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Old 11-29-2012, 09:22 PM   #26
LaffyTaffy
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tldr: It started once and ran fine with a new fuel pump controller (see video) but then went back to sucking. Which line do I tee into to test the fuel pressure (see picture)? I think the problem is electrical and related to the fuel pump. Thoughts?

Ok so my progress on the car has been glacially slow, but I've managed to do a few things. I was convinced that it was either the fuel pump controller or the immobilizer so I bought a used fuel pump controller and a used ECU/key/ignition cylinder/immobilizer (from the same car) on ebay to try out. First I installed the fuel pump controller. Started it once and it died, as usual. Started it again and it ran fine, and showed no signs of dying. There was white smoke coming out of the exhaust and I wasn't sure if it was just condensation or signs of something bad. It was about 55deg F outside that day. Video here (sorry for the crappy angle):


Any thoughts?

Anyway I shut it off (bad idea) and started it again and it died, just like it used to. Then I tried just the new ECU by itself and it was a totally different set of problems. The security light came on and the car turned over but never fired once. I swapped it back and the car went back to starting up and then dying like it had been. This leads me to believe that its not the immobilizer. Also, it was basically on E and it had been sitting for a while so I filled it up with gas. Started it again with new gas, same thing.

Now I want to check the fuel pressure, but I'm not sure which line is the high pressure line. Can anyone tell me (I think those are the fuel lines...)?




Also, whenever it dies, the fuel pump starts making a loud funny sound right before the car dies (will post video). I monitored fuel pump duty with the green test connectors connected and it had no problem going from 0% to 33% to 100% and back to 0%, and it sounded just fine (and quiet). The dealership replaced the whole fuel pump unit recently so I don't think it's a bad pump. Also, the one time I was able to start it and keep it running, the car ran fine, and the fuel pump was quiet as a church mouse. Also, I did short the cigarette lighter socket shortly before the starting problems began. I think the problem is something electrical but I don't know where to look. Any ideas?

Line A is the fuel feed line. (43.5 PSI, car off)
Line B is the fuel return line. (0 PSI, car off)
Line C is the fuel vent line.
Now I know. Now you know.
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Last edited by LaffyTaffy; 12-13-2012 at 06:50 PM. Reason: I learned it!
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Old 12-03-2012, 09:00 PM   #27
LaffyTaffy
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Quote:
Originally Posted by flyboynextdoor View Post
Theres at least three of us guys having the same problem on rs25.com right now...

http://www.rs25.com/forums/f13-troubleshooting

You'd think with this many people having problems we could hatch a solution.
Thanks for the link. I tried a new (used) MAF from ebay, as in the thread above, but no luck (it actually seems to have made things worse). Granted, I had no screws holding the MAF in place because I stripped them trying to get them out, but it's all I could do at the moment. I'll get some more screws and try again. Until then, anyone have any thoughts?

Anyone?
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Old 12-04-2012, 11:20 AM   #28
tuzzio
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Those screws for the MAF sensor suck. Been there done that. It made it worse because you're sucking air there as well. It's metered air. Dont rule that out until its properly secured down

Edit:
Quote:
Originally Posted by LaffyTaffy View Post
Also, I did short the cigarette lighter socket shortly before the starting problems began. I think the problem is something electrical but I don't know where to look. Any ideas?
Did you pull each and every fuse under the engine bay and behind the change holder and see if any are bad? That's a good starting point.
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Old 12-04-2012, 06:01 PM   #29
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I'll give it a try. How do I test fuses?
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Old 12-04-2012, 07:03 PM   #30
mechatricity
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Quote:
Originally Posted by LaffyTaffy View Post
I'll give it a try. How do I test fuses?
Either with a cheap fuse tester, or just take a good look at them- it's pretty obvious when they're blown, the metal will be separated in the center.
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Old 12-04-2012, 07:41 PM   #31
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Thanks for the tip.

Ok, I checked all the fuses in the box on the driver's side of the engine bay and in the compartment under the steering wheel. Are those the only two fuse locations? I checked all the normal looking thin fuses (10, 15, 20, 30) but there were a bunch of fatter looking things that may or may not have been fuses. Some of them were transparent on top, so I made sure that the metal bits inside were intact, but I didn't know what to do about the opaque ones. All the fuses I looked at checked out.

Any other thoughts?

How do I test the fuel pressure?

Jumper the fuel pump relay lines together?
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Old 12-05-2012, 08:42 PM   #32
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New MAF screws. No luck.

