Fuel pump questions.

[Bleedsblue]

I just got my car a week ago. Last night I put 20 bucks in gas in it after running it low. I pulled away and drove up the street. I felt it buck a little and looked down at my fuel guage and it read under 1/4 of a tank! I pulled over to call my mechanic. The gas guage slowly came back up to 1/2 of a tank but it still felt sluggish. We hooked it up to a guage and it was running 30-32 psi and bouncing a bit. Sould I replace the pump and sending unit? What should I use for a setup? It is a 99 SVT with just bolt-ons. No engine stuff yet. Walboro 255?

 

[01yellercobra]

I'm not sure what the idle psi is supposed to be, but it's going to flucuate a little. It's the nature of the returnless set up. I wouldn't run anything like the Walbro. They're not designed to have the voltage change. They're designed to run 100% all the time.

 

[Quadcammer]

30-32 psi at idle is perfect. Whats it do under load?

 

[Bleedsblue]

30-32 psi at idle is perfect. Whats it do under load?

iIt maxed out at 32. It never went above it even at high rpms. I read the spec on line and it said 35-55 psi.

 

[Quadcammer]

those specs are wrong.

Max fuel pressure on an NA car should be 39psi.

Fuel pressure corresponds to load not rpm. Basically, you need to measure engine vacuum vs. fuel pressure.

Correct rail pressure is 39-(vac/2)

 

[Bleedsblue]

those specs are wrong.

Max fuel pressure on an NA car should be 39psi.

Fuel pressure corresponds to load not rpm. Basically, you need to measure engine vacuum vs. fuel pressure.

Correct rail pressure is 39-(vac/2)

Ok, so bad pump then? :shrug:

 

[006]

Ok, so bad pump then? :shrug:

Nope.

When a pump goes bad, it just dies.

I would suggest to replace the fuel filter first.

Also, any incorrect level readings is attributed to a bad level sender. The floater arm could be getting stuck or the metal notches on the contact board or could be breaking off.

Check all your harnesses on the back to make sure they are nicely plugged in.

Worst scenario, you can get a SVT focus fuel pump for ~$160 or get a stock OEM replacement pump for about ~$100 (pm me for details)

Visual:

 

[Bleedsblue]

Nope.

When a pump goes bad, it just dies.

I would suggest to replace the fuel filter first.

Also, any incorrect level readings is attributed to a bad level sender. The floater arm could be getting stuck or the metal notches on the contact board or could be breaking off.

Check all your harnesses on the back to make sure they are nicely plugged in.

Worst scenario, you can get a SVT focus fuel pump for ~$160 or get a stock OEM replacement pump for about ~$100 (pm me for details)

Visual:

$100??? A motorcraft pump is $359 with sending unit.

 

[006]

$100??? A motorcraft pump is $359 with sending unit.

Like I said, PM me for details.

 

[Brutal Metal]

those specs are wrong.

Max fuel pressure on an NA car should be 39psi.

Fuel pressure corresponds to load not rpm. Basically, you need to measure engine vacuum vs. fuel pressure.

Correct rail pressure is 39-(vac/2)

I see up to 46psi at WOT when I datalog my fuel rail pressure Quad?

 

[01yellercobra]

$100??? A motorcraft pump is $359 with sending unit.

I just had to replace the pump in a neighbors car. I used a Focus pump and swapped it in the canister. I paid $75 at Autozone.

 

[Brutal Metal]

They have SVT Focus pumps with a Ford Part # at autozone for $75?? What?

 

[01yellercobra]

They have SVT Focus pumps with a Ford Part # at autozone for $75?? What?

It wasn't an SVT pump. It was a 2000 Focus. But the car was a V6 Mustang. Didn't need a whole lot of fuel flow. It dropped right in though. Might be worth cross checking part numbers. It wouldn't surprise me if Ford used the same weak pump in all the cars.

 

[olgreydog7]

Steve at Tousley got me a SVT pump for about $120 IIRC. It may have changed since then. But it did come with the basket and it plugs right it.

 

[Quadcammer]

I see up to 46psi at WOT when I datalog my fuel rail pressure Quad?

You shouldn't.

whats your delta P set at?

 

[01yellercobra]

Steve at Tousley got me a SVT pump for about $120 IIRC. It may have changed since then. But it did come with the basket and it plugs right it.

My neighbor checked on that because I thought it would be a cheaper alternative. $185 shipped to CA.

 

[olgreydog7]

My neighbor checked on that because I thought it would be a cheaper alternative. $185 shipped to CA.

Ford probably raised the price after we all started buying them.

 

[Brutal Metal]

You shouldn't.

whats your delta P set at?

The minumum psi I see in the logs is 37..

 

[Quadcammer]

Ok, so I'm assuming your tuner simply raised your delta pressure (or base fp) to account for injectors that may be a bit undersized.

Since on stock cars, idle fp should be about 30psi and 39 at wot, it seems your delta P was raised 7 psi to 46psi.

Nothing to worry about, but not my favorite way to get around a lack of injector.