Does anybody know how low.....

[dirtymudder]

The factory idle can be set when the engine is initialy started? I have a 2000 Ford E-150 chateau van with the larger V-8 5.4L?.When I first start the engine it revs high, a lot higher than other newer Fords that I have driven (f-150s,
2000-2002)The engine knocks for a few seconds then settles down. I just don't like how high it revs.Is there a certain RPM they have to stay with or can they adjust it down?

 

[OneQuartLow]

Should be okay into the 5-600 range but warmup is usually toward 1K. In newer vehicles this is under the control of the ECU, possibly with an adjustable mechanical idle bump. During warmup the ecu will run in cheat mode which can expose setup problems. I'd get a factory service manual or visit a friendly dealer and ask to browse.

If it started recently I'd say you have a failing sensor, maybe throttle position or flow. You could visit autozone and ask them to dump codes. That might point to a problem. If nothing turns up then I'd move on to the manual and adjust to spec.

David

 

[MolaKule]

The ECU usually has cold run at 1,200 rpm to 1,500 rpm.

Settling down to around 700 rpm is the norm, all under control of the ECU computer.

If the engine is knocking and then settling down, it sounds as if the engine ECU is leaning out the mixture just after the enrichment cycle for cold run is being executed. It may be leaning out too quickly.

[ December 20, 2002, 03:11 PM: Message edited by: MolaKule ]

 

[dirtymudder]

The knocking I was refering to sounds like the valve lifters, The rev up just seems way to high on the first few seconds of start up.

 

[OneQuartLow]

Lifters usually have more of a ticking sound, if words can describe those things accurately.

I'm assuming the sound happens after the vehicle has been off for a while? Could be caused by too high rpm at startup, not enough oil, or several other things. Figure out the idle and then the sound.

For the high startup rpm, unless someone here has a similar vehicle we might not get better information. I would have an autozone read codes. Something might turn up like a sensor out or on the way. If nothing shows, visit/call a friendly dealer and ask for startup idle information. Ask for the spec from their service manuals. I'm betting something is wrong but without knowing that engine can't say for sure.

David

 

[Patman]

I recently had my rpms jumping much higher on a cold start than I liked, and asked around about having it programmed out, and on the LT1 f-body it can be done, this much I know.

However I eventually found out it was caused by a vacuum leak. Once that was fixed the high idle at start went away.

 

[Bio-T]

One thing you can try is disconnect your battery. While the battery is disconnected, turn on the headlights for a moment and then off. After 20 minutes hook the battery up and start the car. You are resetting your ECU/ECM and it will revert to factory settings. This will not cure any mechanical noises, but it may slow your idle to a more desirable level. Try it, it is only a 1/2 hour job and free, and allows you to clean your battery terminals while you have the cables off.

 

[OneQuartLow]

quote:

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Originally posted by 59 Vetteman:
One thing you can try is disconnect your...

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Good tip. This can work. I've also seen the behavior problems return later if whatever happened the first time recurs, be it a failing component or driving situation. Give it a shot.

One caution though. Some vehicle stereos have security features that are triggered by failed power. When this happens the stereo will be unusable until a dealer code is entered. For that reason I might first stop by autozone for a scan just in case it turns up something obvious.

David