your tach jump around"?

 

It means your tachometer jumps around sporadically....it displays no stationary rpm reading.

 

maybe the "noise" you hear is amechanical issue w/ engine.knock sensor cannot tell difference and continuously retards timg trying to stop what it believes is "pinging"causing poor driveability and ses/43.whole process repeats each drive cyle until engine is shut down and restarted.if it is detonation check for proper egr system function and flow.

 

I underestand, my tach is regular, no trouble with it

 

I will do, thanks

 

Hello, this is the file log with WinALD, please help me, thanks!!

http://www.adrive.com/public/6729319...548c064d9.html

 

i'm having the same problem....did you get yours running better?....if so what was it?..

 

I don't know! I'm going to swap the Egr valve and solenoid, I've changed a lot of parts w/o success

 

Finally problem solved!!! It was the ground wire to ESC module broken!!

 

I found my problem. I went to change the knock sensor and it had permetex or sealant blocking the hole. The knock sensor was not into the coolant so it was not picking up the sounds in the motor so It set code 43 during the knock test.