86 irregular idle
Thread Starter
Instructor
Joined: Apr 2004
Posts: 115
Likes: 2
From: Kissimmee, FL
86 irregular idle
I have an 86 and the engine has been missing at idle and while driving at a constant speed. Check engine on light showed MAF issue. Replaced MAF, still missing. Replaced plugs and wires. Still missing but not as bad. Idle speed varies.
Any ideas as engine has over 103K on it. Also on another note, when driving a while and engine hot, tends to not start when trying to start it soon afterward, only clicks for a few times. Then starts up OK.
Thanks,
JD
Any ideas as engine has over 103K on it. Also on another note, when driving a while and engine hot, tends to not start when trying to start it soon afterward, only clicks for a few times. Then starts up OK.
Thanks,
JD
Last edited by jdenn47; Jul 18, 2010 at 10:06 AM.
Racer
Joined: Aug 2009
Posts: 496
Likes: 4
From: Cordova TN
I have an 86 and the engine has been missing at idle and while driving at a constant speed. Check engine on light showed MAF issue. Replaced MAF, still missing. Replaced plugs and wires. Still missing but not as bad. Idle speed varies.
Any ideas as engine has over 103K on it. Also on another note, when driving a while and engine hot, tends to not start when trying to start it soon afterward, only clicks for a few times. Then starts up OK.
Thanks,
JD
Any ideas as engine has over 103K on it. Also on another note, when driving a while and engine hot, tends to not start when trying to start it soon afterward, only clicks for a few times. Then starts up OK.
Thanks,
JD
If you have a fuel pressure gauge hook it up and see what pressure you are getting when the car is idling. Should be somewhere around 43 and steady.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
I have an 86. The missing can be due to a bunch of things.
1. The first thing is plugs and wires.
2. could be a cracked dist. cap
3. a bad injector
4. The wire on the dist. cap is not tight or has corrosion on the metal tang.
5. bad coil. gets hot and shorts intermittantly.
as for the starting, my starter just wore out. It would start up cold, and I'd get to the market, buy milk or whatever, get back out to the car, and no start. happened 3 times.
I took the starter apart, cleaned up the commutator, and replaced the brushes and solenoid, and it's been in there 3 years without a problem.
It;s a bear to get out, but well worth it if you don't have to walk in summer heat.
Also, right above the starter is the wire harness. Don't mess with it trying to push it out of the way. The plastic vacuum lines are in the harness, and if you push it out of the way, you break the vacuum line, and you have to unwrap it and put new vacuum lines in that connector. What a bear!!!!If you break it, your heater will not shut off.
1. The first thing is plugs and wires.
2. could be a cracked dist. cap
3. a bad injector
4. The wire on the dist. cap is not tight or has corrosion on the metal tang.
5. bad coil. gets hot and shorts intermittantly.
as for the starting, my starter just wore out. It would start up cold, and I'd get to the market, buy milk or whatever, get back out to the car, and no start. happened 3 times.
I took the starter apart, cleaned up the commutator, and replaced the brushes and solenoid, and it's been in there 3 years without a problem.
It;s a bear to get out, but well worth it if you don't have to walk in summer heat.
Also, right above the starter is the wire harness. Don't mess with it trying to push it out of the way. The plastic vacuum lines are in the harness, and if you push it out of the way, you break the vacuum line, and you have to unwrap it and put new vacuum lines in that connector. What a bear!!!!If you break it, your heater will not shut off.
Racer
Joined: Aug 2009
Posts: 496
Likes: 4
From: Cordova TN
I have an 86. The missing can be due to a bunch of things.
1. The first thing is plugs and wires.
2. could be a cracked dist. cap
3. a bad injector
4. The wire on the dist. cap is not tight or has corrosion on the metal tang.
5. bad coil. gets hot and shorts intermittantly.
as for the starting, my starter just wore out. It would start up cold, and I'd get to the market, buy milk or whatever, get back out to the car, and no start. happened 3 times.
I took the starter apart, cleaned up the commutator, and replaced the brushes and solenoid, and it's been in there 3 years without a problem.
It;s a bear to get out, but well worth it if you don't have to walk in summer heat.
Also, right above the starter is the wire harness. Don't mess with it trying to push it out of the way. The plastic vacuum lines are in the harness, and if you push it out of the way, you break the vacuum line, and you have to unwrap it and put new vacuum lines in that connector. What a bear!!!!If you break it, your heater will not shut off.
1. The first thing is plugs and wires.
2. could be a cracked dist. cap
3. a bad injector
4. The wire on the dist. cap is not tight or has corrosion on the metal tang.
5. bad coil. gets hot and shorts intermittantly.
as for the starting, my starter just wore out. It would start up cold, and I'd get to the market, buy milk or whatever, get back out to the car, and no start. happened 3 times.
I took the starter apart, cleaned up the commutator, and replaced the brushes and solenoid, and it's been in there 3 years without a problem.
It;s a bear to get out, but well worth it if you don't have to walk in summer heat.
Also, right above the starter is the wire harness. Don't mess with it trying to push it out of the way. The plastic vacuum lines are in the harness, and if you push it out of the way, you break the vacuum line, and you have to unwrap it and put new vacuum lines in that connector. What a bear!!!!If you break it, your heater will not shut off.
Thread Starter
Instructor
Joined: Apr 2004
Posts: 115
Likes: 2
From: Kissimmee, FL
Replaced Plugs, wires and fuel filter. (All needed replacement soon)
Still rough idle and when you open the throtle, it hesitates for a sec.
Could it be injectors? Cleaned at 82K, now has 104K.
Air filter is a K&N, cleaned recently.
Thanks
Still rough idle and when you open the throtle, it hesitates for a sec.
Could it be injectors? Cleaned at 82K, now has 104K.
Air filter is a K&N, cleaned recently.
Thanks
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
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Thread Starter
Instructor
Joined: Apr 2004
Posts: 115
Likes: 2
From: Kissimmee, FL
Could the rough ideling be caused by a bad O2 sensor or TPS system issue?
I have no check engine lights on anymore.
I have been told that it is possible that the coil or dist. cap could be the problem which would also cause hard starting. Any thoughts ?
I have no check engine lights on anymore.
I have been told that it is possible that the coil or dist. cap could be the problem which would also cause hard starting. Any thoughts ?
Last edited by jdenn47; Aug 12, 2010 at 08:51 AM.
Thread Starter
Instructor
Joined: Apr 2004
Posts: 115
Likes: 2
From: Kissimmee, FL
Replaced Dist. and Rotor. Still runs idles rough and run rough.
Engine service soon light comes on sometimes when started and then stays off when started another time. Can the MAF, which is new, be causing the whole problem? Or can this possibly be a fule presure reg. or pump problem?
Engine service soon light comes on sometimes when started and then stays off when started another time. Can the MAF, which is new, be causing the whole problem? Or can this possibly be a fule presure reg. or pump problem?
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
I hope you didn't screw the idle screw in or out. There is a procedure to adjust it. If it is at one end or the other of it's travel, the IAC cannot compensate for various things.
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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