Fuel Cut #3

[scheides]

Ooh, good idea shane!

Sleepy, try this, if you have a fuel pressure gauge to go with that AFPR :)

[sleepydsm]

Yes, the FP gauge is mounted on the AFPR. I will try to increase the FP, but should I then use the MAFT to lean it out a bit or just let it be with a higher FP?

[Kevin 1G Drummer]

You'll wanna lean it out a little with the maft.

[sleepydsm]

Tonight, I turned the FP to 55psi and the car ran lean as hell. I was, uh, testing, and at wot it went to 14.1:1(knock city). I felt the car pulling major timing (i'd hope so at 14.1:1) and was slow as shit. I set the FP back to w/e it was supposed to be stock and then i was back at 11ish:1 at WOT, but with my pal Fuel Cut.

Refresher:
255HP installed about 4 months ago
Stock 450's
Stock EPROM ECU
Aeromotive AFPR
GM MAF/MAFT with fuel cut switch on, (will be switched off tomorrow)
I will also do another boost leak test tomorrow.

I am considering just getting some evo 560's and doing e85 with a chip burnt on the dyno.

Anyone know if Shane can eliminate fuel cut on the chips he can burn?

[123abc]

FWIW, I figured out thanks to twack that my sputtering at 5k was due to a 30 gap at the plugs. Gapped them down to 25 and she pulls to slightly past 6k. I don't need to go that high anyways.

[Shane@DBPerformance]

If you raised your fuel pressure and it went lean, then something isn't right. It could have been so rich that it misfired causing lean readings(misfires cause a lean reading due to the oxygen not being used) or something in your fuel system like the pump or filter is having a problem or something else is weird.

Evo 560s won't be big enough for E85, unless you don't plan on making any power. I turn off fuel cut when I do chip tunes.

[sleepydsm]

Did another boost leak test, found the TB shaft seals were leaking and two of the injector seals were pretty bad. I replaced all four injector seals, and I also flipped the fuel cut switch on the MAFT to allow factory fuel cut. (I misplaced my Instructions for the MAFT, so according to Tuners it's switch #3 needs to be in the down position, maybe someone can confirm that)

I just don't get why no one else has problems running 15psi on the stock fuel system/ecu.

[Andrew7dg]

Stock exhaust?

When I replaced my exhaust, major boost creep happened and it would go to like 19 psi. BOOM, fuel cut... But you Probably have a gauge to look at that.

I would get fuel cut all the time in my car just because of the exhaust

Do you have something with MMcd To see what the computer is seeing? Have you looked at your FTs? I had to adjust mine to the GM maf-t because it was off. Thats why there are adjustment knobs in the box. Every GM maf reads slightly different. GM ECU corrects this already but we are working off of this box.

These tuning knobs shouldn't be used for tuning bigger injectors. IMO they suck because they only tune LOW, MED and HIGH and there needs to be more points to tune with then just three. An SAFC ontop of the GM maf-t for tuning would be Ideal. If you were to do that though, the 2G MAS plus and SAFC reads much much better then the GM MAF-t (I have had bad experiences with the MAF-T). I believe the SAFC also takes into account Trottle position.

[sleepydsm]

Stock exhaust?

When I replaced my exhaust, major boost creep happened and it would go to like 19 psi. BOOM, fuel cut... But you Probably have a gauge to look at that.

I would get fuel cut all the time in my car just because of the exhaust

Do you have something with MMcd To see what the computer is seeing? Have you looked at your FTs? I had to adjust mine to the GM maf-t because it was off. Thats why there are adjustment knobs in the box. Every GM maf reads slightly different. GM ECU corrects this already but we are working off of this box.

These tuning knobs shouldn't be used for tuning bigger injectors. IMO they suck because they only tune LOW, MED and HIGH and there needs to be more points to tune with then just three. An SAFC ontop of the GM maf-t for tuning would be Ideal. If you were to do that though, the 2G MAS plus and SAFC reads much much better then the GM MAF-t (I have had bad experiences with the MAF-T). I believe the SAFC also takes into account Trottle position.

I have exhaust, the car is not boost creeping. I'm running 15psi and wondering why my ecu is seeing too much airflow, i just find it hard to believe I'm exceeding the max set airflow (which I know isnt a huge number, but still).

[sleepydsm]

I will get DSMLink soon enough, so I'll just quit bitching.

On another note I've been going throught a lot of the stock things and making sure they are ok. All maintenance things are done, I'm very good about that. Coil pack and transistor tested fine, I've been doing boost leaks like every day haha, I will check the injector pulse width soon, car has good fuel pressure, and a new fuel pump, a newer filter, etc. I'm just making sure everything is OK before I actually try to make modest power.