[Blown95ImpalaSS]

Hi guys, car has been healthy for a while time but I just noticed a few small issues. Car is FBO + inlets + stage 1 inline pump + e50 mix.

Symptoms include:

- weak ish cold start
- hiccups occasionally on warm start (sounds like a small miss pop, pop pop, pop, then idle stabilizes)
- lambda bank 1 & 2 don't immediately go to 234.95 after pull, they kinda bounce for a sec
- car sounds like it has MHD burble set on soft, but it's turned off
- no codes

Here are a few logs where you can see the lambda issue, but fueling is otherwise in good shape:

e50:

https://datazap.me/u/blown95impalass...a=2-3-15-16-22
https://datazap.me/u/blown95impalass...a=3-4-14-15-21

91 pump gas:

https://datazap.me/u/blown95impalass...a=3-4-15-16-22

Maintenance includes:
- index 12s w/about 20k miles on them
- new O2s w/about 20k miles on them
- VCG, OPG, new plugs, new coils etc.
- BMS catch can, RB pcv valve, VTT crankcase breather


Do I need new injectors already?!

Here's a filthy pic:

[bbnks2]

When people refer to lamda on decel "bouncing around a bit" they mean more like this:

Those logs don't look bad at all in regard to AFR. If you weren't hitting 235 or it wasn't staying at 235 on decel then that would point more to an injector sticking open. I don't think you'll ever see both banks go lean at exactly the same time and a <1sec difference is negligible.

Idle and cold starts could be in the tune or just normal. Really impossible to tell over the internet.

[Blown95ImpalaSS]

Cool, appreciate the reply bbnks2. I'll keep an eye on it

[Blown95ImpalaSS]

Gents, I logged a warm start today and it was super funky/missed a bit, then smoothed out after 5 seconds or so. See anything in this log that would point to a hardware issue?

https://datazap.me/u/blown95impalass...og=0&data=3-21

How many miles on plugs?

Pull them after they've sat overnight and see if you notice anything weird.

[Bimmer_Engineer]

Originally Posted by Blown95ImpalaSS

Gents, I logged a warm start today and it was super funky/missed a bit, then smoothed out after 5 seconds or so. See anything in this log that would point to a hardware issue?

https://datazap.me/u/blown95impalass...og=0&data=3-21

Do you have the cold start idle turned off on MHD? I was experiencing something similar and it went away after I put the cold start idle function back to stock...

[Blown95ImpalaSS]

Originally Posted by FCobra94

How many miles on plugs?

Pull them after they've sat overnight and see if you notice anything weird.

Roger that. Plugs have about 5k on them, put new NGK set in before tuning, WOT logs are good besides that delayed returned to 234.95

I still think VCG or valve cover cracked. Keep ya posted either way

[mosherif11]

Any luck on what causes this for you? I know it’s been about a8 months but I’m struggling over here to figure it out.

I have Small popping/ hivcup sound at idle & my car doesn’t like start ups... it’s not long cranks it’s just more exaggerated hiccups...

[Blown95ImpalaSS]

Car is long gone but I did fix this before it sold. One of the index 12s went bad after ~30k miles of e50 mix. Took forever to figure out. Once replaced everything was bang on

[feuer]

Originally Posted by Blown95ImpalaSS

Car is long gone but I did fix this before it sold. One of the index 12s went bad after ~30k miles of e50 mix. Took forever to figure out. Once replaced everything was bang on

How did you figure out?

[Blown95ImpalaSS]

Originally Posted by feuer

How did you figure out?

After the symptoms mentioned above, at WOT sometimes the car would be perfect, then other times randomly break up. Tuner (Wedge) suggested injectors but I thought it was a long shot because they were 12s. Eventually removed injectors and replaced one that was way more gunked up than the rest. Clean logs after that.

I miss the e90 a lot. Should have kept it and installed a real lsd