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Next: 2000 Ford Taurus With No Heat
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 1) Posted: Sat Oct 20, 2007 9:45 am
Post subject: 93 Taurus Idles Too High
Archived from groups: alt>autos>ford (more info?)
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Hi all, sure hope someone can point me in the right direction.
My Taurus GL, 3.0L auto runs great, when its happy, but lately what I
am having is really high idle speeds after driving it for a while.
Start it up, drive a bit till its warm, and it idles as expected. Keep
driving, and sooner or later, within ten minutes or so, when I get to
a traffic light or whatever, the engine doesn't idle down to normal,
but hangs way up there, like maybe closing in on 2000 rpm. (hard to
guess) Makes life really interesting when I try to stop it 
I pull over, pop the hood, and try to force the throttle closed as a
test, but it is closed all the way, no doubt about it.
Turn off the engine, and then start it back up, and its idling
normally again. Sometimes it will repeat after a while, other times,
it runs fine.
I have cleaned the throttle area to make sure no gunk is hanging
things up, and even used a toothbrush on the inside of the throttle
body around the blade. The cable is not binding.
I am not at all familiar with how the computer controls the engine
speed beyond the throttle position sensor and am thinking the idle air
control valve, but everything I have read, tells me the IAC will cause
low idle speeds, not very high ones. I was told that if I unplug the
IAC, and the engine stalls, its probably working okay, but perhaps
that is a faulty statement?
I have a shop manual, but the idle control ckt is apparently
addressed in the emissions control manual, which I cannot find for
less than $275, so I am hoping someone might have an understanding of
what controls what, and where I should be looking? Odd that turning
the car off and then restarting "fixes" the problem, so I am thinking
electrical, somewhere, but not sure where.
There is no check engine light, and no trouble codes when I have it
checked.
Any advice would be appreciated,
John |
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External
Since: Jun 22, 2003
Posts: 559
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(Msg. 2) Posted: Sat Oct 20, 2007 5:49 pm
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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The IAC is just as capable of giving a high idle as it is a low idle....
When we start driving, the IAC moves to full open... this allows it to
slowly close when the throttle is closed giving a "dashpot" effect..... The
spring and the solenoid in this device are only so strong and it doesn't
take much to make the spool hang in the bore....
Of course, we have checked to see if there are any DTCs in the PCMs memory,
right?
"John" wrote in message
> Hi all, sure hope someone can point me in the right direction.
>
> My Taurus GL, 3.0L auto runs great, when its happy, but lately what I
> am having is really high idle speeds after driving it for a while.
>
> Start it up, drive a bit till its warm, and it idles as expected. Keep
> driving, and sooner or later, within ten minutes or so, when I get to
> a traffic light or whatever, the engine doesn't idle down to normal,
> but hangs way up there, like maybe closing in on 2000 rpm. (hard to
> guess) Makes life really interesting when I try to stop it
>
> I pull over, pop the hood, and try to force the throttle closed as a
> test, but it is closed all the way, no doubt about it.
>
> Turn off the engine, and then start it back up, and its idling
> normally again. Sometimes it will repeat after a while, other times,
> it runs fine.
>
> I have cleaned the throttle area to make sure no gunk is hanging
> things up, and even used a toothbrush on the inside of the throttle
> body around the blade. The cable is not binding.
>
> I am not at all familiar with how the computer controls the engine
> speed beyond the throttle position sensor and am thinking the idle air
> control valve, but everything I have read, tells me the IAC will cause
> low idle speeds, not very high ones. I was told that if I unplug the
> IAC, and the engine stalls, its probably working okay, but perhaps
> that is a faulty statement?
>
> I have a shop manual, but the idle control ckt is apparently
> addressed in the emissions control manual, which I cannot find for
> less than $275, so I am hoping someone might have an understanding of
> what controls what, and where I should be looking? Odd that turning
> the car off and then restarting "fixes" the problem, so I am thinking
> electrical, somewhere, but not sure where.
