idle problem

[caRalliArt]

I took my evoX fmic off and replaced it with the stock one.Now the car doent idle very well.It tries to die.The rpms bounce between 500 and 1000.What is causing this? I checked the intercooler and pipes.They all seem to be on and tight. Is this a vacume leak?

[wwralliart77]

Make sure the line to the fuel pressure regulator didn't come off; that causes the afr to lean out and could cause your engine to stall and potentially blow. If you're tuned, were you tuned with the larger ic? If so that could pose a potential problem, since you were programed to receive a larger amount of air.

[caRalliArt]

It drives fine.But it doesnt idle.If the fpr line came off wouldnt it run like crapp?

[highcaliber]

Mine would do that from time to time after a long (2+hr) drive. After I got my evo x I/C, BOV etc installed and had it tuned, it stopped and hasn't had a problem since. The MAF sensor in the RA is stupidly sensitive, to the point where even changing from the factory airbox causes the check engine light to come on. (I'm sure you knew that already so I'm not intending to lecture here) so I wonder if changing from the larger (and likely less restrictive) evo I/C to the smaller stock I/C with smaller piping might cause it to freak out?

Did you have a tune when you had the evo I/C in? If you did, and you went back to stock, you might need to have the car re-tuned to stock.

or I might be full of hot air...

[KrazyRA]

I would say change the tune back to stock with stock pill. or your MAF sensor went bad. That sounds like how mine was and they replaced the MAF sensor went back to normal.

[wwralliart77]

So you removed all your mods and went back to stock since you were/are planning on selling your RA? You are now having some idle issues since you swapped out your ic.

If you were tuned for certain mods that are no longer installed, the vehicle still thinks they are there and tries to compensate. Which is the most likely cause of your idle issues. +1 on reloading your stock map being your best bet.

[MTZL]

Evo X GSR & MR has the same idle issues.
I think it has to do with fast acceleration & deceleration.
Every performance car has idle problem after fast acceleration & deceleration.

I put it Neutral anytime I come to full stop. Idle better than in 1st gear.
I remember seeing idle stabilizer or some sort. I need to further educate myself before I mislead yal. :rolleyes:

[caRalliArt]

It never had this idle problem before.I flashed back to the gst 91 base flash.still have problem.any ideas?

[MTZL]

Maybe vacuum line?

Pic of your engine bay?
List of mods?

Does the problem still exist putting it in neutral?

[caRalliArt]

Genius.I looked really hard at all the vacume lines and found the fuel pressure regulators vc line was unplugged.good tip.thanks

[BravoZero]

Genius.I looked really hard at all the vacume lines and found the fuel pressure regulators vc line was unplugged.good tip.thanks

Glad you found the problem. How could that have happened?

[MTZL]

Glad to hear its taken care of.

[caRalliArt]

I must of accidently knicked it off.its dierectly under the uicp.I noticed the hose has no clamps.I recommend everyone put some zipties or clamps on it

[TrailBrake]

I know this is an old thread, but does anyone have pics that show the vac lines mentioned? Just this week I had some random idle issues, and I wanted to double-check a line hasn't popped off.

[KyleKitchen]

I know this is an old thread, but does anyone have pics that show the vac lines mentioned? Just this week I had some random idle issues, and I wanted to double-check a line hasn't popped off.

First, take off your spark plug cover.
(the big plastic piece that says MIVEC Turbo on it and covers your motor)

On the front passenger side of the motor attached to your fuel rail there is a little silver check valve looking thing with a hose coming off it and connecting to the intake manifold.
That's the fuel pressure regulator valve.
http://i210.photobucket.com/albums/bb261/kirradude1025/modp_0907_06_o2008_mitsubishi_lancer_evo_xengine_b ay.jpg

And also check your vacuum line on your BPV/BOV.
That line goes to your intake manifold too.
http://i257.photobucket.com/albums/hh206/ksquaredcripple/Boost%20Contoller%20Stuff/BPVline.jpg

Either of those can cause your issue.
Especially the BPV/BOV vacuum line.

[TrailBrake]

Excellent. Thank you kindly. All my lines are secure.

[KyleKitchen]

Excellent. Thank you kindly. All my lines are secure.
Good to hear!

If you're still idling weird, I'd check a few other lines too.
Better to be safe than sorry! ;)

http://i257.photobucket.com/albums/hh206/ksquaredcripple/Boost%20Contoller%20Stuff/bcpic.jpg
http://i257.photobucket.com/albums/hh206/ksquaredcripple/Boost%20Contoller%20Stuff/ElbowLine.jpg
http://i257.photobucket.com/albums/hh206/ksquaredcripple/Boost%20Contoller%20Stuff/wgline.jpg

[TrailBrake]

Great, thanks. I'm going to save these images in the event the site crashes again ;)

[TrailBrake]

I'm going to go out on a limb in this posting, but I have noticed a pattern that seems a little outside the norm. This is only my personal findings, and I was wondering if anyone else had found this.

