darksurfer11

I recently got my EBL and am loving it soo far. I have been recommending it to everyone I know with the potential to use it. I have run into an issue where on a cold start, idle will be around 8-900 RPM and as it warms up, it will climb to about 1000-1100 RPM with a slight surge between 9-1100 RPM every so often. my engine is a 383 with vortec heads, comp cam 12-256-4 cam and 50mm 454 TBI with 90# injectors bumped to 18psi with VRFPR. ALL senors are new, so swapping parts aren't a big deal. I am getting correct readings on the CTS, MAP and TPS. I have it set right now for idle to drop when warm to about 650 RPMs in park, but they are instead increasing, so I am at a loss on what to do...Thanks for taking the time to help out!!

RBob

iTrader: (1)

Check the IAC step count. As the engine warms up the IAC should be closing, which is a lower count. Once the count goes to 0 the IAC can't bring the idle speed down any further.

In this case there may be a slight vacuum leak, or even the PCV may be passing too much air.

Can try closing the throttle blades a little to see if you can get between 5 & 10 IAC steps on a warm engine with no other loads on it.

If you haven't disabled async injector mode most likely should. Zero this table:

INJ - ASync Transition PW - TBI Only

RBob.

darksurfer11

Went out this morning and modified the inj-async transition pw - tbi only and changed the ae tables to match up with the increased injector size. The IAC count is at 0 and the idle is still around the 1000 RPM mark. However, when I rev the motor in park for VE Learning, I get a VSS malf code. Would my VSS cause high idle and slight surge without affecting the speedo and shift points (Although when I went WOT yesterday to test my spark table for knocks, she hit 5k RPMs and didn't upshift until I let off the throttle)? My ABS light has been on for a while, so I do probably need to get down there and clean it or at least check it.

Tuned Performance

iTrader: (92)

just a guess here but the malf of the vss comes from a check and is thrown because the ecm thinks the vehicle is in motion. sounds like you have a vacuum leak or need to adjust down the idle speed screw now.

darksurfer11

I was hoping it wouldn't be a vacuum leak. I have sprayed all around the intake, TBI and various hoses to try and find one...which leaves the underside of the intake as the likely culprit...My MAP readings do flutter from about 29-31 (mostly sits at 30) in park, I was just hoping it was due to the cam.

Edit: Also, I thought a vacuum leak would cause a surge all the time and not just when the motor is warmed up. Please correct me if I am wrong.

Ronny

iTrader: (1)

If you are confident there are no intake vac leaks then I would not pull the intake at this time.

did you disable asynch as of yet? If not do so.

Surges are not that unusual on a new build. I would idle OL. I am OL-I and OL up to 8mph. I would make all values in VE table for idle rpm.map cell and surrounding the same.

Lock idle SA degree so it does not wander with surge. I idle 20 d. Experiment with say 17-23 area.

Proportional gains may need to be reduced due to large inj's at higher fuel pressure. try 50%.

darksurfer11

I disabled the asynch this morning and it still idles high. The surge only happens sometimes when in park, so I wasn't too worried about it, the main concern was the higher idle than I have in the IAC-Idle Speed : Park and IAC-Idle Speed : Drive by about 4-450 RPM in park and 200 RPM in drive. When the motor is started cold, the idle speed is lower than when it warms up and that has me confused, shouldn't it be the other way around?

Forgive me for the noob question, but how do I adjust proportional gains? I have been running VE learns for these injectors and have multiplied the AE TPS and MAP tables by .575 as I went from stock 350 injectors to the 90# ones (61/106).

Ronny

iTrader: (1)

Idle speed may be low due to cold manifold and not necessarily improper IAC position. Unless the IAC is wired incorrectly. My IAC is wide open yet on a cold morn 35-40dF it idles barely at 800 rpms then slowly climbs in RPM as the manifold gets heat. My heads have no crossover and no ext manifold riser.

If you search my recent thread on PG's you will see the tables RBob refers to