Goes lean when throttle is applied

No, it is attached to the bottom of the diaphragm, but mine was offset slightly, so you could actually see a groove getting worn into it by the seat.
If you remove the vacuum nipple, is it rubbing the spring inside?

 

[SleepinGVR4]

No the vacuum nipple is not rubbing on the spring. I took it back apart to make sure. And then I reset my FP and reset my ecu. Everything reset back to 100% but then after a couple minutes of idling, the LOW trim went back to 81%.

Another thing I noticed is, say I'm in 5th gear and going kinda slow, but instead of down shifting I just give it more throttle. My WB reads lean, around 16 - 17 until my rpms get back up. And say I'm just cruising in 5th (WB is reading stoich) on the highway and let off the throttle, instead of the WB immediately reading nothing, it goes rich first (12 - 13) and then reads nothing. And by nothing I mean it just displays those dashes because its so lean its not reading anything because the injectors barely need to spray any fuel when its coasting.

I don't remember my car doing this when I first put it together. Seems like its getting progressively worse.

Also Jeff I can't find the piece of paper with the specs of my eprom chip printed on it. Do you print the deadtime on the top of the actually eprom chip with the other specs?

 

No, you either need to email me or PM me with your full name so I can look it up.

 

[SleepinGVR4]

PM sent

 

Have you done a boost leak test recently? Are those Delphi 850's? Do you have the vacuum port of the SX regulator connected directly to the intake manifold, or does it still go through the FPR solenoid? Does the fuel pressure drop 7-9 psi when you attach the vacuum line? I'm a little concerned with the huge difference between your LOW and HIGH TRIM.

 

[SleepinGVR4]

I have done a boost leak test lately. The only leak I found was that the vacuum solenoid for the stop leak kit was bleeding off pressure. I figured this was normal. /ubbthreads/images/graemlins/dunno.gif

Actually I think they are FIC 850s. I remember 850 being written on the sides of the injectors. Would a faulty injector cause this?

The vacuum port for the FPR goes to the intake manifold with just my boost gauge tee'd into it. Yes the vacuum drops 9 psi when I attach the vacuum line.

My FP seems to have changed to when I set it last, its almost at 40.

 

[prove_it]

Yes a bad injector would cause this. Keydiver could shine more light on that and how to test for it.

 

[SleepinGVR4]

Well can't I just use the MMCD software and test each injector one by one like that?

 

[SleepinGVR4]

So I noticed that when I took the vacuum line off the FPR tonight there was a drop of fuel on the end. So figured the diaphragm had a hole in it. So I went to Hills house and he was nice enough to let me swap his Aeromotive regulator on. Didn't help. Car still acted the same. I probably do need a new regulator but that's not the problem. So I'm out of ideas.

 

[prove_it]

You could have a bad injector then. Pull your plugs and see what they look like. If one is different from the rest then suspect that injector. Check that one. I forget, what fuel pump are you using? My friends talon has a bad pump and at times it goes lean, sometimes way too rich. He has a low volume 255 plugged to run high volume.

 

[Hertz]

Quoting SleepinGVR4:
So I noticed that when I took the vacuum line off the FPR tonight there was a drop of fuel on the end. So figured the diaphragm had a hole in it. So I went to Hills house and he was nice enough to let me swap his Aeromotive regulator on. Didn't help. Car still acted the same. I probably do need a new regulator but that's not the problem. So I'm out of ideas.



I posted about that in another thread. I bet a healthy % of people with stock FPRs have this problem. Mine went out at about 140k miles. May have even been before that.

Did you reset your ECU since swapping? Did you observe any changes in the fuel trims?

I would think that a bad FPR like that would have the intake sucking in extra fuel through the vac lines and blowing air into the fuel lines under boost.

 

[SleepinGVR4]

I'm running a Toyota Supra fuel pump. I wish I knew a way to monitor the voltage as I was driving. I'm going to pull the plugs again today. I just replaced them 700 miles ago before I took this big trip to the south, and didn't know any difference between them.

