Idle problem revisited, getting closer...
Thread Starter
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
tpis, who I trust more than anybody when it comes to tpi, sells their MAFs for 85-89s. Everywhere else is 86-89. I think they are not the exactly the same, but compatable, The one from my '87 T/A is an exact replica, no difference at all, even the markings and numbers are identical.
Thread Starter
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
It's handy if you don't have a scan tool and you want to know if your in open or closed loop. It will also tell you if you are running extremely rich or lean.
http://members.shaw.ca/agent86/Field...ice%20Mode.pdf
http://members.shaw.ca/agent86/Field...ice%20Mode.pdf
Drifting
Joined: Feb 2003
Posts: 1,978
Likes: 2
From: San Antonio Texas
Check out your Coolant Temperature Sensor. I once had similar problems and I found a bad connection at mine (CTS). You may or may not get a code 15 with this problem. This sensor seems to affect A/F mixtures at different temps.
Thread Starter
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
I've replaced the sensor and checked the wiring, everything seems ok with it. That was one of my first "solutions." I have kicked around putting a 3k resistor in the connecter and seeing what happens, just for grins.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
...
Huh? So you unplugged your maf and your car ran bad. How is this related to HIS problem??
This makes no sense. It costs more to specify a specific unit. Unless there is a difference, all the aftermarket vendors would simply say '85-89' to be cost effective for them. SOMETHING is different.
btw, the one time I needed a question answered from GK he couldn't do it. He's a smart guy, but doesn't know everything. Nobody could.
-- Joe
Huh? So you unplugged your maf and your car ran bad. How is this related to HIS problem??
This makes no sense. It costs more to specify a specific unit. Unless there is a difference, all the aftermarket vendors would simply say '85-89' to be cost effective for them. SOMETHING is different.
btw, the one time I needed a question answered from GK he couldn't do it. He's a smart guy, but doesn't know everything. Nobody could.
-- Joe
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
I mentioned how my car behaved with an unplugged good MAF to let him know how his should act. I have already admitted that I don't know his problem but I am trying to help. Looking back over this thread you have offered nothing at all to help. Since I am at a loss to help I am going to shut up, why don't you?
You offered ZERO tech. I offered him advice, he took it, and got the expected results from unplugging the maf.
-- Joe
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Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
He's just trying to help. I didn't mean to snap.
You have to follow a troubleshooting path, and avoid getting different advice from numerous people. It sounds like your on the road to success, but be weary of going down a rat hole.
-- Joe
You have to follow a troubleshooting path, and avoid getting different advice from numerous people. It sounds like your on the road to success, but be weary of going down a rat hole.
-- Joe
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
When you are getting help from someone you should follow completely through with the recommendation before going to any other advice. You are close to a solution, good luck.
2nd Gear
Joined: Jul 2008
Posts: 2
Likes: 0
Dirty Throttle Body?
I have followed some of the thread and the replies re: rough idle. In looking at another corvette site, it stressed how dirt build up in the throttle body can raise the idle speed, and make the engine run poorly. Wynn's apparently makes a solvent spray that does a great job cleaning up the throttle body on the L98 engine, with a careful application of a tooth brush. The solvent is usually only available through a distributor, as they go after the shop repair business more than the DIY. Just a thought that it may be something you want to check. A friend bought the kit and cleaned the TB on his 86 himself, and he said he couldn't believe how much better the engine ran.
Thread Starter
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
Thanks for the suggestion defvet. The engine is fairly new and I just cleaned the intake, tb, and IAC valve and passage ways 5 months ago, they still look great.
I'm getting a used, working MAF off an '87 hopefully monday or tuesday. Hoping that solves the problem!
I'm getting a used, working MAF off an '87 hopefully monday or tuesday. Hoping that solves the problem!
Drifting
Joined: Apr 2007
Posts: 1,339
Likes: 2
From: port charlotte fl
Carry on with all the previous recommendations and you can save this 'till last if you want to.I had something similar and narrowed it down to the IAC valve. I fitted a cheap NAPA one with not much better result.Incidentally,when you ask for anything at NAPA they try to sell you their expensive product.They can usually find a cheaper version if you ask. Anyway,I then got the expensive one and tried that with no better results.All the instructions tell you is to make sure the pintle doesn't protrude further than an inch and an eighth.The way it works,it should be self aligning.Here's what I did and it makes no sense to me but it worked.Jump the A+B pins.Hold the IAC valve in your hands and have someone turn on the ignition.It spits out the pintle and spring pretty smartly.I did it alone and spent an hour looking for the spring!Screw the pintle back in to exactly one and one tenth inches and make sure the spring engages the slot.Put it back in and try it.Mines been perfect ever since and it still makes no sense!!
It may be worth a try as you mention that on occasion you have started the car with the jumper in which fully closes the IAC,and the thing runs good.
My original symptoms included a high idle,hunting,stalling at lights and a real stinky exhaust.
It may be worth a try as you mention that on occasion you have started the car with the jumper in which fully closes the IAC,and the thing runs good.
My original symptoms included a high idle,hunting,stalling at lights and a real stinky exhaust.
Le Mans Master
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
[QUOTE=staugur;1566626765 Jump the A+B pins.Hold the IAC valve in your hands and have someone turn on the ignition.It spits out the pintle and spring pretty smartly.I did it alone and spent an hour looking for the spring![/QUOTE]
I did that and never did find the spring OR the pintle.
I did that and never did find the spring OR the pintle.
Thread Starter
Melting Slicks
Joined: Jan 2008
Posts: 2,065
Likes: 1
From: Jasper Texas
Checked codes today, had a mysterioius 33 stored. MAF theory is looking stronger and stronger! Should have one from an '87 tomorrow, we will see! If that don't work, I'll try one from an '85 also, but I don't think there is any difference.
