FutureX 2001

It's been the number one issue on my car and it's starting to get to me. Calling on any mechanics for guidance...I'm probably going to end up taking it into a shop soon.

Problem/Scenerio:
You're driving, as you let go of the accelerator to where the RPMs should fall below 1k, the Idle surges back up and holds at anywhere between 1100-1600rpm. If you do not hold the brake while that occurs the car will drive itself, the idle/acceleration never goes down. You can drive without giving it any gas. At a constant RPM rate.


RPMs DO NOT fluctuate. They do not bounce up and down while idle, they just stay high after an initial surge.

This is NOT an idle adjustment issue. I have a helm and I have attempted to follow the flowchart. The first time this occured (a while back) I narrowed it down to the Fast Idle Valve (which the helm says should not be adjusted, it's factory adjusted), I replaced it and the problem went away. It's been months since then and the problem has returned.




What I know:
-Problem only occurs in drive gears (Reverse, D4, D3, 2, 1). Does not occur in P, N. In fact if the RPMs are too high, I can shift it into neutral or park, the RPMs will temporarily surge even higher, than fall down to about 650 (normal range) I can then put it back into drive and the rpms stay low. Until next acceleration that is...

Video Example:




Things I have checked, Ruled out:

1) Idle speed set too high- This is not the problem, I calibrated this when the car was previously in working condition- and it normally (when not malfunctioning) rests at ~650rpm.

2) Throttle Body sticking, doesn't seem to be the problem, removed it to clean and test the TPS sensor as well.

3) EAVC sticking or malfunctioning. Initially I thought this was the problem, there is NO check engine light however. Swapped EAVC with known working EAVC problem continues.

4) Fast Idle Valve. According to the test in the helm it is functioning, this part was replaced with a dealer part less than 5months ago to fix the SAME problem in the past...but I swapped it yet again just for testing purposes with an EBAY one, problem continues.


5) Replaced the ECU, I swapped the Bayou ECU with my Stock one for testing purposes, no change.

6) Purged the cooling system again with heater set to full and car at normal operating temp, no change.

7) Inspected throttle/cruise cables, seem fine- even disconnected them and re-set them.

8) PCV acts fine per helm instructions

Don't see any damaged hoses...

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ari_one

You didn't mention it but am I right in assuming you've bled the cooling system with heater on, right?

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reboticon

^^ That was going to be my question.

I would check the vac hoses by the control box on the firewall, and the ones right near there that attach to the vacuum actuators on the intake. I think they are 8 and 10.

Type I or Type II?

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Fixing legends is easier than fixing lolcats, but the parts are way more expensive..

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FutureX 2001

*added to initial post*

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fuzzy2k3

thats is crazy
Im no expert so other can correct me if Im wrong, doesnt bad VSS cause erratic RPM fluctuations?

sr5guy

Sounds like a sticking throttle cable (or cruise) that might be getting pulled on when the motor torques up in gear. Disconnect both throttle cables and test it.

Don't forget to investigate the obvious.

To investigate fast idle valve: Have a friend put the car in drive and see if there is suction on the fast idle valve pipe (the largest tube that runs into the intake). Just put your thumb over it and see if it sucks on it - it shouldnt have any suction after the car's warmed up.

-Matt

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The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

FutureX 2001

About 5 months ago, I used that exact same method to test my fast idle valve, because I had the same exact symptoms as I do now. It was in fact sucking air in at that time while warmed up, so I went ahead and replaced it with a dealer part. The problem went away, now the problem is back 5months later....but this time it's not sucking any air while warmed up. How can I check the cables, are they in the HELM as well?

----

And the person who talked about the VSS: No, the VSS is erratic reporting of the Speedometer, our GS had that problem about 4-6 years ago, and I got that taken care of... Not the same issue.

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sr5guy

I ninja edited my above post while you were responding.... lol disconnect the cables.

If the valve is new and its doing the same thing there is a possibility that there is an air bubble in the system somewhere or a blocked coolant passage or hose preventing hot coolant from getting to the fast idle valve.

-Matt

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The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

sr5guy

I know its easier said than done but try pulling the strut bar off and see if you can feel the temperature of the hoses going to the valve. This is of course after you've determined if its sucking when in gear. Also try banging on the valve with a small hammer with engine on, heater on and bleeder open to dislodge any air bubbles.

-Matt

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The dude with a chip on his shoulder.

Stop asking me to compare my chip with Telion's damnit. Mines better.

FutureX 2001

I thought about the Throttle cable today and was looking at the helm.

If the throttle cables were sticking, wouldn't the problem also occur in Neutral/Park....because there is no problem in those positions when I accelerate and let it idle

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FutureX 2001

Updated...

Problem Persists. Checked Accel/Cruise cables. Completely removed Throttle Body and cleaned it out, tested the attached TPS sensor for dead spots. Re-bled the system again. Removed the EAVC cleaned it up a bit and the air boost valve above it. Swapped the ECU with the original stock one, no change.....

Don't know what to make of it...next stop mechanic I guess. is there a Transmission control module? I noticed something that says KA AT near the ECU itself, to the right by where the glovebox is.... really don't know what cause is.....Transmission Shifts fine....

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MarcD

I have not messed with the Fast Idle Thermo valve on the legend, but have on some 4th gen accords. I remember having a high idle and removing the top cover of the valve and turning the top of the plunger clockwise (has a screwdriver slot) brought the idle back down, Seems like sometimes the valve can back itself out some and cause a high idle. Just a hunch...

mellofelow

FutureX. Why don't you take your car to this shop. They specialize in Acuras. It's not far and they're probably more knowledgeable than dealership. What do you think? Let me know if you want to stop there because I may want them to do my clutch.

Honda & Acura Auto Specalist La Puente, California - L&T Japanese Automotive

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STROMUNG end of summer '08 GB

MarcD

You can also check the PCV valve to make sure it is working ok and also you may possibly have a vacuum leak- try spraying some throttle body cleaner around the vacuum lines and see if that causes any stumbles in idle

FutureX 2001

*moved to initial post*

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