88 WS6 TransAm GTA

iTrader: (1)

Well heres the deal. Ive had a rough idle for a while now. This morning, the ecm FINALLY threw a code 43, but only for a minute. Ok, knock sensor. So I replace it (forgetting that its threaded into a coolant passage... make that HOT coolant passage). Now, the code 43 is constant. I checked the old knock sensor, and was roughly 3.9 ohms. So the sensor isnt bad. What else is throwin this code 43? There is no knock.

Also, the car is running EXTREMELY rich, to the point that it makes your eyes burn and tear when you bend down to the exhaust pipes. But yet, the ECM doesent seem to be picking up a rich condition from the 02 sensor (fairly new as well). All the injectors tested at roughly 17.5 ohms, all within .2 ohms. No problem there. Fuel Pressure is at 48. Tune up is fresh.

Could this be the Ignition controll module causeing this code 43? I dont have access to a scanner, so I dont know what my knock counts are. Maybe I should check into that.

Thats about it... any help would be appreciated guys! Im about to go friggin INSAAAAANNNEEEEEEEEE!!!!!!!

88 WS6 TransAm GTA

iTrader: (1)

ttt

Ed Maher

Knock sensor resistance does not make it correct. The KS is a microphone for the engine, and when it is bad that means it isn't 'hearing' things right. Code 43 sets when the ECM sees way too much activity from the KS. This could be from bad wiring, bad memcal or a bad sensor.
Eliminate the sensor by bypassing with a 3.9k resistor at the sensor connector. If the code goes away, either the sensor is bad, or you are truly getting gross knock, or you are getting false knock as from perhaps an exhaust leak, loose accesory bracket, maybe even a severly worn engine.
If the code stay, bypass (cut) the KS wire by the ECM. If it goes away your wiring is bad.
If the code stays your memcal (or more accurately, the ESC filters) are probably bad.

As for the over-rich condition, don't know what to tell you. There's a million ways something like that can happen, most of the compter related ones would set a code. Since you are apparently only commenting on overrich at idle (since it's hard to sniff the tailpipe while you drive), it's entirely possible that it's just your elevated FP causing it. From my own experience you can run your FP way high and have 108 idle BLMS and be way overirch and the CM will still not set a code. beyond that, a vacuum, leak on the driver's side cylinders would make the pass die run way rich. OR any of a million other little dumb things. Even your code 43 could be causing it if it's making the ECM pull a lot of timing from you. Basically, you can only troubleshoot one problem at a time, fix the 43 first.

88 WS6 TransAm GTA

iTrader: (1)

OK... heres an update. I bypassed the knock sensor, and got rid of the check engine light. BUT::::: Now at WOT, approx 3500 and up, theres a loud tap. It almost sounds like an electrical type of tap, which Im pretty sure its not, only way to explain it. So now what? I always use 93 octane gas, and base timing is set at 8*. I reconnected the knock sensor, and on went the light, and away went the "tap". Whats goin on with this?

88 WS6 TransAm GTA

iTrader: (1)

BTW: This only happens at full throttle in 2nd gear and above, not in first. Also, I have just swapped the entire distributor to rule out a bad ignition controll module. I might be getting it on a scanner later tonight, Ill post the results (if we can figure out how to use it)

Any tips on using a Snap On brand scanner?

Ed Maher

Does the tap sound more like marbles rattling in a coffee can? If so thats detonation. Seems to me that my above statement may have been correct. When your ECM sees the KS is dead it is permanently stealing some timing from you, which it can do under some circumstances. Thus you don't get any knock at WOT when it is hooked up, but you're also running rich at part throttle/idle because your timing is retarded. When you bypass the KS you get to hear the detonation that the ECM was hiding from you. That is why i don't advocate just haphazardly bumping timing. Mine wouldn't take more than the stock 6' w/o knock, thats when i got into the chip. Once i was in the chip i was able to isolate where my knock was coming in by tweaking the curve and observing. I couldn't get her to take any timing right around the torque peak, but everywhere else it was OK. Led me to believe that my injectors weren't balanced and it was giving me a lean hole that knocked at peak VE (torque). Swapped in flowmatched injectors and suddenly i didn;t need to take out 5' of timing at peak torque anymore, so i must;ve been on to something.

