2004 Taurus High Idle issue

3111 Views 114 Replies 9 Participants Last post by retho78, 5 mo ago

retho78

Discussion Starter · 5 mo ago (Edited)

Hello,

I have 2004 Ford Taurus with high idle issue. I did a live data scan with my OBD2 tool and the RPMs during cold start is approx. 1450 and when driving or at operating temp, it stays around 925. Also, when the AC/heat is on, the RPM drops to around 750 to 800.

There are no check engine light/codes. I sprayed brake cleaner around all the hoses/vacuum lines and it didn't make any difference. I swapped the throttle body & MAF sensors and it didn't resolve the issue. Also, the fuel pressure fluctuates between 39.5 to 41.5, so could it be a bad fuel pressure sensor, faulty fuel injector(s) or the manifold runner control o-ring?

Thanks in advance.

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chartmaker

· #81 · 5 mo ago

The EGR valve can leak in 3 ways.
Suck on the small tube with a bit of hose and the diaphragm should hold the vacuum. Leaking will not effect running. At idle there should be no vacuum on the line from the solenoid.
The exhaust path can leak and let exhaust into the intake at idle and make for rough idle but should not mess with fuel trims.
Air can leak in through those vent holes through the shaft seal and let air into the intake. That would lead to higher fuel trims at idle.

So a exhaust leak through will make for bad idle, slow idle. A leak of air though the haft will make for high fuel trims at idle and may make high idle.
-chart-

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retho78

Discussion Starter · #82 · 5 mo ago (Edited)

I vacuum pressure tested the EGR while idling and the engine stumbled, didn't do the "suck" test though.

retho78

Discussion Starter · #83 · 5 mo ago

So, did the "Suck" test and engine stumbled/idle dropped.

retho78

Discussion Starter · #84 · 5 mo ago

2

Update:

I swapped the EGR valve and cleaned the EGR line, then did a smoke test and smoke was still leaking from the EGR vent holes. Also, check the pulleys with the belt off and didn't notice any binding. Drove it around for few minutes this morning and RPM is still high. Live data scan attached for review.

Wondering if the throttle body itself is faulty.

Rectangle Parallel Beige Font Electric blue

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Architect

· #85 · 5 mo ago

A bit far-fetched but perhaps you can have a careful look at the cruise control cable. I vaguely remember the throttle could get stuck against a loose cruise-control cable after which it cannot fully close. For completeness, the gas and cruise control cables of my 2000 Vulcan:

Motor vehicle Automotive fuel system Air gun Trigger Auto part

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retho78

Discussion Starter · #86 · 5 mo ago

Okay, I'll check it out.

retho78

Discussion Starter · #87 · 5 mo ago

Well, I found a small leak by the IMRC, so ordered a new o-ring. I am hoping that will fix the issue.

Thanks!

rjacket

· #88 · 5 mo ago

retho78 said:
Update:

I swapped the EGR valve and cleaned the EGR line, then did a smoke test and smoke was still leaking from the EGR vent holes. Also, check the pulleys with the belt off and didn't notice any binding. Drove it around for few minutes this morning and RPM is still high. Live data scan attached for review.

Wondering if the throttle body itself is faulty.

View attachment 222250

I know it sounds unlikely but smoke from the vent holes of the new egr valve suggests it is faulty.

I suggest you test the removed egr valve using the methods in the chrisfix video. This will confirm if your old egr valve was faulty.

Then remove the new one and test that.

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retho78

Discussion Starter · #89 · 5 mo ago (Edited)

rjacket said:
I know it sounds unlikely but smoke from the vent holes of the new egr valve suggests it is faulty.

I suggest you test the removed egr valve using the methods in the chrisfix video. This will confirm if your old egr valve was faulty.

Then remove the new one and test that.

Okay, thanks.

retho78

Discussion Starter · #90 · 5 mo ago

I watched Chrisfix's video and tested the old one. The diaphragm is staying in place when I have the vacuum port closed, so appears to be working as designed.

rjacket

· #91 · 5 mo ago

retho78 said:
I watched Chrisfix's video and tested the old one. The diaphragm is staying in place when I have the vacuum port closed, so appears to be working as designed.

For future testing, it may be worth hooking the smoke machine up in the same manner that was done in the South Main Auto video I shared earlier. The mechanic - Eric O - is extremely knowledgeable about how the various systems on vehicles are supposed to work and his diagnostic methods reflect that and avoid false positives.

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retho78

Discussion Starter · #92 · 5 mo ago

Yes, I ran the same set up for smoke testing after watching the South Main Auto video.

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rjacket

· #93 · 5 mo ago (Edited)

I should also have added that the Taurus does a lot of self testing and going by memory, I believe the EGR monitors take the longest to complete (edit it is the EVAP monitors that take longest to complete). You can access the status of these monitors in the mode 6 test in Forscan.

Sometimes, it is only by running these tests that you can uncover a problem. For example, that same test tells you in which cylinder you have misfires regardless of whether you have a code or check engine light.

Running these same "tests" will show you which monitors have not had enough time to complete. That can at least tell you that you should drive more to let the computer collect enough data to advise if there is a problem and for you to get a look at the collected data.

