Rich off idle

[CJK440]

Getting close to being fully dialed in. WOT is good and drivability once moving seems fine. Tip seems fine, getting back on the throttle after a shift is fine too.

What I am seeing now is once the car comes to the commanded 800rpm stabilized idle and I goose it a bit the AFR goes real rich. I've read as low as 9.9 but my LM2 blinks which I think means it hit its lower limit which is 7.something. It only does it for a fraction of a second but if I let the clutch out as usual to get the car moving, it will stall. I have to rev it a little to get past this rich spot then let out the clutch and its annoying.

If this was a holley I'd just throw a smaller primary squirter on it until it goes away.

What should the AFR log look like ideally from a stabilized idle to a little rev? Should it remain near 14.7 or am I wanting a slight enriched reading during the transition?

 

[CJK440]

One thing I never did was dial in the LWFM. There are conflicting reports on what influence it has on my '04 but I might as well dial it in. It will just cost me a road trip then cut and pasting the histogram data to LWFM. I'm doubting that is the cause for a super rich off idle spike......

What would I play with otherwise to keep AFR near lambda off idle?

 

[oxfordgt]

Transient fuel at that RPM

 

[CJK440]

LWFM seems dialed in. Still have a rich spike off idle and I do have it at tip in but since I'm moving its not as noticeable.

This is a screen grab from Livelink after blipping the throttle after a time at idle. Blue is AFR, yellow is load and red is TP relative.

Transient fuel at that RPM

So this is what I have available in transient fuel. After a web search I'm puzzled as to where to start with PRP. I'm guessing is some combination of the puddle and trapped tables. The only one that involves RPM is "Transient fuel trapped in puddle". To quell the rich spike should I increase or decrease this?




I'm using Deka 60's with stock PI heads and assume they have a different spray pattern which would change the volume of fuel clinging to the walls but I am not sure if the rate of evap/deposit would change.

 

[oxfordgt]

I have never messed with the puddle. You have less options then I do but out of that list I would try tip in.

 

[CJK440]

I noticed my manifold volume was scaled down around 7.5 ish. I kicked that back up to 10.0 since I am running a tork tech kit and figured the terminator MV parameter should be good. It worked wonders for driveability. I also noticed it behaved better at cold start too.

 

[decipha]

If you have a RICH TIP-OUT followed by a lean out thats indicative that the manifold volume is too high, reduce the manifold volume to correct that. Note that reducing the manifold volume will lean out (remove) tip-out fueling.

If you have a RICH TIP-IN followed by a lean out then thats indicative that the manifold volume is too low, increase the manifold volume to correct that. Note that Increasing the manifold volume scalar will enrich (add) tip-out fueling.

MAN_VOL scalar - a smaller manifold volume will remove transient fuel faster so transient fuel isn't active as long at tip in.

its common practice on the 94-02 cars to reduce the manifold volume to increase tip in fueling

 

[ClubVenom1]

If you have a RICH TIP-OUT followed by a lean out thats indicative that the manifold volume is too high, reduce the manifold volume to correct that. Note that reducing the manifold volume will lean out (remove) tip-out fueling.

If you have a RICH TIP-IN followed by a lean out then thats indicative that the manifold volume is too low, increase the manifold volume to correct that. Note that Increasing the manifold volume scalar will enrich (add) tip-out fueling.

MAN_VOL scalar - a smaller manifold volume will remove transient fuel faster so transient fuel isn't active as long at tip in.

its common practice on the 94-02 cars to reduce the manifold volume to increase tip in fueling

Would this also work for a lean tip out on a 03-04 terminator?