Weird AFR/RPM issue and false knock with 2018 Intake Manifold. Help?

[Joe 5.0]

My tuner is going to take a look at it again soon. As far as I know, they've done the exact same setup (18 mani, gt350 airbox with stock tb, ff tune, even down to the same exhaust - tsp headers + mbrp street catback) with another one of their customers. I spoke with the other customer and they said they used to run a pmas and since the switch to the gt350 airbox, their drivability got better :shrug:.

I spoke with my tuner today and he said they haven't had issues with the sleeve they use to fit the airbox to the tb, but he'll take a look at it anyways.

I'll let you know if messing with the airbox does anything, but if nothing is fixed, next best bet is the mani.

Also forgot to ask, are you on 93 or e85? Mine hesitates on startup as well but only when I'm running e85. Pretty sure it's normal, but I could be wrong.

Yes, please let me know if messing around with the airbox fixes things. My tuner (who has been extremely patient with me) told me that the AFR fluctuation is normal with open element intakes like mine. I'm at the point where I just want the car running perfectly and I'll be done (until boost later down the road).

The hesitation has been occurring on 93 octane. My tuner said it's fine, but the car didn't do this beforehand. Sometimes the car starts perfectly, other times I get the delay/hesitation.

I need to get my O2 sensors re-angled before I fill up with E85 and go datalogging.

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[BmacIL]

@Joe 5.0 did you ever find out from your tuner what the low oil pressure light was from?

 

[Joe 5.0]

@Joe 5.0 did you ever find out from your tuner what the low oil pressure light was from?

Yes! The tuner didn't account for the oil gauge that is part of the performance package. A simple email and tune revision fixed the issue.

 

[BmacIL]

Yes! The tuner didn't account for the oil gauge that is part of the performance package. A simple email and tune revision fixed the issue.

I think I may have the opposite problem LOL.

 

[Joe 5.0]

I think I may have the opposite problem LOL.

What issues are you experiencing?

 

[BmacIL]

What issues are you experiencing?

Low oil pressure light/display in the cluster (because no PP gauges), but I did not touch anything at all that would affect this. I'm 99.99% sure it's not a real thing.

 

[Joe 5.0]

Low oil pressure light/display in the cluster (because no PP gauges), but I did not touch anything at all that would affect this. I'm 99.99% sure it's not a real thing.

You've probably already done this, but email your tuner and let them know the situation. I wouldn't sweat it.

You magically have low oil pressure after uploading a tune? I highly doubt that!

 

[BmacIL]

You've probably already done this, but email your tuner and let them know the situation. I wouldn't sweat it.

You magically have low oil pressure after uploading a tune? I highly doubt that!

Well I also did the manifold, TB and CAI swap, but again, it would not cause this, and the sending unit is down below.

 

[Joe 5.0]

Well I also did the manifold, TB and CAI swap, but again, it would not cause this, and the sending unit is down below.

I wouldn't stress it. I would just avoid driving the car until you hear back from your tuner.

 

[BmacIL]

I wouldn't stress it. I would just avoid driving the car until you hear back from your tuner.

Can't do that unfortunately, but I honestly am not that worried as I am 100% certain I didn't change anything in the the physical oiling system of the engine. Shaun thinks I may have a different pressure sensor from what he would typically expect and will be changing it in my tune update.

 

[heyitzkhan]

Did you all ever figure out the idle fluctuation issues you were having with the 18' manifold? Some people are saying its normal with the IMRC's locked out; I beg to differ.

 

[BmacIL]

Did you all ever figure out the idle fluctuation issues you were having with the 18' manifold? Some people are saying its normal with the IMRC's locked out; I beg to differ.

I think for @Joe 5.0 it was fixed changing to the stock throttle body. I still have a less stable idle than I'd like as well. I may switch over to the stock TB for that reason. I think it's been giving me fits along with a very non-linear torque response around ~15 degrees (is normal with this throttle body, the way the airflow changes with opening angle).

 

[Joe 5.0]

I think for @Joe 5.0 it was fixed changing to the stock throttle body. I still have a less stable idle than I'd like as well. I may switch over to the stock TB for that reason. I think it's been giving me fits along with a very non-linear torque response around ~15 degrees (is normal with this throttle body, the way the airflow changes with opening angle).

I'm still having the same issues. Switching to the stock throttle body only made them slightly better.

 

[aleccesarenriquez]

I'm not sure what variable changed for me other than switching tuners but I'm no longer having idle issues. On 93, there was no fluctuation at all. On E85, there is a tiny bit of fluctuation (maybe like +/- 20 rpms) but nothing concerning. On my previous tune, it would fluctuate so heavily it would occasionally cause my car to stall or other times sound like I'm intentionally revving (not ideal when next to a cop lol).

 

[heyitzkhan]

Just curious, are you all using zip ties or billet lockouts for the IMRC's?

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