Hey Guys,

alright, so here is the thing, i'm installing a free B&M fuel pressure gauge and a B&M CommandFlo adjustable fuel pressure regulator on the fuel rail.

so all is dandy, i install it correctly, look for leaks while primed/priming, all looks good to go and i set it at the pressure i read on the gauge before i took the old one off set ~40psi when primed and ~37psi while running.

i start the car and it runs like hell, runs really chopping, popping in the exhaust and if you floor the throttle, it would just bog and then eventually go after about 3000rpm. also, i managed to drive it home and if you put any sort of load on it, it just bogs, jerks and stumbles like it's not getting enough fuel.

so i kept adjusting the pressure up and up to eventually a point where it would idle but still bog, i'm at about ~45psi running pressure. is there a limit that you can go to high? and why if i kept the stock fuel setting would it make my car run like ****? it's a d16z6 in a 94 ex if it helps...

hopefully someone can clue me in here, everytime i incrementally turn up the pressure it seems to get better but i don't want to go to high, i do have a header/exhaust and intake.

thanks a bunch,
James

 

The '94 system requires that the fuel pressure vary with the manifold vacuum. This is done by the vacuum hose on the stock regulator. Unless you have a fully tuned setup (modified ECU), you should go back to the stock regulator.

 

i'm beginning to think that way, they ONLY reason i decided to put it on is cause it was free, so i figured why not. i have done some reasearch and figured out after the fact that these B&M things are just garbage but was marked for like $40.00, i would be pissed if it did this and i had paid for it....

thanks anyway, it's hard to track one of these down around here

 

It was free for a reason...because it's useless craptrash. Throw it away.

Keep the gauge though, that won't hurt anything.

 

i will keep the gauge, thanks...

so i reverted back to the way it was (took off the gague, replaced banjo bolt, went to the junkyard, got a stock FPR) and now it's still doing the same thing... i replaced the fuel filter last night and same problems,

it also has a hard chatter now when you engage the clutch to try and take off, it rattles and josles everything in the car, i might drive the thing off a cliff

any advice would be good..what about the ECU, can you fry that somehow?

also, the timing can't be changed all of a sudden right?

 

Make sure the vacuum lines are hooked up properly. Is the CEL on, any codes stored?

Timing can change all of a sudden when the timing belt skips a tooth because it is loose or worn. So you should definitely consider that.

 

i have checked all my sensors i thought i might have knocked off, all the vacuum lines, and i'm baffled because all i touched is the damn regulator which i put back to stock, along with the fuel filter i got a new one and took the gauge off/on to see if there was a leak or change.

i did the timing belt about 6 months ago with a new pump/tensioner/belt, was running just great until this little mishap here

i did reset the ECU, several times actually, and it's not throwing a CEL, even when you put it under a heavy load and it stumbles hard.

the only reason i keep thinking timing is because of the poor running conditions, i have the top timing cover off and from what i can see the timing hasent changed because after about 3k RPM it comes alive like nothing is wrong. Seems like it is backfiring at idle as well

I was talking to a few people and what if somehow with some extra pressure (like the regulator is junk and stuck open) could i have knocked something loose such as particles go... I replaced the fuel filter and maybe check out the rail and individual injectors for pluggage?

i don't think i unplugged anything, what about the TPS? (only thing i touched)

i want to have it stumble right off a cliff... Thanks!

 

So you've confirmed the timing marks still line up (you can do this only removing the top cover) and checked the spark timing with a light?

The next thing I'd try is to disconnect the fuel injectors one at a time to see if it's isolated as one or more dead cylinders, or a more general problem.

 

Also,

at this time i was running my nitrous lines, and mounted the zex box on the inner frame rail on the passenger side. i have no idea how this could cause any problem, i didnt fill the nitrous or even turn on the box yet because this crap happened.

today i took the bottle and clamps out because i mounted the bottle in the trunk, and thought i might have drilled into the fuel tank but how could that cause a problem? the fuel pump does not pressurize the tank correct?

here is my gauge and it is rock solid, set at ~37psi (which is stock) and when you give it throttle at idle, it goes up to around ~42 then back down.
also, when you detach the vacuum hose, it rises to ~47psi (which i thought was in spec)
*sorry for the blurry pic****


thanks for anything!

 

i will check this for sure, along with the timing... if i unplug 1 injector, should the engine stall or lower RPM or how will it act to isolate the problem? How does the engine behave with only 3 injectors? same as if you unplug a plug wire?