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Old 11-15-2007, 11:07 AM   #1
Defiant Autospeed
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Default Weird fueling issue. Not enough fuel, add a pump now insanely rich???A/F weirdness.

Ok so here is the situation. FYI this is apparently resolved now. WHich is what makes me post this, I want to figure out just what the heck was going on.

I have an 07 FXT. TD05-20G 8cm, Tial 44mm EWG, TXS tmic, Alch injection, and a UTEC for EM, TurboXS Tuner for widebandStock injectors. Stock 07 injectors a pretty big. Bigger than the old STI pinks. (for those that dont know)

I ran an 18G at 18PSI and had plenty of injector
I was running my 20G at 17PSI with enough injector.
I could peak at 20PSI and taper to 15 at redline on the 20G and had JUST enough injector.
With the new boost controller, 20.5PSI, holding 18 to redline, With alcohol injection, I was running out of fuel. I was ok up to about 5000RPM, where it would go
5250 --11.7-1
5500 --12.5-1
5750 --13.2-1
6000 --14.1-1
And it would hold 14.1 to redline.


I thought it was a glitch, so I did 2 more pulls.

I am running a 10gph nozzle on the alch, so I adjusted the spray to come on at 12PSI, and set it to max flow at 17PSI so that it would be spraying at full bang well before 20PSI. I verified that the alch was in fact spraying before I installed it as well.

But I was still that lean up there.

SO, I decided that its time for fuel system upgrades. I slapped one of my fuel pumps and was going to order injectors today.

Then I went to the track last night.

On the way down I noticed that it was all the sudden, where it was struggling to get to 11.2ish-1, it was doing 10.2ish. My laptop battery was almost dead (I plugged it in to charge all day and didnt notice my wife had unplugged the cord from the wall the day before ) so I didnt do any logging or pulls on the way there. I fired up the laptop and made a run down the track. I was at 10-1 to 10.2 from 4500ish to 6000, then at 6000 I went WHAM 9.2-1.

Now, keep in mind I had set my map up to POUR gas at 6000+ since the earlier lean issue. I knew (well, THOUGHT) I was out of injector, so I set it up to give everything it could.

Here is the one last variable, that I think could possibly explain it at least a bit.


When I first installed the alch kit, I didnt have any alch, but I DID have distilled water. So I filled the spray container about halfway up with pure water. The next day I added alch, but likely only about 30%.

Then a couple days later, is when I started tuning it and ran into the lean up top issue.

Then I installed the fuel pump. Which shouldnt help more than maybe 1-2% IDC change. Certainly not enough to take a 14.1 and turn it into 9.2-1.

There were only 2 changes made since the leaning out up top issue.

1. installed walbro fuel pump
2. Added more alch to the mix, bringing it to about 50/50

And now its WAAAAAAAAAY rich.


Is it possible that I was getting almost straight water and it wasnt mixed enough (shouldnt it pretty much be perfectly blended as soon as you pour it in and it gets shaken??)?

Would straight water not change the a/f at all? (I have good alch injection experience, but almost none with water only injection)

OR
Do you think there was some other issue? The alch seemed to be working perfectly, obviously its working normally NOW, and something, I dont know what, but SOMETHING wasnt right before.

OR
Was I ok with the injector size, but somehow sucking the rails low at high RPM, and the additional flow from the pump is keeping the fuel pressure where it should be?
*I dont THINK this would be it. I dont think stock injects are enough to drop fuel pressure. But it would at least make a little sense.


Any ideas??

I mean its fine now, I dont NEED injectors now



*edited to add important setup info*
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Last edited by Defiant Autospeed; 11-15-2007 at 01:50 PM.
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Old 11-15-2007, 11:59 AM   #2
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Have you had a chance to datalog after that incident? It seems as though your IAM might've dropped for some reason causing you to run the high det. (failsafe) fuel map instead of your primary one.
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Old 11-15-2007, 01:48 PM   #3
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I have a UTEC (I should have put that in the OP) so my timing only changes if there is a det event, and only for 5 sec then its back to normal.

Yes I datalogged, that is how I know how rich I am running.

I knew something was up when I wasnt able to make the normal changes to the fuel map with the alch turned on.

Now that everything is working, my fuel map is starting to look like an alch injection fuel map, I still have a LOT of tuning to do on the fuel map before I even start adding timing, which will just send me even richer and need more fuel tuning
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Old 11-15-2007, 04:41 PM   #4
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If you are tuned to pretty much the max on the stock pump (which you are) and then install a fuel pump, it will richen up like you say.

I had a stage 2 STI tuned to low 11 AFR's and then installed a Walbro and my AFR's went to the low 10's AFR.

