05 GTO idle/fuel problem

[slowhawk]

Car has longtubes and a 244 duration Cam.I'm having a problem only at idle with getting the fuel where it needs to be. The L-terms peg to 24% on both banks.I've tried huge VE table adjustments and even big MAF changes with no affect.Car starts and idles near 17-1 A/F before L-terms knock it down to the desired 14.7-1. The only table that affected and fixed the idle problem is the injector flow table.I got the L-terms to -2% with A/F in check with a 25% IFR change.Of coursee this is not a permanent fix but atleast showed it can be done.

Now,the question is ,why isn't the VE or anything else not changing the fuel supply at idle? When driving A/F -L-terms are perfect,it's just the idle area.

Car idles at 65KPA at 1000rpm.

[E.A.]

I am having the same issue with a GTO I have in house right now. I had the car running flawless with the 42's and the ProCharger. Now all I did was an injector swap to a set of 60's since I will be going to a heads and cam soon.

But this is the EXACT same issue. Hmmmm

[Scoota]

I'm assuming you have the WB02 sensor in your header to check the A/F at idle. Big cam and exhaust will give you an incorrect and lean reading if you are sampling it from the tail pipe due to exhaust pulses.
When you say you have been adjusting the VE table, I'm guessing you've been doing that in SD with the Maf disconnected and running an air temp sensor. I may have misunderstood your post but it looks like you are trying to adjust the VE table with the Maf connected.

Cheers Scotty.

[E.A.]

I'm assuming you have the WB02 sensor in your header to check the A/F at idle. Big cam and exhaust will give you an incorrect and lean reading if you are sampling it from the tail pipe due to exhaust pulses.
When you say you have been adjusting the VE table, I'm guessing you've been doing that in SD with the Maf disconnected and running an air temp sensor. I may have misunderstood your post but it looks like you are trying to adjust the VE table with the Maf connected.

Cheers Scotty.

Mine was in SD mode, no MAF, O2 was in bung before cat.

I will mess with it more starting next week with the new heads in it, and see if the issue still pops up. It wasn't a major issue, just minor.... I am sure I am just overlooking something silly. Need to look at it again with a clear head, and usually that leads to a "DUH" moment.

Thanks for the post though! Have a good weekend

[slowhawk]

I'm surprised nobody had the answer Yes,you can adjust VE with the MAF still hooked up or vise versa.

After 25 downloads I found the answer I needed. For me it was the max pulse width for idle.It was set to 4% but the car was idling at 7%.I changed the max idle % to 8% and everything fell back in order.Instead of a real ruff idle with L-terms at +24% no matter what was changed it brought it back to -2 to 2% at idle and smoothed out alot.

[Scoota]

I'm surprised nobody had the answer Yes,you can adjust VE with the MAF still hooked up or vise versa.

Well not really. The VE table should only be touched when in SD mode. It's a backup table as such.
The correct way to do a maf tune (although not many people do it) is to do an SD tune first by correcting the ve table and then calibrate the Maf once reconnect.


Cheers Scotty.

[joecar]

+1.

It's a matter of eliminating the unknowns.

[slowhawk]

Well not really. The VE table should only be touched when in SD mode. It's a backup table as such.
The correct way to do a maf tune (although not many people do it) is to do an SD tune first by correcting the ve table and then calibrate the Maf once reconnect.


Cheers Scotty.

There is alot of opinions on the right way to do things,and there is alot of ways to get a tune done right.

The post is not -how to tune? It was how to fix the shitty idle? So,it is nice to see people come into the post -not to help the idle problem but to pick at other tuning ways. Where were you guy's a week ago when I posted????

[joecar]

Slowhawk,

My apologies, I was possibly in a hurry and may have not seen your original post...

You did say "Of course this is not a permanent fix but atleast showed it can be done" so we're offering suggestions...

Is the AFR wrong until CL is entered...? Are there any afterstart ECT modifier tables in your calibration...?

Cheers,
Joe

[slowhawk]

I understand for the suggestions. The IFR is back to normal.The AFR was wrong all the time.It's all done and running great now.