MAJOR BOG AND LOSS OF GAS PRESSURE

[Jerryk]

I'm sure Mark has more to add than me but is it possible one of the fuel pumps is failing? So it can keep up as the load builds (its marginal) but the sudden hammering of the throttle/demand for fuel may cause it to not be able to keep up and then the computer shuts it down..? I believe some 03 Cobra owners have already had pumps replaced so it would not be unheard of.

Jerry

 

[Dana]

I am also leaning towards a fuel pump problem of some kind. Maybe a pickup or internal connection or filter. After the fuel filter is changed, that will be one of the next things, but we may let the dealer struggle with that.

Dana

 

[bassin247]

did you look at the fuel pump duty cycle? If you are at 100% duty cycle and you are seeing 10 psi, you could almost certainly blaim it on the pump or filter.

 

[Dana]

I didn't think to log the duty cycle.
One of the problems is the AutoTap logs at such a slow rate, it can be difficult to make a determination, but that is one of the things I plan on doing next.

Dana

 

[mike79]

Isnt there a module for the fuel pump itself>? Could that have gone bad? When I had a FPS go, it actually burned the wire out that goes from the sensor to the EEC. Whats even wierder, is that the wire was fine at idle, but under load, the thing sent way too much gas into the engine.

 

[bassin247]

Originally posted by mike79
Isnt there a module for the fuel pump itself>? Could that have gone bad?

Yes, The FPDM, and it is possible there is something wrong with it although I haven't heard of one failing yet. Usually it's the pump.

 

[davidmax]

I would guess pump.I think I read that you had about 30 psi fuel pressure but I like to see 40+ from a single pump way more reliable and less to go wrong,and a manually controlledd toggle switched Boost-A Pump will raise you to about 60-70 psi.
If you've read my crazy posts the fuel system is the weak point in the system,and on all my 500+hp 'Stangs I do I add a return fuel line.Better driveability,more fuel pressure and enough to supply the 94Lb. injectors and larger discplacement of my engine 5.2 litre(318 c.i.) VS 4.6 so the discplacement and thee XTRA large injectors will keep you from whats called fuel starvation.
If I had the time to read the manual(shop manual) to see what electronic devices are built into 1st thats not contained in 2-6 I would.If you have an SVT mechanic at the dealer that knows his stuff you can give him 50.00 smackers and he could print it out for you and more than likely find thhe most likely cause.
Case in point many turbo charged cars like the Subbie WRX are switched to a max of 13 lbs. of boost.However you can only access 7 or so lbs. in 1st and 2nd.You can buy a plug and play unit for 150.00 that will switch all 5 gears to 13 Lbs of boost and when you go with a larger inter cooler and larger turbo you obviously want max.Boost A.S.A.P thats why you spend your hard earned money.
I would go to a return fuel syystem or build one with Earls braided hosing and fittings to the same spec,remove the old line and get a nice 225 lph pump with boost a pump to prevent starvation,but your car is not ready for a chip till this issue is resolved and all your mods must come off off,they took a bath on this car and there making it up in service where they'll crucify you for a K&N filter.
That is why I recomend 50.00 to the head SVT tech and he will try to find the problem just tell him you dont like Ford service and he wont disagree with you they also pay like crap.
I pay my techs 5-15.00 more per hour!!! and these guys are sharp,but when we find a smart tech who can think on his feet we always try to snatch him and were highly succesful and he brings his factory training with his tools.I just hired a guy from a dealer in Co. that went to all 3 SVT schools Focus/Cobra and lightning and has been through the refreshers every year for 6 weeks but hated it there(in Co.)so he has brought so much SVT knowledge I just keep picking away at his brain so I can learn more.The best of luck,Dave Smilovic.

 

[Lethalchem]

I've had my car only do this to me twice, and both times I was racing in the top of 3rd. The check engine light flashes for a good 30 seconds, then shuts off and everything runs fine. It feels as if the SC just stops working completely. I know this isn't exactly what the author of this thread is describing, but does the cause sound the same? An intermittant pump problem though? Is that possible?

 

[Get Ready]

I do not get a check engine light. And it only does it in first gear/

 

[Get Ready]

We may have found the problem. Ill know more in a couple days Ill post a new thread we details if the end results are good.

 

[Get Ready]

New Pump Its Fine Know

 

[racerat]

Originally posted by Get Ready
New Pump Its Fine Know

So one of your fuel pumps failed?
Do you know what the cause was?

 

[03DOHC]

Originally posted by racerat
So one of your fuel pumps failed?
Do you know what the cause was?

I've been hearing about fuel pumps going out more and more. I think if there's going to be any gauges in my car it's going to be an A/F.

 

[Poisonous Mods]

OX03 had a bad case.

We all thought it was the Fuel Pump but it was all his wiring from what he say's. He still has a little problem from the last time ive heard.

His Fuel Pump was fine.

 

[racerat]

Originally posted by 03DOHC
I've been hearing about fuel pumps going out more and more. I think if there's going to be any gauges in my car it's going to be an A/F.

Wouldn't a fuel pressure gauge be more beneficial? :shrug:

 

[Get Ready]

Where taking a closer look at the old pump know, It looks like its internal. outside looks fine. except the pump looks like its not made very well. A lot plastic;

 

[Get Ready]

Advice always keep your fuel tank at least a quater full do to heat build up in side the tank. can burn up the pumps. under wot.

 

[03DOHC]

Originally posted by racerat
Wouldn't a fuel pressure gauge be more beneficial? :shrug:

My fuel pumps started to go out and it showed up on the dyno as going lean. Tested OK otherwise.:shrug:

 

[Grover03]

I think my fuel pumps went on me today also. I now have zero fuel pressure.
Oddly enough the car ran lean on the last dyno last weekend and previously it had always ran rich - could it have been a sign of failure?

Grover

 

[Dana]

For both pumps to go out at the same time is unlikely, although possible. Or one could have gone out some time ago, and not caused a problem until the second one quit.
This may have been the cause of the lean dyno run. One had gone bad.
I would look else where first, possibly a fuse?

Dana