>
> There is no check engine light, and no trouble codes when I have it
> checked.
>
> Any advice would be appreciated,
>
> John
> |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 3) Posted: Sat Oct 20, 2007 6:02 pm
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Oct 20, 11:49 am, "Jim Warman" wrote:
> Of course, we have checked to see if there are any DTCs in the PCMs memory,
> right?
Acronyms kill me As I mentioned, I hooked it up to the code
reader, and it reported nothing. Is that what you mean by DTCs in the
PCM? Is there more to check than using just the OBD1 reader?
>
>
>
> > Hi all, sure hope someone can point me in the right direction.
>
> > My Taurus GL, 3.0L auto runs great, when its happy, but lately what I
> > am having is really high idle speeds after driving it for a while.
>
> > Start it up, drive a bit till its warm, and it idles as expected. Keep
> > driving, and sooner or later, within ten minutes or so, when I get to
> > a traffic light or whatever, the engine doesn't idle down to normal,
> > but hangs way up there, like maybe closing in on 2000 rpm. (hard to
> > guess) Makes life really interesting when I try to stop it
>
> > I pull over, pop the hood, and try to force the throttle closed as a
> > test, but it is closed all the way, no doubt about it.
>
> > Turn off the engine, and then start it back up, and its idling
> > normally again. Sometimes it will repeat after a while, other times,
> > it runs fine.
>
> > I have cleaned the throttle area to make sure no gunk is hanging
> > things up, and even used a toothbrush on the inside of the throttle
> > body around the blade. The cable is not binding.
>
> > I am not at all familiar with how the computer controls the engine
> > speed beyond the throttle position sensor and am thinking the idle air
> > control valve, but everything I have read, tells me the IAC will cause
> > low idle speeds, not very high ones. I was told that if I unplug the
> > IAC, and the engine stalls, its probably working okay, but perhaps
> > that is a faulty statement?
>
> > I have a shop manual, but the idle control ckt is apparently
> > addressed in the emissions control manual, which I cannot find for
> > less than $275, so I am hoping someone might have an understanding of
> > what controls what, and where I should be looking? Odd that turning
> > the car off and then restarting "fixes" the problem, so I am thinking
> > electrical, somewhere, but not sure where.
>
> > There is no check engine light, and no trouble codes when I have it
> > checked.
>
> > Any advice would be appreciated,
>
> > John >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Aug 22, 2007
Posts: 66
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(Msg. 4) Posted: Sun Oct 21, 2007 12:46 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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John wrote:
> Hi all, sure hope someone can point me in the right direction.
>
> My Taurus GL, 3.0L auto runs great, when its happy, but lately what I
> am having is really high idle speeds after driving it for a while.
>
> Start it up, drive a bit till its warm, and it idles as expected. Keep
> driving, and sooner or later, within ten minutes or so, when I get to
> a traffic light or whatever, the engine doesn't idle down to normal,
> but hangs way up there, like maybe closing in on 2000 rpm. (hard to
> guess) Makes life really interesting when I try to stop it
>
> I pull over, pop the hood, and try to force the throttle closed as a
> test, but it is closed all the way, no doubt about it.
>
> Turn off the engine, and then start it back up, and its idling
> normally again. Sometimes it will repeat after a while, other times,
> it runs fine.
>
> I have cleaned the throttle area to make sure no gunk is hanging
> things up, and even used a toothbrush on the inside of the throttle
> body around the blade. The cable is not binding.
>
> I am not at all familiar with how the computer controls the engine
> speed beyond the throttle position sensor and am thinking the idle air
> control valve, but everything I have read, tells me the IAC will cause
> low idle speeds, not very high ones. I was told that if I unplug the
> IAC, and the engine stalls, its probably working okay, but perhaps
> that is a faulty statement?
>
> I have a shop manual, but the idle control ckt is apparently
> addressed in the emissions control manual, which I cannot find for
> less than $275, so I am hoping someone might have an understanding of
> what controls what, and where I should be looking? Odd that turning
> the car off and then restarting "fixes" the problem, so I am thinking
> electrical, somewhere, but not sure where.
