My car has been acting really weird (several posts on it) since I hit the dyno. I've been trying to figure out why it is still acting strange at idle. I'm now starting to wonder if it is just my car camming since this is the first time I've had overlap dialed in with my cams. At first I thought the car was missing but it hasn't thrown any misfire codes in the 500mi of driving with the issues. At idle the exhaust note gives sounds kinda like this....dum....dum,dum...dum. I just don't know if Skunk 1's are aggressive enough to "cam". At cold startup in the mornings the car also has a little idle hunting issue, revs up and down slightly a few times before settling down. Could this just be a fuel issue?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ActiveAero &raquo;</TD></TR><TR><TD CLASS="quote"> At idle the exhaust note gives sounds kinda like this....dum....dum,dum...dum. ?</TD></TR></TABLE>

Sounds like you may have bent valves.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by skunked &raquo;</TD></TR><TR><TD CLASS="quote">

Sounds like you may have bent valves. </TD></TR></TABLE>

If he had bent valves his idle would fall and the car would want to kill. At least that is what I've experienced with bent valves.

Plus, valves just don't bend for no reason, overrevving or mis-shift only. I've been silently following Active's threads regarding this problem and I don't recall there ever being any mis-shifts or overrevving.

 

From what I've seen, I wouldn't classify Stage 1's as "camming" a motor.

 

Damn you seem to be having a lot of problems with your car. Best of luck getting that all worked out man.

 

[QUOTE=92TypeR]

If he had bent valves his idle would fall and the car would want to kill. At least that is what I've experienced with bent valves.

Plus, valves just don't bend for no reason, overrevving or mis-shift only. QUOTE]

Well just to fill you in, when you bend valves slighty it will cause a rough idle as he has described above. In more severe cases the car will not run at all. Also if you read his original post he talked about having these problems since he left the dyno.............that would leave me to beleive the tuner may have adjusted the cam gears too much causing clearence issues resulting in bent valves. Just my 2 cents.

 

Have you tried:

restting your ECU?
Checking your cam gear settings? to make sure they didn't slip
Checking your fuel pressure?
Adjusting your TB ajust screw?

 

what I would suggest to take the bent valve issue out of the picture is this. Mark the current position of both of your adjustable cam gears. then Zero them both out and make sure they are both still level at TDC (to ensure you didnt skip a cog). then run the car and see if you have the same idle issues and noise. if it runs perfect, then go to another tuner and get it done again. If so, you may have a bent valve issue (the noise) or maybe just a map sensor problem with the idle up/idle down problem.

 

I was having bad idle problems when I had my exhaust cam wetoddid too much.... Also, timing was affecting my idle. I would check those two things. Doesn't sound like bent valves, I was going through the exact same thing 6 months ago and that's how I solved my problem.

 

Thanks for the info guys.

I don't think it is bent valves. My compression checked out with around 225psi on all four cylinders. Besides that I just had that problem and I know what it's like to have them slightly nicked.

I have reset the ECU and it does nothing. Right when these problems started to occur I got a MAP sensor CEL, and have since replaced it with a new one. Also these problems only started to arise towards the end of my dyno session in which I had the cams dialed in with overlap and my fuel pressure extremely high in order to get out a very lean spike. I found out the next day that my fuel pressure was set way to high for the stock pump and turned it back down, the problem didn't go away. However I have a new Walbro pump and 290cc injectors fixing to go in. The Walbro is of course overkill but my reason for it is that I don't want my stock pump to go out, especially knowing how hard I pushed it that one day. Hopefully the injectors will allow me to cure the lean spike in my dyno without runnng my base fuel pressure high. I wish these things would fix it but I doubt it.

Tommorrow when I swap in my new injectors and pump I'll set the cam gears back to zero and see how she runs.

 

.....sounds like a fuel issue to me. I wouldn't worry about it unless you've lost compression/ power. I can help you tune the idle a bit when you get back up this way. As for the overlap on the cams - that'll do it a bit. My spec b's were a lot harder to get to idle smoothly once I had lots of overlap.....

You do realize you'll have to go back and get your fuel straightened out again when you install those injectors, right? Next time please don't change a damn thing once you leave the dyno. Otherwise you paid for nothing. Got it?

 

Do you think you might have too much overlap? Like someone suggested go back to 0 and start over see if that fixes the problem. You intake charge could be getting some contaminates at the low end (Idel) this will give you a strange Idel. Look into that just to eliminate the possibility if nothing else.
The Skunk 1 Cam profiles are not too far off from stock so keep that in mind when tuning. There is another guy that just installed Skunk 1 cams maybe you can get a hold of him and see if he ran into similar problems. I think he posted it in the R forum as well.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Black R &raquo;</TD></TR><TR><TD CLASS="quote">

You do realize you'll have to go back and get your fuel straightened out again when you install those injectors, right? Next time please don't change a damn thing once you leave the dyno. Otherwise you paid for nothing. Got it? </TD></TR></TABLE>

I HAD to change my fuel pressure from my last run on the dyno. It was at 66psi which is WAAAAY too much for the stock fuel pump. Besides turning it back down to a still high 56psi (but now backed with a Walbro), I touched nothing. I haven't going full throttle and I checked my plugs today, a nice golden brown.

Today however I set my exhaust cam back to 0 and it seemed to cure my rough idle a good bit. I'll have to wait until the car completely cools overnight to see if it still trys to hunt idle on startup.

I know I will have to compensate for the injectors by around 20%. Thankfully the VAFC does a good job of taking away fuel. I of course plan on hitting the dyno once they are in.

 

Try taking out the VAFC temporarily and see if that works. I had the exact same problem and somehow when i removed the VAFC it went away.