backfiring...what should my fuel pressure be set to with AFPR?

Matt94GT

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Well lately my cars been backfiring on me. Its when I giver in 1st up to about 5,000rpm+ then drop it in 2nd and floor it (ie, racing etc).

Any suggestions? I did install a adjustable fuel pressure regulator and fuel rail pressure gauge and my mechanic said he bumped it up for me a bit. I did notice a bit of a power gain to tell ya the truth, but mabye its a bit too high and thats whats causing this? What should I set it to? I have a Mild H/C/I setup.

Thanks
 

rgs

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matt our combos are a lot alike.

i got mine set to around 37-38 i believe with vac on
 

EThorpe

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Sounds like it's a bit rich, don't blow the mufflers out :p

Did this happen after the new Regulator was installed? Bump it back to stock and see it the backfire goes away? I think the normal pressure is about @36-40psi and drops to about 30'ish psi on the stomp. If it still backfires after you put it back to stock? then maybe a Plug wire is biting the dust under a load?

Do you have a timing adjuster+chip in that car? Bump the timing up a little when you rich'n that shit up.
 

EThorpe

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Well? what happen'd? Did you fix it? What was it :dunno: To rich?
 

Matt94GT

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Well it wasnt doing it for a while but did it the other day when I ripped 2nd gear. My fuel pressure is at 40, should I drop it down a bit?
 

Matt94GT

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WOW....My fuel pressure must of been at like 45ish before because it was @40 with the vaccume line on.

Anyways I bumped it down to 38 with the line off, it didnt back fire in 2nd any more but i got some backfiring on light throttle at lower rpms in 3rd and 4th. I put it up to around 40 and got a bit of both now, I just turned it down to 39 hopefully thats the sweet spot.

BUT hot damn, the car pulls like I remember it pulling when it had the stock AFPR and then some, wow feels like its got a lot more balls now.
 
adjust yer timing...

if you want you could increase the timing a bit and run 93... thats what i did... felt much nicer after i did that... first free mod i did to my car, lol...

but i think it could use a nice timimg adjust and what octane fuel do you run?
 

97vertstang

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bump ur timing back to 16 and make sure ur whole ignition is in good working order.coil, wires, cap, and rotor.if evrythings good it shouldnt backfire at all at 35-40 vac off.
 

Matt94GT

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I got the pressure at 42 now and it doesnt backfire at all. Seemed to pull a bit harder down at like 39 but I got some backfiring? I got fairly new plugs, wires, cap & rotor. I run 94 Octaine. I think I might put my timining up even more from 14 to mabye 16* again???
 

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