Suddenly goes very lean on startup, no changes made to tune!

[The Alchemist]

Well, someone also pointed out that as the motor warms up, the IAC counts also come down as well, which then richens up the AFR. At least it's not pegging the AFR at 18-19 anymore on cold startup.

[Russ K]

The IAC position has no effect on the AFR, as it is only by-passing air around the throttle blade. It is not an unmetered vacuum leak.

Russ Kemp

[jmoody66]

Try this tune, I set up your open loop table.
Russ Kemp

I tried to PM this to you but it says your box is full and wont accept anything until you clear it up. I didnt want to hijack this thread.


I noticed you offered help on this thread and was wondering if you could help me. My problem is that upon cold start, according to my new lc1/xd16 innovate wideband, I am seriously lean...like 16.x until it warms up or if I give it some gas. It doesnt idle rough or anything but it concerns me. Also could you help me with a rich condition? My car runs great and when I punch it it goes really rich, like 9.x, which explains the black soot in the exhaust.
I dont know if it matters but I installed my lc1/xd16 and did the calibrations but did nothing else. I have the hptuners with the mpvi box but not the pro box...does this mean I cant log my AFR or is that what the rs232 looking wire is for?
Overall its running good but these two things are haunting me.

Thanks in advance for your consideration,
Jerry

[Russ K]

I set up your open loop & stoich AFR tables. You were not in SD mode because the Maf wasn't failed in your tune. I set the Maf fail Fq to 0, so now the car will be in SD mode. You need a MPVI Pro, or find out how to use an A/C pressure sensor circuit for the wideband to display in the scanner. It will be next to impossible to tune the AFR without the WB input into the scanner.

Russ Kemp

[jmoody66]

I set up your open loop & stoich AFR tables. You were not in SD mode because the Maf wasn't failed in your tune. I set the Maf fail Fq to 0, so now the car will be in SD mode. You need a MPVI Pro, or find out how to use an A/C pressure sensor circuit for the wideband to display in the scanner. It will be next to impossible to tune the AFR without the WB input into the scanner.

Russ Kemp

Thanks Russ. I put it in and scanned it so Im attaching the file.
I couldnt test cold start up to see if it was leaning out but will tomorrow. I did notice now that when I stomp on it, redneck term with a mullet, that my gauge only shows 10.7 vs 9.x which is better. Whats ideal in my case? I hear 12.x or 13.x...etc. Whats a good safe number? Do I control this a/f ratio on the open loop/eq ratio tab?
I see timing as high as 40 in my scan...sure seems high. Opinions?
I also had a tad bit of knock retard close to frame 2600. Possible reason why and how do I get rid of it?

[Russ K]

You really need to read the help files to set up your scanner when using a 2 bar map. You need to log the commanded AFR as well. As for the AFR, if your intercooled, 12.0 @WOT, and 11.5@WOT if non intercooled is a good range. You set the commanded PE to were you want it, then adjust the VE table so the actual AFR matches the commanded AFR. But the car need to be in open loop when tuning the AFR.

Russ Kemp