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2003 Mitsubishi Evo 8 from hell.....fast idle, dumb Dad
Greetings from Southern California. My son's 2003 Evo with 140k miles has a 15-1600 RPM idle that has alluded me as well as mechanics that charged, but didn't repair.
There are a couple things in the scan data that trouble me, mostly because I probably don't understand them completely. In closed loop with the engine warm Idle Adv shows around 22 degrees, CKP sensor shows 1500-1600 rpm, but CRANK Signal value is NO. Can someone explain the difference between CKP Sensor and CRANK Signal please?
The reason I am focused on the CRANK sensor is because we have looked at just about everything else as listed below. Bypass test done. CKP Sensor responded with rpm change, but CRANK Signal did not change to YES. Sensor was scoped and produced square waves. A few short spikes. Don't know if they are normal (noise) or not. Three wire, 12v power, 5v signal, ground.
NO codes.
Smoked for external vacuum leaks. None found.
TPS sensor checked, tested and calibrated. 566mv
Throttle Body cleaned and checked. Throttle plate fully closes. No idle screw to mess with, only stops.
IAC checked, changed, tested visually and with meter. IAC p
The crank signal parameter probably refers to the start authorization/starter motor command.... when you turn the ignition key to te start position it should show yes as long as you engage the starter motor. Verify this condition and if the pid shows "on" , "active" or something similar during cranking just forget about it.
The spark advance at 1500 rpm looks normal. With the throttle body completly blocked off the motor should die, if it does not then there is unauthorized air making its way into the engine. What engine exactly is in the car. Try to scan it in generic OBD2. If this works out then post comprehensive scan data, best under varying conditions.
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
Thank you for the reply. I will try to post some scan data. Tried OB2 generic. I get some CHECK CODE and that's it. In Autel's defense, they state they support back to 2008, not 2003, but was hoping for more.
I didn't block off the TB, just the IAC ports, but yes I agree it should have made a difference. I have wondered if there is a place with a check valve or similar that doesn't allow smoke through but air gets in from the crank case or somewhere internal. Tried smoking through the air intake and the brake booster and no leaks were detected. Also, I would think fuel trims would show a lean condition, but they do not.
I will run a scan and post it here tomorrow hopefully.
Look for vacuum leaks --- If you don't see anything obvious or blocking of the brake servo hose or crankcase breather dosen't work try Paul's water spray method, simple but very effective another method is t to use a rubber hose as a stephoscope
Higher tech methods are smoke test the inlet or an ultra sonic leak detector.
" We're trying to plug a hole in the universe, what are you doing ?. "
(Walter Bishop Fringe TV show)
