Hi guys,

I've been trying to get my evo running normally for a month now but can't seem to do that so I decided to reach out and ask for help.

My Car: 2003 Mitsubishi Evo (49K miles)
Mods: Tanabe Downpipe, APEXi Air Filter, Fujita Intercooler Pipes with T-Bolt Clamps
Maintenance (Within the Last Month): New Valve Cover Gasket, New Spark Plug Surround Gaskets, New NGK Iridium Spark Plugs

Initial Problem: Idle started dipping low at idle in neutral.
Solution: Replaced the IAC valve with brand new OEM part. Had throttle body serviced (replaced all seals and cleaned) via milspec. Checked MAF and didn't need cleaning. Tightened all intercooler pipe t-bolt clamps. Performed the base idle learning procedure.
Outcome: Engine held base idle and ran great for about 2 weeks with no problems.

Current Problem: When I start my car, my engine holds base idle with no problem. When I drive in 1st or 2nd gear and pop it into neutral to come to a stop, the idle starts dipping below base idle and 1 out of 5 times stalls my engine. When I drive using 3rd, 4th or 5th gear and pop it into neutral to come to a stop, the engine doesn't dip below idle and has no problem holding base idle.

This problem has been hell in traffic. Can anyone please provide some input into this problem? or have any ideas of what it could be?

Thank you in advance for your help.

 

Are tuned? What rom do you have?

It may be in the tune and or BISS. I didn't see a BOV in your mods list, so I'm assuming it's OEM recirculated. Is that correct?

Does it dip down with the AC on/off or both?

 

Sounds like my issue! ^ talk to Christian he's fixing my issue as well.

 

Tune: Stock ECU with factory tune
BOV: Stock Evo 9 metal bypass valve (recirculated)
Dip with/out A/C: Haven't checked this yet but will.

One thing I did notice today was the idle is now slightly rough.. almost like a have mild cams. My evo sputters a little at idle and isn't smooth (one tone).

 

Did this start soon after you installed mods?

Check your maf sensor connector. It could be loose or damaged.

Also do a boost leak test.

It may or may not be the tune, but I would do the above first. After that checks out then you need to log when this is happening to get to the bottom of this.

 

After the car is idling turn it off. Inplug the ISC and turn it back on. Turn the BISS screw out until the idle is a little higher than you would like. That way it will drop to that higher rpm and the ISC will be able to pull it down. If the base is too low and the rpm fall too fast the ISC can't respond fast enough. With the big cams I have mine to naturally fictional 1200 then the ISC pulls it down to 1000.

 

I have the same problem after I swapped ams heads and they can't seem to figure out the solution. Only thing they said i can try at the moment is buying new ecu to see if it fix the problem. The car isn't tuneable and every time goes from gear to neutral, rpm would dip to 500rpm or below and sometimes stalls. We tried boost leak testing, replace bov, replace maf, replace injectors, replace iac...nothing works....

 

I only had an air filter, metal bypass valve and downpipe on the car when the problems began. The intercooler pipes came after the problems. Replaced the stock intercooler pipes and couplers because I thought a hose was shot somewhere.

MAF sensor connector looks solid.

Unfortunately, the RPM dipping when pulling out of gear happens all the time now.

 

Has anybody tried adjusting the idle stepper table, I had similar problems especially with the a/c on but I do have cams and a light flywheel. I adjusted the table a little and it helped

 

Plan on getting a vacuum/boost leak test by the end of the week.

 

Good deal. Keep us updated.

 

sorry about the late reply guys.. only appointment avail was today.

did a vacuum/boost leak test using smoke and nothing. they found a super tiny leak by the throttle body coupler but nothing that would cause the problems i've been having so back to the drawing board.

man... this love/hate relationship with my evo is really getting to me.

 

you need to stop the stepper motor in evoscan then set the biss

 

What would I need from Evoscan? I'm assuming I need the software and a compatible cable? Can someone point me in the right direction?

Thanks in advance.

 

anyone?