either idles or goes 3k or higher

[spinsirs]

idles ok but only responds once the gas pedal is 1/4th the way down and then it runs fine between 3-7k rpm.
while a 1992 gsx ecu is in the car.

i just bought a refurbished 1990 gsx ecu on ebay, with it
the car starts up and sounds good for 2 seconds and revs fine but the car shuts off after 3 seconds(no stuttering just like the fuel injectors instantly cut off).

do i buy another ecu? should i try rewiring mod to make 92 ecu fit? could it be other issue like pressure leak somewhere that is signaling the engine to shut down when the 1990 ecu is in the car?

i bought the car with the 1992 ecu and in its current half running state.

thanks for any help

if anyone near olympia wants to make a quick 15 bucks and test my 90 ecu in their car let me know

i switched the pins for the 92 ecu(6 and 14) seems to be running good now. any reason why this shouldnt be done besides the tachometer being a bit weird now? its idle is about 2k could ecu still be at fault?

 

[jason91dsm]

Check your timing it can cause a high idle. 2k is to high of an idle

 

[xxNocturnalxx]

IIRC if you switch pins to install a non 90' ecu in a 90' you will have tach problems. Best bet is to find a 90' ECU, don't waste your time or hack wires like others will mention to make it work.

 

[BurrowZ]

Just a heads up, I'm not sure if this is your issue but when I idled that high it was my throttle cable. It was cold and would idle well, but when it warmed up it would open my throttle just enough to keep it at 2100. I slacked it a little bit and it fixed the problem.

 

[jb2zero0six5]

Double check the wiring, return it to stock for correct operation of the '90 ECU.

 

[spinsirs]

thanks for the ideas, i will continue looking on ebay for a not 200+ dollar ecu and send back the faulty 1990 ecu.
i plugged up all the vacuum lines that were open and the car idled great at 1k but now ,later the same day, its idle is back to 2k(warm or cold). i checked the throttle cable and it was fine, had enough slack.
what specific ecu problems have people experienced swapping later year ecu into a 1990.

 

[richard5309]

Have you checked your ISC? TPS? The biss screw? When you swapped the ecu, were you sure that your sensors were compatable with it? I.E. I bought a 1g TB for my 2g and thought leaving the 1g TPS on it would work just fine, but I was wrong.

 

[xxNocturnalxx]

You can run a 91+ ECU with no ill side effects except a bouncy tach because the 90' uses a different coil configuration and a tach filter, the power transistor is different as well.

I would use your good 91 ECU until I found a good 90' ECU to replace it, you won't hurt anything in doing so.

 

[jgore1989]

get ahold of boss innovations hes kid4g63 om here. hes in tacoma right off i5 and 512 and always has tons of spare parts. if he doesnt have one he can probally get you one. hes a really cool guy i beleive his number is 253 241 5136.

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)


http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html

 

[spinsirs]

thanks again for all the input(going to inqure about ecu to kid4g63)

on the way to school today it started out at 2k but by the time i arrived (5 minutes later) it was idling around 1k.

reading the thread from Iugrad92turbo it was saying turbo dsm's dont generally have idle problems from vacuum leak, should i jump straight to tps and ignore leak hunting on throttle body?

 

[92AWDHX40]

never rule it out it could be many things giving you issues thats why i posted so you can start somewhere and rule it out.