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chartmaker

· #94 · 5 mo ago

OBD-II Monitor Exercised Drive Cycle Procedure
Drive Cycle Preparation overnight resting before starting.
1. Idle vehicle for 15 seconds.
2 Drive at (40 MPH) until ECT is at least (170 F). .
3. Is Inlet Air Temp within (40 to 100 F)? If not stop here.
HEGO
4. Cruise at (40 MPH) for Up To 4 minutes. Executes the HEGO monitor.
EVAP
5 Cruise at (45 to 65 MPH) for 10 minutes (avoid sharp turns and hills) Gas tank ¼ to ¾ full.
Catalyst
6. Drive in stop and go traffic conditions. Include five different constant cruise speeds, ranging from (25 to 45 MPH) over a 10 minute period. Executes the Catalyst Monitor.

EGR
7. From a stop, accelerate to (45 MPH) at ½ to ¾ throttle. Repeat 3 times. Executes the EGR Monitor.

SEC AIR/CCM
(Engine)
8. Bring the vehicle to a stop. Idle with transmission in drive for 2 minutes. Executes the ISC portion of the CCM.

CCM (Trans Auto)
9. From a stop and in overdrive, moderately accelerate to (50 MPH) and cruise for at least 15 seconds. Stop vehicle and repeat without overdrive to (40 MPH) cruising for at least 30 seconds. While at (40 MPH), activate overdrive and accelerate to (50 MPH) and cruise for at least 15 seconds. Stop for at least 20 seconds and repeat step 9 five times. Executes the transmission portion of the CCM.

Misfire&Fuel Monitors
10. From a stop, accelerate to (65 MPH). Decelerate at closed throttle until (40 MPH) (no brakes). Repeat this 3 times. Allows learning for the misfire monitor.
This a summary of Ford drive cycle.
I have had several reset of PCM due to battery install, battery cable and such All except EVAP reset in normal driving is a short time.
EVAP requires gas tank at level noted and outside air temp as noted.
-chart-

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rjacket

· #95 · 5 mo ago

retho78 said:
Update:

I swapped the EGR valve and cleaned the EGR line, then did a smoke test and smoke was still leaking from the EGR vent holes. Also, check the pulleys with the belt off and didn't notice any binding. Drove it around for few minutes this morning and RPM is still high. Live data scan attached for review.

Wondering if the throttle body itself is faulty.

View attachment 222250

The throttle body is quite expensive so you wouldn't want to change it for no improvement.

Your idle is only a little bit high and not causing any problems so at this point it is a question of what benefit is there in spending time and money trying to fix anything but the most obvious, cheap and simple issues eg an o-ring.

retho78

Discussion Starter · #96 · 5 mo ago

rjacket said:
The throttle body is quite expensive so you wouldn't want to change it for no improvement.

Your idle is only a little bit high and not causing any problems so at this point it is a question of what benefit is there in spending time and money trying to fix anything but the most obvious, cheap and simple issues eg an o-ring.

Yes, going to replace the o-ring on the IMRC and drive some miles, and go from there.

rjacket

· #97 · 5 mo ago

retho78 said:
Yes, going to replace the o-ring on the IMRC and drive some miles, and go from there.

I've attached the diagnostic tests for the air intake system including for issues that are not setting codes. I think you've either checked or changed parts to do with most of these, but might be worth reading through for the sake of completeness and the specific details they say to look for.

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retho78

Discussion Starter · #98 · 5 mo ago

Update:
Replaced the IMRC O-ring and it's still leaking. I think the intake is warped and not sealing properly 🙄

I might look into buying a used upper intake manifold and throttle body on ebay or junk yard, and swap it out in the summer.

rjacket

· #99 · 5 mo ago

retho78 said:
Update:
Replaced the IMRC O-ring and it's still leaking. I think the intake is warped and not sealing properly 🙄

I might look into buying a used upper intake manifold and throttle body on ebay or junk yard, and swap it out in the summer.

Since I don't have an IMRC, I don't know much about it but I did read that it has a tendency to get sludged up to the point that Ford rewrote the strategy to cycle it at lower speeds so it wouldn't get stuck. I think your driving pattern was generally detrimental to a clean intake so I wonder if there is some sort of issue there.

Also, I know you've cleaned the throttle body, but did you actually remove it so you can inspect it from the other side and see what the fit of the butterfly valve is to the bore? I think that shining a light through it might help to see if there is an issue.

Additionally, with the air intake accordian removed, and the throttle return spring, accelerator cable and cruise control cable removed, have you checked the actual action of the butterfly valve if you manually operate the butterfly valve.

With the accelerator cable reattached, how does the valve move and come back to close if you have a helper press the pedal?

With the air intake accordian reattached but the throttle cables unattached, is the warm idle still too high?

Also, what LT fuel trims at warm idle are you currently seeing? Best to provide that snapshot after a long drive rather than just a 5 minute warm up.

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Automender12345

· #100 · 5 mo ago

retho78 said:
Update:
Replaced the IMRC O-ring and it's still leaking. I think the intake is warped and not sealing properly 🙄

I might look into buying a used upper intake manifold and throttle body on ebay or junk yard, and swap it out in the summer.

I would use some high vacuum grease on the O ring to seal it up. Initially I would say use silicone RTV but there could be two issues with it. Some RTV will damage O2 sensors at least they use to. Second is that gas effects RTV. You can also just use adhesive tape to the joint to see it it changes things.

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