sorry, i did a search and got some good info. only question i have that i didnt find is,

i have a b16 with toda spec bs and stock bottom end. i went to the dyno months ago and wasnt actually done tuning but with 370cc injectors and now my stock injectors, the fuel curve is very jumping, doing lean, rich, lean, rich through the rpms at full throttle. when we lowered it down under 30 psi with the 370s, the fuel curve was real smooth.

But it is only unstable as i increase the fuel pressure. i did find out 32 psi vaccuum on is more ideal for my setup. so either its probably that which is all in the tuning, or could it be:

1. my B&M fuel pressure modifier not regulating the fuel with higher pressure???? (i took it apart and put it back together) or

2. my stock fuel pump having a problem.

Could it just be that the stock pump cant flow that much fuel since its too rich at 42 psi. i have a toda program.

just wondering if i should go ahead and upgrade my fuel pump even though i will lower my fuel pressure down to 32 psi?? thanks for any info

 

Stock pump is more than enough. (depending which one it is) One thing I would check is fuel filter. If your pump couldn't keep up it would drop off not surge like you explain.

FPR would be my next check/possible problem area, next would be fuel pump ground.

Good luck.

 

problem may be in the ecu program. if not you may want to put your car on a dyno or jackstands(scary) and run the car , look at the fuel press guage to see if the fuel press is decreasing as you move up through the rpm range if so then it is a fuel pump problem. i didnt catch what year car you have but if its a 92 civic (only92) then honda had a recall on that years fuel pump. the fixed the problem in 93

 

help much appreciated

its a 2000 si with 50k miles. changed the fuel filter once. same cap, rotor and wires from factory. i was gonna do some maintenance this weekend anyway and replace that stuff.

it could be the b&m not regulating as the pressure increases since the pin hole maynot be stable as pressure increases at throttle. i do need to get a new crush washer because i have a tiny tiny tiny leak under the fuel filter bolt. i had a bigger leak when i put the guage in to adjust the pressure. when i shut the car off, the pressure doesnt drop til like 30 minutes to an hour later.

i will see how it runs with 32 recommended psi. or i could just get a stock regulator or get an AEM one, but if it isnt necessary whats the point. so stock 00 Si pump is more than enough?? thanks

 

your injectors are way too big. install the stock 240's..and retune.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by TECH43 RACING INC. &raquo;</TD></TR><TR><TD CLASS="quote">your injectors are way too big. install the stock 240's..and retune.</TD></TR></TABLE>

yeah thanks man. sorry for the whole story, i already put in my stock injectors at 42 psi fuel pressure and the a/f ratio is jumping all over the place like it did with the 370 injectors at the dyno with 42 psi.

at the dyno in december we lowered to 20 something and the fuel curve was real smooth with the 370s.

so my problem now is that the fuel pressure is too high with the stock injectors, even at 42 psi. it gets worse as i increase cylinder pressure and increasing overlap, since the ecu is dumping more fuel. like i said, im gonna see how it runs at 32 psi which is recommended.

 

its real simple. 370's are too big. done. end of story.

all you need are 240's, and a good tune up. your b&m might be screwed up. the spring in them sucks..unstable..and wears out after a while. the aem is a great regulator, get one. a stock fuel pump is fine too. 240cc injectors can support 200+ whp..and we know you are no where near that.

another thing.....most of these chips for honda ecu's..the fuel curve is really aggressive. duty cycle is high.. sometimes close to 95%.....so that combined with 370's..makes your setup way too rich.

 

haha. yeah i put my stock 240cc injectors in like 4 weeks ago. sorry you missed that but its cool.

thats why i put them in since the 370s were just too damn big. ill see how it runs with lower pressure. i checked out the b&m spring, it looked ok. so it could be that 42 psi, the duty cycle is too high. thanks for the help ppl

 

Where in the hell did you get that 240cc injectors can handle 200whp? Also, why are you running at 42psi? Stock fuel pressure on my gsr is 50 at idle(yes thats what the freakin gauge reads). People usually say you're running 310s at 80% duty cycle at 200whp. Either way, Im going to go with 370s. Again, what type of fuel management are you running? This is by far more important then injector size or fuel pressure.

 

^^^^ummm, that wasnt me who said you can run 240cc with 200 hp.

but as far as fuel management, im just running a b&m fpr and switched back to stock injectors.

i have a p28 with toda program.

your running 50 psi stock?? i mean, im not sure if you have big cams or not, but it all depends on your setup. with 42 psi plus the toda program, the a/f ratio across the rpms is very unstable. by lowering it down to 30 or so with stock injectors, the fuel curve smoothens out big time. this is what most ppl run with my setup and have squeezed over 180 hp.

as far as the 370 injectors, i had them in and my vafc was tuned down to -20% across at wide throttle and -38% at idle!!! ive learned that ppl with my setup usually run stock injectors, stock fuel pump with no problems

 

My friend with a turbo gsr is running 440s with the vafc and has it set to -38 all the way across the board. Either way, Im running Toda As, currently on stock ecu and stock injectors, along with stock fuel pressure and dont have any problems...with raised compression, head work, modified gsr IM and some other goodies. READ: I have NOT taken my car past vtec, this is simply for break in. It will be dyno tuned using hondata and 370s. BTW, what did you do with your 370s?

 

having the load on the vafc dialed that far back, your bound to be having some crazy *** advanced ignition timing, which isnt good for the motor at all,

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95 integra &raquo;</TD></TR><TR><TD CLASS="quote">My friend with a turbo gsr is running 440s with the vafc and has it set to -38 all the way across the board. Either way, Im running Toda As, currently on stock ecu and stock injectors, along with stock fuel pressure and dont have any problems...with raised compression, head work, modified gsr IM and some other goodies. READ: I have NOT taken my car past vtec, this is simply for break in. It will be dyno tuned using hondata and 370s. BTW, what did you do with your 370s?</TD></TR></TABLE>

it really depends on your entire setup and you can calculate what injector size that is ideal for your setup. when i had the 370s in, i did have to tune them down alot, and i did learn that you really shouldnt go that low on the vafc since the ignition timing curves arent used from the ecu program. basically as Eddiebx said, the timing will be too advanced.

 

****UPDATE! i posted this like a month ago. UPDATE!

i lowered my fuel pressure to 32 psi vaccuum on. ran much smoother where the motor was not making a surging sound as it did. it still did it alittle though.

yesterday, figured ill solve the problem by putting the car on the lift to see if the fuel pressure drops or surges at WOT. not only does the fuel pressure not go past 36 psi, it flutters too. tried to narrow it down whether its the fuel filter, fpr, fuel pump or injectors. my stock injectors are in and i have highered and lowered the fuel pressure alot since last year. so they might have taken a ****.

i did frequent compression tests til 3 weeks ago. 200 psi accross.

so yesterday i did a test again. got 175 accross the idle is rough so i think its the head gasket cracked.

So now i have to change the head gasket and figure out this unstable fuel curve problem. basically it did this with other chip programs too but mostly with chips with richer fuel maps.