SparkPLUG Question/Sputter WITH VIDEO

[rowland2004]

Have a 92 GSX
Big 16g
550cc
255 pump
SAFC
@21psi

Just wondering if i might need new spark plugs since when my car warms up it sputters a little at idle and anything under 50% throttle.

But here a Vid clip u can hear it idle a little. Thanks

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[toojung2die]

Just wondering if i might need new spark plugs since when my car warms up it sputters a little at idle and anything under 50% throttle.
But here a Vid clip u can hear it idle. Thanks

I couldn't hear the engine at all. Clean car though. Do you have an AFPR? You might be over running the stock FPR with the 255 pump. If you haven't changed or gapped the plugs in a while it couldn't hurt to put a new set in there. If that's not the problem you'll have a spare set. What are you using to tune the S-AFC?

 

[rowland2004]

Yea i have LC-1 Wideband with gauge

But also i just was reading since i have the stock MAF and have a GREADY BOV into the atmosphere that might be the Prob.

So maybe i need to get a MAFT.

 

[Freerevving]

Yea i have LC-1 Wideband with gauge

But also i just was reading since i have the stock MAF and have a GREADY BOV into the atmosphere that might be the Prob.

So maybe i need to get a MAFT.

Everybody's so dead set on 255lph pumps and most of them are the high-pressure ones
This means that they flow better at high pressure (idle) and closer to weaker pumps at full throttle (although they still flow much better at WOT too)

Why not just use a 190lph? That's what I have ready for install... from what I know they don't have the classic problems of the 255 (which REQUIRE an AFPR too run smooth at idle). As long as you plan on less than 500hp the 190 pump is plenty enough

My AWD Talon had a stumble at idle due to the 255 pump, and it only happened after the engine was warm. Ran well besides that, but there was no way it would pass emissions

Pre-ignition might be making your problem worse... one step colder plugs may help (BPR7ES)... but most of the problem is with the extra fuel at idle

 

[Maranello993]

Recirculate the BOV and get an FPR.

 

[rowland2004]

yea think i might have a FPR because when i pop the hood i see a FUEL pressure gauge that says around 40psi at Idle.

AND thanks for the response guys.

 

[Freerevving]

yea think i might have a FPR because when i pop the hood i see a FUEL pressure gauge that says around 40psi at Idle.

AND thanks for the response guys.

if you can adjust it try dropping the pressure to 36 or 37

You may need to go lower than that, but it's a good starting point

 

[toojung2die]

yea think i might have a FPR because when i pop the hood i see a FUEL pressure gauge that says around 40psi at Idle.

That's too high. With the vacuum line disconnected to the AFPR the 1G base fuel pressure is 37 psi. When you connect the vacuum line the FP will drop a few psi more.

 

[rowland2004]

Sweet ill take a pic real quick and let u guys see what i got. AT 5AM here

 

[rowland2004]

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Heres what i have.

 

[toojung2die]

Heres what i have.

You have a fuel pressure gauge on your fuel filter. Not a bad place to have one but the photo doesn't show if you have an adjustable fuel pressure regulator. The fuel pressure regulator is on the driver's side of the fuel injector rail. The stock fuel pressure regulator is connected directly to the left end of the fuel rail. I'm betting you have a stock regulator with a high flow 255 fuel pump = higher than normal base fuel pressure.

 

[rowland2004]

ill check if anyone has a pic of one ill check and see thanks.