high idle issue, (thinking its in drive mode???)

sblythman · 03-01-2012, 04:51 PM

hey guys i am having a problem with a high idle... i have recently placed a raptor supercharger kit onto my au xr8 and got it tuned. When it was getting tuned the tuner told me that the car kept thinking that it is in "drive mode" and that my revs were holding at about 1400 rpm and also doing the same when driving (kind of feels like cruise control is on sometimes)

He told me to fix this i could elongate the holes in the TPS to allow it too be rotated a little bit and this would fix the issue or i could drill a 3mm hole in the butterfly and this would stop it? i was just wondering if this is correct before i go ahead and do it as i have no idea? At the moment the car idles ok at start up but when i pull up after driving the revs will hold at 1400, sometimes releasing the clutch a little bit like i am about to take off and then pushing the clutch back in can make the revs drop but i am just uncertain how to fix this as its really annoying.

crakrz · 03-01-2012, 05:03 PM

Starting question. What software has this been tuned with? "DRBASE" (drive idle rpm) can be adjusted through the software, no matter what they are using. Who is your tuner. Are they experienced with the Ford EECV?
-Craig

sblythman · 03-01-2012, 05:08 PM

Paul at cve tuned it with a j3 chip but I dont know what software was used?

crakrz · 03-01-2012, 05:22 PM

Paul would most likely be using a TI Performance chip and Tunerpro software. He certainly has the runs on the board from all reports.
Did he measure the TPS voltage at closed throttle to arrive at that assumption? I don't understand why someone would want to drill a hole in the butterfly when they have all the throttle body air flow parameters available to them on a laptop. Drilling butterflies was common practice before we had tuning options. It sounds like the idle set screw has been adjusted and now the TPS is greater than 1.2v at closed throttle. Therefore by drilling a hole, the idle set screw can be returned to its stock position. Not the correct way to do it at all. It's a hack way of correcting the issue.
-Craig

crakrz · 03-01-2012, 05:30 PM

I forgot to mention that the only way the ECU thinks that it's in DRIVE mode is when you move the shifter. Maybe he means Part Throttle. This could we diagnosed with a timing light.
-Craig

sblythman · 03-01-2012, 07:40 PM

ok so what do you suggest i do?? i dont remember him measuring the tps voltage. it either idles at 750-800 or it is idling at 1800 rpm (not 1400 as i wrongly said before). when i drive it i can feel it like accelerating by itself. does that sound like part throttle??

crakrz · 03-01-2012, 08:01 PM

First up, can you describe whats happening when it idles fine, and describe what's happening when it idles at 1800. Is it consistent? The more detail the better. I realize you will have to type a small novel here to describe everything, but it will paint a better picture of what the issue is.
-Craig

sblythman · 04-01-2012, 10:45 PM

it goes like this.
it starts and idles around 1800 for a couple of seconds then slowly drops down to about 750-800 rpm and has mildly grumpy idle (kind of like a grunting sounds nice)
i then go to drive it and when i pull up to a stop when i clutch in the revs will hold at 1800.
However if i pull up to a stop and let it roll up in second and let the revs go down to about 1000 rpm while rolling and then put the clutch in the revs will idle nicely around 750-800. Or if i release the clutch a bit with no accellerator like i am about to take off then that will make the revs drop down aswell
After about 15-20 minutes of driving though nothing will stop it from idling at 1800rpm.
when i am driving it feels as though i have my foot slightly on the accellerator pedal but i dont??
sorry bit confusing i hope that makes sense...

crakrz · 06-01-2012, 01:43 PM

I forgot your car was a manual. And I don't know what impact the supercharger has had on your tune in regards to idle settings. I can only suggest that if your tuner says to try this or that, let him do the mod so that you cannot be blamed for getting it wrong. As i have not tuned a supercharged vehicle, I can't offer anything else, sorry.
-Craig

sblythman · 06-01-2012, 11:07 PM

Well I tried rotating the tps but that didn't help so maybe I should try drilling the hole... Just still hesitant about that as it is not and easy reverse.

crakrz · 07-01-2012, 08:19 AM

Without knowing what your TPS voltage actually is, you will only be guessing. AU's can be anywhere from 0.7v-1.2v at closed throttle.
I would not drill into the t/blade unless your tuner tells you what that will actually achieve. Have you spoken to him again. He should be able to diagnose the problem with a timing light and a multimeter.

