Running out of fuel with 660s and big 16G? WTF - DSM Forums: Mitsubishi Eclipse, Plymouth Laser, and Eagle Talon Forum: DSMtalk.com

TALONTED TURBO · 02-21-2003, 01:30 AM

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 · 02-21-2003, 01:47 AM

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 · 02-21-2003, 01:49 AM

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

Quadcylla · 02-21-2003, 08:20 AM

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

TALONTED TURBO · 02-21-2003, 09:29 AM

Quote:

Originally posted by anconover
pump rewired? go with a FPR and turn down to maybe 43psi.

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

TALONTED TURBO · 02-21-2003, 09:30 AM

Quote:

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

No MAS, I have VPC!

Taboo · 02-21-2003, 11:02 AM

Quote:

Originally posted by TALONTED TURBO
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 · 02-21-2003, 11:36 AM

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 · 02-21-2003, 11:56 AM

"No MAS, I have VPC!"

Sorry missed that.

turboniam · 02-21-2003, 10:09 PM

Quote:

Originally posted by anconover
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 · 02-22-2003, 01:22 AM

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 · 02-22-2003, 01:58 AM

Quote:

Originally posted by Cam
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 · 02-22-2003, 11:13 AM

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 · 02-22-2003, 11:15 AM

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 · 02-22-2003, 01:29 PM

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