Question about 1990 Ford F250

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My 1988 f150 does the same thing..idling problem!

When the engine is hot or cold it will idle really high and guzzle alot of fuel..i changed the idle air control valve and nothing changed,but when i disconnect the idle air valve the problem goes away..im thinking the computer is telling the valve to function improperly, so the computer may have a short, but i dont know for sure ..Help me out plz!

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Having the proper thermostat in fuel injected vehicles is very important.They have a engine coolant sensor to tell the computer the temp of the coolant. If the engine is running too cold,(or cold all the time), the computer is going to tell the idle motor to raise the idle and to give it more fuel, which can damage the cat converter. These vehicles need a 192-195 degree thermostat. Also check the TP sensor (throttle position sensor for proper voltage) the green wire should read .7 to 1.00 volts.

Posted on Oct 07, 2009

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High idle gmc 1988 s15 poor fuel economy no check engine light


Change the temperature control sensor to the front if the engine near radiator
1 start the truck let it run till you think it is at normal operating temperature
2 unplug the temp sensor if the idle changes then the sensor is bad

Feb 08, 2014 | 1988 GMC S-15

1 Answer

How to set idle speed of toyota yaris


no year, no joy (3 generations and 3 base designs)
first off all modern cars there is no idle set.
that ended back in 1988 with carbs. USA, all my posts are for
USA Cars, if you are not USA< then now the time... to say so.
on EFI cars, the idle is controlled by the ECU at all times.
its one of its major hard jobs.
and is the last thing top work right on all EFI cars.

so, to work on any car, the first thing is to
open hood and find out which of 6 engines, it has.

that is first. after checking all fuses)
the 1999 is the first car, and all 1999+ here are OBD2 engines
and ECU controls idle. totally. at ALL times.
post the symptoms ???

1: what year?
2: what engine. there are many.
3: is the CEL , check engine glowing running
yes, then scan it, to see the DTC errors.
4: is idle to low, say RPM hot or cold engine.
5: is idle too high, say rpm ,hot or cold
6: is idle out of control , varies. hot?


why not post the symptoms and let us guide you on the correct path.




Dec 28, 2013 | Toyota Cars & Trucks

1 Answer

How to adjust idle?


hot engine ?, cold or both,, EFI runs in 3 modes, cold ,warm and hot.

name it.

which engine option (displacement)??????



there is no idle adjust, that is the PCMs, job 100%, all the time.

Carbs are gone.

here is rule one for all EFI.

idle is the last thing to work correctly.

anything the causes a gross imbalance of engine power to engine load, under idle will cause , idle controls to fail.



low idling causes. (over 50 but, here ar basics)

1: AFR (air fuel mixture too lean) usually surges. (clogged or leaking injectors. or fuel pressure way to high)

2: air leaks, cause racing, so not that. (speed density car ,if is)

3: egr stuck open. low idle and misfire.

4: ISC stuck closed (IAC electric)

5: cam belt slipped, timing retarded, compression at 1/2 spec, and well, valve will bend soon....

6: CEL glowing running? can be in limphome, limp cancels Idle controls (in may cases) RTM read the FSM on DTCs.



if fails hot?, is hot = 180F temp or more? "thermometer time"

if not, the PCM goes , quite nuts.

Dec 23, 2013 | 2010 Honda Civic LX

1 Answer

Car engine idles really high then really low, why?


It can be issue with IAC( idle air control valve) causing the problem.


There are many other possibilities causing these idle issues. Engine idles rough.

There are few help links with solutions to troubleshoot such idle issues.

I suggest you refer the link below and follow its troubleshooting details:------

Click the link below:-----

Ford Expedition IAC valve replacing

http://technoanswers.blogspot.com/2012/12/ford-expedition-iac-valve-replacing.html

Bad miss at idle?

http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html

-----------

Stumbling and stalling at idle after engine rebuild?

http://schematicsdiagram.blogspot.in/2012/03/stumbling-and-stalling-at-idle-after.html

------------

1999 Ford F-150 Idles rough and quits when gas pedal is pressed less?

http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html

---------

Engine stumbles coming off idle when warm?

http://repairhelpcenter.blogspot.com/2012/01/engine-stumbles-coming-off-idle-when.html

------------------

Erratic idle on car?

