Fueling on hybrids

[AWSAWS]

Hi Guys,
I have been trying to run E50 with meth injection. I am working with Trebila and he's doing a great job.
However the fueling appears to be an issue for my car.

Is 20+ psi on GC turbos, running E50 and meth injection ( with stage 2 fuel-it low pressure pump) just too much too ask? My port injection meth system should flow alot of meth.

Any way I can calculate how much air is being moved and how much fuel is required.

Say 11 degrees at 6800, AFR\lambda of 0.85

I basically don't know if my hpfp is weak or lpfp is maxed or maybe 02 sensors are reading wrong.

I have tried resetting adaptations. I was basically wondering with a jb4 and a flash would it be a good idea to drive a bit with the jb4 off? To help learn in values?

I've attached a log when running 23% ethanol and meth. HPFP still went too low.

Thanks.

[Chris@VargasTurboTech]

Post that on datazap so people can easily see it and read!

The GC's make more power than stock frame designs per pound of indicated boost but you seem to be running out of hpfp a little earlier than I'd expect, especially spraying methanol.

[RSL]

Has your LP fallen lower over time at idle/normal driving too? I see your starting LP is 59-60psi and "cruise" is about 57psi. Curious if those continue to get lower. I had issues with JB4 app fuel pressure readings being lower than the interface and both were lower than MHD (INPA matched MHD readings). Over the course of months, the pressure dropped as well, so 2 things going on: incorrect (low) readings and declining pressure. I turned FOL off months before, but that never stopped LP from reaching new lows almost weekly. It got to be ridiculously low (like 40psi at idle per JB4 app, low 50s on MHD/INPA). HPFP stayed OK the whole time, but that was all on 93 only and 21-22psi on RR600s.

During that time, I had checked the LPFP twice, reset the usual adaptations and FCV multiple times and even replaced the filter/FPR. No help. I finally had enough, pulled the JB4 out and though MHD/INPA read ~12psi higher, FP was still below "norm" (low/mid-50s at idle). I replaced the LP sensor even though I had no codes for it and reset the EKP. Problem solved. Idled 65-66psi, drive is around 70-71psi, WOT is 79-80psi (on MHD, confirmed on INPA). That's been 2 months and no change in those pressures. JB4 never went back in, re-scaled flash only for low 20s psi, done.

I'm honestly not sure which resolved it: new LP sensor or resetting the EKP, but both are cheap/free quick things to try. Why mine got so low in the first place is unknown, but could really only be a couple of things.

[AWSAWS]

Has your LP fallen lower over time at idle/normal driving too? I see your starting LP is 59-60psi and "cruise" is about 57psi. Curious if those continue to get lower. I had issues with JB4 app fuel pressure readings being lower than the interface and both were lower than MHD (INPA matched MHD readings). Over the course of months, the pressure dropped as well, so 2 things going on: incorrect (low) readings and declining pressure. I turned FOL off months before, but that never stopped LP from reaching new lows almost weekly. It got to be ridiculously low (like 40psi at idle per JB4 app, low 50s on MHD/INPA). HPFP stayed OK the whole time, but that was all on 93 only and 21-22psi on RR600s.

During that time, I had checked the LPFP twice, reset the usual adaptations and FCV multiple times and even replaced the filter/FPR. No help. I finally had enough, pulled the JB4 out and though MHD/INPA read ~12psi higher, FP was still below "norm" (low/mid-50s at idle). I replaced the LP sensor even though I had no codes for it and reset the EKP. Problem solved. Idled 65-66psi, drive is around 70-71psi, WOT is 79-80psi (on MHD, confirmed on INPA). That's been 2 months and no change in those pressures. JB4 never went back in, re-scaled flash only for low 20s psi, done.

I'm honestly not sure which resolved it: new LP sensor or resetting the EKP, but both are cheap/free quick things to try. Why mine got so low in the first place is unknown, but could really only be a couple of things.

This argument definitely has some substance. I reset adaptations with INPA and things seemed to get much better. The car is not 100% but things appear to be better.

Although on my last log (not posted here) the high pressure pump dropped again but the trims were diving and the car ran so rich that it was back firing after letting off the gas. So much fuel left in the exhaust.

Yesterday I had reset adaptations with MHD and JB4 many times but they didn't seem to have an effect like INPA did. Maybe something about my software or module versions. I don't know.

Check this out. This is the same car and roughly the same type of pull on the same fuel. Before trims are maxing out and hpf drops. After the trims just dive and hpf stays strong. Like you RSL I am not 100% sure of the problem or the cure.

[Sticky]

Weren't you having HPFP issues anyway?

[AWSAWS]

Weren't you having HPFP issues anyway?

To sum it up.
On the test at 20 psi and E50 fuel. The before shows trims over 25. The car is demanding more fuel and the hpfp pressure is dropping. It needs more fuel and the pressure is already too low so its doubly bad.

In the after the trims are below 25. The car is actually holding fuel back and the pressure is well within range. It's actually doubly good.

It was after that I tried 22 psi that the hpfp pressure dipped but the trims again were signaling that fuel needed to be pulled out.

[RSL]

The boost curves are different and you're working off of a relatively fixed level that the DME sees. I can say that when changing scaling (which is essentially what you're doing with JB4 over what the DME is fed AFAIK), fuel trims can move quite a bit. While you need to pay attention to where the trims are and account for them in the BEF, just saying that simply changing target (scale) may move trims significantly in portions of the RPM band from where they were. Doesn't solve the fuel pressure problem, just something to be aware of.

