ECMlink Pesky idle surge

[jamel16]

I have a situation, so this is for all you geniuses out there. I have a pesky idle surge that I cannot diagnose. I’m not sure if it’s mechanical or tune related.

This is a new build , so I’m trying to stabilize my idle before its first drive. I have done a boost leak test, smoke test, verified timing, verified ISC operation, Rebuilt S90 throttle body, FIAV block off , verified functioning MAP sensor. I will note that this build will mainly be on E85, so that’s what’s in the tank.

I have read every post on idle surge that I could find. I even went as far to manipulate timing tables with no change. What’s crazy is idle would be stable for 2-4 mins then the surge would start. I am completely baffled.

Build consist of: 2.0 L
Manley pistons
Eagle rods
Stock crank
2g cylinder head w/oversized valves and Delta cams 264/264
Evo 3 intake manifold
Rebuilt S90 throttle body
JMF manifold
FP HTA 3076
ECMLink v3

Please help

 

[pauleyman]

Post a log. Does it coincide with the change to closed loop?

 

[Sirius1995]

I'd start by vacuum leak test (not cylinder leak down test) and check that vacuum lines are connected correctly and no visible cracks or cuts in the lines

 

[enriquez2000]

Like @pauleyman said.. get us a log!

I like to lock in open loop to see if its jumping around VE cells hunting for fuel.

 

[jamel16]

Here are two of the logs, I was adjusting things, so it might look wonky.

 

[jamel16]

I'd start by vacuum leak test (not cylinder leak down test) and check that vacuum lines are connected correctly and no visible cracks or cuts in the lines

I checked all lines visually and with a smoke test.

 

[enriquez2000]

Your idle switch doesn't appear to be activating saying that it is closed in number 2... you can simulate that in RPM/TPS tab

On the 1st one your VE table is all over the place in the low end and it shows you going super lean as it hunts for fuel

try this and see if it smooths you out down low. its by no means a tune just trying to stop the car from fuel hunting

VE needs a ton of work

 

[jamel16]

try this and see if it smooths you out down low. its by no means a tune just trying to stop the car from fuel hunting

VE needs a ton of work

Thank you, I will try it out in the