Help diagnose a CEL

ecktt · Postby **ecktt** » September 21st, 2011, 6:32 pm

I have a CEL that comes back 5-10 mins after driving every time I clear it. If not cleared, it remains even after a restart. I used EvoScan 2.8 with a OpenPort 1.3 cable to display the DTS but both ODBII EFI and MUTII EFI return nothing. Only clearing the MUTII clears the CEL.

Here a little history that might be relevant. I have a small oil leak on the return line from GT35 turbo. When I took it to the mechanic to fix this past weekend, I noticed the O2 sensor wires we stripped and shorting at the base of the sensor and so could not be fixed. Luckily I had a spare Walker O2 replacement. Unluckily the bloody cable was to short, so I chop the old O2 cable off and T'ed it into the new cable. Around the same time I had idle issues and had to change a mechanically faulty Idle Air Control solenoid. The new one looked different from the old one but works. I am also using a Tephra V7 90550701 ROM on an EVO 7 GSR.

What can this CEL be?

xtech · Postby **xtech** » September 21st, 2011, 10:06 pm

short data port pins an count the flashes.......go online see wat it is

ecktt · Postby **ecktt** » September 22nd, 2011, 6:35 pm

I got the car scanned today. P0400 EGR. This confused me for 2 reasons.

I set the EGR Test bit (P0401) to 0 and also Disabled EGR/Timing Advance Bit to 0. Well see how it goes.

R. Mutt · Postby **R. Mutt** » October 5th, 2011, 4:54 pm

Did it work? That should have fixed it...Tephra mod makes it simple to clear that cel. I've been getting IACV related cel on an VIII GSR (can't remember the code offhand)...cleared it and it comes back. Funny thing is the car idles well.

Wondering if the screw on the base of the tb by the sensor needs to be adjusted?

Kronik · Postby **Kronik** » October 7th, 2011, 10:49 pm

^how much is your iscv steps at when at idle?? ever adjusted the biss screw?

ecktt · Postby **ecktt** » October 11th, 2011, 6:28 pm

R. Mutt wrote:Did it work? That should have fixed it...Tephra mod makes it simple to clear that cel. I've been getting IACV related cel on an VIII GSR (can't remember the code offhand)...cleared it and it comes back. Funny thing is the car idles well.

Wondering if the screw on the base of the tb by the sensor needs to be adjusted?

Yes, it stopped the CEL but now cold idle is horrible. I have to play with Idles table soon to up the values. I think +10% in the cold region should stop her from sound like a 1st gen RX.

R. Mutt · Postby **R. Mutt** » October 17th, 2011, 6:33 pm

ecktt wrote:
R. Mutt wrote:Did it work? That should have fixed it...Tephra mod makes it simple to clear that cel. I've been getting IACV related cel on an VIII GSR (can't remember the code offhand)...cleared it and it comes back. Funny thing is the car idles well.

Wondering if the screw on the base of the tb by the sensor needs to be adjusted?

Yes, it stopped the CEL but now cold idle is horrible. I have to play with Idles table soon to up the values. I think +10% in the cold region should stop her from sound like a 1st gen RX.

That and the screw kronik mentioned are the two good points of focus...though I've never played with the latter it's said to resolve many idle issues. Also, sometimes the sensor just needs some cleaning if you're car is older.

Was any of this related to the super you put in or are they mutually exclusive issues?

ecktt · Postby **ecktt** » October 26th, 2011, 10:11 am

R. Mutt wrote:That and the screw kronik mentioned are the two good points of focus...though I've never played with the latter it's said to resolve many idle issues. Also, sometimes the sensor just needs some cleaning if you're car is older.

Was any of this related to the super you put in or are they mutually exclusive issues?

Kronik wrote:^how much is your iscv steps at when at idle?? ever adjusted the biss screw?

I'll see what my mechanic can do about the cleaning and tinkering about the biss screw as i'm not confident in doing those things. My iscv(s) are about 65% lower from stock v7 otherwise she'll cold idle at 2000rpm and gradually come down with the Delphi 1200cc injectors.

I want to believe all things may have been related because of the time line but there is no proof to support that. She's back on 0w20 oil and warms up quickly now so the cold idle doesn't bother me long enough to warrant a re-flash.

Kronik · Postby **Kronik** » October 26th, 2011, 10:40 am

there was a fix for the cold idle problem, mine starts and idles normal after a bit of adjustment to the ISCV demand adders. but you need to disable the iscv, adjust your biss screw, enable back the iscv and adjust the steps to suit your desired rpm.

do a log and see how much the ISCV steps are at idle, when my biss screw was adjust incorrectly (that was me digging up before i knew about it or had a cable), the ISCV was doing like 60 steps to keep idle rpm and that caused a CEL and returned idle control error code

ecktt · Postby **ecktt** » November 5th, 2011, 2:37 pm

I'll have to do that. this past week, she started hunting between 1100 and 1600 RPM when cold. The thing is, as soon as temp gauge reads 1/4 way, its like a switch and then she idles perfectly.

Kronik · Postby **Kronik** » November 5th, 2011, 10:30 pm

well then you need to check what your Min Coolant Temp for Closed Loop is set to. if you have it defined, if you dont i will give you the address.

also check how your warmup ignition map is setup