I am a bit reluctant to say much as I am not working on the car itself and don't know the whole picture. If the tuner had gone with the Quarterhorse option for tuning, you would have full live datalogging in front of you to diagnose the issue. And he is certainly aware of the QH, I'm sure.
Thats not helping you now, but it would have taken all the guess work out of it from a tuners point of view.

Some of the 'possible causes' for your symptoms are "unmetered air" entering the system somewhere, eg, vacuum leak, crankcase ventilation, faulty ISC, faulty/dirty maf, dashpot settings in ECU, Closed throttle spark correction via ECU, there are more and the list is long......

You will have to go back to your tuner unless someone else can offer an easy solution for you. If you want to try a small 2mm hole in your t/blade, thats up to you. Who knows, it might work. It would certainly cancel out all this other stuff if it works. And I would have learnt something myself along the way.

I wish that I could have given you a magic pill to fix it, i really do. I realise this is very frustrating when you just want to drive it and enjoy it.

-Craig

5.0 ED · 07-01-2012, 08:31 AM

There is no proper definitions capable of allowing you to tune a supercharged engine with tunerpro, they are all basic definitions. Settings like TB airflow arnt included and so on.

crakrz · 07-01-2012, 09:02 AM

I was hoping you might see this thread and give some advice as you are more qualified in this area.

-Craig

sblythman · 07-01-2012, 01:35 PM

thanks heaps guys for your help. So 5.0 Ed your saying something like this can only be resolved by for eg. the drilling of a hole in the t/b?? that it can not be tuned out? i suppose i could always fill the hole with an epoxy resin or something like that if the problem is still there, but i will call paul and just confirm the situation with him because he also "prescribed" the rotating of the tps but that did nothing.

Steve Coupe · 08-03-2012, 08:43 PM

sblythman, I hope you got your problem sorted. What did you find out?
I have a AU 5.0 windsor with EEC V and the AU T5 gearbox. (no supercharger for me (yet)).
Almost the same description of the problem: at start up is idling at about 1800rpm. If I put the clutch in to take off the revs drop down to where they shoud be with the load.
Just hoping you might have a quick fix for me?!

39ClevoUte · 08-03-2012, 08:55 PM

The fact that you can change the outcome by changing the way you pull up means that something is changing. Not as simple as sticking TB is it??

Steve Coupe · 08-03-2012, 09:04 PM

Quote:

Originally Posted by 54Ghia

The fact that you can change the outcome by changing the way you pull up means that something is changing. Not as simple as sticking TB is it??

I dont think so. The butterfly valve is smooth and the revs hold the same every time so I think it must be being controlled by the idle control valve. I was thinking it might be something to do with the VSS signal to the computer??

5.0 ED · 08-03-2012, 09:07 PM

It can all be tuned out, just not with the definitions available for tunerpro.

You can tune it out with my BE AU v8 definition, no need to drill holes in anything.

And on AU there should never ever ever ever be a reason to elongate holes on TP sensor since it is self adjusting in the eec, otherwords weather its set at 0.8volts at idle or 1.1volts at idle, the eec will adjust to suit it as if it was never changed.

39ClevoUte · 08-03-2012, 09:07 PM

What about a faulty temp sensor. Ie the ecu thinks the engine cold sometimes and applies the "choke". Increases air flow and richens up the fuel.

Steve Coupe · 09-03-2012, 11:25 PM

Yeah, I will have to get my guy to hook up the lap top to see what the ecu is doing. Like I said, just hoping for a possible quick fix.

Steve Coupe · 21-03-2012, 03:04 PM

Just an update for anyone interested.
I had previously put a new (from a wrecker) idle air control valve on (the first thing I tried). This did nothing. So I got the guy I know to hook up to the diagnostic plug and everythig is perfet (exept VSS fault which is because I am not using the VSS). The command signal to the idle control valve was telling it to close but it was not closing. So I tried a third idle control valve and it worked! Something so simple! I know not to trust second hand parts but to have two failed in the same way is unlikely. Anyway, sorted now. Hope this might help someone else.