I'd recomend you get a good knock sensor in there and put your timing back to stock. If you want to play with timing, do it in controlled setting like the track so you can tell if you're getting into knock. As it is now, you have been giving up prolly 30hp or so due to your ECM retarding timing from the knock you had. Or at least get a scanner on it to see how much knock it is really seeing.

88 WS6 TransAm GTA

iTrader: (1)

Thanks Ed, youve been a big help here!

The sound I was hearing was more like an sparky type of a sound, as opposed to marbles, but beings that Ive never heard detonation befor (thank ***), Im not quite sure.

I have been thinking for a while now that my injectors are the culprit. When I first got the car and it was stock, I mean BONE STOCK (down to air and fuel filters @ 39k miles). She ran PERFECT. But, OF COURSE like most 20 year olds(also those who are young at heart ), I needed more. Apon installing my AFPR, and setting it accordingly (48-50 psi), I noticed that the car now idled rough, which it never did befor. I set it back to how it was factory, but to no avail. I have heard rumors on the later style of injectors werent the best, and had problems, but I havent really confirmed this. They all tested within .2 ohms of eachother, but that doesent really tell me how good they are when the car is on.

Im gonna go ahead and get the new injecotrs as planned after all, and then Ill go from there. Im goin with 19# SVO's due to their price, and how great the 24# worked in my GTA.

If all works, I might have the car on a scanner tonight for some real numbers.

One more thing... how come now that I have a new KS in the car, does the SES constantly stay on, as opposed to only seeing it once for approx. 1 minute when the old sensor was in there? Is it because the new sensor is more sensitive than the old? Now, the SES comes on within 10 seconds of starting the car, and stays on.

Thanks again!

88 WS6 TransAm GTA

iTrader: (1)

BTW: she still feels pretty damn good up top, cant wait to see how it is once this is all sorted out!

Ed Maher

If the SES light is on constantly, are you sure that you have the correct KS, or that you didn't overtorque it? I don't know the torque spec offhand, but it doesn't have to cranked way in there, thats for sure.
It is also possible to get a bad KS out of the box. Don't rule that out, it's happened to everybody at some point. Hell, i've had bad TPS's and O2s a couple times myself. Really sucks cuz most places won't retrun an electrical sensor like that once you use it, regardless of if it was DOA. If you keep it clean, or just get real pissy over it you might be able to get another one though....

88 WS6 TransAm GTA

iTrader: (1)

Just an update... I finally went ahead and ordered the 19lb. SVO's, theyll be here tomorrow.

For a second, I was thinking to myself... "Hey Rob, you have a perfectly good set of SVO 24's out in the garage... save the money of buyin new injectors again, and get the stuff to burn your own proms, and youll be able to use the 24's!"

Yeah, thats a great idea, but one problem... TIME. I have no other transportation with the GTA still being down (sigh). So, off goes the prom burning project again... ehh maybe in a few months.

OK... now that Im done talking to myself...
Ed, Ill be installing the new injectors tomorrow, and Ill let you know if they fix the problem. The SVO's are rated at 39.6 psi (I think?), so Im gonna set the FP at about 40-41, and go from there. Im also gonna bump the base timing down to 6*, and go from there too.

Ill let ya know how it all turns out tomorrow night!

Ed Maher

OK, that shouldn't be too bad, keep us updated. You should get the PROM bunring stuff if you can though..

88 WS6 TransAm GTA

iTrader: (1)

Yeah, I plan on it. Just gonna take some time to get some extra money together. Im great with computers, and have done some programing in the past, so I dont think Ill have a problem with it, just so long as I have you guys here to help me when I screw up!

88 WS6 TransAm GTA

iTrader: (1)

Ohhhhhhh k... update time.

New injectors are in... no change in problem. Im gonna replace that new KS again, see if that does the trick. I set the fuel pressure of the new SVO 19's at 40.

One question... I thought SVO's were the 4 micro hole style injectors as opposed to the pintle style? My 24 SVO's are the hole style, but the 19's are the pintle. Also, I thought they were supposed to be black with a Pink top... Mine are Grey with an Orange top. WTF is up with that?

Well, if the new sensor doesent to the trick, Im pretty much out of options here.

377Z

iTrader: (1)

BOO!!!

Back from the dead.

88 WS6 TransAm GTA, what ended up curing the problem? I'm having the exact same problem (and its on my convertible too, strangely)--code 43, rich idle.

87350IROC

iTrader: (2)

Wow, same problem here too. What was your solution?