Hesitation at full acceleration! (fuel pump?)

[titogs95]

doug99rs
Driveability Symptoms:
Hesitations, poor performance, vibration, shudder, low gas mileage, idle problem, exhaust note discrepancies, air/fuel ratio out of spec, CHECK ENGINE LIGHT

Needed Information:
---Outside temperature (within 10 degrees or so), vehicle temperature(Cold start, half-way to normal operating temperature, normal operating temperature, Above normal, overheating), At idle?, Under light-medium-heavy acceleration, Deceleration- slight-moderate-foot off accelerator or downshifting agressively, At what speed, what gear, how much boost, and how consistant does it occur? Every drive cycle, very intermittant, every time during the same driver demands of the drive cycle?

Hi, I am having the following problem:

1.Everytime i am starting the motor I feel a hesitation by the time I am slamming the gas pedal. I warm up the car and everything. So, I slam the pedal and suddenly (arround 4K to 6K RPM) I feel that the car shuts down and comes back again (it happens for less than a second)
By the time that it happens it feels like the whole engine stops and come backs againg, It is annoying because I can fell the kick in the whole car!
Condition:
half-way to normal operating temperature
Florida average temeperature
Idle good!
Under heavy acceleration
what gear (arround 1 or 2 gear)
It happens arround 1-3 times a week
No check engine light at all
I have an A/F gage but it doesn't help by the quick time!

Another thing (must be related) That i am driving crussing arround and suddenly I do a full stop on a signal light and the car shuts down by itself! WTF! (It happens arround 5-8 times a week) at normal operating temperature

I am starting to belive it is the fuel pump, It feels like a fuel cut ( I know how it feel when you are on a gs-t with a big turbo and the fuel cut shows up!)

TIA

Tito

 

[90CherryTSI]

but myself as well as about 3-4 others have recently reported the same thing. Coasting to a stop, engage clutch, and RPMs drop and car dies. Happens every once in a while, and the hesitation thing, having it also on my 90 TSI. Doing boost leak this weekend to see if that's it. I let mine warm up also.

 

[titogs95]

but myself as well as about 3-4 others have recently reported the same thing. Coasting to a stop, engage clutch, and RPMs drop and car dies. Happens every once in a while, and the hesitation thing, having it also on my 90 TSI. Doing boost leak this weekend to see if that's it. I let mine warm up also.

Good, but what is the solution?
About the ""Coasting to a stop, engage clutch, and RPMs drop and car dies"" I don't really care! What i do care Is:
"""I feel a hesitation by the time I am slamming the gas pedal."""
That problem Is really annoying!

 

[GSX503]

Good, but what is the solution?
About the ""Coasting to a stop, engage clutch, and RPMs drop and car dies"" I don't really care! What i do care Is:
"""I feel a hesitation by the time I am slamming the gas pedal."""
That problem Is really annoying!

What kind of turbo do you have? I have a TO4 Turbo and its pretty big. My car is doing the same thing, I believe its fuel cut. I can run up to 4500 on 2nd gear then the car jerks, sounds like engine shut off, then quickly come back on.
I am running 19 pounds, but a buddy of mine said its fuel cut and be careful that I might blow my motor. But today I just received my 255 fuel pump and installing right now.

Also my car idles at very low rpm.
will keep update

 

[ACKERSON]

Ok all the information you guys are seeking is here on the forum, you have to SEARCH for it. titogs95 what mods do you have? list everything and we can go from there. The dying at a stop thing is probably the most common problem for any dsm, there are probably a million threads on it as well as tons of info on vfaq. Hesitating at full throttle is most likely unrelated.

 

[TurboJunky]

It's fuel cut.

My car was experiencing the same due to simply boosting too much for the fuel system.

You could also have a boost leak. Make a pressure tester (a la vFAQ) and test it up to normal boost levels.

 

[GSX503]

I finish installing fuel pump and rewire. I can run up to 19 psi without fuel cut but running rich. Now I'm having problem with my indash fuel gage. It is not correct, I fill up the gas tank and the gage goes up to the 3 quaters of the tank. So now I'm estimating my gas mileage in order to not run on a emty tank.

Why I'm I still running rich? How can I recorrect my fuel gage?

NEED HELP PLEASE ANYONE.

 

[blue92laser]

Why I'm I still running rich? How can I recorrect my fuel gage?

NEED HELP PLEASE ANYONE.