There are no loose vac lines, no codes, and I have tried two different MAFs. My battery is Optima Red Top with excellent measured output. The results remain the same:

Over time, my car begins to run a little off (rougher/less stable idle, more jerky/less responsive shifting, and overall decreased performance). My solution has been to force ECU adaptation every 8 weeks or so. This is the general timeframe between my car running great and being a little off.

Here is the adaptation mode steps I follow, which are consistent with what I have seen in the factory manual, and also matches adaptation for early 90s Bosch LH & EZK ECUs.

- warm car up to proper operating temperatures
- disconnect battery ground strap
- wait a few mins
- reconnect battery ground strap
- let car idle in park (no accessories on) for 5-10 mins
- go for a spirited drive

If I do this adaptation every 2 months or so, the car is fine. Every time I let it go past about the 2 month mark, the car runs a little 'funny'. To some this might sound like BS, and that's fair enough. All I know is it's a repeatable pattern I have seen since buying the car in Dec 2010, so there must be something to it.

My car is a early '09 Ralliart, which was delivered in January '09. Does this sound like an ECU bug, or is there more to this equation?

[BravoZero]

I'm going to go out on a limb in this posting, but I have noticed a pattern that seems a little outside the norm. This is only my personal findings, and I was wondering if anyone else had found this.

There are no loose vac lines, no codes, and I have tried two different MAFs. My battery is Optima Red Top with excellent measured output. The results remain the same:

Over time, my car begins to run a little off (rougher/less stable idle, more jerky/less responsive shifting, and overall decreased performance). My solution has been to force ECU adaptation every 8 weeks or so. This is the general timeframe between my car running great and being a little off.

Here is the adaptation mode steps I follow, which are consistent with what I have seen in the factory manual, and also matches adaptation for early 90s Bosch LH & EZK ECUs.

- warm car up to proper operating temperatures
- disconnect battery ground strap
- wait a few mins
- reconnect battery ground strap
- let car idle in park (no accessories on) for 5-10 mins
- go for a spirited drive

If I do this adaptation every 2 months or so, the car is fine. Every time I let it go past about the 2 month mark, the car runs a little 'funny'. To some this might sound like BS, and that's fair enough. All I know is it's a repeatable pattern I have seen since buying the car in Dec 2010, so there must be something to it.

My car is a early '09 Ralliart, which was delivered in January '09. Does this sound like an ECU bug, or is there more to this equation?

Interesting... how many miles do you put on the car during those 8 weeks, on average?

So you're saying during the "ECU relearn" period, everything is fine, but after the initial relearn period is done it starts running rough?

[TrailBrake]

Interesting... how many miles do you put on the car during those 8 weeks, on average?

So you're saying during the "ECU relearn" period, everything is fine, but after the initial relearn period is done it starts running rough?

On average, I drive about 1000km (600 odd miles) in an 8 week period. The car runs well after the ECU relearn, and continues to run well for the duration of 8ish weeks. After that point, the the car feels off, so I do the ECU relearn and all is well again.

When I posted earlier about a rough idle, I hadn't done an ECU relearn for about 9 or 10 weeks, and wanted to see if I could break the cycle. Once again, I had no codes and no vac line leaks. ECU relearn got the car back to a well-performing state.

This is a little frustrating, but not a real show-stopper. I was just wondering if anyone else had noticed this.

[MTZL]

Ever put your RA in neutral coming to a stop?
I have notice I solve all idle problem after "spirited driving"

[TrailBrake]

Thanks for the tip. I don't believe I've tried shifting to neutral, but I will certainly give it a shot the next time idle goes wonky. ;)

[TrailBrake]

My problem ended up being the throttle body/throttle position sensor (as the two are attached and can not be replaced independently on our cars).

When the idling really started to surge (after some heavy use of the gas pedal), the darn thing finally generated a code (P2135). Prior to this there had been no codes.

In the end, replacing the unit rectified the issue.

[TxRalli09]

Lucky i had an idle issue recently turned out the timing chain had stretched i wish was it was just a disconnected line... would have saved me a lot of money

[Skyline Fever]

My car does this sometimes, and I never modded it once.
I love my car, but I always knew it wasn't the most precisely built car out there. Flame away, but I wished Honda made a rally car.