jbrx7tt

Hi I just had BDC tune my car last week and the boost is great, much better than before and the car really feel more responsive at all levels. He is a really good guy and I recommend him however he seems to be stuck on this issue as well. The issue I am running into is that when it first starts, the idle jumps up & down until it finally warms up then it is fine after that. I know he added a bit more fuel at start up however it is not a "smooth" start up rather a jumpy one until the car is warm. Frankly it is annoying.

Has anyone encountered such an issue with the PFC? If so, were you able to correct this and how did you accomplish? Any suggestions of what it "might be"?

Let me know, thanks in advance....Jon

cewrx7r1

iTrader: (2)

This is a common problem with the PFC. It normally isn't hard to fix if you really understand how to tune the PFC and all the factors affecting idle. But with some highly modded engines, the auto idle control just can't handle it and you have to go to a manual idle control system similar to used on early engines with carburetors.

Your tuner (who is BDC) should know how to fix it, else he isn't a total tuner.
First you tune the idle for a fully warmed up engine, then go back and do it through cold start and warm up.

Bring it to Houston, Kyle and I can do it! Or PM us and we can help your for a fee, if you have DATALOGIT access for your PFC.

jbrx7tt

He is a good tuner although still learning some of the PFC I beleive (most does Haltech from what he said) however we did not get the chance to do it from cold start like you indicated which may definitely be part of the issue. It did not idle weird like this prior to the tune so I figure it has to be the computer and not the idle screw or anything like that. I guess if we cannot figure it out before he leaves Colorado I will give you a call, not sure about driving down to Texas. I don't have a Datalogit but do have a commander, can it fixed through just the commander? Thanks again for your help, much appreciated.

DaleClark

iTrader: (55)

Did you set the idle screw to a half turn out before installing the PFC? Also, did you do the whole idle learn procedure?

Dale

BDC

Idle learn procedure -- Nope. Doesn't ring a bell, Dale. Is there some documentation on it anywhere?

Thanks,

B

BDC

Not a "total tuner"? What, because I may be unfamiliar with an aspect of the PowerFC that is already challenging to many other people who do the same thing I do? Good grief. Could you be any more condescending?

B

DaleClark

iTrader: (55)

My PowerFC FAQ has the idle setting procedure for an out-of-the-box PFC. Big one is the idle screw - just under the entrance to the throttle body is a flathead screw in a recessed hole. Make sure it's all the way in, then back it out a half turn.

With a new PFC, you let it idle with no load for 10 minutes, idle with the defroster on for 10 minutes, then idle with the AC on for 10 minutes. I'm not sure if the PFC dynamically learns idle over time if you don't do this or what. Problem is the only way I've found to have it re-learn is by doing a full reset of the PFC then shutting the car off and switching it on. In the Commander, this is in the Etc menu - All Data Init. Make sure you've got your map saved first!

Dale

87GTR

iTrader: (61)

Yeah I did the idle learn on mine. warmed the car up, disconnected the neg on the battery for 30 sec, reconected the battery, started it up. noload 10 min, my defrosteter didnt work, so I just used the fan on high with no a/c for 10 min, then a/c on 10 min.

mine idles solid at 780

The only trouble I have is from a full cold start. My car goes to about 2000 rpm and stays there until water temp gets to 80C, then drops right to 780.

My car was tuned by igy here in Okinawa, he tunes tons of PowerFC and he said he has no idea why my car does it.

If I put my normal ecu back in and do a cold start it does not do the above problem.

if someone what to take a look at the dat file, to see if they can figure it out I can post it.

jbrx7tt

Yes when originally installed the PFC I did the idle screw procedure outlined in the FAQ. After installed, about a week later the screw did not stay in, it was erratic then due to it not staying tight until I got a new spring for it. However after that I put it back in and it was fine in start up again. It feels like it is trying to "do the right thing" by giving it sufficient fuel at start up but somehow it is not smooth.

cewrx7r1

iTrader: (2)

I was contacted by someone in the last 6 months about an idle problem.
His engine idled fine until PFS power tuned his PFC. After that the idle was irratic, the car ran great on boost, and the tuner was stumped.

After reviewing all the changes made, it became apparent what the cause was.
The recalc funtion was executed.

If this was a few yeas ago, we all would have been scratching our heads trying to figure out what happend, and would try different things to fix it. But now we know that the recalc screws up the O2 idle control and cruise areas. Thus these areas have to remain as they were if you want to run the O2 control function.

Thus this PFS professional tuner was not up to date with his knowledge of the PFC. To me this is not acceptable!

I told the individual how to correct this problem for free.
This was posted here back in 2005.

BDC

Great.

B

BDC

Wow. No wonder I've been having an issue with this. Well, if worse comes to worst, the procedure can be done on this car if need be. Jon's is the only one that I'm having that issue with; the others aren't. If all else fails, I've got his current map saved on this laptop here.

Thanks for the info, Dale.

B

jbrx7tt

Do you think I could fix the idle by disconnecting my PFC, reconnecting it and going through the procedure over again with the newly tuned map? Any issues with doing that?

BDC

Worth a shot, Jon. I'm still in town until Thursday so we can take a few minutes and try it if you'd like.

B

jbrx7tt

Thanks Brian I'll give you a buzz....appreciate your extra effort.