Running out of fuel with 660s and big 16G? WTF

TALONTED TURBO · Feb 21, 2003

OK, I have a big 16G, cams, FMIC, AFC, VPC, Walboro 225 HP, etc. I had 550s, and at high rpms in cold weather I was going lean up top at 7k, about .84 on the 02 voltage.

So i got 660s, definitly way more than enough fuel for any 16G.

I installed 660 VPC Chip, so things run fine, and at 6-7k rpm on the AFC, i richened things up,

Drive the car, 7k, .88, so i tried to richen it up to about .92...

guess what, wont go any higher, its like im out of fuel again... WHAT GIVES!!!

Only probs I know of is i have walboro 255 HP pump, and no adj. FPR, ...im runnin 47psi base fuel pressure, but wouldnt that make me go even richer!!

Anyone that can help let me know.

Tom

turboniam · Feb 21, 2003

It is possible to run out of fuel with 660s on a 16g.

The first place you should start would be the AFPR.

After that, see how much fuel you have to play with.

anconover · Feb 21, 2003

pump rewired? go with a FPR and turn down to maybe 43psi.

Quadcylla · Feb 21, 2003

What MAF are you using? You could be going lean up top due to MAF overrun.

TALONTED TURBO · Feb 21, 2003

anconover said:
pump rewired? go with a FPR and turn down to maybe 43psi.

Yes my pump is rewired, sorry forgot to mention that.

TALONTED TURBO · Feb 21, 2003

Quadcylla said:
What MAF are you using? You could be going lean up top due to MAF overrun.

No MAS, I have VPC!

Taboo · Feb 21, 2003

TALONTED TURBO said:
Drive the car, 7k, .88, so i tried to richen it up to about .92...

guess what, wont go any higher, its like im out of fuel again... WHAT GIVES!!!

What gives is the fact that you base your belief that you're running out of fuel on highly inaccurate data such as the stock O2 sensor output voltage. What are your EGT, timing, knock, IPWs and fuel trims?

whitegst97 · Feb 21, 2003

It sounds a little odd because im running a 20G with the stock 450's and i ruun from 4k to 7k .94's. But when i hit around 18 psi's for more than like 2 or 3 secs i get fuel cut. Is it true that if i take out the side honeycombs that fuel cut could be extended or something similar?

Quadcylla · Feb 21, 2003

"No MAS, I have VPC!"

Sorry missed that.

turboniam · Feb 22, 2003

anconover said:
pump rewired? go with a FPR and turn down to maybe 43psi.

On a 2g, I think you are correct that base fuel pressure should be 43psi, but on a 1g I believe it is suppossed to be 37.5 psi as the base.

Cam · Feb 22, 2003

I really dont see why you guys are saying yurn down the fuel pressure?????? How would that richen him up??? Seems to me it would lean the car out through the entire fuel curve!!! Im i just a retard or does this not make sense?

turboniam · Feb 22, 2003

Cam said:
I really dont see why you guys are saying yurn down the fuel pressure?????? How would that richen him up??? Seems to me it would lean the car out through the entire fuel curve!!! Im i just a retard or does this not make sense?

No your reasoning is incorrect. I can't remember the term, but I think it is FPR Overun.

If you run the car with too much fuel pressure, the car will not run right and have a high miss.

Many people are now recomending an AFPR to go with the Walboro 255 fuel pump because of the overun of the fuel pressure regulator.

Hopefully, someone else will be able to fill in the gaps.

anconover · Feb 22, 2003

well if its a rewired walbro, he should have a FPR, if it were a non high pressure un-rewired u wouldnt so much need 1, but spend the money and get a SX fpr, dont bother ordering spoolinup/chargedair, theyre on constant back order for the next yr or so, i emailed em other day.

anconover · Feb 22, 2003

hehe just re-reading original post, all these mods and no pocketlogger? id suggest a logger and FPR as ur next mods 4 sure...

Cam · Feb 22, 2003

I still dont see how less fuel pressure will richen it up. You said fpr over run, Im pretty sure that is when too much pressure...but the regulator wont let enough fuel pass through, so it causes a really rich condition by shoving more fuel through the injectors....the only place it can go. .....Im just think in terms of if there was no regulator, fuel pressure would be very low if any at all, so the fuel would not "want" to go through the injectors as easy as going back to the fuel tank. If you blocked off the fpr and the fuel had no were to go , it would shoot out all the fuel it possibly can through the injector( maximizing the amount of fuel that can flow through the injector in the time it is open). So more fuel pressure, blocking off more and more of the fuel going back to the tank(fpr), is just a gradual(sp?) increase from the "no regulator" scenerio to the "block'd-off" scenerio. Rember these are just therotical...im not telling people to go block off the regulator to get alot of fuel...just stating how im thinking about the less fp = richer condition, in a over run prolbem!!! If im wrong someone please set me straight, I thought I completely understood the entire fuel system and modifications(fuel system is pretty basic) but now I feel stupid......Hopefully Im not the stupid one!!LOL

anconover · Feb 22, 2003

never said hed richen up by putting an FPR, simply stating he needs 1 in order to tune for shit. another question, what kinda boost are you running, and as taboo said, what are ur EGT's etc?

things to check as well.... boost leaks, shitty fuel filter, pinched lines etc.

TALONTED TURBO · Feb 22, 2003

anconover said:
never said hed richen up by putting an FPR, simply stating he needs 1 in order to tune for shit. another question, what kinda boost are you running, and as taboo said, what are ur EGT's etc?

things to check as well.... boost leaks, shitty fuel filter, pinched lines etc.

I am runnin 17psi right now. I dont have an EGT gauge or a pocketlogger... yes thats right lol dont tell me I need one I know, but the car is going on the dyno (and tuned) latter this week, so hopefully Pruven Performance can figure it out. I am going to the CAS FPR, my friend has one and is selling his car so Im gonna take his. My base fp is 47psi at idle, which is ridiculous! So when I turn that down, we'll see how it goes..

turboniam · Feb 23, 2003

TALONTED TURBO said:
My base fp is 47psi at idle, which is ridiculous! So when I turn that down, we'll see how it goes..

Turn that shizzle down a good 10 psi!!!

Running out of fuel with 660s and big 16G? WTF

TALONTED TURBO

turboniam

anconover

Quadcylla

TALONTED TURBO

TALONTED TURBO

Taboo

whitegst97

Quadcylla

turboniam

Cam

turboniam

anconover

anconover

Cam

anconover

TALONTED TURBO

turboniam

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