Anyone?
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Old 12-05-2012, 09:00 PM   #33
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Here is video (mostly audio) of the fuel pump during a few starts:


Every time the car dies, its accompanied by that awful fuel pump noise. Anyone know what that is? Occasionally it'll run fine for a few seconds before it starts making that sound. It seems like as soon as it starts making that sound though, the car dies.

Any help is greatly appreciated!
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Old 12-05-2012, 11:14 PM   #34
holyjoetart
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Sounds like you need to pull out your fuel pump and inspect for any blockage on the outlet and suction side. I would also make sure your fuel lines aren't crossed.

Kind of a shot in the dark, but it would be a good place to start.
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Old 12-06-2012, 06:15 PM   #35
LaffyTaffy
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Will do.
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Old 12-08-2012, 04:03 PM   #36
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Finally tested the fuel pressure and these were the results:

Note: the marks on the gauge are 0, 10, 20, 30, 40, etc... PSI. If I understand the fuel system correctly, shouldn't the pressure stay at 43.5 psi? There was no fuel leaking from the lines going to the gauge, so does that mean its leaking out of the injectors or the FPR? It seems like the FPR is working at least partially correctly, because it holds pressure at 43.5 PSI. I think the lack of pressure explains the hard start but not the stalling. You can also see that when the fuel pump starts sounding weird, it doesn't generate as much pressure.

Any thoughts?

Next up is visual inspection of the fuel pump assembly (and maybe I'll actually start the car with the fuel pressure gauge hooked up).

Last edited by LaffyTaffy; 12-08-2012 at 05:16 PM.
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Old 12-08-2012, 10:38 PM   #37
holyjoetart
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You could also try bypassing your fuel pump controller to see if your controller is failing.

If that doesn't work, it might be time to buy a new pump
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Old 12-08-2012, 11:17 PM   #38
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Quote:
Originally Posted by LaffyTaffy View Post
Finally tested the fuel pressure and these were the results:
Fuel Pressure Test

Note: the marks on the gauge are 0, 10, 20, 30, 40, etc... PSI. If I understand the fuel system correctly, shouldn't the pressure stay at 43.5 psi? There was no fuel leaking from the lines going to the gauge, so does that mean its leaking out of the injectors or the FPR? It seems like the FPR is working at least partially correctly, because it holds pressure at 43.5 PSI. I think the lack of pressure explains the hard start but not the stalling. You can also see that when the fuel pump starts sounding weird, it doesn't generate as much pressure.

Any thoughts?

Next up is visual inspection of the fuel pump assembly (and maybe I'll actually start the car with the fuel pressure gauge hooked up).

If I was seeing that right and your fuel pressure was dropping to 0 every time the pump finished priming you're pump assembly / the internal check valve is no good. The thing should prime and HOLD fuel pressure, i.e. after you prime it and or come home and shut the car off, if you took fuel lines off, expect to get sprayed with gas. If that thing is going back to 0 that quick, your pump assembly needs replacing.

I think your key here was you saying the "dealer replaced the pump assembly not too long ago" -- ever have a problem like this before that replacement?

Get a walbro, might as well upgrade while your at it, and my money's on the problem going away, assuming I'm reading that gauge right.

I have a strong feeling that noise is the internal gears in your fuel pump having stripped out, pressure dropping to zero, and bam, no more fuel.
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Old 12-09-2012, 08:30 PM   #39
LaffyTaffy
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Quote:
Originally Posted by johnyquest View Post
The thing should prime and HOLD fuel pressure
That's what I thought.




Quote:
Originally Posted by johnyquest View Post
the internal check valve is no good
Is the check valve inside the pump or is it part of the pump assembly? In other words, will upgrading to a Walbro pump fix the problem (~$80) or do I need a whole new pump assembly (~$500)?
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Old 12-09-2012, 10:16 PM   #40
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Quote:
Originally Posted by LaffyTaffy View Post
That's what I thought.






Is the check valve inside the pump or is it part of the pump assembly? In other words, will upgrading to a Walbro pump fix the problem (~$80) or do I need a whole new pump assembly (~$500)?

Correctly installed new pump should do it.
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Old 12-13-2012, 01:08 PM   #41
LaffyTaffy
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Used fuel pump assy from ebay and SHE LIVES!!! Thanks so much to everyone for all the help!!!
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Old 12-14-2012, 04:14 PM   #42
roadtrip1098
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I just bought an 06 STi same color, same symptom, dealer replaced the fuel pump, runs great now.
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Old 12-14-2012, 05:13 PM   #43
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Good to hear!
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