FIXED: Installed Edelbrock SC. Now car is throwing CELs

[Ultramaroon]

Originally Posted by localhost

Yeah, definitely going back to the stock header is a good test - just a real pain haha. And yes, I do have the Ecutek cable and software.

I've emailed my local tuner to see if they can fit me in since I'm fairly certain it just needs to be custom tuned to compensate for the header but I'm not sure if they even do any tuning in the winter.

You can log with that stuff, right? Take a minute or so of cruising when it's all warmed up. Sample all the channels you can and post it up on datazap.me


https://datazap.me/u/ultramaroon/log...?log=0&data=38

[localhost]

Originally Posted by Ultramaroon

You can log with that stuff, right? Take a minute or so of cruising when it's all warmed up. Sample all the channels you can and post it up on datazap.me


https://datazap.me/u/ultramaroon/log...?log=0&data=38

Yep it can log but I don't have a laptop that can run the Ecutek software without being plugged in. But I also have my OFT from when I was still NA, so I'll probably just use that.

[localhost]

Datalog: https://datazap.me/u/rb28dett/nov-17-cruise

Short cruise after everything had warmed up. Very little throttle throughout, with one instance up to 4k RPM with light throttle as well.

[Decep]

The edelbrock tune is not for catless headers.

[Ultramaroon]

Originally Posted by localhost

Datalog: https://datazap.me/u/rb28dett/nov-17-cruise

Short cruise after everything had warmed up. Very little throttle throughout, with one instance up to 4k RPM with light throttle as well.

Certainly shows something out of balance. I'm still an amateur at this but lots of experienced people will see it.

[toast]

An engine is basically an air pump. Your air pump can now flow about 20% more air because the outlet is less clogged. You can't run the tune designed for 20% less air.

It is difficult to drive because the throttle tables in the Edelbrock tune are left like they are in stock form - a small pedal input results in a large change in throttlebody opening. In stock form this is done so the car doesn't feel like a slug. When you have forced induction available this makes it very tough to keep the engine in vacuum.

Swap the headers or get a real tune ASAP.

[toast]

Headers change the VE. The calculation for load uses VE in the divisor, so for a given measured airflow the ECU will undervalue the engine load and will not add the appropriate amount of fuel until the AFR shows lean and then it will attempt to correct it up to the maximum fuel trim allowed.

I've never seen fuel trims over 27%, I didn't know they could go as high as his log is reporting. I guess that is also determined in the tune.

[thinkV]

Originally Posted by localhost

I double checked the bracket and it was tight. No movement at all. The connectors on the back were all also completely seated and locked in place.

Connectors: https://i.imgur.com/VRWgCsM.jpg

Bracket: https://i.imgur.com/FmrgCLO.jpg

Just FYI there's another hidden bolt on the left of that backet quite far down that goes straight into the block, that one in particular is the grounding bolt, so check that one too.

[localhost]

Originally Posted by thinkV

Just FYI there's another hidden bolt on the left of that backet quite far down that goes straight into the block, that one in particular is the grounding bolt, so check that one too.

Yep, all 3 bolts are nice and tight.

Reading through these comments I'm fairly certain my catless header with a tune that isn't expecting one is the root cause of these issues. I'm going to swap back to the OEM ones this weekend and see if it gets better.

[localhost]

Originally Posted by solidsnake11

Hope it fixes your issues.

Anybody here ever have the O2 sensor 1 go bad? Because that would defiantly throw things off.


O2 sensor 2 may be throwing things off without the cat. Ecutek says something about turning it off for boosted application IIRC.

Injector driver defiantly needs grounded. My car came without the bracket and was doing very weird stuff before I grounded it.

Is there a way to verify that its correctly grounded other than just checking the tightness of those bolts? I'm guessing checking if there's low resistance between the injector ECU housing (or that bracket) and the battery negative should be good?

[Ultramaroon]

Originally Posted by localhost

Is there a way to verify that its correctly grounded other than just checking the tightness of those bolts? I'm guessing checking if there's low resistance between the injector ECU housing (or that bracket) and the battery negative should be good?

It's not the problem. Just make sure the screws are tight.

[Ultramaroon]

Yeah. I didn't mean to sound dismissive. It's just that it's an Occam's razor thing. Don't get too caught up in the least likely stuff.

[localhost]

Originally Posted by solidsnake11

OP please update the fix to help others.
Thank you.

I haven't fixed it yet. I'm planning on swapping back to the OEM headers on Saturday when I have some time and seeing if it fixes it.

That said, I had to drive the car to work today and I noticed something very interesting.

Under very light throttle and low rpm, the LTFT is sky high as I've shown in the previous log (over 35% sometimes). I've been driving it like this for the past few days to avoid damaging something but today I had to give it some gas and get it to the higher RPM to make a merge and I noticed that at around 4500rpm and beyond, both LTFT and STFT would drop to 0 and stay there as long as I was on the accelerator. I suspect 4500rpm is where the system transitions from PI to DI and there's a noticeable hiccup/blip/lack of acceleration for a split second before the car starts accelerating again and LTFT and STFT both drop to 0.

Essentially, below 4500rpm LTFT is very high and the engine is probably using PI. Past 4500rpm it uses DI and fuel trims are perfect (so is AFR). There is also a small noticeable transition between these two modes noticed as a momentary lack in acceleration.

I didn't have my OFT plugged in to log, but I did have the torque app for monitoring and I was able to get some data logs with that. The resolution is low but it shows exactly what I mean: https://datazap.me/u/rb28dett/nov-21...a=3-5&mark=153 . Every time you see LTFT drop down to 0 was when the engine had crossed past 4500RPM.

I've linked it to an area where I could be above 4500rpm for a (very) short period of time due to traffic.

Question is whether this behavior is because of the wrong header for the tune or if there is something going on with my injectors/fuelling.

[localhost]

Originally Posted by solidsnake11

Logs shows your AF is great in boost.

Yep. I noticed that AFR generally looked pretty good regardless of RPM or boost pressure and tracked the commanded values pretty closely. At least the engine doesn't seem to be running lean.