MAF question
Thread Starter
Racer
Joined: Jan 2010
Posts: 347
Likes: 12
From: Deltona FL
MAF question
86 stock motor
I am getting a maf code, and will be changing out the maf and releys, My question is does the MAF affect the start up idle?
When I now start the car in the mornings or after sitting a few hrs it idles @ 600. It used to be right about 1k until it went into closed loop but not anymore. Is this related to the maf or something else I have to look at?
I am getting a maf code, and will be changing out the maf and releys, My question is does the MAF affect the start up idle?
When I now start the car in the mornings or after sitting a few hrs it idles @ 600. It used to be right about 1k until it went into closed loop but not anymore. Is this related to the maf or something else I have to look at?
Team Owner
Joined: Jan 2003
Posts: 20,315
Likes: 245
From: Summerland B.C. Canada
You may have an IAC problem.
http://members.shaw.ca/agent86/IAC%20Diagnosis.pdf
Have you diagnosed the MAF code and is it the only code ?
Is the TPS idle voltage in spec ?
http://members.shaw.ca/corvette86/Code%2033.pdf
http://members.shaw.ca/corvette86/Code%2034.pdf
http://members.shaw.ca/corvette86/Code%2036.pdf
http://members.shaw.ca/agent86/IAC%20Diagnosis.pdf
Have you diagnosed the MAF code and is it the only code ?
Is the TPS idle voltage in spec ?
http://members.shaw.ca/corvette86/Code%2033.pdf
http://members.shaw.ca/corvette86/Code%2034.pdf
http://members.shaw.ca/corvette86/Code%2036.pdf
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Short answer is yes - it can depend on the type of issue/failure the MAF is experiencing.
My advice is to tackle one issue at a time. Start with the MAF circuit since you have that set trouble code.
600 RPM is pretty much where you expect an automatic to idle once warm....so that is a good thing.
On an '86 - when you first hit the key on startup there is a cold start "switch" that is "open" or "closed" (depending on the temperature of the engine's coolant). This cold start switch enables an extra fuel injector (9th) to provide additional fuel to the engine upon start up. When the extra fuel is delivered by the 9th injector at startup you should expect the RPM to be a bit higher (up ~1000 or so) as a result. Perhaps your cold start circuit or injector needs attention if you have long crank times or other issues related to start up.
My advice is to tackle one issue at a time. Start with the MAF circuit since you have that set trouble code.
600 RPM is pretty much where you expect an automatic to idle once warm....so that is a good thing.
On an '86 - when you first hit the key on startup there is a cold start "switch" that is "open" or "closed" (depending on the temperature of the engine's coolant). This cold start switch enables an extra fuel injector (9th) to provide additional fuel to the engine upon start up. When the extra fuel is delivered by the 9th injector at startup you should expect the RPM to be a bit higher (up ~1000 or so) as a result. Perhaps your cold start circuit or injector needs attention if you have long crank times or other issues related to start up.
