Fuel Pressure issue on 99 cobra

[LJHoffman77]

I went to start my cobra up for the first time this year and I had a hell of a time getting it to start. Once running it ran pretty rough, but eventually settled down to a normal sounding idle. So I took it for a drive around the neighborhood. The engine sputters and almost dies whenever there is any kind of load at all, so it was nearly impossible to drive. When I got it back home I hooked up my Predator tuner and looked at the fuel system data while it was running. My fuel pressure stayed around 5 or 6 psi the whole time. From what I've read on here I should be seeing closer to 30 psi. I also checked the stored codes and found P0190 "Fuel Rail Pressure Sensor". I've been searching through the forum and still don't know what I should do next. Would a faulty pressure sensor cause the pump to put out such a low pressure, or is it just my fuel pump going bad?

Any help or direction for other things to check would be greatly appreciated!

 

[green99_svt]

Check the pressure with a gauge. I've seen the sensor fail and cause it to read low pressure and then run extremely rich by running the pump at a high duty cycle. Also the check the wiring for damage or loose connections to the sensor.

 

[Black*Death]

My guess is a failing fuel pump?

 

[Mach828]

Fuel pump. The fuel pump will cause the fuel rail pressure sensor code to go off, because it wants to see 39-40psi, but the sensor is reading less.

If you have a tuner like sct to datalog you will see the fuel pump duty cycle read .50. This means 100%, as in she is done and giving everything its got but only managing 6psi at the rail.

 

[LJHoffman77]

I do remember seeing the fuel pump duty cycle reading around 50%. I'm going to get a pressure gauge to check the the pressure at the fuel rail just to be sure.

Any suggestions for where to buy the fuel pump? Anything else I should be checking and/or changing (besides the fuel filter) while I'm at it?

 

[LJHoffman77]

Well I'm 99% sure it's my fuel pump, so now my question is what I should replace it with? I've read where quite a few people have replaced the pump with the SVT Focus pump. Is this worthwhile doing, and if so what year focus do I need to get the pump from?

Are there any other options out there as far as fuel pumps go? I'm not planning on going to forced induction so I don't think I really have any need for a higher flow pump.

 

[Mach828]

Hard to find the actual OEM svt focus pump, but its a good deal. Getting a 255 pump is the way to go.

 

[MrAjsTech]

Having this problem. Just did a fuel pump, fuel filter, and fuel pressure sensor at the fuel rails. I have SCT data logs. When car was running good at the beginning of the data logging session fuel pump duty cycle was at .25 and fuel rail pressure was at 39-40. I gave it gas to replicate the problem and fuel pump duty cycle flat lined at .5 and fuel rail pressure is anywhere from 2-10. Anybody have any ideas? I have data log and videos of the incident occurring. Car will also completely shut off on my going 35 mph down the street.

 

[01yellercobra]

I know it sounds dumb, but did you install the fuel filter correctly?

 

[UncleSAm]

I know it sounds dumb, but did you install the fuel filter correctly?

Was going to say the exact same thing

It's one of those things that's stupid easy to mess up

 

[forged00]

I know it sounds dumb, but did you install the fuel filter correctly?

+1 on the filter being backwards. I've been guilty of this before. Another issue I've found before on my '00 2V was that it would drive just fine for about 20 minutes, then it would start to lose fuel pressure and run like ass. I would park it, then after about two hours I could drive it just fine for about another 30 minutes before it started choking out again. I had already replaced the filter and pump. After about a week of this I ended up dropping the tank and pulled the fuel hat completely out and found sediment build up inside the fuel hat. What was going on was that after driving for so long that sediment would get sucked up into the pre pump filter on the bottom of the fuel pump and start clogging it resisting the amount of fuel it was about to suck up. After it would set for a while that sediment would float away, then once you started driving it would suck it all back up again. I found the reason for the dirt in the tank in the first place was because the gromet for the filler neck to go into the tank was actually worn out pretty bad and had a decent chunk missing out of it. Replaced the grommet and cleaned the tank out pretty well and never had another issue with it since.