gary96gt

I have a 96 GT, i bought a zex wet kit and am worried about the fuel pressure.

I have a mechanical gauge on the schrader valve and when you cycle the key it snaps to 40 lbs. but when you start the car it bleeds down to about 30 psi. now when you tap the throttle it goes back up to about 40 but if you hold it at 5000 rpm's it again bleeds down to 30. my concern is do i have a bad pump or is it saposed to do this?

please help


Gary

nitrous_bob

are you sure it's working correctly? it should sit about 36 psi with the vac line still attached.

watch it around WOT and see if it stays pegged about 42 psi

if your not certain it's all good... don't squirt it

fuel pressure is pretty much the most important thing you need to have right on when your on the smack

gary96gt

well i just bought a brand new hi volume pump from o'reilly's. said 45-50 GPH at 40-50 psi. the gauge on the schrader valve still shows idle at about 30psi but it still jumps fast when you tap the throttle to 40 or a little over. could this be a simple deal where it stays at 40 if i stayed at WOT? anyone else experience this?

luckythirteen13

fuel pressure is always lower at idle but 30 seems really low. do you have a gauge mounted where you can see it while driving?

gary96gt

its under the hood so no, but i sprayed a 100 shot tonight and except for a little surge (i think the bottle was cold) it was AWESOME. now with the new pump it stays about 42 psi so i think we're good. but i you let it sit it drops to 30.......

nitrous_bob

could be an inaccuracy in the gauge at the low rpm

since you have a schrader tap, you can run a length of hose to any gauge and just have a buddy hold it out the window. to watch it while you concentrate on driving.

the most important thing is that it hits adequate fp, and stays there while your wot on the juice. dry kits will spike to 80 psi cuz the fuel boosts at the injectors, not sure what your wet kit needs. read your plugs often. you'll see fouling/deterioration b4 you see detonation.

best testing is at the track... adjust timing and watch for your mph to slow down... thats when you exceed optimal timing and start going lean b4 you break anything

gary96gt

after the first run and now subsequently the first bottle i pulled all the plugs and they are perfect. im running a 100 shot but i didnt adjust timing honestly because i dont know how, is this bad? i dont have a pressure gauge on the bottle so im assuming im out because it bogs down then im guessing my zex kit is reading low bottle pressure and shuts the system off so it runs w/o the spray. getting the bottle refilled tomorrow so im excited to spray it some more...

got my first victim though, getting on the highway i ran a lt1 trans am from 30 to about 95 and put about a bus and a half between us. i never had a problem with lt1 cars up to about 70 but they would always pull me after that. i would imagine the guy was like wtf just happened LOL

nitrous_bob

well timing is a huge thing

if the plugs look good though....your good

and bottle pressure is big too, once you tail off to less than 800 psi your getting low and the hit will be much less, and i call it empty at 600 psi