Fuel Pressure Drop @ WOT...

Contour Enthusiasts Group Archives

Haven't posted in a while, thought this would be a terrific opportunity:

I just received the lastest iteration of the SCT chip from ADC for my forged turbo 3L (this one actually opens the secondaries...

). I took a run with the boost controller on "stock" (6 psi), and noticed that she still seems to fall on her face above 5k. Punched up the boost controller to my "high" setting (12.5 psi, max I could go w/o secondaries), and took a run. Again, fell on her face at around 5.5k. Out of the corner of my eye, I see the fuel pressure gauge doing something.

So I stare right at the thing, mash the gas, and it drops to 20psi almost immediately over 4k. Needless to say, I got my lilly white a$$ off the accelerator. The turbo timer was reading 15.3:1...

I have the 255l/hr high-pressure Walbro pump. I have a new Purolator fuel filter, and the FPR is quite functional (immediate blip from 42psi @ idle to 65 at WOT), my vacuum/boost gauge is tapped right off the FPR fead.

Ideas? I ain't running this thing any higher than 50% throttle at stock boost. One suggestion was that the pump cannot get enough current under load, but I can't remember hearing any audible change in pitch of the pump during the run.

Silly question, but what MAF and injectors are you running? If the MAF doesn't have the correct function programmed in, it could very well lean out the car above 4K no matter the size of the injectors. Also, you could be maxing out your MAF airflow at that point and at 5 volts it will start to do funky things.

Rick

Hmm.
Fuel drops to 20 at 4K rpm.

Well it is going to richen the injectors on opening the secondaries.

What size injectors? You're saying you have a return-style system?

I'm guessing with that setup you have 39's or bigger. IF they all went static open then they might be able to drop the pressure significantly and the excess fuel would kill the power.

IF the car was starting to go lean then it should have had a bit more power before it got too lean but I'd guess at 12.5psi you'd have already hurt something.

If it is returnless like I thought most cougars were....then it is a programming issue I think.
Need to list injector size. I don't buy the whole voltage drop thing. The pcm code has parameters to change the fuel injector pulsewidth based on electrical system voltage. Meaning if the alternator died and the voltage dropped, the code will automatically adjust the injector parameters for it.

What does the maf voltage indicate when this happens? You probably should datalog with an obd scanner what the maf is doing and what the fuel trims look like when it happens.
You can easily watch the O2 sensor voltage and get an idea if it is falling or not to help narrow down a lean or rich condition, but don't trust a narrow band for exact fuel ratio.

99 cougars are return. He said he has a fuel pressure regulator which aren't found on returnless systems. He has 42's and a large enough maf.

I did have a similar issue once. One of the fittings on the pump wasn't seated right. This was before the focus SVT pump was available. I had to rig a Walbro. It sprayed gas back into the tank at WOT but the pressure only got too low when I exceeded 300 hp.

Yeah if he is returnless he NEEDS to ditch that Walbro, but he says he has a FPR, which would suggest he is return - so it should be ok with the Walbro. I would also check the fule lines. Might have a leak or tear in the hose in the tank.

Yeah, this is why I wanted him to clarify. Basically what stazi was saying is where I was going with that.

I know for sure that a walbro on stock lines has been more than enough fuel so far, even with 55psi WOT. The sudden loss of power sounds to me like a complete dump of fuel or a complete loss.
Too bad he can't datalog injector duty cycle. Thats one thing the eManage was excellent at. It would log maf voltage, injector pulse width and injector duty cycle by measuring those items directly. Along with TPS, RPM, pressure. With the EO1 you could display all that right to the screen in the car.

And of course it worked well on top of a chipped car.

See that is another thing he said that threw me off...I've never heard of 65psi WOT so I'm again wondering if it is a returnless since I don't even know the fuel pressures that they hit.

Return you won't see more than 55psi at WOT IIRC. 65 is high.

True though Tom, if it is returnless and he doesn't have a 'smart' pump then it will go lean at the top end. I ran into that wall too.

Sorry I have responded sooner on this- Turkey Day and all...

Car setup:

-3L forged internal ADC T3/4 60 trim
-SVT Lightning MAF, as required by ADC
-42lb/hr injectors from SVT Lightning, as supplied by ADC
-ADC chip for turbo kit
-Return-style fuel system (otherwise I wouldn't be running the Walbro, folks

!)

The Walbro pump has been getting progressively louder since I originally fired the engine. At first, it was barely louder than stock. Now (and since the problem manifested itself) it's clearly audible from the cabin, and quite loud from outside the car. Keyser may be onto something...

Looks like I'm dropping the tank again...

I didn't think you had to drop the tank to change the pump in our cars?

You don't I can pull my pump in like 30 mins.

Well, there may be something wrong with the pump but I can't see how it would make it run MORE Than 55psi wot.

In the case of the noise...they're all noisy but I don't know how that compares with yours. I've been running mine since 2003 and its sounded about the same. Pretty whiny when the fuel gets down to about half tank or below.

War:

Same here- But recently (within the past 2 weeks), it's been noisy regardless. As in you-need-to-turn-up-the-radio-to-drown-it-out noisy. Kind of like that sound you hear on airplanes as they bring out the flaps. Only constantly.

As for dropping the tank, yes- That's how I do it. I don't believe in pulling the rear seats out and cutting up my floor. I drop the tank. It's two retaining straps, and several connections including the fill tube (which is the hardest).

Just pop up the bottom of the rear seat, pop the lock ring with a flat screw driver and hammer (counter clock wise?), undo fittings/connectors and remove the assembly for tinkering.

It can be done very quickly! I forgot to reinstall the tank gasket and had to go through these steps, and it was under 10 minuets....if that.