For richness, get an AFC. If you rewired the Walbro fuel pump, it was a bad idea. I've heard stories. As for your fuel guage. Did you even tap into the right wires for the rewire? The rewire will never have an affect on any of those sensors or wires. Maybe you should go back and check everything over.

 

[Raph]

I finish installing fuel pump and rewire. I can run up to 19 psi without fuel cut but running rich. Now I'm having problem with my indash fuel gage. It is not correct, I fill up the gas tank and the gage goes up to the 3 quaters of the tank. So now I'm estimating my gas mileage in order to not run on a emty tank.

Why I'm I still running rich? How can I recorrect my fuel gage?

NEED HELP PLEASE ANYONE.

so u removed the old fuel pump and put the new one in..maybe you should check to see if the floater(the fuel sending unit- a.k.a -the thing in the tank that swims in fuel to tell you how much fuel is in the tank)ist bent (maybe when you took it out,you may have bent it ever so slightly...causing a wrong reading)

my suggestion would be to remove the fuel pump assembly out of the tank(with all the wires still hooked up) cover the tank up..turn the car to the acc position..move the floater(fuel level sending unit) with your fingers to the top position to see if the needle also goes all the way to the top... )if not ..maybe you can ytweak it ever so gently with your hands..check the contacts on the potentionmeter to see if theres any grit on them causing a faulty signal..clean with alcohol solvent .

ive done this to other cars before..but not to my dsms(gauges accurate)

be careful ,donot cause any static and stuff while working around gasoline ! dont blow yourself up

i hope this helps..if not(or you have already checked this) good luck

 

[GSX503]

I'm asumming wires are hook up right, I follow the rewire threads. If not, I asume car should die seconds later after starts up. But I will probably redue the whole intire process. I will print out what Raph said too so I can try to solve this problem.

Thanks guys.

By the way anyone no where I can get an oil return line, my stock broked.

 

[GSX503]

For richness, get an AFC. If you rewired the Walbro fuel pump, it was a bad idea. I've heard stories. As for your fuel guage. Did you even tap into the right wires for the rewire? The rewire will never have an affect on any of those sensors or wires. Maybe you should go back and check everything over.

So what kind of stories are there about rewiring the Walbro. I installed the 255 pump first and it seems to work alittle better than stock. I still hit fuel cut with it at 19 psi. After rewiring the pump, I can hear the pump, but people said that it is suppose to be load but not in my car. The only noise I hear is the pump pumping while boosting. Sounds similar to turbo sucking air shhhhhhhhhhhh.
Any thoughts.

 

[realhp=turbo]

Ive been having the hesitation problem myself. It only does it at WOT or close to. It feels like the ecu is pulling timing. Like Ill go throttle it and launch and at wot it feels like she wants to fall on her face. If I let off alittle, it re-gains timing (im assuming) and proceeds with full factory boost ( When the turbo is cold but motor is warm) WTF? What would cause that with a close to factory set up? My mods thus far are all free. Minus the honeycomb removal. (bcs restrictor tube removal, plastic air box funnel removed, paper vectoring removed from air box)
mike

 

[realhp=turbo]

So what kind of stories are there about rewiring the Walbro. I installed the 255 pump first and it seems to work alittle better than stock. I still hit fuel cut with it at 19 psi. After rewiring the pump, I can hear the pump, but people said that it is suppose to be load but not in my car. The only noise I hear is the pump pumping while boosting. Sounds similar to turbo sucking air shhhhhhhhhhhh.
Any thoughts.

You can hear your fuel pump? Damn you got good ears! All I hear is my turbo and my motor. Even in a Ford where you can hear the fuel pump pressurise the system at start up, I cant hear the pump working while the car is running let alone while at WOT. Are you sure its the pump your hearing?

 

[GSX503]

You can hear your fuel pump? Damn you got good ears! All I hear is my turbo and my motor. Even in a Ford where you can hear the fuel pump pressurise the system at start up, I cant hear the pump working while the car is running let alone while at WOT. Are you sure its the pump your hearing?

Yeah, I'm pretty sure its the pump I'm hearing. It wasn't like that until I rewire the 255 Walbro. I had the 255 on for about 2 days, and I wass pissed because it seem to make no difference. So a buddy of mine told me that inorder for the 255 Walbro to work. I have to rewired it, so when I did , took it for a test drive ssshhhhhh coming from the pump when accelerating.
My buddy said he hears his pump making noise at stop lights, not me.