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Fuel Pressuer!?

This is a discussion on Fuel Pressuer!? within the LT1 forums, part of the Vehicle Specific category; We are adding nitrous to car and we were told that we needed 44 psi of constant fuel pressure so ...

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    Junior Member prater_1's Avatar
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    Fuel Pressuer!?

    We are adding nitrous to car and we were told that we needed 44 psi of constant fuel pressure so we got a adj. fpr(aeromotive)! Dad said we were getting 30 psi at idle with the old one and now with the adj. fpr we are getting 80psi!! We tried turning down the pressure but once it got down to around 65 psi it started running rough and then started chocking out and back firing around 60psi!! We have checked with 2 different gauges and are getting the same readings!! What are we doing wrong?

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    Is this an Lt1? your tag says 02 z/28. Also after that's answered, did you do anything else while putting in this FPR? probably a bit** but put on the old one and see what happens. or check it over thoroughly to make sure everything is done right. Accidentally unhook a sensor in the process? backfiring would be ignition or too much fuel buildup. Also try unhooking your battery so it can remap itself. If you already put in the assistant pump for the nitrous i would check to make sure its operating correctly as well.

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    Junior Member prater_1's Avatar
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    It is a 96 Z28 LT1! Its our drag car. We did install a new summit 58mm tb also the battery was diconnected while it was being replaced. The old fpr was holding steady at 30psi and thats the reason for replacing it! As it stands we still are running a new factory fuel pump(areotex) but we are going to buy a walboro 255!

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    Are you running the Aeromotive 13107 regulator for LT1 cars?

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    Is this a stock cam or after market? Also what size injectors and what else is this beast running after market? And is she tuned or not? what happens when you bring up the rpms? is there a vacuum line i conjunction with the fpr that isn't hookedup?

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    Junior Member prater_1's Avatar
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    Quote Originally Posted by pajeff02 View Post
    Are you running the Aeromotive 13107 regulator for LT1 cars?
    Yep thats the one!


    Quote Originally Posted by 93TransAm View Post
    Is this a stock cam or after market? Also what size injectors and what else is this beast running after market? And is she tuned or not? what happens when you bring up the rpms? is there a vacuum line i conjunction with the fpr that isn't hookedup?
    Its a after market mild cam, at this moment its running 24# injectors(soon to be 32s), lth, a 2400 stall(yes we know its to small, our first time so we were unedumacated) 410 gears with moser axles, 28x9x15 slicks and a 58mm tb with a descreened maf and yes its tuned( by pcmforless) but not yet for the new tb! We havent driven it but it runs fine when we rev it up!! Everything is hooked up as it should be!!

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    Only thing i could think of is maybe the MAF sensor was damaged in the descreening process or possibly a bad plug or plug wire. how new is the opti? what rpm does it idle at? my brother was having a similar problem on on his 300zx TT (yes i know totaly different type of car) and it was a bad spark plug, even though he had just changed them. it cracked and failed due to too much fuel from a bad O2 sensor. is the car throwing any codes or light? also i was just having a similar problem with my lt1 and it was a clogged catalytic converter. it was making it run way too rich and backfiring excessivley at idle and occasionally mid rpm.

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    Junior Member prater_1's Avatar
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    Quote Originally Posted by 93TransAm View Post
    Only thing i could think of is maybe the MAF sensor was damaged in the descreening process or possibly a bad plug or plug wire. how new is the opti? what rpm does it idle at? my brother was having a similar problem on on his 300zx TT (yes i know totaly different type of car) and it was a bad spark plug, even though he had just changed them. it cracked and failed due to too much fuel from a bad O2 sensor. is the car throwing any codes or light? also i was just having a similar problem with my lt1 and it was a clogged catalytic converter. it was making it run way too rich and backfiring excessivley at idle and occasionally mid rpm.
    Its running fine just at 80psi! As for rpm at idle 800-900ish

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    Does the adjustment do anything? Have you checked your vacuum source? Have you checked the pressure with another gauge to verify?

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    Junior Member prater_1's Avatar
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    The fuel pressure lowers when i "twist" the adjustment bolt but about 65-60 it starts running like crap! Yes we've checked it with two different gauges and get the same results. Vacuum lines were checked and triple checked!

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    if it likes it and its not too rich f it. I'd rather too rich than too lean and blown. :P

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