Ok I installed a BBK (walbro) 255lph fuel pump on my 91' GTA 305 tpi. It runs a runs fine but when I floor it I don't go anywhere, it spits and sputers and throws out a pretty decent amount of black smoke. I also have an adjustable fuel pressure regulater (also BBK) with stock psi setting and a set of 32lb.hr. Venom fuel injectors. I have a video of what its doing I just need to download it. But do you think that the fuel pump is too much for this engine at the moment?


Thanks,
Steve

 

STOP DRIVING THE CAR

U will wash down the rings with fuel and it is beyond stupid rich with 32# injectors on there.

Visit the DIY PROM and start researching for u do another thing.

later
JEremy

 

I already pulled the pump out and replaced it with the nissan one that I had to ghetto in there before I put the walbro in.

 

lol

The pump doesnt have a damn thing to do with it.

Injectors 40% larger than what it came with does unless the appropriate tuning has been done at a minimum.

ITS THE INJECTORS, THEY ARE TOO BIG WITH CHANGING SETTINGS IN THE PROM

 

but I've had the injectors in the car for over a year and I've never had this problem untill I put the pump in.

 

Probably becasue your stock fuel pump could not flow enough fuel for those injectors. Now you got a better flowing pump, those injectors are flowing there full rate. Unless the computer is reprogramed for those injectors it will not run right. I suggest going back to stock(19#). You dont need injectors that big unless you are running a turbo or supercharger.

 

Thats the thing I'm in the process of doing a twin turbo set up on it and I almost have my daily driver finished so I can start getting this car ready to be torn apart and since I had to ghetto in a Nissan fuel pump into it when the discount auto parts one went out and they wouldn't warrenty it out and instead of buying another stock pump I figured since its going to be boosted soon get the bigger pump.

 

In that cause you need to get a reprogramed prom to work with those injectors.

 

I've been told that lsracingchips.com does a good job and I was thinking about goign with one of theres.

 

Listen to the guys above, you can NOT run a NA 305 on 32#/hr injectors!!!

Untill you have installed turbos or an SC, run the engine on 19#/hr injectors... with a good high volume fuel pump.

Reinstall the high volume pump and 19#/hr injectors.

 

What doc is saying is that even with custom programming, the 40 PPH injectors probably won't work. In order to get the injector pulse width appropriatly low enough to deliver correct fuel at idle and low RPMs, the pulse width will be so short that the injectors may not even operate due to the propagation delay of the injectors themselves (it takes a few mS for the injector pintle to actually move after receiving the electrical signal at the solenoid). Raising the pulse width enough to get them to open consistently would deliver too much fuel at idle. It would be similar to attempting to fill a ½ ounce perfume bottle without spillage through a 4" valve on a fire hydrant.

 

Went ahead and swaped old injectors out and put the 255lph pump back in last night. Now what would be the best for fuel pressure, I currently have it set at about 43 psi which should be around stock.