Fuel pump will change your tune, I don't care what anyone else says!
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Old 11-16-2007, 09:27 AM   #5
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Yes, fuel pumps change your tune. They flow different rates at different PSI's.
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Old 11-16-2007, 11:43 AM   #6
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But change it that severely????


Do we really think the 07 injectors are enough to suck the rail pressure down like that? I know they are pretty big in stock form, but that big? I think they are only 565s, which is only 25cc more than the Pinks.





I was always one to argue that a pump wont make a real difference (well, maybe a small one) but apparently, that was because I had only tuned cars that werent REALLLLLLY pushing the limits of their stock fuel system like I was.

I take it all back. Do a pump!




I cannot believe the stock injectors are handling this setup BTW. I mean I know the alch is helping, but even before the alch, 18PSI on a TD05-18G 8cm, and 17PSI on the TD05-20G 8cm they were handling it.
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Old 11-16-2007, 11:47 AM   #7
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Quote:
Originally Posted by wcbjr View Post
Yes, fuel pumps change your tune. They flow different rates at different PSI's.

They may flow different rates, but the pressure in the rail wont change as the factory pressure reg is going to do its job regardless.

I think the problem I was having is that I was pulling enough fuel that the pump couldnt supply fuel fast enough to keep the pressure in the rail where it should be. I think my motor was drinking fuel faster than the pump could send it, so the rail pressure went low, which sent the flow rates down.
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Old 11-16-2007, 11:48 AM   #8
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Quote:
Originally Posted by Defiant Autospeed View Post
Ok so here is the situation. FYI this is apparently resolved now. WHich is what makes me post this, I want to figure out just what the heck was going on.

I have an 07 FXT. TD05-20G 8cm, Tial 44mm EWG, TXS tmic, Alch injection, and a UTEC for EM, TurboXS Tuner for widebandStock injectors. Stock 07 injectors a pretty big. Bigger than the old STI pinks. (for those that dont know)

I ran an 18G at 18PSI and had plenty of injector
I was running my 20G at 17PSI with enough injector.
I could peak at 20PSI and taper to 15 at redline on the 20G and had JUST enough injector.
With the new boost controller, 20.5PSI, holding 18 to redline, With alcohol injection, I was running out of fuel. I was ok up to about 5000RPM, where it would go
5250 --11.7-1
5500 --12.5-1
5750 --13.2-1
6000 --14.1-1
And it would hold 14.1 to redline.


I thought it was a glitch, so I did 2 more pulls.

I am running a 10gph nozzle on the alch, so I adjusted the spray to come on at 12PSI, and set it to max flow at 17PSI so that it would be spraying at full bang well before 20PSI. I verified that the alch was in fact spraying before I installed it as well.

But I was still that lean up there.

SO, I decided that its time for fuel system upgrades. I slapped one of my fuel pumps and was going to order injectors today.

Then I went to the track last night.

On the way down I noticed that it was all the sudden, where it was struggling to get to 11.2ish-1, it was doing 10.2ish. My laptop battery was almost dead (I plugged it in to charge all day and didnt notice my wife had unplugged the cord from the wall the day before ) so I didnt do any logging or pulls on the way there. I fired up the laptop and made a run down the track. I was at 10-1 to 10.2 from 4500ish to 6000, then at 6000 I went WHAM 9.2-1.

Now, keep in mind I had set my map up to POUR gas at 6000+ since the earlier lean issue. I knew (well, THOUGHT) I was out of injector, so I set it up to give everything it could.

Here is the one last variable, that I think could possibly explain it at least a bit.


When I first installed the alch kit, I didnt have any alch, but I DID have distilled water. So I filled the spray container about halfway up with pure water. The next day I added alch, but likely only about 30%.

Then a couple days later, is when I started tuning it and ran into the lean up top issue.

Then I installed the fuel pump. Which shouldnt help more than maybe 1-2% IDC change. Certainly not enough to take a 14.1 and turn it into 9.2-1.

There were only 2 changes made since the leaning out up top issue.

1. installed walbro fuel pump
2. Added more alch to the mix, bringing it to about 50/50

And now its WAAAAAAAAAY rich.


Is it possible that I was getting almost straight water and it wasnt mixed enough (shouldnt it pretty much be perfectly blended as soon as you pour it in and it gets shaken??)?

Would straight water not change the a/f at all? (I have good alch injection experience, but almost none with water only injection)

OR
Do you think there was some other issue? The alch seemed to be working perfectly, obviously its working normally NOW, and something, I dont know what, but SOMETHING wasnt right before.