>
> There is no check engine light, and no trouble codes when I have it
> checked.
>
> Any advice would be appreciated,
>
> John
>
Take off your IAC valve and clean it out with carb cleaner or such.
Check all vacuum lines around the engine and replace any that look cracked.
Bob
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External
Since: Jun 22, 2003
Posts: 559
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(Msg. 5) Posted: Sun Oct 21, 2007 5:40 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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DTC = diagnostic trouble code. PCM = powertrain control module. Sorry for
dumping acronyms on you.... that's just about all we speak in the shop any
more... Some folks look at us like we're speaking in tongues.... 8^)
Shutting the car off will stop the airflow through the IAC... this could be
enough to allow the spring to over come whatever may be hanging the valve
open.... At idle, the PCM never runs the IAC duty cycle up to 100% so the
IAC might not get to the spot on the pintle that is causing the grief.
However, once you are underway, the IAC will be commanded to 100%ish duty
cycle forcing it to full open....
My best suggestion - clean or replace the IAC and re-assess.... >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 6) Posted: Sun Oct 21, 2007 10:35 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Oct 20, 11:40 pm, "Jim Warman" wrote:
> DTC = diagnostic trouble code. PCM = powertrain control module. Sorry for
> dumping acronyms on you.... that's just about all we speak in the shop any
> more... Some folks look at us like we're speaking in tongues.... 8^)
I understand. I spent 25 years as an electronics engineer before I
walked away. I miss the money, but not the acronyms
> Shutting the car off will stop the airflow through the IAC... this could be
> enough to allow the spring to over come whatever may be hanging the valve
> open.... At idle, the PCM never runs the IAC duty cycle up to 100% so the
> IAC might not get to the spot on the pintle that is causing the grief.
> However, once you are underway, the IAC will be commanded to 100%ish duty
> cycle forcing it to full open....
>
> My best suggestion - clean or replace the IAC and re-assess....
That makes sense. I will do that this week. The Taurus shop manual
says not to try to clean the IAC, only replace, but I have had so many
people say they have cleaned it, that I figure its worth a try.
Thanks a lot for the explanation and the advice.
John >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 7) Posted: Sun Oct 21, 2007 10:37 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Oct 20, 11:46 pm, Bob Urz wrote:
>
> Take off your IAC valve and clean it out with carb cleaner or such.
> Check all vacuum lines around the engine and replace any that look cracked.
>
> Bob
Thanks Bob. I guess I will give that a shot. Hopefully it will at
least make a difference, then I won't mind if I have to replace it. So
long as I am confident it is the problem, I don't mind putting out the
cash. Its not a cheap part, considering what it does <g>
Much obliged,
John >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Jan 02, 2007
Posts: 464
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(Msg. 8) Posted: Sun Oct 21, 2007 8:45 pm
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Sun, 21 Oct 2007 10:35:48 -0700, John wrote:
>On Oct 20, 11:40 pm, "Jim Warman" wrote:
>> DTC = diagnostic trouble code. PCM = powertrain control module. Sorry for
>> dumping acronyms on you.... that's just about all we speak in the shop any
>> more... Some folks look at us like we're speaking in tongues.... 8^)
>
>I understand. I spent 25 years as an electronics engineer before I
>walked away. I miss the money, but not the acronyms
But bafflegab is fun! Toss around those $25 words casually and
confuzzle the hell out of everyone!
>> Shutting the car off will stop the airflow through the IAC... this could be
>> enough to allow the spring to over come whatever may be hanging the valve
>> open.... At idle, the PCM never runs the IAC duty cycle up to 100% so the
>> IAC might not get to the spot on the pintle that is causing the grief.
>> However, once you are underway, the IAC will be commanded to 100%ish duty
>> cycle forcing it to full open....
