Fuel Pump Issues!

[cav33r]

At the risk of sounding like a idiot im having some issues. I have a r33 gtst. Ive just recently replaced the std fuel pump with a walbro255lph and since ive installed it the car has been running like a dog. Its been splattering and just generally running like a pig lol. So i really need some help would the best bet just put the std back in until i get a tune? Or is there something else i can do in the mean time to get it running half normal again

[Ben C34]

Unless your car was tuned to suit a half dead pump putting a walbro in won't make it run bad or need a tune..

Ideally you will have run a direct feed to the battery, but again, if not there won't necessarily make it run like crap.

[cav33r]

Yeah its doing my head. So i guess eother put the half dead one in then when i get it tuned put the walbro back in or just dont drive it until i get it tuned lol

Edited September 20, 2014 by cav33r

[KiwiRS4T]

Its got nothing to do with getting tuned either you got a dud pump or you did something wrong installing it.

[scotty nm35]

Run a temporary power feed directly to the pump, my guess is it will run a lot better.

[cav33r]

So if the direct power souce doesnt work then i can rule out everything else and bascially conclude the pump was a dud

[KiwiRS4T]

So if the direct power souce doesnt work then i can rule out everything else and bascially conclude the pump was a dud

There is also the actual fitting of the pump - location in the cradle/tank, attachment and orientation of the pickup and filter and correct connection of the fuel lines.

[cav33r]

Fuel lines have been put back to orignal positions so no real issue there. And it sits in the cardle basically the same as the standard one and put the cradle back in the housing in the tank. So basically exactly how the standard one was is how the walbro is. Ive just emailed the guys i bought it off to see if they will send me a replacment one under their warranty basically to see if it is the pump or somethin else.

[cav33r]

And i used the orginal sock off the standard pump because i was looking at the tiny tiny sock they supplied with the pump and basically said yeah no lol. So i put the orignal longer sock back on it

[GTR-N1]

Some workshops can run the new pump in vitro to check flow rate.

I once had a brand new but faulty 044 and the flow rate was barely over 20.

Had to replace it with another 044.

Yes, the faulty one was genuine from Just Jap; but alas, Bosch would not honour the warranty.

They did pull a swifty though. After testing in Melbourne they sent it back in the original box. But it didn't have the texta mark I placed on the faulty one. Caught the buggers out!

[cav33r]

Hahaha shifty ones. Well ill see how i go. If i can handle this company to send me a replacement pump and i get it fitted and it still does the same then i have to look deeper into the issue but if it doesnt well it was obviously the pump then. So fingers crossed

[cav33r]

Ive just been doing some more reading on what could possibly be causing this problem besides it being a dud pump, ive found that pump i have may not necessarily be a high pressure and if there is any more then 60psi of pump pressure running through it it could cause it to drop in power. I had a look at my fuel reg this morning while on idle and it was showing like 105 psi so obviously under load and boost the fuel pressure is sky rocketing. So my thoughts is if i drop the fuel pressure and get the combined fuel and boost psi under 60 should it then resolve the problem?

[cav33r]

And this is the graph of the flow rates

[Ben C34]

No way should you be running 105 psi base.

That's mental.

Like really mental.

You have problems. You can't just drop the pressure on the reg and expect the car to run correctly.

Edited September 21, 2014 by Ben C34

[cav33r]

i know it is i haven had it tuned since ive gotten the car. Previous owner had it tuned to that . Ive just now realized how stupid high it is. I look at it this morning and got a little bit confused.

[cav33r]

So could that be the issue? The standard pump was actually handling that quite well so i never needed to check it. Until now. And now realizing how stupid high it is

[Dose Pipe Sutututu]

buy a cheap fuel pressure gauge & T-piece.. see what your base pressure is at... less work than putting out the fuel pump and putting in the stock one. report back once done

[cav33r]

Ive got a fuel reg on there now and its showing 105 psi on idle. F**king high i know.

[Dose Pipe Sutututu]

drop the pressure on your fuel reg then? easy

[cav33r]

Yeah thats the plan. Havent had time to yet at work and car at home