Fuel Pump Cause Hard Starting?

[gmc9sqm]

i bought my car a couple of months ago and could not figure out why i could not run more that 10 pounds of boost so after talking to a local shop they told me to upgrade to a 255 fuel pump. So i bought it and pulled out the old pump and i realized that it already had a 190 in it, but i went to all the work to get the old one out so i still installed the 255. well after i put it all back together i got a problem i cannot figure out??? when the 190 fuel pump was in, the car would start great weather it was ice cold or if it was warm, now that i have the 255 fuel pump installed, my car will not start when it is cold. it will just keep cranking and nothing will happen. the only way to get it started is if you roll it and pop the clutch and hold the gas peddle on the floor it will start but it acts like it is flooded so you have to keep your foot on the gas for about thirty seconds and then it will idle by itself. once the car is warmed up you can shut it off and come back in a hour and it will start perfectly fine. I'm out of ideas?????any help would be great! SORRY FOR THE LONG POST

 

[Gstclipse69]

Well first, the fuel pump shouldnt be the culprit for not being able to run more than 10lbs of boost. Have you checked for boost leaks? How is your boost controller hooked up? The 190 should be fine for your setup now. If you decide to keep the 255 in you need a fpr, because the 255 will have overrun the stock fpr.

 

[tbonitz301]

Yes, overunning you stock FPR with a 255 wally will definetely cause some super rich conditions at startup. An aeromotive AFPR would work nicely.

 

[gmc9sqm]

yes i did finally figure out that i had a couple of boost leaks. but anyways i already have an AFPR and it is set at 37 psi of fuel.

 

[gsxtasy]

I have a similar problem and have yet to figure it out. Its either spark or fuel and I'm leaning toward fuel problem. Hope somebody can chime in with some advice.

 

[theebluecrx]

Clean your throttle body.