OR
Was I ok with the injector size, but somehow sucking the rails low at high RPM, and the additional flow from the pump is keeping the fuel pressure where it should be?*I dont THINK this would be it. I dont think stock injects are enough to drop fuel pressure. But it would at least make a little sense.


Any ideas??

I mean its fine now, I dont NEED injectors now



*edited to add important setup info*
...d00000d.....the stock pump is 145l/hr
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Old 11-16-2007, 11:49 AM   #9
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...mebbe ya shoulda already talked ta yer Uncle
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Old 11-16-2007, 11:55 AM   #10
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Dude you know me, ,I know everything right? @myself
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Old 11-16-2007, 12:48 PM   #11
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I wonder if you're maxing out the maf sensor. Have you logged the maf voltage?
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Old 11-16-2007, 01:09 PM   #12
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Im running speed density, the MAF isnt read for fueling.
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Old 11-16-2007, 03:49 PM   #13
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pressure can stay the same, but flow(volume) will increase. VF-39 flows a lot less air than a GT35R even though they are at the same pressure. Fuel pumps are the same thing.
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Old 11-16-2007, 05:17 PM   #14
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Right. Thats what I am saying. On the stock pump there wasnt enough flow to keep the pressure in the rail where it belongs. Now that the pump can flow a lot more, the pressure stays solid and the injectors are able to get fuel into the cyls (because there is actually enough fuel there for them to inject)
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Old 11-17-2007, 12:29 AM   #15
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You and I are not saying the same thing. Pressure is staying constant, you aren't sucking the fuel out of the lines. The Walbro flows a lot more volume than the stock pump at the same pressure, just like the VF39 vs the GT35R.

Pressure and volume are two different things.
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Old 11-17-2007, 09:22 AM   #16
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That's what I was trying to say earlier, too, SloRice. I hear what you are sayin'.
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Old 11-17-2007, 12:51 PM   #17
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Quote:
Originally Posted by Defiant Autospeed View Post

Is it possible that I was getting almost straight water and it wasnt mixed enough (shouldnt it pretty much be perfectly blended as soon as you pour it in and it gets shaken??)?
Just to add, water and alcohol are miscible. As soon as you pour it in, it "dissolves" and disperses throughout. I really cant see this being your issue, but I would look to the fuel pump first, as others have already mentioned.
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Old 11-18-2007, 03:54 PM   #18
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Quote:
Originally Posted by SloRice View Post
You and I are not saying the same thing. Pressure is staying constant, you aren't sucking the fuel out of the lines. The Walbro flows a lot more volume than the stock pump at the same pressure, just like the VF39 vs the GT35R.

Pressure and volume are two different things.

You are not understanding what I am saying though (or so it would appear).

I know the pump has the same pressure, I know its only a higher volume.

BUT
If the stock pump cant flow enough volume to keep the rails full, the pressure will drop.

If the volume the injectors are flowing, or trying to flow more than the volume than the pump can put out, the pressure drops below the required spec.



Which is why with the higher volume pump, pressure wont drop below spec(or isnt dropping below spec in this case I mean).
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Old 11-18-2007, 03:55 PM   #19
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Originally Posted by cucamelsmd15 View Post
I would look to the fuel pump first, as others have already mentioned.
I already have and the pump fixed the problem. That was the entire point of this post I posted that the pump fixed it in the first post.
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Old 11-18-2007, 11:41 PM   #20
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i think it was the pump.. here is why i think so...

On the dyno a couple of weeks ago, we found that one of my pumps was losing fuel pressure as soon as we came onto a few psi of boost on the dyno. Things would lean up like yours and the tuner let out before any damage was done.

Fortunately my fuel system uses 2 fuel pumps, so we made a quick alteration just as a test to see what happens to fuel pressure with 2 pumps running... A side effect of turning on the second pump was that the AFR's went from normal around 14's down to the 8's... The fuel map needed a retune it seemed.

Unrelated to your issue, we still found fuel pressure dropping on boost, but it was occuring at a higher boost level than before, but still to be taxing even one of my fuel pumps. but we later traced it to a faulty FPR which was opening once pressure reached a certain boost level.

So I have seen what happens to the fueling of the car when you change the number of fuel pumps running on the car.. even with a constant fuel pressure, it makes the ecu require a retune immediately.
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Old 11-19-2007, 12:04 AM   #21
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I think I missed the part about you installing a new pump last night (too drunk). Yeah if a pump flows more than the one it replaces, more fuel will flow through the FPR making your AFRs rich.
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Old 11-19-2007, 04:30 AM   #22
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man you been having all sorts of problems with your xt man, i hope that you get that running right man. good luck
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