you mention Injector latency, I see it is based on Barometer..... possible Baro failure?

I figure starting with the easiest is the way to go

 

QFT
My car does this at cruising speeds while on the hwy. Periodically I just cancel the cruise control and reset it. I feel like you're chasing your tail with this one houston. BUT if you do find something be sure to share lol

 

you car will drop into the 11's and 12's at cruise?

BTW...I am a tail chaser...lol (I mean was...haha)

 

The log shows 13.8 which I think is fine for open loop cruise because i see the same on pretty much every 8 I ever tuned.

Can you log it when it goes into the 11-12 range ?

What injectors are you running BTW ?

 

Tailchaser.... lol

No, it normally drops a point. 13.5-13.8
I didn't see 11-12 in your log. I only notice 11-12 under WOT.

 

Previously I didn't have my cobb in the car and it never dawned on my to log it (I always assumed it was my tune). now that I know its not my scaling

Tomorrow I will just drive until it does it...lol it usually take 30+ min of driving to go into the 11-12 range. but I haven't been driving that much recently

I am running brand new stock red's and yellow's

 

I havent loged that yet....reasons above ...WOT it not issue at all, its rich but I have it tuned that way for the time being

 

never mind. I had sock injector colors backwards smh

 

I feel like the latency is at issue (assuming you are mechanically sound) on the secondary injector, If Inj Pulse width goes down, and car goes rich, it's pretty obvious what's up.

 

well in an effort to get rich logs I have a lean issue for the first time...ugh

cruising at 70ish trying to get data and it randomly went lean. I don't see anything obvious on the log but check it out.

I did get a mild rich log but from what you guys say low 13's are normal closed loop

After it cools down I plan to pull the UIM and check around.

 

The lean spot coincides with reduced accel pedal and maf so suspect it is a slight downhill or where you let off slightly for a few seconds . So ........normal

 

killing me....lol

so what you are saying is that the car should stay in the 16's even though the target is 14 assuming no hill or accel pedal change?

I just know that what is going on is not right but I can't get the data...

here is another log of going lean with no change to accel pedal and no change to Calc load

 

hmmmmm -ok you got me !I'll stop saying it's normal now . LOL

 

:D

so I dont think its a vacuum leak but I will check. should I consider ohming out wires?

 

it is safe to say I would see a vacuum leak in the STFT #'s right?

I am at a loss unless the ECU is possessed or there is a "resistance" in a wire somewhere (I have been through 2 MAF's and 2 o2 sensors with the same results (so to speak)...hhhmmmm

 

I am convinced the richness is normal. Think about the gear you're in during the rich stint. If under WOT that sounds like a perfectly acceptable A/F ratio. I wish OL/CL was more controllable.

 

I agree and my WOT is right on target. its just the funky thing while cruising.

just more joys of an 8

 

I've poked around in my car trying to figure out what causes this issue, but the thing I don't get is why you these cars will go OL at 3500rpm and cruising, but stay CL until 5500rpm at WOT. Seems like you would want it to go OL earlier at WOT than cruise.

I wasn't aware that the Baro sensor had an effect on latency, I might try swapping mine with a friends and see if that changes anything, mine actually broke(but was glued back together and seals still) so that might be an issue.

 

well, I swapped the Baro with the one on my "spare car" and no issues as of yet!

I am about to take a long road trip so lets see what happens

 

I'll take 13s over 16s any day. Even in a nice vacuum situation (40-50 MAP) you should still maintain your target AFR if your TPS is above 0%.

Overrun is a different situation entirely... your fuel will actually cut and your AFRs will swing up to 20... that is completely normal.