Ruff idle.
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From: OSTERSUND
Ruff idle.
I hav ebeen reading the threads about diffrent problems with ruff idle, and now I´m stuck!
I have replaced: spark pluggs, wires, PCV, vaccum lines, Fuel regulator valve, Air-filter and Fuel filter.
I have cleaned: MAF-sensor, The Hall sensor (timing sensor) and I only get codes like 11 or 111. As You know "PASS"
I still have a very ruff idle it is almost as it backfires. There is a "farting" sound from the tailpipe.
Oh You say it´s the valves!
Yeah but why does it run perfektly as soon as it get some load on the trottle? And how come I have a milage around 24-25 miles/ gallon?
Please is there somebody out there who can help me, because I´m stuck.
Tiwan/ Sweden
I have replaced: spark pluggs, wires, PCV, vaccum lines, Fuel regulator valve, Air-filter and Fuel filter.
I have cleaned: MAF-sensor, The Hall sensor (timing sensor) and I only get codes like 11 or 111. As You know "PASS"
I still have a very ruff idle it is almost as it backfires. There is a "farting" sound from the tailpipe.
Oh You say it´s the valves!
Yeah but why does it run perfektly as soon as it get some load on the trottle? And how come I have a milage around 24-25 miles/ gallon?
Please is there somebody out there who can help me, because I´m stuck.
Tiwan/ Sweden
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From: Corpus Christi, Tx. 78418
The Idle Air Bypass Valve, also referred to as the IAC, on the 4.0L engine is located top LH front of engine, LH side of air intake assembly. In my 92 EVTM it appears to be mounted near the Air Charge Temperature Sensor on the driver's side of the engine.
BTW what year Aero do you have?
Could be a fuel injector that's not opening, but I think that would cause a code to be stored and you're getting pass codes. What was the condition of the plugs you replaced?
You might also check the Throttle Position Sensor as a possible problem. It could have a bad spot at the idle position.
Ron
BTW what year Aero do you have?
Could be a fuel injector that's not opening, but I think that would cause a code to be stored and you're getting pass codes. What was the condition of the plugs you replaced?
You might also check the Throttle Position Sensor as a possible problem. It could have a bad spot at the idle position.
Ron
Last edited by rlmdad; Jun 11, 2005 at 05:43 AM.
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From: OSTERSUND
My Aero is a -91 2WD.
Thanks for the tip. Do You know of any method to check IAC and Throttle PS.
Meassuring by ohm or voltage?
You also mention the fuel injectors, but wouldn´t I have sensing problems at engin load? It only accures at idle, independent of rev. It even stops at decellaration.
Tiwan.
Thanks for the tip. Do You know of any method to check IAC and Throttle PS.
Meassuring by ohm or voltage?
You also mention the fuel injectors, but wouldn´t I have sensing problems at engin load? It only accures at idle, independent of rev. It even stops at decellaration.
Tiwan.
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Joined: Sep 2003
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From: Southern California
To check the IAC, unplug it while the van is idling. If the engine dies or almost dies, then the IAC is likely to be OK. You can check the TPS by measuring the resistances between pins while someone presses the gas pedal. As long as the resistances vary smoothly you should be OK.
I think the problem with the bad idle is most likely an adjustment problem. There is a little screw that limits the idle speed, and it's toward the front of the throttle body. This screw is stopped against the throttle body itself, which is aluminum. Over time, it does wear down that spot, and you end up with a low idle. Just turn that screw a couple of turns and you should be able to bring the idle up to the point where the shaking stops.
I think the problem with the bad idle is most likely an adjustment problem. There is a little screw that limits the idle speed, and it's toward the front of the throttle body. This screw is stopped against the throttle body itself, which is aluminum. Over time, it does wear down that spot, and you end up with a low idle. Just turn that screw a couple of turns and you should be able to bring the idle up to the point where the shaking stops.
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Joined: Nov 2001
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From: Oak Harbor, Washington
Originally Posted by copper_90680
Just turn that screw a couple of turns and you should be able to bring the idle up to the point where the shaking stops.
That screw is only there to set the throttle blade so that it does not seize in the throttle body when it cools down. It's not there to set the curb idle speed and should not be used as such.
Tiwan: have you tried looking for a vacuum leak? With fuel mileage like 24+, you've got to have the basics pretty well covered, and you still haven't told us which engine you have so we can't give much specific advice. I guess I could assume, since you mentioned cleaning the MAF, that you've got a 4.0l ?
If you have a 3.0l, the IAC is here:
But if your idle is rocky, I doubt that's the problem. Unless it's also very low, in which case it could be sludged.
Both the 3.0l and 4.0l have a history of vacuum leaks at the injector port o-ring seals. Test by squirting a little aerosol carb cleaner at each injector's base. I know, it's not easy to get near some of them, and you'll have to take out the doghouse for the rearmost ones.
Last edited by asavage; Jun 11, 2005 at 07:19 PM.
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From: OSTERSUND
I´ve been checking almost everything?
My Aero is a -91 4.0L EFI-fuelsystem 2WD Canadian/European mod.
What i have checked: ACT; MAF; IAC; TPS. And the vaccum lines.
Changed fuel pressure regulator, fuel filter, air filter, parkpluggs and wires.
Still: When cold smooth idle and running at load, but as soon it has warmed up idle starts to backfire but running at load has not changed!
I have god mileage and as I said runs perfectly at load or engine break.
At crusing it is notisable with some shudder, but at for example at a red light it even shudder so hard that it stops on me.
Anyone with an idea or two?
Tiwan.
ps. Do I have a EGR-valve and in that case where have Ford put it on the 4.0L ds.
My Aero is a -91 4.0L EFI-fuelsystem 2WD Canadian/European mod.
What i have checked: ACT; MAF; IAC; TPS. And the vaccum lines.
Changed fuel pressure regulator, fuel filter, air filter, parkpluggs and wires.
Still: When cold smooth idle and running at load, but as soon it has warmed up idle starts to backfire but running at load has not changed!
I have god mileage and as I said runs perfectly at load or engine break.
At crusing it is notisable with some shudder, but at for example at a red light it even shudder so hard that it stops on me.
Anyone with an idea or two?
Tiwan.
ps. Do I have a EGR-valve and in that case where have Ford put it on the 4.0L ds.
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FTE Community Team
Joined: Nov 2001
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From: Oak Harbor, Washington
Suggestions based upon what you've posted:
a) Vacuum leak. Won't show at cold start because the mixture is darned rich at that time anyway. I had a vacuum lead at No. 6 injector seal on my '90 3.0l a couple of months ago, and it ran much as you describe.
b) Faulty injector. On a warm engine, perform cylinder balance test. See this post.
Regards,
Al S.
a) Vacuum leak. Won't show at cold start because the mixture is darned rich at that time anyway. I had a vacuum lead at No. 6 injector seal on my '90 3.0l a couple of months ago, and it ran much as you describe.
b) Faulty injector. On a warm engine, perform cylinder balance test. See this post.
Regards,
Al S.