http://schematicsdiagram.blogspot.com/2011/12/erratic-idle-on-car.html

-----------


Cold start problem and vehicle shudder around 2500 to 3500 rpms

http://repairhelpcenter.blogspot.com/2012/10/cold-start-problem-and-vehicle-shudder.html

----------

Low idle when cold out side?

http://repairhelpcenter.blogspot.com/2011/12/low-idle-when-cold-out-side.html

-----------

GMC Sonoma Stalls and idles low

http://technoanswers.blogspot.com/2012/10/gmc-sonoma-stalls-and-idles-low.html

--------


GMC Idle Air Control (IAC) Valve Replacing?

http://schematicsdiagram.blogspot.com/2011/12/gmc-idle-air-control-iac-valve.html

-------------

1996 Camry intermittent engine failure while idle?

http://repairhelpcenter.blogspot.com/2011/10/1996-camry-intermittent-engine-failure.html

------------

Engine quits at idle?

http://repairhelpcenter.blogspot.com/2011/10/engine-quits-at-idle.html

-----------

Car overheats and Air blows hot at idle?

http://howtobyme.blogspot.com/2011/11/car-overheats-and-air-blows-hot-at-idle.html

---------

High Idle Problem

http://repairhelpcenter.blogspot.com/2012/10/high-idle-problem.html

-------

While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

---------

Idle flair is noticed on car? Rough idle? car will not idle? Erratic idle speed?

http://technoanswers.blogspot.in/2012/02/idle-flair-is-noticed-on-car-rough-idle.html

--------

High rpm in neutral? Inconsistant high RPM in neutral?

http://technoanswers.blogspot.in/2012/02/high-rpm-in-neutral-inconsistant-high.html

-------

Vehicle stumbling at idle and shows code 54?

http://schematicsdiagram.blogspot.in/2012/03/vehicle-stumbling-at-idle-and-shows.html

----------

Rough idle, staling and Erratic shifting?

http://technoanswers.blogspot.in/2012/03/rough-idlestaling-and-erratic-shifting.html

-----------

While stop engine idles like cylinder missing?

http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html

---------

These details will help.

Thanks.

Feb 15, 2013 | 2003 Pontiac Grand Am

1 Answer

The idle jumps when engine is cold from 1000 to 2500 rpms and starts really rough requires pushin gas petal to start


Being efi (electronic fuel injection) the idle should be higher when starting off cold...in the older days, you used to use a choke, a handheld lever that you pulled out to shut off the air to result in a rich mixture...due to cold air there is alot of oxygen molecules, so a choke increases the fuewl mixture to compensate aiming for that 14.7:1 air to fuel mixture ratio


BUT it should not be that high, what is happening is that is dumping too much fuel in and you are having to go WOT (wide open throttle) to prevent a "flooded" condition..

Why ???? Well, it could be a faulty air flow sensor, a faulty or out of adjustment idle control, bad fuel, bad air filter, fuel filter, fuel injectors bad....etc etc

So, more info is required to solve it......when was the car last serviced, and does it only occur when cold, or do you notice that it is hard to start when hot as well.

Sep 27, 2010 | 1992 Honda Prelude

2 Answers

Ford F150 engine backfiring, running/idling rough


I Have a 1999 ford f150 4.6 that back fires and is just running really ruff when idling alot of nack fire a sord of like a pulse going on what is my problem?

Apr 16, 2010 | Ford F-150 Cars & Trucks

1 Answer

ENGINE SURGES AT IDLE


with the engine running lift hood and lisen for a vacum leak and check all your vacum lines. if no vacum leak can be found then replace the idle air control valve.

Apr 16, 2009 | 2001 Ford F150 Styleside SuperCrew

1 Answer

2001 FORD F150 ENGINE SURGES AND DIES AT IDLE


Check all of your vacume lines. If it isn't a vacume line it is most likely the O2 sensor.

Apr 16, 2009 | 2001 Ford Crown Victoria

2 Answers

96 f-150 idles really high


I just solved this problem on my truck after fighting with it for 2 yrs. Mine is the 5.0 though, check your PVC valve and replace if it is bad. After that Take off your IAC and spray down with carb or brake cleaner and scrape all the carbon build up out of it and work the spring inside. you gotta really clean it out though! After that if it's opening and closing easily put it back together and it should work! you might have to adjust the idle a bit to get it all the way. But after doing this my truck went from a 2000 rpm idle down to about a 700! I hope this helps you!!

Mar 12, 2009 | 1996 Ford F150 Regular Cab

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