90 Lumina 3.1 - Trouble Codes 34 & 43 - Advice?

[euro1990]

Hey all. Just got my 90 Euro back together this weekend (after 5 new valves from my broken timing chain... back in May). She's running good enough, but I'm getting a solid "Service Engine Soon" light, and the codes 34 and 43 keep coming up. 34 has something to do with MAP sensor low voltage, and 43 was something like "Electronic Spark Circuit Fault."

 

I grabbed a couple MAP sensors from the yard (green clip and vacuum line, right?) but swapping that out made no difference. I've had a hesiation problem over 3500 RPM's for quite a while, and it's still there after putting it all back together.

 

I did an idle re-learn, and the car runs well (no stalling, smooth idle) but the MAP code and hesitation have gots to go.

 

If anyone has any ideas or advice, lemme know!

[90lumina3.1]

low voltage may or may not be the map sensor problem, it could also be high vaccum. but it sounds to me like you're having low voltage problems ... do you have a real old battery or anythin like that? check around.

[euro1990]

Naah, brand new battery, good alternator (putting out 14.3 volts). I dont know what the hell to do. The car is honestly running great (besides the hesitation problem, which I had months before I had to put this car back together).

 

Ah well, I'm glad she's back on the road. I'll figure it out.

[MotorCityMike]

Have you checked for vacuum leaks? If the MAP doesn't see the right readings it will throw a code. Is your car dist.less? If it has a dist. it may be the computer advance control wire thats disconnected and why you're getting hesitation and a code 43.

 

Do you have access to a scanner that reads in real time? It would help diagnose the problems you're having.

[euro1990]

I never did a check for leaks, but everything seems sealed up good... not a ton of vacuum lines on this motor.

 

Rhedalert and I are thinking it's the knock sensor, so for now that's what I'm tryin. Kinda makes sense, and that's almost for sure what code 43 is.

 

Thanks for the ideas!

[90lumina3.1]

just a thought, if you didnt fix it already. mine used to do that alot. it would act like it was gonna stall, or idle really high. it turned out to be low tranny fluid, i think. its doin it again, and im getting valve knock alot now. freaky.

[euro1990]

Thanks for the reply... I sure hope it aint the trans, it was rebuilt only 30k ago! But it could use a check I guess.

 

Hate to say it, but I'm considering switching teams. Looking at a 99 Nissan Maxima SE 5-speed. I hate to say it, but GM just dont make anything like that. Well, at least not with a 5-speed. If there was a stick GTP out there, I'd grab it!

[90lumina3.1]

bleh... GM does make GTP 5spds. they make tons of 5spds. you could get a lumina 5spd as well. or if anything... make it a project. drop a getrag into your euro. i know i want to

[euro1990]

Maybe you're talking about some other kinda GTP, but I've never heard or seen a 97+ Pontiac Grand Prix GTP with a manual transmission. If so, it musta been totally custom, and a big project car is not what I'm looking for.

 

If you know where I can get a 99+ GTP with a manual trans made by GM, lemme know!!

[ismellrealbad]

I hear a town called "not a chance in hell" has them.....go 2 miles, makea right at the light, then its your next left, 3 more miles, then look for the huge gaping hole in the ground labeled "hell". It should be there that you find them

[eclipse5302]

just a thought, if you didnt fix it already. mine used to do that alot. it would act like it was gonna stall, or idle really high. it turned out to be low tranny fluid, i think. its doin it again, and im getting valve knock alot now. freaky.

 

Check your trans vac modulator. If you're loosing fluid and cant find the source, it could be a bad modulator. They go bad and the inside diaphram leaks. The engine vac pulls the trans fluid into the intake to be burned. Then you get all sorts of problems.

 

Jason

[eclipse5302]

And the code 43 can mean either the knock sensor, or the ignition module. The code shows up because the ignition module and knock sensor fail a test for continuity to each other.

 

Sounds like you might want to do a visual on the wiring to make sure nothing is burned/cut. Most likely, it's gonna be a wiring problem. Or the ECM could have a problem. I find it hard to believe you are getting a MAP error and the car still runs OK...must be something werid going on there.

 

If the MAP sensor was bad, you'd know it. The car would run like crap (because the MAP sensor is one of the main sensors in a SD system). Might not be a bad idea to scan the car too. That way you can tell if the MAP sensor is reading vac, and if it's correct. It should be roughly 17-19 hg at idle, or about 8 kpa.

 

Jason