My plea for tuning help...

[Goldfinger911]

I recently bought a low miles 2002 WS6 M6. It has a Cartek 382 Stroker LS1 and a bunch of goodies (below). It has a couple of problems that I have been trying to solve with no luck. I have been reading this forum and several books for a week straight. No luck. I dont know whether or not to keep trying to fix the tune that came on it, or start over with a base tune from one of the EFILive gurus here. Hopefully someone can give me a good base tune? :)

The problem is, the car starts right up... and fast idles fine, at an AFR of 14:1. Then over the next 1-2 minutes it gets leaner and leaner. Until it reached 18:1 and starts lean missing. It even gets to 19.2:1 while missing. It does this hot or cold also.

The second problem is when driving, when I let off the gas, the throttle seems to stick between 1800-2200 rpm. Rolling or stopped. Then if it blip it, it comes down. It is not physically sticking, I have checked that. It seems to be IAC related. Maybe a th. follower or th. cracker problem?

The car specs and tune are below.

Should I keep tweaking or start over? one thing I noticed right away, is they did not have the engine displacement correct, which I fixed, and they had a MAF calibration for a stock MAF. I have a Delphi 85mm MAF descreened. I found out that it is off a 2002 Z06. I updated the MAF cal table for this model and year.

2002 Trans Am WS6 M6
Cartek 382 Stroker LS1 (all forged inside 3.905" x 4:000")
Cartek Stage 3 heads
Cartek cam 230/234 .600 lift 113-LSA
SVO 30lb injectors
Boost-a-pump with 60psi pressure at idle
Fast 90mm Intake
TPIS 90mm TB
85mm Delphi TB
11:1 Compression
GMMG Exhaust
No Cats
Moser 9" with 4:10, 35 splines, and Detroit Locker

PLEASE PLEASE PLEASE someone take a look and make suggestions, or if you have a great base tune for a stroker, let me know? :) I have been reading and reading for a week straight with no luck. I have tuned AEM standalones and Toyota ECU's, so I am not a total newb.

[trudynosports]

First of all it sounds like you may have an O2 issue. You didn't mention whether you were in OL or not so I would put the car in open loop and see if it stops leaning out. Then, if your going to keep the MAF, you need to tune the car on MAP and then on MAF independant of each other and then re-enable both. I bet most of your issues are AFR related. Get the AFR as close as you can to correct and then start working on the rest.

I'm not on my work laptop right now so sadly I can't look at your tune up.

[Goldfinger911]

I am pretty sure it is using the standard open/closed loop config. remember I am an LS1 noob. Is converting to Open Loop only as simple as disabling {4206} and then setting up {3605} ?

(I just installed an LC-1 with a FlashScan V2. I will be able to wire andlog my AFR's with the V2 next week when my connectors arrive.)

[5.7ute]

It is set for open loop. Your closed loop enable temp is set for 140 degC & long term fuel trims are disabled.

[Goldfinger911]

If you could look at the tune when on your laptop, that would be awesome.

Apparently the tune is an open Loop tune.

What are the effects of having the Long Term Fuel Trims disabled?

Any input will be GREATLY appreciated! :rockon:


First of all it sounds like you may have an O2 issue. You didn't mention whether you were in OL or not so I would put the car in open loop and see if it stops leaning out. Then, if your going to keep the MAF, you need to tune the car on MAP and then on MAF independant of each other and then re-enable both. I bet most of your issues are AFR related. Get the AFR as close as you can to correct and then start working on the rest.

I'm not on my work laptop right now so sadly I can't look at your tune up.

[joecar]

If you could look at the tune when on your laptop, that would be awesome.

Apparently the tune is an open Loop tune.

What are the effects of having the Long Term Fuel Trims disabled?

Any input will be GREATLY appreciated! :rockon:The effects are that the non-WOT/non-PE AFR is determined by either the B3605 OLFA table (GM OS) or the B3647 Fuel vs RPM table (COS) instead of being trimmed to AFR 14.7 by closed loop feedback from the NBO2 sensors.

[Goldfinger911]

If someone with more experience than me, could look at the tune I posted, and give me your thoughts, I would be so happy.

Thanks in advance.

[Goldfinger911]

Well, I tried a new tune from scratch. All I did was make the suggested changes for open loop, tone down the idle learning delay, adjust the IFR for my 30lb SVO's, smooth timing and make a slight mod to the VE. The car started great, and around 140-150 deg F, it went lean again. Mid 19's :1. I opened the BiDi controls and commanded an AFR of 11.0:1 and the idle smoothed out, but the gauge read 13.8:1, not 11:1.

So, why the hell is there such a difference? What can I do to get it close. I want it close to I can proceed with the RAFIG and VE tuning.

Here is the new tune I created. Anyone??

[NewV]

I'm no expert and don't want to give bad advice. But from what little I know you are now ready to begin VE tuning. The solid VE is what will allow you to get your commanded AFR. It seems to me your 13.8 vs 11 is possibly the result of VE needing work.

[joecar]

As NewV said, you should "correct" your VE table using the Auto VE tuning tutorial (requires a wideband O2 sensor).

But, first, recalculate your IFR table for your injectors...
you need to measure your fuel pressure, and if it's not constant (within a few psi),
you need to somehow account for this in each cell of the IFR table.