Time for a Cp-e HPFP! Before & after logs

[ms6dj]

So, I've got quite alot of stuff hooked up to the car now, and it's past time for a fuel pump upgrade. There's consistently some momentary hesitation and sputtering at WOT shifts from 2-3, and sometime 1-2 that aren't there under any other conditions, and it doesn't happen if I ease the pedal in after this kind of shift (rather than lift/shift/slam pedal). AP is flashed with a map same as mods. Tested for boost leak, checked spark plugs, all is well.

Checking out the datalogs, fuel pressure is dipping too much. Not catastrophically as others have reported, but it's enough. And with all the mods on the car, during WOT the fuel psi needs to be at least 1650-1700 if not higher due to the higher volume of fuel required to maintain safe AFR when more o2 molecules are being forced into the chambers with higher-than-stock boost (I believe... correct me if that's wrong... pV=nRT, anybody?). AFR is a bit too lean in many spots as well, which may be caused by several things but it looks like inadequate fuel pressure is likely the culprit. And since this mod is highly recommended across the board for both engine safety and performance to match all the bolt on mods, it's high time I got it.

I have the cp-e HPFP on order, should arrive this week. I ponied up the extra cashwa for cp-e for peace of mind and lifetime warranty from a well established place. I should get it next weekend, after which I want to post up datalogs for after the install. I've put up the 'before' logs for now. And until I get it installed, no more WOT, just to be on the safe side. Going to be tough...

 

[Blendercloud]

I've noticed some hesitation coming out of mine as well. We're both using the same AP map. I need to duplicate this log and see where my parameters stand.

At first, I originally thought that the stock exhaust was maybe choking out the turbo (not exhausting fast enough). It seems as though I should dig a little deeper.

 

[ms6dj]

Hopefully the new fuel pump cures it.... I am pretty confident it will. I will be sure to let you know how it goes and post the after logs. I believe I'll have to reset the ECU and let it relearn the fuel trims, so it may be another several days after the install until I can get some nice data.

New pump arrives this Saturday and between that and installing the H&R springs, it should be a nice day.

 

[Mistersix]

subscribing to this thread!!!

 

[FORZDA 1]

So, .... There's consistently some momentary hesitation and sputtering at WOT shifts from 2-3, and sometime 1-2 that aren't there under any other conditions, and it doesn't happen if I ease the pedal in after this kind of shift (rather than lift/shift/slam pedal). ....

This problem is likely not the HPFP, it's the long transition time from open/closed/open loop in the ECU. If you're running the OTS map, it needs to be tweaked to drop the open loop delay time in half or more....(been there, done that on the OEM HPFP), or you can just shift without lifting throttle.....

You can go ahead and buy that $695 HPFP for your peace-of-mind though.

Edit: Did you perform the MAF calibration with the AP?

 

[ms6dj]

This problem is likely not the HPFP, it's the long transition time from open/closed/open loop in the ECU. If you're running the OTS map, it needs to be tweaked to drop the open loop delay time in half or more....(been there, done that on the OEM HPFP), or you can just shift without lifting throttle.....

You can go ahead and buy that $695 HPFP for your peace-of-mind though.

Edit: Did you perform the MAF calibration with the AP?

I am running an OTS map... still have yet to work with ATR but it's sitting on my PC. Sounds like I need to dive into Cobb's documentation already! Been putting it off. Thanks for the tip, I'll look around to see what I can find on tweaking the open loop delay time- that would be great if it cured the issue. In the meantime, Forzda do you have a link to any threads on this (or is it discussed in Cobb's documentaion?) There's a 'Closed Loop - Exit Delay' table (well tables A, B and C but I think I've read only table A is used), it's set to 30 in table A, and 80 in B & C. Is this what you're referring to as needing to be halved or more?

Also, haven't done any MAF calibrations... glanced at it in Cobb's docs... sounds like I need to get into those more. Don't know much about tuning (obviously) but Cobb's docs look fairly meaty.

I do still think the HPFP should be a good investment whether or not it cures this actual problem... just to keep things safe. ~$600 is not too bad for me, luckily. Hopefully I'll find it to be worth the investment; (sad2) We'll see soon enough.

I did get the HPFP but forgot today was Father's Day, so I was only able to get the springs in this weekend since I blew my time on that first. Hoping to get it in this week sometime. Also will check in with ATR to see if I can make use of your tips Forzda.

 

[ms6dj]

EDIT to the above (laptop is choking on the Edit link): I read Cobb's docs at work today (being a programmer stuffed in tallcube makes it easy). They weren't as bad as I thought. So, yes the MAF calibration had already been performed using the historically learned LTFT data method (though I didn't know it was called that, I had read that's what you should do every time after resetting ECU or map flash)- I did not alter the MAF table manually but rather let the car learn per Cobb's instructions- did this as soon as I flashed the map and after ~75 miles of light throttle driving several weeks back- the problem still persists after that. I do need to check up again on my LTFTs to see if they're in line, but assuming they're within +/-8% and ideally near 0, that leaves the open/closed loop adjustment as the only other thing I can check.

I did find some values at another forum regarding the Closed Loop issue mentioned. I will try reflashing with these values and log another ~75 miles to calibrate MAF again before doing the fuel pump to see if this solves the issue. They are posted below, and are indeed half of what is in the Exit Delay tables in the OTS map I'm using.

Exit Delay A
15

Exit Delay B
40

Exit Delay C
40

Closed Loop - Max Load C
2.00 2.00 2.00 1.20 1.55 1.57 1.57 1.40 1.30 0.40 0.33 0.00 0.00 0.00

Closed Loop - Max Throttle B
75.00 75.00 75.00 75.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00

Closed Loop - Max Throttle C
75.00 75.00 75.00 75.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00

Closed Loop - Max Throttle E
75.00 75.00 75.00 75.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00 60.00

 

[ms6dj]

Checked LTFTs on the drive home today... in great shape. Never strayed outside -3/5 over highway cruise, stop/go, part throttle and WOT. Went to 0/1 and stayed there for the times I could go WOT. So looks like the MAF calibration is set well.

 

[ms6dj]

Pump is in and ECU is loaded with unmodified OTS map. Need to drive the ~75 miles for MAF calibration and then I'll log things. After that I'll flash the map with the closed loop modifications, recalibrate MAF, and post logs again, to see if there's a difference with before FP, after FP, and after FP+closed loop change.