Edit:
Do Cougar's not have the access hole in the floor pan?

I think there is a difference...I know the 98 contours have access to it, but newer contour don't have as good...might be the same with the cougars??

Originally posted by Swazo:
Do Cougar's not have the access hole in the floor pan?

Yes i was just back there wiring my bottle heater up last week, and thought to myself "i need to put a Walbro in there!" lol

speaking of which...what is the stock RETURN style fuel pump in a 99 cougar V6 good for? 250whp guessing?

If its the same as the contour then its right around 300 wHP.

I should clarify that its 300 wHP with proper stock fuel pressure and larger injectors.

Too much fuel pressure, greater than 65 or70 psi will slowly eat up the stock pump.
You'd need about 6 30# injectors to max out the stock pump I'm guessing.

drop the tank?...why? All you do is pull the seat up and its right there,no cutting,at all

In later models Ford made the hole smaller than the access panel for the tank.

That's right, in Derek's '00 we had to do a little trimming to be able to access it to swap out the pump for an SVT focus pump

My early 1999 I didn't have room either. No way I was dropping the tank though.

I made two small cuts with a die grinder and bent the metal back out of the way. The I lifted out the pump, did my thing on it, and reinstalled it.
THen I just bent the metal back in place, sealed the two cuts with RTV and put the rubber plug back in.

Cougars have an "access" port, as you call it, but it's only half as big as it needs to be to get to the ring.

Dropped the tank last night, didn't find anything "unusual", per se, but found a few things that we corrected in order to make a *possible* difference.

The pump itself appeared fine- It was snugly in the fitting, the screen was only a little nasty. We noticed that the screen was actually somwhat smashed at the bottom where it was hitting the bottom of the tank (Walbro's longer than stock), so I took some more plastic off the top of the pump to fit it into the gasket fitting a bit more. Also, we noticed something interesting. This pic is a bit rough, hopefully you'll be able to see what I'm talking about.

The picture shows the top of the pump housing with the pump installed. You can see the top of the fuel pump as viewed from the perspective of the fuel outlet. It's off center- By a good bit, too... Maybe a restriction? We removed some of that obstructive plastic to open her up a bit. Then, we trimmed down the outlet line to allow more of a "chamber" for the fuel to travel rather than immediately being "shoved" around a corner into an off-centered hole.

We re-assembled everything, took it for a test run, and she held 60psi at WOT all the way up at 12.5psi (after spinning through 1st, 2nd, and 3rd... Amazing what running a chip with the secondaries turned on will get you...

). Also, somehow the noise has gone- Barely audible now, just like when I first fired it up.

Then, thinking all was well, I went to fill up (had less than 1/8 tank left), and about 10gal. into the fill, fuel started POURING out of the bottom of the car.

Think I may have busted the fill tube gasket... It appears to be coming from the filler neck.

Oh, and poo-poo on whoever designed the thing- You can't get the filler breather tube hose back on for beans unless you drop the entire fill tube! There's just not enough slack!

So overall you now have enough fuel. Excellent.

Originally posted by DanG:
Cougars have an "access" port, as you call it, but it's only half as big as it needs to be to get to the ring.

So much work for taking some snips and cuttin an access area. No one will even know but you. Good you figured out the issue though.

Originally posted by todras:

Originally posted by DanG:
Cougars have an "access" port, as you call it, but it's only half as big as it needs to be to get to the ring.

So much work for taking some snips and cuttin an access area. No one will even know but you. Good you figured out the issue though.

Exactly my thought! Shoulda just cut the damned thing.

BTW, this is the same engine that you used the Mazda6 exhaust cam in right?

Yea, as far as the 12psi and the spinning out in 3rd...Yep...I know exactly what you mean. Funny, people who haven't experienced that kind of power don't really know how fast and powerfull they really can be.

Yup... 3L oval port intakes, Mazda 6 exhaust cams.

Just dropped the subframe outta her- Turns out both of my swaybar endlinks had torn- One completely off... Fun. Good thing I know a good welder!

Originally posted by DanG:

Just dropped the subframe outta her- Turns out both of my swaybar endlinks had torn- One completely off... Fun. Good thing I know a good welder!

You mean sway bar brackets right?

Originally posted by warmonger:

Originally posted by todras:

Originally posted by DanG:
Cougars have an "access" port, as you call it, but it's only half as big as it needs to be to get to the ring.

So much work for taking some snips and cuttin an access area. No one will even know but you. Good you figured out the issue though.

Exactly my thought! Shoulda just cut the damned thing.

My SHO doesn't have any access. Someone figured out the location to cut on SHOForum. Just followed the measurements and cut a hatch with my wheel. Bent the hatch back, replaced the FP and spray painted the exposed metal and bent her back and then filled with RTV. Good to go. Dropping tank=PITA.

This...

and this...

is muuuuch easier than this...

Yes, I meant swaybar mounts...

All is well, turns out I popped the fill neck seal into the tank and was running around with no seal on the tank, causing the horrific fuel loss. Got a new seal (old one was ripped), also threw in a little "upgrade" while I was there. Boxed the control arms as well as the swaybar mounts:

Linky

All in all, turned out pretty well. Drove it around tonight, 13psi of boost, never went below 40psi of oil pressure. Best part, I didn't leave a trail of fuel behind me! Anyone got a match?

Good thing you're not a smoker that ashes out the window!

Nice subframe fix but WHY didn't you convert over to the twin bolt style swaybare bracket and mounts? That stid tab-and-bolt setup they gave us on our cars SUCKS!

NOTE TO SELF: Buy a welder!

Never knew it existed. Remember, I'm just a stupid Cougar owner.

With a hairdryer.

That I installed myself.

On an engine I built myself.

Or something like that.