Would a new 255lph(walbro) FP cause the car to run richer than with the stock one(was failing to build sufficant pressure) ls injectors tho. also hooked up the evap return line to tank(hardline) to the nipple on the top of the TB was fine before both thses were done will unhook the evap thing as was just a test.

edit: maybe running rich is the wrong term I got about 40-50 km's LEES than I did on the last tank may not be anything but just wondering still get nasty black soot on the rear so it's still richer than it should be imo

 

anyone ? car is not "base mapped" for the wally 255 w/ls injectors. but could this causr richer running ?

 

Yes it will.
and enough to blacken a bumper also.

Tune for it with adjustable fuel pressure regulator and then you can benefit from the 255lph pump.

Whatever was done with the evap line should be changed if it differs from the routing shown in the factory service manual for your particular vehicle/motor/setup.
And Evap does not reduce horsepower if that was your worry.

The fuelpump has a check valve that is supposed to hold pressure for the next keycycle/startup, this function of your existing pump is most likely what has failed, not the pump itself. try to determine what pump you need for whatever engine you are running and order a pump for that application. Or tune for your new 255lph

 

Also all B-series injectors flow the same 240cc

D-series and B18B(LS) have a stock 70ish lph pump.

B18C/B16A cars have 135lph.

This has been an argument for some over the years but there is no doubt that 255 on an untuned vehicle runs richer.... period.

 

The pressure sits at 40-41 psi pump is brand new. was supposed to get the car tuned last Thursday but I had to fix an issue so if tuned I should be fine ?

evap canister is sold lol so I figure i'll just leave it for now till I can head by a pick n pull

 

Ok my money is needed else where so this tune isn't happening. can I use the fuel pump from a 99DX ? as this thing has knocked at least 60 kms off my 420-430 fuel millage. for some reason ALL the junk yard removed the tanks

 

I think you have another problem, at 40-41 PSI, fuel pressure is fine, within limits, [38-46 PSI] ! have been running a Holly 255 lph for years without any issues, I do have an adjustable FPR so I can turn up the pressure when I autocross and use my 75 shot nitrous system.

I would check the function of the ECT sensor.

Question, is car easy to start when cold but harder to start once warmed up to running temp?

If so, it is a symptom of running rich, and the ECT sensor supplies ECU/ECM with engine temp info, it will allow ECU/ECM to "lean out" the A/F ratio as engine warms up, if that is not happening, engine continues to run rich. 94

 

No the car starts fine hot/cold. this literally started happening the first full tank after the new 255 pump. ECT sensor is 3 months old replaced it before. going to try and find a new(old) ls pump anyone know if it matters obd2 or obd1. TBH I don't think it's richer just using more fuel plugs look the same as before

 

If the plugs are not indicating a rich burn, [dry black "fluffy" deposits] then you are not running rich. 94

 

I never had this problem after I swapped in my 255 and I didn't have an adjustable FPR

 

I'm really starting to think it's this damn new pump . have an 01 GS-R one arriving early this week only got like 335-340 km's to this tank mind you I was trying a new driving style but still.

 

got my GS-R pump today will be throwing it in tomorrow and see. I'm with beecee18 on this, as 40-60 kms lost does make a diff to me in my daily driving

 

the pump shouldnt really make any difference. 41psi of fuek pressure is 41psi of fuel pressure regardless of flow. it just means more fuel is being dumped into your return line. I say your 3 month old ect may be at fault, or you have another component failing.


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Is that purge line hooked to full vacuum or partial? I'm kinda thinking its evaporating your fuel much faster than it would with the charcoal can- the more the car is driven, the more vapor pressure builds, more vapor pressure being sucked into engine instead of being regulated by charcoal canister.

 

Ouch...that's rough. Hope you figure it out, that's no bueno man.

 

it vents under the car. however there are 2 things 1 I missed a bolt that holds the assembly(5 of 6 bolts) and I didn't TQ them to 50 odd pounds...have bought new bolts and have yet to tq them I have a feeling I was lousing fuel that way we will see.

 

update have filled up at the same gas station past 3 fills last fill I got 408.6 KM's mixed town rural driving . but on this tank I only got around 385-90kms. does driving style REALLY have a big role on this I do take it up to 3.5-4K pretty often and do several 2-5 flat out runs

 

Bump anyone ?? it's about a 20ish KM loss

 

Have you even tried the gsr pump that was coming yet?
Other than trying that to see if indeed it was the pump, other thing to look at is the o2 sensor.

 

Of course "driving style" has an effect on gas milage. 94

 

Can't get the walbro one out the clip won't come undone, I fought with it for the better part of a day last week.

by driving style I more mean could it take 20-30 km out of your mpg ?

 

Yes, driving style will absolutely kill your gas mileage. That's why grandma in her 4 cylinder camry is getting 35- 40 mpg. And that guy in the bone stock hatch next to you is laughing at you when you pull away from the stoplight for the same reason. Most people are getting from a to b, and not trying to waste gas doing it.

 

well tried something "newish" today went fully retarded on the dizzy and the car seems happier ? (stock cams and gears) any reason noticed a nice jump in mpg driving style has stayed the same. was previously set in the middle

 

I am running a gsr swap with ITR transmission with a 4.7 FD in my 94 vx civic with a walbro 255 in the tank and I can get 31 mpg when taking it easy staying out of vtec. 26 mpg when I am on the throttle a lot. I did notice it smelling richer after the 255 swap but I have checked my plugs every oil change and they show its running normal

 

my fuel pressure used to sit at 38 psi now sits at about 45 or so idk if it matters but I lost 10-15 kilometers to my tank's fill up. but it wouldn't come undone so I can't try the gsr one . last tanks were 405 km's 390 km's and 380km's that's with rather aggressive driving and in town not highway.