The fuel pump on my GTA is the only thing that hasn't ever been replaced or messed with. I think my worst fears have finally been realized. Follow the red line in the chart below and tell me I'm not seeing things.
On a side note, when I put the scanner on the car, it tells me that the fuel pump is only seeing about 11 volts while the battery is putting out 12. Don't know if this makes any difference, but I imagine it does.

 

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Hello Red,

I thought you had gotten your problems fixed and gone on a long vacation since I hadn't heard from you. Don't worry about the 11 volt reading at the fuel pump, that is a normal reading and you haven't seen a code 54 have you. What is your fuel pressure readings off the rail and if it drops, how fast and how much?

 

No code 54. If I remember right, that's the EGR code, right? I replaced that thing when I bought the car a couple years ago.

Here's where the pressure gets interesting...
I get different reading every time I turn the key. Sometimes it'll be as low as 30psi and other times it'll have the needle pegged past 60psi. When I was doing the pinch test above, I set it to 45psi and it held. As soon as I took my clamp off the line, it dropped immediately to 37psi. I turned the key on again, then off, and watched the pressure go fairly quickly from 45psi down to 34psi. It only took about a minute. I know it's not supposed to bleed down that fast.
I did the return line test on that sheet as well and it looks like the pressure regulator is okay.
I replaced the fuel filter before doing these tests and no difference whatsoever in the "start then die" problem. It still cranks right up, then bogs out after about thirty seconds.

I never got it working right. Although I did get it running, this all started again soon after. I just got fed up with it again, and at the prospect of having to take the entire rear end apart to swap in a new pump. I'm almost thinking about having someone else put it in for me.

 

Code 54 is low voltage at the fuel pump, code 32 is the EGR. BTW, if your fuel pressure drop is no lower than 34 or 37 that is not bad, it is normal for the fuel pressure to drop off a little after the pump shuts off. When the pressure gets up to 60 what exactly are you doing for the pressure to get that high? Do you have an adjustable fuel pressure regulator on there.

 

It gets lower than 34 every now and then. I'm not doing a thing to adjust the pressure. I have an Accel regulator on there. If I set it to 45psi and re-prime the pump again, it'll shoot to a random pressure all by itself. I always have to set it back down to 45.

 

ACCEL!!!!!, no comment on them as I personnally don't use any of their products. Others on the board have had problems, most notably with their fuel injectors. I don't know about their fuel pressure regulator, sounds kind of iffy.

 

I guess I can try using another diaphragm in there, but I don't know. I hooked a vacuum hose to it and sucked on it to see if the pressure went down, and it did. The test on that sheet says to apply ten pounds of vacuum, but I don't have the tools necessary. I thought I did taste gas fumes while doing that, but when I pulled it off at the regulator and sniffed it, I didn't smell a thing.
I don't know what to do at this point. Think it's safe to assume it's my pump?
The car was running fine for a long time with that regulator on there.

 

What did you use for a vacuum source, a shop vac? That's definitely more than 10 pounds of vacuum and did you do that before or after you went to step 3 of the chart you have shown here?

 

Is your screw on your Accel really sensitive when it comes to setting pressure??? Have you ever tried to set the pressure and just for giggles take your finger and push/press the bolt in the AFPR??? What does the pressure do??? The bolt on my AFPR was not flat and used to cause huge irregularities on my readings. I ended up removing the bolt and making a blunt taper from the center out much like the end of a sharpened pencil. Its probably not the case here but its free advice. Also have you ever replaced the fuel pump relay????

 

Trickster, I just sucked on the end of the hose by mouth. I did it after step three, just for giggles.

Razor, yes it's extremely sensitive. I only turn the bolt a hair and it'll jump a good 10psi. Sometimes though, it won't move a bit, then all of a sudden jump off the chart.
Fuel pump relay is new.

 

[QUOTE]Originally posted by redrummer
[B]Trickster, I just sucked on the end of the hose by mouth. I did it after step three, just for giggles.

:werd:

 

Maybe try to remove the bolt and see if it was like mine. Its a pain to remove the plenum just for this but it should not be that sensitive. I know mine drove me crazy until I removed the bolt and made the flat blunt point. I also had irregular readings and found that I could get different readings on different days.