Fast 102 fuel system issue
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From: Hurley, VA
Fast 102 fuel system issue I've got a FAST 102 with FAST ls2 rails 42lb racetronix injectors and racetronix fuel pump and hotwire kit. I'm running the stock regulator which I think may be an issue. Fuel pressure usually sits at 64psi which is higher than stock but occasionally it will bounce between 60-68 erratically and my fuel trims sometimes are normal and sometimes are at -30. With this set up do I need a aftermarket regulator to keep it stable or is my stock regulator messing up?
Shouldn't need an aftermarket regulator, I assume we are talking about the 255 pump?. Its normal for the FP to be around 62-64 with the upgraded pump and hot wire kit. I'm running the same setup and no issues. Though i dont run fuel trims because im OLSD but AFR stays right around 14.7 at idle.
Could be the regulator or could a couple of cells in the tune possibly be off? Are you running a wideband?
Could be the regulator or could a couple of cells in the tune possibly be off? Are you running a wideband?
Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
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From: Hurley, VA
I wonder if that's the reason for the trims being so far off. I actually went from TR6 to TR55 plugs and with throttle now my fuel trims will go 20 percent lean but at dead idle I'm getting -25 at least. With any throttle at all tho fuel trims go right in line but I have a weird lean spot now between 2000-3000 free revving it. I'm beginning to think these injectors are junk as we'll. I've always had random full lean spots on the wideband. If I force open loop I actually get low 13s afr when it's commanding stoich. I think I may ditch these Injectors and possibly retune it myself or find a better tuner.
I've got a FAST 102 with FAST ls2 rails 42lb racetronix injectors and racetronix fuel pump and hotwire kit. I'm running the stock regulator which I think may be an issue. Fuel pressure usually sits at 64psi which is higher than stock but occasionally it will bounce between 60-68 erratically and my fuel trims sometimes are normal and sometimes are at -30. With this set up do I need a aftermarket regulator to keep it stable or is my stock regulator messing up?
When the car was tuned the tuner setup your injector calibration table based on psi, size and a couple other things.
If you have a 42lb injector that's open for 4ms at 58psi
That same injector open for the same time is going to flow more fuel at a higher fuel pressure.
That's why your fuel trims are -30.
Thread Starter
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From: Hurley, VA
The car was tuned the way it sits tho. The pump has been in the car a couple years before the 408 went in and the new tuner tuned the car I never had the 10.0 afrs at heavy throttle low rpms like I do now. Trims will sometimes actually go to normal at idle occasionally while I'm sitting at a constant 64psi but sometimes sky rocket. Pulled the plugs and went from tr6 to tr55 and trims will go lean with throttle (do have a vac leak) and the tr6 plugs were black at the bottom of the porcelain but white at the top.
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Thread Starter
10 Second Club
Joined: Jan 2010
Posts: 2,317
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From: Hurley, VA
The regulator is on the pump module. With the stock rails the thing that looks like a regulator is the fuel pulse dampener. I'm sitting at 62 on the dot with a different fuel pressure gauge.
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I'm at 62 with the Racetronix + Hotwire kit.
And if you want a 42lbs injector, get the LS3s (if you want 42 at the rail) or the L9H (if you want 42 @ 3-bar and 50 @ 4-bar). There's actually injector data for them. Who knows what the Lucas injectors really want - no real data on them. Both are the short 34mm injectors. There isn't really anything great in the 48mm size except for maybe the Siemens 60lbs. In the 60mm LS1 length, I'd get the FAST 36lbs (Bosch White from the 3800 Supercharged Motor and ASA Race Motor - lots of good data), or the Ford Green Top 42s.
And if you want a 42lbs injector, get the LS3s (if you want 42 at the rail) or the L9H (if you want 42 @ 3-bar and 50 @ 4-bar). There's actually injector data for them. Who knows what the Lucas injectors really want - no real data on them. Both are the short 34mm injectors. There isn't really anything great in the 48mm size except for maybe the Siemens 60lbs. In the 60mm LS1 length, I'd get the FAST 36lbs (Bosch White from the 3800 Supercharged Motor and ASA Race Motor - lots of good data), or the Ford Green Top 42s.
