Fuel Pump Added Still Problems

[b11dragone]

Ok... so i originally needed help because my car was boosting insanly high, and when doing so bucking and backfiring. After discussing this problem with many people I decided to go with a walbro 255lph high pressure fuel pump to fix the problem. So I installed the pump and it worked great for about 10 minutes, now its bucking and backfiring even worse than before. And now you can here the fuel pump when I start the car. What could be wrong now?

 

[4whlbst]

Since you have a "whinebro" fuel pump installed the noise is common. As far as the backfiring and bucking does it happen all the time or only during full boost runs? If its only on a pull through at full boost than you are most likely hitting fuel cut. Meaning that your car is reading too much air and you are hitting 100% duty cycle on the injectors. I would look into injectors and an safc. If it is all the time than I would first start with the condition of the spark plugs, they could be fouled, also check your spark plug wires, if your valve cover gasket is leaking or the wires are old they could be shorting out. Replace the wires and plugs and see if that helps. Check those things out and then see how the car is running then.

 

[leet]

The reason you are having issues is because you did not install an Adjustable Fuel Pressure Regulator, in addition to your 255.

You are running insanely rich.

Check out the Aeromotive regulator.

 

[OwN1GST]

also check your plugs and wires I had the same problem and it ended up being my wires.

 

[b11dragone]

the problem is only happening at full throttle....when I drive normally the car runs fine....it can't be running insanely rich either because the problem was happening before i put the fuel pump in, i installed the pump in hopes of fixing it...which it did for about 10 minutes...im thinking that a fuel line broke or something cause gas was leaking out of my car when i got out of work today

 

[4whlbst]

If there is gas leaking out of the car than that is most likely your problem. It is probably a small enough leak that it doesn't affect part throttle driving. But at wot your need for fuel is most likely exceeding the amount that can make it past the leak. Having the higher pressure pump would excacerbate the problem. Did you recently change the fuel filter? It could be as easy as the gasket on the filter. Start with checking the rubber lines by the fuel rail.

As far as having the 255 hp pump installed w/o an adj. fpr. Your car will run fine, it wouldn't cause the problem you are having. Though it will increase your base idle press as much as 10 psi. This causes the cylinder walls to get flooded with fuel and causes premature wear since the oil is being washed off the cylinders. Also this will cause the car to idle rougher and the performance of the car will be affected. This is the problem I have with my 97 gsx as well. I am running much slower w/ the walbro installed than before. You do need an adj fpr and a gauge to work well with that pump.

Good luck with finding the problem, let us know what it was when you find it.

 

[b11dragone]

Thanks guys. I will let you know what the problem is tom. I will be working on it all day. Later

 

[FASTSPOOLINGST]

you stated that your boost is running insanely high and your car is bucking, that my friend is probably fuel cut

backfiring i agree with the post above, it is from running rich as hell, you need a AFPR, that 255 is over running your stocker. Even if it is not the problem, u r still going to need one with that 255, or u are gonna be running pig rich all the time. Don't do any highway pulls anytime soon, cuz you will get some nasty backfires. When i was racing a vette on the highway with my gs-t, around 6k, after i was a couple cars in front of him, my car let out the loudest damn backfire in the world. later on, he told me a huge flame shot out the muffler too. I didn't have a fpr and i also had the 255 pump. If u are running stock or a 16g, u should have got a 190 anyways, that way you wouldn't have to get the fpr.