Hertz, I'm not running the stock fuel pressure regulator its an old school SX regulator. Yes I reset the ecu and I did notice a Low fuel trim change. It went from 81% to 82.5%. /ubbthreads/images/graemlins/banghead.gif

And I did think about fuel getting sucked into the intake manifold but wouldn't my car run rich then? I don't know.

 

[Hertz]

Do you have a turbo timer? Many of them can switch over to show voltage... or you talking about voltage at the pump?

Oh werd! 82.5% is good, that means you're at least in the range where the ECU can compensate.

 

[SleepinGVR4]

No I don't have a turbo timer. I'm talking about voltage at the pump.

Yeah well it should be at 100%

 

[SleepinGVR4]

I pulled the plugs, and pulled my fuel pump last night. The plugs were all white from running hot and lean. But no one plug was worth than any other. I double checked and made sure they were all gaped correctly.

I then pulled my fuel pump. I have a small rubber hose that goes from the actual pump to the hard line underneath the sending unit (about 3" of hose). I noticed it was looking pretty worn out, although I didn't find any holes in it. I found some extra 5/16" rubber fuel/emission hose laying around and replaced it. I'm pretty sure that fixed part of the problem, it doesn't hesitate and go lean anymore when I apply the throttle. But its still running lean under boost, in turn causing it to knock. Another part of my problem has to be my FPR is in need of a new diaphragm. SX performance says they still have the rebuild kit but none of their vendors have it listed on their sites. Typical. /ubbthreads/images/graemlins/mad.gif

My fuel trims were a little better. My Low trim stayed at a 100% a lot longer this time before it went to 81.5%. My middle trim is at 100% now. But my High trim is actually over 100%. I think that has to do with the fact that when I give it some throttle and let off my A/F hits 10.5 - 11.0 and then reads lean. Makes me think the FPR can't keep up.

 

[Hertz]

Quote:
My Low trim stayed at a 100% a lot longer this time before it went to 81.5%.

That probably has more to do with the ambient air temperature being lower.

 

[JNR]

Did you use the correct seals on the FIc (assuming) injectors? They are slightly different than the densos(stockers).

Not too many people seem to agree with this, but when I was running my FICs (650), I shaved down my isolators so that the rail and injector would sit in there better, and at the same level as the densos...If you compare the two, you will notice there is ~1/32" (iirc) difference from the seating area and where the injector sits in the rail...IMO, this can cause an issue, although doesn't sound common. I never got my FIC setup 100%, but as I recall, this did help slightly and should be done anyway.

 

[SleepinGVR4]

I used the insulators and o-rings that came with the FIC injectors. I did not shave them down, well because that never even crossed my mind. Although I had a hell of a time putting them in. I put a little bit of oil on the o-rings and insulators. They just kept popping out, I did finally get them seated. But not before I broke a fuel rail, tightening down the fuel rail bolts.

I'm going to try my other fuel pump and see if that helps.

I checked my fuel filter (fuel lab, pretty much brand new). The filter was kinda dirty but it didn't look that bad.

I got SX to sent me a new regulator rebuild kit. So if anyone still runs one you can get the rebuild kit directly from them.

 

[SleepinGVR4]

OK so I rebuilt my regulator and put my other fuel pump in. Problem still persists, and I'm getting angry. /ubbthreads/images/graemlins/mad.gif

I going to try another coil pack to humor myself. Maybe try another CAS. I need some serious help with this guys, my car is my daily and it needs to run correctly.

 

Sean, just to go over a few things:
1) you are running a 3G #482 or EVO8/9 MAS. right? Unhacked?
2) Those are a Delphi-type injector, like this:
click
They will have the number "17113743" laser-etched around the top circumference.
To be so lean on top but rich down below sounds like you have some other brand injector, but I may be wrong. /ubbthreads/images/graemlins/dunno.gif