Could this be why my car runs like poo while it's boosting?

[Verticaljump1]

Okay, I remembered somthing that may explain why my car stutters really bad at WOT above 15PSI. I just put in 560cc injectors and a fuel pump (walbro 255lph). I bought the fuel pump used, so all it came with was the pump, rubber spacer, and wires.

Look at the picture so you will understand what I'm saying.

*Look at the stock fuel pump (top pump), to the right of it is an orange spacer, an o ring, and a orange cap. .

*Look at the Walbro 255lph fuel pump (bottom pump), it will have an identical orange spacer as the stock pump did, then to the right of that is an o ring, and to the right of the o ring is the Walbro supplied cap .

When installing the fuel pump, I do not recollect recieving any "Walbro Supplied Cap" simply because I bought the pump used. Because of this, I used the "Orange Cap" that was used on the stock fuel pump. This means that instead of the "Walbro supplied cap" (the clear cap to the right of the o ring on the walbro fuel pump), I used the stock "orange cap" in place. Did I hinder the fuel pumps flow by doing so? Because according to my a/f gauge, the car drives rich until WOT (when it's above 13-15PSI) the a/f gauge reads all the way to lean (super lean, the led's were buried into the lean section of the gauge). My guess is that the stock cap directly hinders the flow of the fuel pump, which would not enable it to meat the fuel requirements above 15PSI. Is this an accurate assumption? If this is the problem I will order an install kit right away.

I tried making the car run rich via the maf-translator, I tried making it run lean with it, I tried everything and still had the same problem. Idk if it's knock or not because I personally haven't experienced a knock situation. But the car makes a rapid puh-puh-puh-puh sound when I am above 15PSI, and it barely accelerates if that. If the fuel pump isn't the problem then I don't know what is, this is fustrating . THanks for all your help guys, have a good day~Brandon.

 

[5150DSM]

It's not the cap.
I don't see an AFPR in your mod list and if you don't have one, that is your problem. The 255 pump is overrunning the stock FPR and the 560's are just exacerbating the condition. You need an AFPR(adjustable fuel pressure regulator) to set and maintain your base fuel pressure and a linear 1:1 boost to fuel psi ratio. Overrun=non-linear flow, non-linear flow= untunable
Do a search for "FPR overrun" or similar and you will find all the info you need.
Aloha

 

[98spydert]

It's not the lack of AFPR. The over run condition is only present around base fuel pressure (i.e. idle and low throttle/rpm).

I'm assuming that you don't have a logger and that's you're first major problem. If you have no data to look at, you're making blind guesses, plus you have no idea if you've made the proper adjustments for your different sized injectors.

Second major problem is there's a pretty flashy light gauge in your car that's ABSOLUTLY USELESS! Get rid of the stupid a/f ratio gauge. Use the money you make selling that to some Honda guy and purchase a logger than can give you real information you can use.

First buy or borrow a logger, second do a serious boost leak test to rule that problem out.

Buy looking at the knock count on your new logger, you should be able to tell if you're running lean and then you can refer back to your possible pump problem as the source.

 

[Verticaljump1]

Boost leak would make sense but not in my case, I have blow thru. The gm maf is right in front of the throttle body elbow, and I've tested that numerous times for leaks and there are none. FPR is makin a lot of sense, but I thought I would ask about the fuel pump just in case. I DO have a datalogger, but I just changed the batteries and the software got erased, I have a disc to reload it but my disc drive doesn't work so I have to go to the library and get it installed. I'm not trying to be ignorant or anything. Thakns for both of your guys' help though~Brandon.

 

[BoostinAWD]

Get a new set of plugs. Make sure they are gapped correctly, if that doesnt fix you may have messed up a plug wire.

This could very well be the problem. When did the car run fine before this happened?
What are your translator settings at?

Maybe those evo injectors arent really evo injectors. Just a thought

 

[psychlow]

Are you sure all of your injectors are fully plugged in?

A single unplugged injector will cause the problems you describe.

 

[sweet97]

Okay, I remembered somthing that may explain why my car stutters really bad at WOT above 15PSI. I just put in 560cc injectors and a fuel pump (walbro 255lph). I bought the fuel pump used, so all it came with was the pump, rubber spacer, and wires.

Look at the picture so you will understand what I'm saying.

*Look at the stock fuel pump (top pump), to the right of it is an orange spacer, an o ring, and a orange cap. .

*Look at the Walbro 255lph fuel pump (bottom pump), it will have an identical orange spacer as the stock pump did, then to the right of that is an o ring, and to the right of the o ring is the Walbro supplied cap .

When installing the fuel pump, I do not recollect recieving any "Walbro Supplied Cap" simply because I bought the pump used. Because of this, I used the "Orange Cap" that was used on the stock fuel pump. This means that instead of the "Walbro supplied cap" (the clear cap to the right of the o ring on the walbro fuel pump), I used the stock "orange cap" in place. Did I hinder the fuel pumps flow by doing so? Because according to my a/f gauge, the car drives rich until WOT (when it's above 13-15PSI) the a/f gauge reads all the way to lean (super lean, the led's were buried into the lean section of the gauge). My guess is that the stock cap directly hinders the flow of the fuel pump, which would not enable it to meat the fuel requirements above 15PSI. Is this an accurate assumption? If this is the problem I will order an install kit right away.

I tried making the car run rich via the maf-translator, I tried making it run lean with it, I tried everything and still had the same problem. Idk if it's knock or not because I personally haven't experienced a knock situation. But the car makes a rapid puh-puh-puh-puh sound when I am above 15PSI, and it barely accelerates if that. If the fuel pump isn't the problem then I don't know what is, this is fustrating . THanks for all your help guys, have a good day~Brandon.

You could have your arm broken and not believe you need an AFPR. You can use the stock spacer, o-ring and cap onthe walbro, it's OK. I am at a loss as to why you REFUSE to get an AFPR???????????????