I have been having this weird problem.When im low on gas my car has alot of power,seems to get more fuel to the motor...but when i have any more than a quarter tank its lagging.i just changed my injectors and coils....im stuck...can it be a fuel pump problem?

 

Thats pretty damn weird... but yea, I'd be checking the pump out.

WHen I read the title I was thinking

"damn, now what in the HELL could cause that?"

im still tryin to figure it out..

 

Maybe it runs richer when the tank is full, Is it stock fuel pump?



Gil

 

yeah its the stock fuel pump

 

I think this might be along the right lines.

Perhaps your fuel pressure has dropped because of the low fuel, and you are running too rich to start with so it is leaning you out (leading you to more power)

Maybe it is just the weight savings of not lugging around all that gas

 

That seems like your running lean to me, get some type of fuel comp, or atleast go to a qualified mechanic and let him check.

 

what type of fuel comp?

 

the apexi safc II is the cheapest decent model aailable. Im saving up for one right now

 

how much and where do i get it?

 

maybe your gas cap isnt working so you have low pressure in teh gas tank making it harder for the fuel pump to do its job and you run leaner.

 

i have a new gas cap i tryed that thanks tho...damn im stuck

 

I don't understand how a low tank of fuel can affect the fuel pump. If anything, a full tank would help siphon gas up the pump! wouldn't it?

 

But it also has more pressure to work against since it's a looped system, and the return is generally at the bottom of the tank, who knows. I'd just upgrade the fuel pump (Since it's a good idea anyway) and then go from there.

 

Have you checked out your FPR?

 

is it a really noticable amount of power loss with more gas? , try pulling your pump out and cleaning the filter on it. i would think with less gas you would run leaner due to lack of fuel. try rewiring your fuel pump http://1300cc.com/howto/how2/rewire.htm here is a good write up, maybe you should try it

 

I just cganged the filter under the hood and the filter on the pump, last night i also just put a order for a walbro high pressure fuel pump..it will go good with my 720cc secondaries and hopefully solve this problem...thanks guys...and where and how much can i get a SAFC?

 

surprised nobody said it.......

you run better with a low tank cause all that extra weight is gone from the full tank!!!!




























ok ok im joking

 

You'll have to have an S-AFC to use those 720s, or you'll run into some nice bog when they come on. You can find them all over, from stores (rx7store.com, etc) Import stores, ebay, anywhere.

 

Speedmachine has a S-AFC

BTW-weight factor was posted earlier

 

but a from 1/4 to a 1/2 wont make that big of a diffrence. I doubt highly its a weight issue.

you can get a safcII almost anywhere. www.horsepowerfreaks.com www.rx7.com www.rx7store.net. www.fc3s.org www.rx7trix.com its made by apexi

TurboSmoke

 

yeah lol definately its not from weight! ha...thanks guys ill have to buy one of those safcIIs then too.