Fly-by-wire throttle setup

**fred007** · 06-23-2013, 04:03 PM

I have a LS1 from a 2000 vette in my jeep. It's run pretty good for a while, but when I replaced the manual with an 4L60e transmission I went to a 2002 "stock" tune for my setup. Since that time, I have an issue with idle remaining high for some period of time especially when the jeep is at severe angles. By this I mean that I can bump the throttle and the RPMs remain around 2000 or so for 3-4 seconds. This is a real problem when crawling rocks as I need the throttle to be what is dialed in at the pedal, not something the computer might hold high for a bit.

I have HPTuners and saw there are quite a few settings for idle settings. But, before I go experimenting around with those, I was wondering if anyone had any suggestions for me.

I am also planning a test to make sure the pedal itself is okay, but have not been able to test that yet.

Any help/pointers would be greatly appreciated. Thanks!

**cammed goat** · 06-23-2013, 05:41 PM

The issue started as soon as you fired up the Jeep after the swap? Or did it take a little time for the symptoms to start?

**Mean Green Z28** · 06-23-2013, 07:03 PM

You need to put in a tune from an automatic car. The manual tune holds the rpms up a bit so the revs don't drop drastically during shifts; not needed on auto cars .. atleast this is the way I solved a similar issue on a friends lt1 car. It was much easier than trying to figure out which tables needed to be changed etc. ... im sure there's another way, this ones mine lol

**fred007** · 06-23-2013, 07:14 PM

Not sure exactly when the issue started, but recollect I've always had it with the automatic tune. However, it does seem to be getting a bit worse. My plan is to throw on the scanner and watch throttle position when we create this issue. Wondering if I will see the reported throttle position stick up for a bit. (then I would suspect a problem with the pedal)

I am using a tune from an automatic, think the base is from a 2002 Silverado. I can't recall having this issue with the manual tune.

Oh, and the problem seems magnified when in 4 wheel low, which in my case is 4.3:1 so the speed reads much higher than actual speed. i.e. crawling along and the speed is 20mph.

**fred007** · 06-23-2013, 07:20 PM

Base tune is from a GMC Yukon 2002.

**cammed goat** · 06-26-2013, 03:59 PM

Is the tune for a 4X4 Yukon?

**98TransAmWs-6** · 06-27-2013, 06:04 AM

Also isn't a yukon a 5.3 and not a 5.7? But also as said you should make sure the tune was for a 4x4 as well.

**Firebirdjones** · 06-27-2013, 09:04 AM

Sounds like this all happened as soon as you put that base tune in from another year/model.

I've changed all those throttle settings around myself on both auto and manual tunes that I have, I like the engine rpm to drop when I let go of the pedal.

Should be simple to look at your previous tune and see which throttle tables and how they vary. Been a long while since I've looked at mine, but I seem to remember a table in there specifically for this issue.

Edit: as a matter of fact I know there is, because even my 2002 SS with an auto had this problem. I changed it because there was a delay when I let off the throttle. And at highway speeds it had no engine braking for 3-4 seconds, then it would finally start to slow down. I hated that and zero'd out that table so that when I let off the gas, the car imediately slowed. I did this on both our auto and 6 speed cars as they both had this issue.

**fred007** · 06-27-2013, 10:06 AM

Not sure on the base tune, will dig into the details. Good call on comparing with previous manual based tune. Should be able to do that. Thanks for the help, will post back when I get the VIN off the base tune.