Idle and Speedometer

Crashdummy · Post by **Crashdummy** » Fri Oct 06, 2006 3:38 pm

The other day my speedometer pooped out (91, 6 cyl, 5 spd manual conversion) and about the same time my engine died. The car fired right back up but idled low. I checked the fuses and must have pulled the one to the computer because when I started it up again the idle was at 2,000. I tried the relearn procedure but it didn't fix it. I am just wondering if the two could be related? Any help would be appreciated.

Jeff P · Post by **Jeff P** » Sat Oct 07, 2006 5:50 am

Any time my speedometer hasn't worked in my '88, it has never messed with my idle - even with '91 interior wiring. So, I would say they're not related unless something's up with your ECM.

docrodg · Post by **docrodg** » Mon Oct 09, 2006 7:41 am

The main sensor for engine speed the ECM monitors is the Crankshaft Sensor. Since the Speedo get the signal from the tranny sensor and this has nothing to do with the ECM control of the idle. If the idle is suddenly high you may have had something go out when the car initially stalled. Check for a code set in the ECM and ensure you get a code 12 too. Sounds like something has i in loop mode.

Geoff · Post by **Geoff** » Wed Oct 18, 2006 6:19 pm

Mine isnt the same car but sounds like a similar problem.

I have a 1990 BGTZ with the getrag 5spd. and the 2.3L quad four engine.

My car will either idle out and stall or idle at 2500 to 3k. I have replaced both the iacv (idle air control vavle) AND the throttle positioner, still nothing, once in awile I'll go to the store, it will be ok, the service engine light will be off and the spedometer will be working, then I'll get to 4th gear or what seems to be around 40mph or higher and BOOM! the car's service light will come on and BLINK and the spedometer will wuit working, and the car will idle at 2500 to 3k.

My starter strap came off a week back and COULD have kocked the ground strap and shorted something out my friend said, but if it did, it wouldnt have given the car's iacv/throttle positioner power for 1 mile then quit...right?

WHAT the hell is going on? there's either a short in the wire, or the ecm is bad. oh also I took it to advance auto parts and they COULD NOT get it to read, it just wouldnt connect to the car, we checked for vacum lines too. NOTHING.

ANY clues at all would be helpful!

docrodg · Post by **docrodg** » Thu Oct 19, 2006 9:41 am

If the ECM will not flash a code then the wiring from the port to the ecm is faulty or the ecm is fried.

Geoff · Post by **Geoff** » Mon Oct 23, 2006 8:14 pm

My idle air control valve is not hooked up, though driving home today, my spedometer started working and the service engine light went off, mind you it did this 3 times during the 2 hr drive home but if it isnt even hooked up, how is it going back on? the idle air control valve is unhooked because it will get power intermittenly, and cause the car to idle from 2500 to 3k. I hate this, I have no clue what to do, have NO money to fix it.

Anyone live around Kalamazoo Michigan 49006? or Grand Rapids? anyone want a 90 GTZ with about 40 to 45k on the quad four? I'm either gonna trade someone or sell it for like $900.

or a trade for any car that doesnt have a problem?

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