>>
>> My best suggestion - clean or replace the IAC and re-assess....
>
>That makes sense. I will do that this week. The Taurus shop manual
>says not to try to clean the IAC, only replace, but I have had so many
>people say they have cleaned it, that I figure its worth a try.
>
>Thanks a lot for the explanation and the advice.
Of course the shop manual says to replace it, there's profit in just
dropping a new one in, and none from cleaning the old one...
And a cleaning doesn't always cure the problem, so they don't want
dealers cleaning them, it works for a few days, then it acts up again
and the dealer ends up having to replace it for free when the customer
complains.
If it's your money, you don't want to waste it - so try cleaning the
IAC Valve first.
--<< Bruce >>-- >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 9) Posted: Mon Oct 22, 2007 5:37 pm
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Oct 21, 9:45 pm, Bruce L. Bergman
wrote:
> If it's your money, you don't want to waste it - so try cleaning the
> IAC Valve first.
>
Yup, I agree. Its about Ford making money.
I took the valve off today and cleaned it. Didn't make any difference
at all. I was hoping that it would make it a little better, or at
least cause some kind of noteicealbe change, and then I would feel
okay about dropping the $50 or $60 for a new one.
Everything I can find on the IAC seems to relate to low idle, or
stumbling when cold. Haven't seen much of anything that points to the
increased idle after driving for a time. Today I tested it after the
cleanup, and it behaves the same, and always, when I pull over and its
racing, I shut it off, start it up, and its all 'better' until I drive
it again for five minutes or so.....
Unless I can figure out what else might be causing the problem that I
could check, I guess I have to drop the coin and replace the IAC. Just
sucks to buy parts willy-nilly hoping to find the real problem.
<shrug>
Plus that awful feeling you get when you put in the new part, hoping
against hope, and it still does the same thing
I would guess that a vacuum leak would be more consistent, and would
not 'reset' itself after the engine is turned off.
Thanks to all for the great input and comments. Very useful, and I
appreciate it very much.
John >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Jan 02, 2007
Posts: 464
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(Msg. 10) Posted: Mon Oct 22, 2007 10:40 pm
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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On Mon, 22 Oct 2007 17:37:43 -0700, John wrote:
>On Oct 21, 9:45 pm, Bruce L. Bergman
> wrote:
>> If it's your money, you don't want to waste it - so try cleaning the
>> IAC Valve first.
>
>Yup, I agree. Its about Ford making money.
>
>I took the valve off today and cleaned it. Didn't make any difference
>at all. I was hoping that it would make it a little better, or at
>least cause some kind of noteicealbe change, and then I would feel
>okay about dropping the $50 or $60 for a new one.
Did you clean out the chamber that the IAC sets in, and the air
passages in and out of the chamber? If the passages are plugged the
valve can be working just fine but not do anything...
--<< Bruce >>-- >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 23, 2007
Posts: 1
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(Msg. 11) Posted: Tue Oct 23, 2007 12:36 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
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Split the two halves where the rubber hose connects to the intake and
check to see if the passage that connects to the IAC isn't plugged with
carbon. Running a wire or air through there won't do it.
kk
John wrote:
> On Oct 20, 11:46 pm, Bob Urz wrote:
>
>> Take off your IAC valve and clean it out with carb cleaner or such.
>> Check all vacuum lines around the engine and replace any that look cracked.
>>
>> Bob
>
>
> Thanks Bob. I guess I will give that a shot. Hopefully it will at
> least make a difference, then I won't mind if I have to replace it. So
> long as I am confident it is the problem, I don't mind putting out the
> cash. Its not a cheap part, considering what it does <g>
>
> Much obliged,
>
> John
> >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Aug 26, 2006
Posts: 48
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(Msg. 12) Posted: Tue Oct 23, 2007 11:36 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
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Bruce L. Bergman wrote:
> Did you clean out the chamber that the IAC sets in, and the air
> passages in and out of the chamber? If the passages are plugged the
> valve can be working just fine but not do anything...
