Idle Problem ? ECM?
Thread Starter
Pro
Joined: May 2007
Posts: 638
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From: Robesonia Pa
Idle Problem ? ECM?
OK I replaced my injectors and cleaned my plenum and TB, replaced all the gaskets and IAC. Fired up my car (1988) and the idle was way off . Not a problem as I figured it would be- there was a lot of carbon buildup on the back of the butterfly valves. OK I used the IAC Adjustment to set the idle to 400 in drive(auto) Then set the TPS to .541 volts. Road tested car- runs great idles fine - until I try to use the AC it dies- throttle does not kick up. Tried the setting procedure 2 more times - seems to make no difference I get the same idle in drive or in park within say 100 rpm. I also have a memory problem on the car- trip meter and gas mileage reset every time I turn the car off and on . Seems to me like the ECM may not be giving the signal for the AC?
Team Owner
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From: Summerland B.C. Canada
Le Mans Master
Joined: Feb 1999
Posts: 9,916
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From: South Carolina
St. Jude Donor '03 & '05
You just cleaned the IAC? If so, when mine was broke, no codes as GM doesnt give them for the IAC, I finally did the OHM check as above and Voila, IAC was bad, and now it runs great
Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Okay. I had to drive a little bit too as the idle fluctuated. I know there is no "learn" mode, but it learned something while driving.
New gasket with the IAC and proper tightness and all is well with it as long as the plug is good and connected.
The memory reset happened to my friends 1990 Vette. It was the alternator going out and the battery was running the car.
See if you have about 13.5-14.2ish volts at idle via a multimeter at the alternator, and check your battery before starting it to see if she is at 12.8ish to 13.2 votls.
New gasket with the IAC and proper tightness and all is well with it as long as the plug is good and connected.
The memory reset happened to my friends 1990 Vette. It was the alternator going out and the battery was running the car.
See if you have about 13.5-14.2ish volts at idle via a multimeter at the alternator, and check your battery before starting it to see if she is at 12.8ish to 13.2 votls.
Thread Starter
Pro
Joined: May 2007
Posts: 638
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From: Robesonia Pa
Update!
Per the Helms the new IAC was bad. Put the old one in and adjusted Idle RPM and TPS per Vader86s tutorial and all is happy with idle and AC. I was replacing due to some discolor/wear on pintle seat but put it back in.
Now on to the memory
The output leg on the alt is putting 13.4 to 14.28 . it leveled off at 14.2 think I did not have a good ground during contact
Battery measures 12.86 befor start
As for the fuses I reseated the 3 amp and replaced the other
Have not driven yet to see if this works
Thanks for the help so far
Now on to the memory
The output leg on the alt is putting 13.4 to 14.28 . it leveled off at 14.2 think I did not have a good ground during contact
Battery measures 12.86 befor start
As for the fuses I reseated the 3 amp and replaced the other
Have not driven yet to see if this works
Thanks for the help so far
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Le Mans Master
Joined: Feb 1999
Posts: 9,916
Likes: 38
From: South Carolina
St. Jude Donor '03 & '05
Per the Helms the new IAC was bad. Put the old one in and adjusted Idle RPM and TPS per Vader86s tutorial and all is happy with idle and AC. I was replacing due to some discolor/wear on pintle seat but put it back in.
Now on to the memory
The output leg on the alt is putting 13.4 to 14.28 . it leveled off at 14.2 think I did not have a good ground during contact
Battery measures 12.86 befor start
As for the fuses I reseated the 3 amp and replaced the other
Have not driven yet to see if this works
Thanks for the help so far
Now on to the memory
The output leg on the alt is putting 13.4 to 14.28 . it leveled off at 14.2 think I did not have a good ground during contact
Battery measures 12.86 befor start
As for the fuses I reseated the 3 amp and replaced the other
Have not driven yet to see if this works
Thanks for the help so far
Your voltage is fine.
Glad things are workign out now.