2.0 LSJ Idle Surging.

[chood711]

Whats up guys,
I have been reading up on everything for over a year before starting to tune my own car. I still have alot to learn and read up on. My problem is I have a surging idle when I am on my running tune. My afr is sweeping from 10's to high 17's. A buddy told me it could be a exhaust leak so I changed my gaskets and n I have also set dynamic airflow to 1500 rpms so that I am running VE on idle. When I am tuning VE(using 04redline's guide to maf/ve tuning off the redline forums), I have no surge at idle and my afr stays a steady 14.6-14.7. I have attached my running file and my VE tuning file. Any type of input is appreciated.

Attachment 28309

Attachment 28310

[chood711]

anyone have any ideas?

[Google]

My afr is sweeping from 10's to high 17's.

This will cause surging. Adjust your ve/maf and smooth it out.

[chood711]

This will cause surging. Adjust your ve/maf and smooth it out.

Thanks for the reply but I know that the afr goes hand in hand with the surge, but I don't know what is the causing that. When I tune VE, I force the pcm into open loop by failing MAF. Then I disable dfco, ltft, and stft. I leave COT and piston protection disabled and change my open loop tables to 1.00. I do some logging and get my VE dialed in and I the idle is 14.6-14.7, reseting feul trims after any change to VE. Once I get VE dialed in I re-enable the dfco, ltft, stft, and un-fail the MAF. Then the idle is all over the place. I have the Dynamic air set to 1500 rpm so I should be running off the VE table so I dont know why it is sweeping as if I am running 100% MAF.

[Google]

Thanks for the reply but I know that the afr goes hand in hand with the surge, but I don't know what is the causing that. When I tune VE, I force the pcm into open loop by failing MAF. Then I disable dfco, ltft, and stft. I leave COT and piston protection disabled and change my open loop tables to 1.00. I do some logging and get my VE dialed in and I the idle is 14.6-14.7, reseting feul trims after any change to VE. Once I get VE dialed in I re-enable the dfco, ltft, stft, and un-fail the MAF. Then the idle is all over the place. I have the Dynamic air set to 1500 rpm so I should be running off the VE table so I dont know why it is sweeping as if I am running 100% MAF.

When you re enable the maf your using a blend of maf/ve upto 1500. You need to set the maf to 1 rpm and tune the maf. Then once the maf is tuned, set it back to 1500. Also it is a good Idea when tuning ve to zerro the maf table to ensure that the pcm does not use the maf table for the hz it is in.

[chood711]

When you re enable the maf your using a blend of maf/ve upto 1500. You need to set the maf to 1 rpm and tune the maf. Then once the maf is tuned, set it back to 1500. Also it is a good Idea when tuning ve to zerro the maf table to ensure that the pcm does not use the maf table for the hz it is in.

I dialed the MAF in before I started to VE tune, but I didnt zero out the MAF table. I will give that a shot. thanks

[instinct247]

I have read on Cobaltss.net that if you are running a CAI intake, dirt will build up on the butterfly valve in the throttle bottle and cause the rpms to surge at idle. i have to clean it atleast once a month, depending on driving habits. try that also.