anyone have a surging idle??
Thread Starter
Pro
Joined: Oct 1999
Posts: 515
Likes: 0
From: Nashua NH
anyone have a surging idle??
After it warms up, my idle surges...runs at 750-800, then drops down to 400, then up to 900, down to 350, up to 900, down to 400....etc. Replaced the IAC, checked the TPS, replaced O2 sensor, replaced fuel injectors and O-rings, resealed the intake, repaired visible vacuum leaks....where next???? :confused: :confused: :confused:
Melting Slicks
Joined: Oct 2000
Posts: 3,426
Likes: 4
From: Heidelberg PA
Cruise-In V Veteran
Re: anyone have a surging idle?? (Mark85Vett)
I had a similar problem a few months ago. After replacing the AIC and TPS did you disconnect your battery before going through the setup of the TPS.
There is a specific procedure outlined in tech on how to set your idle. It worked for me. :cheers:
There is a specific procedure outlined in tech on how to set your idle. It worked for me. :cheers:
Pro
Joined: Jul 1999
Posts: 741
Likes: 0
From: Eagle IDAHO
Cruise-In I Veteran
Cruise-In II Veteran
Re: anyone have a surging idle?? (DOCTOR J)
Hey Mark, Come on over and we'll hook your car up to the computer and look at what's happening. I'll be around this weekend, better call first. Phone # check IM
Thread Starter
Pro
Joined: Oct 1999
Posts: 515
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From: Nashua NH
Re: anyone have a surging idle?? (ld85)
had the entire upper end apart this spring; cleaned TB, runners, plenum, intake......
Brand new balancer, toqued bolt to spec and installed with red loctite...
Tom, got your IM...I'll call you this weekend; not sure what my schedule is yet
Thanks!!
[Modified by Mark85Vett, 12:44 PM 6/6/2002]
Brand new balancer, toqued bolt to spec and installed with red loctite...
Tom, got your IM...I'll call you this weekend; not sure what my schedule is yet
Thanks!!
[Modified by Mark85Vett, 12:44 PM 6/6/2002]
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Pro
Joined: Jun 2001
Posts: 520
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From: Elverson PA
Re: anyone have a surging idle?? (Mark85Vett)
Did you put a heated 02 sensor on there yet? Mine did that idle thing when I got my longtube headers. Around the same time I found my egr to be faulty and replaced that too, so I can't be sure which really fixed the problem.
Thread Starter
Pro
Joined: Oct 1999
Posts: 515
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From: Nashua NH
Re: anyone have a surging idle?? (black85)
Haven't put the heated O2 sensor in yet, but it was surging before the headers were in...I had a code 32 when I first bought the car (4 years ago) but it went away shortly afterwards and hasn't reared it's ugly head since...
I'm going to try to make it by NHVett's house this weekend so we can hook it up to the scanner and see where my BLM's are
I'm going to try to make it by NHVett's house this weekend so we can hook it up to the scanner and see where my BLM's are
Le Mans Master
Joined: May 2002
Posts: 5,446
Likes: 1
From: 10.70 @ 124mph, Stock Bottom End @ 3620lbs, ECS Racing Team Member. The 1st NMCA LSX Index Rumble World Champion. 2011,12,13 Champion
Re: anyone have a surging idle?? (Mark85Vett)
You must check for codes, This will tell you a lot.
Racer
Joined: Jun 2000
Posts: 428
Likes: 1
From: Friendswood Texas
Re: anyone have a surging idle?? (Mark85Vett)
For what it's worth...
I had exactly the same surging problem on my 86 last month. After lot's of trial and error (cleaning TB, new IAC, new O2 sensor, looking for vacuum leaks, min idle adjust, etc), it turned out to be the MAF sensor. It did not cause any codes to be thrown. I replaced it (and the two MAF relays) and now my idle is steady and smooth.
I had exactly the same surging problem on my 86 last month. After lot's of trial and error (cleaning TB, new IAC, new O2 sensor, looking for vacuum leaks, min idle adjust, etc), it turned out to be the MAF sensor. It did not cause any codes to be thrown. I replaced it (and the two MAF relays) and now my idle is steady and smooth.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: anyone have a surging idle?? (Mike263)
Unplug the MAF and if the idle improves, you need a new MAF sensor. I went through this a couple of weeks ago and it was my MAF, too.
Got one out of a 85 and problem solved.
Remove your MAF and check the tiny wires to see if one is broken. If not, it could still be the MAF internal circuitry. Try borrowing one from a friend to cross check.
Jake
Got one out of a 85 and problem solved.
Remove your MAF and check the tiny wires to see if one is broken. If not, it could still be the MAF internal circuitry. Try borrowing one from a friend to cross check.
Jake
Racer
Joined: Jul 2001
Posts: 346
Likes: 0
From: southwestern Michigan USA
Re: anyone have a surging idle?? (dalfano)
I seem to have an idle problem as well. Just out of curiosity, what does a new MAF sensor cost?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: anyone have a surging idle?? (purple jinx)
O'Reilly's sells a remanfactured one for $150 exchange with a lifetime warranty. I suspect AutoZone has one comparably priced, etc.
Wrecking yards have them too for about $50 ususally with about 30 day warranty. Some "F" bodies may use the same MAF, depending on the ECM you're running.
Jake
Wrecking yards have them too for about $50 ususally with about 30 day warranty. Some "F" bodies may use the same MAF, depending on the ECM you're running.
Jake
Instructor
Joined: May 2002
Posts: 150
Likes: 0
From: Richardson Tx
Re: anyone have a surging idle?? (Mark85Vett)
Autozone sells a MAF for about $156. Did you measure the IAC to make sure it was set correctly before you insatlled it? It should be 1 1/8" (28mm) from base to tip.
