My friend has a turbo d15b vtec (greddy kit). He has a walbro fuel pump, dsm 450cc injectors, and hondata. He went to get it tuned the other day and they said it wasnt getting enough fuel, and the pump was bad. This is the 2nd time this has happened to him. A different shop said the first walbro went bad, now another shop is saying the 2nd walbro is bad. Oh he has a fuel pressure gauge on it and it reads between 60-70psi at idle. He watched the gauge on the dyno and it never lost any pressure. Is there something else that it could be besides the pump?

by the way. we have already tried:

fuel pressure regulator ( 2 oem ones, and an adjustable aem one)
injectors
fuel filter
tested the fuel pressure gauge on 2 other cars

 

The only thing I can say is, check your injectors. My friend had some dsm 450's on his sohc turbo and his car was running bad. So we put the stock injectors back in and everything ran fine.

 

we have already swapped out the injectors. didnt work. the car drives fine, its just when they had it on the dyno it was leaning out bad at high rpms. even with the injectors at 90%. thats what we dont understand. i mean if the fuel pump was bad, wouldnt the car act wierd or something?

 

same thing happend to me but i am running a stock fuel pump and the pressure would drop at a certain point during the runs on the dyno just swapped out fuel pumps and it was fine and also added a new fuel filter.

i could be wrong but isnt idle fuel pressure 45? not sure though

 

i think you are right about the idle pressure. i just dont know why its so high at idle, but not getting enough gas at high rpms. anyone else have any ideas?

 

did they tune the hondata with the fuel pressure at 70 psi?

it shouldn't be that high if you are running the larger injectors?
or did he swap back in the stock injectors then increase the fuel pressure to get it to run better?

have you looked inside your gastank?
overtime they can rust, especially if the car sits for a long period with really low fuel levels, leaving a large portion of the inside of the tank exposed and uncovered.
and you will get gobs of crap caught up in the drain sock on the fuel pump pickup.
i would think it may be possible to mess up the pump if it is trying to suck up the gas but can't get any because of the clog.

my friends miata was having fuel starve issues. we looked in the tank and there was a crazy amount of rust pieces . we pulled out enough to fill a big gulp cup just about.

 

it was originally tuned on the hondata, not sure what the pressure was. they couldnt finish the tune because they said the fuel pump was bad. got it replaced, and went to a different shop to get retuned on chrome. they did a base run with the hondata still in, then they tried chrome.. and it just wasnt gettin enough gas. that was with the 450's. and we havent looked inside the gas tank. is that a pretty common problem or something? oh when the old walbro was removed, the filter looked ok. not really dirty or anything. just sucks, everytime we do something to his car there is always a problem. thanks for the replies guys. keep em comin

is there a way to test the pump?

 

Pop for a new fuel filter, and check the dampener on the fuel rail. There was a post not long ago about a guy maxing 1000cc's at 9psi or something (375whp?), leaning out badly. They swapped in a new dampener, and it was completely different story - 450+ whp iirc, before they tuned vtec (pig rich).

 

im retarded, because ive never heard of that. i searched but i didnt find anything. someone help me hahaha

 

ok swapped out that fuel rail with one that has no dampener. now the pressure at idle dropped to about 45 psi. so i think we might be on to something. thanks guys....keep the suggestions coming tho.

 

I understand that this is ur second Walboro, which makes it hard to beleive that its bad Again.


But I had a walboro that had good fuel pressure but the pump was still bad.Not enough volume, so it would read good pressure but lean out up top.BY the time I replaced it, it wouldnt even idle, but still showed 40psi of pressure.It had a good guage too.

 

Was the fuel pressure that high with the stock regulator on it?????

If it was, u have a problems else where, like the rail(like u found) or the return line.

 

it was that high with the stock rail/regulator. swapped it out with a rail with jut the cap nut on the line, the other rail had the dempener. so i guess that was bad.

 

does that dampener even come on obd-1 cars?

 

last bump, just curious if anyone knows it the dampener comes on obd-1 cars?

 

The fuel dampener comes on most obd1 cars. I've bought a 92, 93, and 95 d16z6 that all had the fuel dampener. My 90 sedan didn't have a dampener, and the 780's needed ~40% duty cycle at 10psi, which sounds right at about 220whp on a stock pump.

 

ok thanks, just seems weird that some cars have it and some dont. i dunno, hopefully we solved his problem