Car won't holder fuel pressure, slowly dies

[trunks]

Fuel pump runs the entire time. If I shut the car off and restart it I'm good for about 10 miles and then it slowly leans out and i hit fuel cut eventually. Brand new alternator last year and all electronics are fine. Is it the fuel sender?

Any help greatly appreciated.

Thanks.

 

[stevo911]

Fuel Pressure Regulator
MPI Relay
Sender
one of the three im putting money on the sender tho.

 

[92awddsm]

Or failing pump, leaking upper seal on the pump to pickup assembly.

 

[trunks]

Looks like the afpr. I can't get it to adjust below 45 psi. Checked the fuel pump and all connections. That side was full of gas. I've been getting 13 mpg lately too. Is there a better alternative to aeromotive?

 

[crimsondragon]

Fuelab but thing is AFPRs rarely fail. You just got bad luck. I wouldn't stray from Aeromotive if I couldn't help it. Contact them and see if there's a warranty.

 

[trunks]

Well I bought a fuelab afpr today. Hopefully that takes care of it. If not the fuel pump is next. The guy at MAP hadn't heard of this before.

 

[trunks]

Well the afpr didn't fix it so a new fuel pump is on the way. I pulled both of the other two hoses that go to the fuel pump with the pump on and gas came out of the them so I assume the sender is fine.

Walbro was not even one month old..

 

[boostx]

Also try adding a fuel pressure gauge to see what’s happening.

 

[romeen]

In your first post you said that the car leans out after driving for a bit. That could be from a clogged fuel filter. When was the last time you changed it?

But in post #4 you say that fuel pressure is high and your getting poor mpg which suggest running rich. There could be a couple different things going on and it's just a coincidence that it's happening at once.
Is your front O2 sensor cycling like it should during closed loop?

 

[kodeblue]

if none of that stuff work, try pulling the fuel rail to make sure there is nothing clogging your injectors like bad fuel. A fuel pressure test under this condition would probably test normal.

 

[crimsondragon]

Before you buy any more parts and spending money like an idiot, take a multimeter and tap the fuel pump and read voltage till it dies. If voltage is slowly dying, you will see it and it'll be electrical. Also, when it starts to lean out do you hear a change in the whine? If you do then it's either your pump or electrical. If you don't hear a change in whine, and the voltage is good, I would rule out the pump. If you do hear a change in whine but voltage is the same, then it's your pump.

 

[trunks]

Thanks for all the reponses. I should clarify that I do have a liquid gauge on the afpr. After driving for some time thats when the fuel pressure loss occurs. At idol it was fine. After limping home I was trying to adjust the afpr back down with the pump turned on through DSM link and it won't drop below 45 psi.

I did check the fuel filter and it was good. I wasn't monitering my o2 volts so maybe they are seperate issues.

Crimsondragon, you sound just like my wife. I checked the voltage at the rewired pump with it on and it was 12.75. I did just install a small amplifier but I had that on as well when testing. I guess it could take it for a drive and wait for the drop and then pull over and test the voltage.

The pump is screaming like a banchee but no change in pitch. There is a wistling sound from it but I'm not sure if that normal since I've never listened to it with the car off.

Pump is on the way so I guess I'll just install that and then assume electrical if that doesn't do it..

 

[romeen]

At idle does the needle on your FP gauge bounce around or is it steady?

12.75V at the pump seems a bit low for a rewired pump (unless car was off and you were just using link to operate the pump).

 

[trunks]

Yeah, the car wasn't running when I tested it. The needle did bounce around a little but it seemed like just engine vibration. It was only like a 1 psi range.

 

[romeen]

If the gauge is liquid filled then the unsteady needle might indicate a leak between the pump and the sending unit (o-ring). But it sounds like a small leak, if any, and I doubt that is what is causing your issue.

How did you "check" the fuel filter?

 

[trunks]

I pulled it out to inspect the micron unit. I've got a fancy aftermarket one that I cannot remember all the specs on - since I'm running e85.

 

[romeen]

You could be right about the fuel pump starting to take a dump on you. I'll be curious to see how this turns out.

 

[trunks]

I'll be installing it Tuesday night, so I'll post back then. I just 'restored' my car back to awd and put a tank on there that had been sitting with nasty gas for a while. Maybe there was some gunk left in there and putting e85 in there cleaned it all out and fudged up the pump. The pump filter was a little grey but not too terrible.

 

[crimsondragon]

WAIIIIIIITTTTTT A MINUTE....you're running E85? Pull your injectors RIGHT NOW.

 

[stevo911]

You just put the tank on? Im willing to bet you got the out or return line kinked a bit.

 

[trunks]

I've got 1150cc injectors for the ethanol. I'll double check my lines but it had been fine for 2 weeks since the install.

 

[crimsondragon]

Pull your injectors. There's been a huge thing going around about E85 clogging them up but no one is sure on the reason why. Generally the symptons are lean and rough idle.

 

[trunks]

Just pull them out and soak in carb cleaner?

 

[crimsondragon]

Pull them out first and inspect them. If there's none of the E85 gunk then we move on.

 

[trunks]

Well pulled the injectors you were right - cylinders 2 and 3 were all full of gunk. 1 and 4 were fine though. How do I clean them up then?