[AWSAWS]

The boost curves are different and you're working off of a relatively fixed level that the DME sees. I can say that when changing scaling (which is essentially what you're doing with JB4 over what the DME is fed AFAIK), fuel trims can move quite a bit. While you need to pay attention to where the trims are and account for them in the BEF, just saying that simply changing target (scale) may move trims significantly in portions of the RPM band from where they were. Doesn't solve the fuel pressure problem, just something to be aware of.

It does actually look like it could be low pressure pump related. Whether it's the monitoring not being ideal or the physical unit not keeping up I don't know.

Would love to double up the walbros to see if that solves this problem.

[RSL]

Did you reset EKP? You're positive the meth is flowing? It's possible you just need more pump, but I'd try everything else first

[AWSAWS]

Did you reset EKP? You're positive the meth is flowing? It's possible you just need more pump, but I'd try everything else first

EKP, I'm not sure. Is it in the INPA adaptations settings?

I'll do some Googling but hopefully it's another thing I can try.

I did E50 runs yesterday at about 20 psi. HPFP dipped to 6 and LPFP to 50 on one of them. I think the problem is the meth is a bit slow to start. Possibly due to my 7 nozzle setup.

Once meth flows I think everything is good. The low pressure pump is getting down to 50 at times though.

Here's visual examples. You can see the trims shooting down once meth comes in. I guess these turbos spool up so fast that there's a big fuel demand before the meth flows fully.







As you can see the logs are totally different from the first time where my trims were stuck on 50.

[RSL]

EKP, I'm not sure. Is it in the INPA adaptations settings?

I'll do some Googling but hopefully it's another thing I can try.

I did E50 runs yesterday at about 20 psi. HPFP dipped to 6 and LPFP to 50 on one of them. I think the problem is the meth is a bit slow to start. Possibly due to my 7 nozzle setup.

Once meth flows I think everything is good. The low pressure pump is getting down to 50 at times though.

Here's visual examples. You can see the trims shooting down once meth comes in. I guess these turbos spool up so fast that there's a big fuel demand before the meth flows fully.

As you can see the logs are totally different from the first time where my trims were stuck on 50.

INPA has it, but it didn't find my module. Maybe it will work for you, but I used Tool32. It was steuern reset IIRC, there's also a null reset IIRC, no clue what that one does.

I can see there were target changes in those logs, no changes in the BEF too between those runs? A lot of things can change trims and you have a lot of variables in the mix, meth is just one. There are some sizeable differences in FOL between some of those logs, but note that both pumps look better at lower FOL, yours and the before/after above. I think the trims need to be addressed in the BEF to keep FOL at a reasonable level. Where the trims peak, AFR seems closer to 13-14:1, but it's hard to tell on screens. From the log in the OP though, it doesn't make it above 13:1 until almost 6000rpm. Might try fattening it up where trims are remotely close to 50.

Trims drive FOL supposedly. Constantly high/pegged trims cause a fake a low HPFP reading to the DME, which in turn, supposedly commands more of the LPFP. So you've got a current-heavy pump on the EKP and JB4 keeps telling the EKP to push it harder. Problem is, it's asking more and more of the pump/EKP, but the problem (high trims) never gets resolved and they cycle continues until you've pegged FOL, which you have. At least that's my take on it.

Anyway, adding AFR in lieu of letting the DME trim it up won't solve an actual fuel shortage, but should stop the JB4 from trying to force the pumps/EKP to do more (which it seems they can't). Of course, the other things you can try is dropping the E content a bit or getting meth in earlier, but relying on meth for fueling could be an accident waiting to happen.

[frontside0815]

Me and a friend had a similar Problem- LPFP Dipped to 50-60 with my custom Walbro 450 (so comparable to fuel it stage 2). Then HPFP crashed and trims maxed out....

Because our tuner said that he had like 10 customers who all had Problems with the walbro 450, we switched the 450 for a fuel it stage 1 (OEM Bucket + 255 Inline).

Now all Problems were gone for both of us! I wouldnt recommend the 450 anymore...I dont know if that helps you, but you maybe could try another pump...

I actually changed everything from HPFP to INjectors, fuel lines etc etc. But in the end only the LPFP "Downgrade" helped!

[AWSAWS]

Me and a friend had a similar Problem- LPFP Dipped to 50-60 with my custom Walbro 450 (so comparable to fuel it stage 2). Then HPFP crashed and trims maxed out....

Because our tuner said that he had like 10 customers who all had Problems with the walbro 450, we switched the 450 for a fuel it stage 1 (OEM Bucket + 255 Inline).

Now all Problems were gone for both of us! I wouldnt recommend the 450 anymore...I dont know if that helps you, but you maybe could try another pump...

I actually changed everything from HPFP to INjectors, fuel lines etc etc. But in the end only the LPFP "Downgrade" helped!

Well that's interesting about the 450 pump. A friend of mine has the 255 stage 1 upgrade and he's fitting stage2+ turbos next month so I'll see how he gets on.

It does seem the lpfp is getting down to 50 quite quickly. I had a go at resetting the EKP with ISTA. It said it did it but things seem the same. Good but not great. Disabling the FOL learning and setting it at a lower value after resetting other adaptations seems to have solved some of the problems.

Seems I need more flow from the pump. I'm interested in a dual 450 setup going forward if I can get the bit. Another thing I'm considering is cutting the bottom off my stage 2 fuel it bucket and attaching a hydramat to go to essentially the bucketless design which seems to have more flow potential.

It looks like my pump does get to 70's psi but quickly drops at the top end rpms. The meth comes in a bit slow but my DIY port injection was always experimental.

Cruising around the lpfp does often seem a bit lower than I would like. Mid 50's.

I'll keep investigating and come up with a plan going forward. Thanks for your help guys.