Idle Issues. Please Help.

[JetIgniter2k]

Hey this is Bryan in Rochester.

Still new to EFI tuning, so sorry for any dumb questions or responces. Current setup: 94 V6 auto converted to 351W, Holley systemax heads, Edelbrock Performer truck intake, twin 61mm TBs, Edelbrock cam, roller rockers 1.5 or 1.7 (can't remember), Electromotive TEC3 engine manegment system, LM1 Wideband, and high flow PVC cold air w/ K&N. Tons more... 292HP / 370TQ to the wheels. Profecianally Dynotuned at Kenedy's in Buffalo. Spent $600 and he could fix the problem and he had it running way too rich. VERRRRRRY UNHAPPY with service. Be Aware!!!!

Problem: Idle ocilates. RPM varies from ~900-~1300 in two second intervals. Map reads from 50-30 respectively. AFR 11-16 respectivly. ADV constant 22. I have tried numerous FPW arangements to smooth it out but with little success. All attempts were made with IAC unplugged and EGO correction OFF. Turning those back on does not smooth out the problem. Occilations stop once I step on the throttle ( as little as +0.02V over closed voltage of 0.78).

Any advice would be much apreciated. My calibration files were made completely from scratch with no refference to how a stock files look. Things could be way out of wack, but doubtful. If possible, can anyone send me coppies of their volumetric efficiency, and timing tables. Thanx.

 

[CBZGT50]

I recently removed my upper intake and after putting the motor back together, I found that the PCV valve kept popping out. I had idle surging from 1000 to 400 rpm. Vacuum is really only used at idle and drops off as the rpms increase. Try finding a vacuum leak, maybe a intake manifold leak.


CB

 

[JetIgniter2k]

Just checked for vacuum leaks. None. But i might have found a goof up. On a stock 5.0 the fuel pressure regulator and PCV lines go into the manifold. But is it OK to have the FPR line piggy-backing off the PCV line. Also found out why im burning a little oil. The PCV line had quite a bit in it. Should i explore possibility of a bad PCV or bad hose routing? Unsure of how to check intake manifold for leaks. Other vacuum lines hold pressure.

 

[CBZGT50]

In the past I have sprayed water (a little) on to each cylinder at the upper to lower intake gasket and see if it clears up for a second. Worst case, Pull the upper intake and put a new gasket and pcv valve in. Check under the upper intake and see if you have a rotted or cracked vacuum line under the intake. I would definatly at a minimum, clean out the pcv valve with brake cleaner.

 

[JetIgniter2k]

The PCV is brand new. I pulled it out of the grommet - no change, i put my finger over the valve - no change, but it was making suction. I believe the IACM is oriented properly. I'm useually pretty good about reading instruction when i install new parts. I'm going to look at my neighbor's F150 to check. I still think the problem is in the calibration files. Thanks for the help so far, but I'm not giving up just yet. Please post any more ideas you may have.
Bryan

 

[jrichker]

See the "Help me create the Surging Idle Checklist" sticky at the top of the forum for some help. Lots of good ideas from guys who have fixed the problem.