My rant

RyeLou

RyeLou

Club Sponsor
I put new cams and a new intercooler pipe on my car a week and a half ago. My car was untuned obviously between now and then so I never got on it. The first time it was brought to redline was yesterday on the dyno for a baseline pull. The pull went fine, no problems with making power...the problem was with the throttle hanging. Now it's somewhat normal for the throttle to hang for litterally half a second or so and the RPMs to fall off slower than you would expect on the Evo. That is something built into the ECU for emissions...I could deal with that. Mine wasn't anything like that though.

After the car was brought to redline and shut down for the pull, the car decelerated to 4K RPM and idled there. It will idle there for at least 10 to 15 seconds, and while actually driving down the road I have to shift to a higher gear to force the RPM's to drop. Once I get them to about 3250RPM they fall on their own like normal.

I've checked for vac. leaks and nothing. The throttle body is functioning like normal with opening and closing. It isn't dirty at all (I did clean it though) The cable isn't binding up anywhere. The idle speed control was also clean. The baseline pull was just that, so there was nothing done to the previous tune that could have caused this. The tuner did what he could to try to fix it, but nothing seemed to work. After each pull it would do this. When I let off the gas and it holds at 4K the the boost releases like normal and goes to 17 vac, which is normal for decelerating and engine braking. Normal vac at idle without the a/c is about 11. It only seems to do this with some sort of load. If you rev it above 4K in a parking lot it has been falling off like normal. No check engnie light either.

Any ideas? The idle speed control could still be the issue obviously, so I'm trying to find another local Evo to switch theirs with temporarily so I can make sure it's that before I order a $225 tiny ass part.
 
Found a local Evo to switch the IAC with. Changed absolutely nothing... I'm at a total loss right now, I have no idea what it could be.
 
I was going to try the throwing parts at it idea but this shit is expensive! I figured maybe $50 for an IAC that would also go on a fucking Chrysler Sebring. No...list is like $316. My cost through work would be about $200.

I am however going to try replacing the whole throttle body and see if that helps. This is gay as hell. After that I'm just selling the fucker.
 
Since I know everyone is on the edge of theirs seats to see this resolved, I'll post updates as they come in.

Went to work and checked all sorts of sensors, vac lines, throttle cable, etc. etc. Just about to give up and we decide to unplug the IAC totally. And it fixed it. So for one reason or another, the ECU is telling the IAC to idle at 4k under these conditions. It isn't the IAC because I tried another one last night. I'm going to get back with the tuner to see if he can figure anything out in the ECU.
 
RyeLou said:
Since I know everyone is on the edge of theirs seats to see this resolved, I'll post updates as they come in.

Went to work and checked all sorts of sensors, vac lines, throttle cable, etc. etc. Just about to give up and we decide to unplug the IAC totally. And it fixed it. So for one reason or another, the ECU is telling the IAC to idle at 4k under these conditions. It isn't the IAC because I tried another one last night. I'm going to get back with the tuner to see if he can figure anything out in the ECU.
Click to expand...

have him make sure the VSS vs. RPM table isn't all screwy
 
So with last night being a bit cooler my car was having a hard time finding idle when stopped. It actually stalled as I pulled into my spot at home. I had to go back out, so I plugged the harness back into the IAC and let it go through it's relearn. It found idle fine after about 15 minutes of driving. I figured I'd try it again and see if it came back with plugging the harness back in.......and it didn't? I have no idea why, but now the car decelerates normal. I won't say it's totally fixed just yet...I'll give it a few days and see what happens, but for now it's working again.
 
Changing the camshafts could have pissed the ECM off. Any Idea what the idle adaptive learn values are ?
 
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Sean said:
Changing the camshafts could have pissed the ECM off. Any Idea what the idle adaptive learn values are ?
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I don't know off hand, I can try to find out.

I know anything is possible, but that doesn't seem likely. I guess nothing seems likely at this point though.. There are plenty of people with the stock computer who run more aggressive camshafts. Some do it on the stock springs/retainers too.
 
And now I have a check engine light on to top it all off.

P0137 - Low voltage O2 sensor B1 S2. In searching the only people who get this code are when they first change the exhaust and have problems with the O2 sensors. I've had the car now for 6k miles and this is the first time I've had a problem, so who knows.

Anyone want to buy an Evo?
 
RyeLou said:
And now I have a check engine light on to top it all off.

P0137 - Low voltage O2 sensor B1 S2. In searching the only people who get this code are when they first change the exhaust and have problems with the O2 sensors. I've had the car now for 6k miles and this is the first time I've had a problem, so who knows.

Anyone want to buy an Evo?
Click to expand...


pintched wire from the install?
 
igotaneed4speed said:
pintched wire from the install?
Click to expand...

After a minimum of 6k miles? And that's assuming he installed it the day I picked the car up, which I know he didn't.

Jeff, I've already posted a few times in that exact forum...haha. Thanks though. I think to start I need to get with the tuner.


As far as the P0137 code goes, one of the guys at work was looking at Mitchell and it said that code can be caused by a TPS issue... The voltage reads correct from the TPS at idle, but who knows. Maybe under load the voltage is dropping out. It would be easy to test with the scanner, so we'll see.
 
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