Throttle position sensor?
--
Mortimer Schnerd, RN
mschnerdatcarolina.rr.com >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 13) Posted: Fri Oct 26, 2007 2:46 pm
Post subject: Re: 93 Taurus Still Idles Too High [Login to view extended thread Info.]
Archived from groups: per prev. post (more info?)
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Well, I appreciate all the pointers and ideas and am back to see if
anyone can think of any place else to look?
I have replaced the TPS and the IAC, and found no difference in the
symptoms. The throttle cable is not hanging, and when the idle heads
up the RPM scale, if I get out and press the throttle blade, it is
most definitely closed, and does not effect the engine speed to press
it 'closed'.
If I just slowly drive around the neighborhood, it doesn't show the
problem, runs fine, and the idle behaves. Its when I go out and run
the speeds up to 40-60 mph, that when I come to a stop, the revs have
climbed and will not come back down. I can then just let off the
brake, and eventually end up in second gear, going 25 mph, its idle is
that high.
What is perplexing is, if I drive on the highway, pull off and the
idle is so high, all I have to do is turn off the key, and restart,
and its back to normal. In fact, just clicking they key off and on,
quick enough to re-catch the engine, does the same thing, and returns
the idle to normal without having to even restart the engine.
I think that rules out any kind of vacuum leak, or mechanical throttle
issue, and points to the computer/sensors/electrical system?
No codes in the computer, and no idea what could make it do that.
There must be a problem with a speed sensor, or something like that,
as I would think that if the car was idling that high and not moving,
the computer would complain about it somehow, wouldn't it?
Where, or what, is the speed sensor for this model? I have no idea
where to look, as I don't comprehend how the whole circuit works, so
any ideas or suggestions will be given my full attention.
Thanks a lot for the help,
John >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Sep 13, 2005
Posts: 123
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(Msg. 14) Posted: Sat Oct 27, 2007 12:06 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
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i would get a scan that shows all sensor values while running if
you can ,and try to interpret if each value is correct.. i have had
several cases there were no codes and running problems did exist
,sometimes in the computer. i dont like the idea about replaceing a
computer , but some fords ive worked on had this problem and a new
computer fixed it .yes i did the test on the sensor values,engine vacume
check, vac line inspect, fuel pressure test ,voltage check on the
system.and a good scan.even did the iac and tps replace as a last ditch
effort, but new computer did the trick.
http://www.minibite.com/america/malone.htm >> Stay informed about: 93 Taurus Idles Too High |
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External
Since: Oct 20, 2007
Posts: 21
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(Msg. 15) Posted: Sat Oct 27, 2007 8:45 am
Post subject: Re: 93 Taurus Idles Too High [Login to view extended thread Info.]
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On Oct 26, 10:06 pm, ds... RemoveThis @webtv.net wrote:
> i would get a scan that shows all sensor values while running if
> you can ,and try to interpret if each value is correct.. i have had
> several cases there were no codes and running problems did exist
> ,sometimes in the computer. i dont like the idea about replaceing a
> computer , but some fords ive worked on had this problem and a new
> computer fixed it .yes i did the test on the sensor values,engine vacume
> check, vac line inspect, fuel pressure test ,voltage check on the
> system.and a good scan.even did the iac and tps replace as a last ditch
> effort, but new computer did the trick.
How did you accomplish the scan of the sensors with it all running?
The OBD1 reader I have isn't that complex. I am not even sure where
to find all the sensors, as the shop manual isn't really for
troubleshooting. I guess I might find more useful info in a chilton or
something, at least for this issue.
I am not thrilled at paying a dealer a million dollars to do such a
test, although I think you did the right thing, and I may be there
soon myself. I having always taken care of my own vehicles, I don't
really know of any shops that I trust to not just replace
everything Being your own mechanic can have its drawbacks I guess
<shrug>
How much was the replacement computer?
Thanks a lot. >> Stay informed about: 93 Taurus Idles Too High |
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