So my car had been running fine. Its an si with b20 vtec built bottom to top at 14lbs of boost with hondata. After it sat for about 5 days now it is running lean right when vtec should hit and bogs down not letting it go past 6000 rpm. Below 4500 rpm it runs fine like it did last week. Thinking it might be fuel filter, injector issue, or a fuel line issue. Just seeing what kinda input you all have. Could it be computer related? It almost seems like the hondata forgot what to do with the vtec. Thanks.

 

Did VTEC get unchecked in the parameters? If it did, then yes you could be leaning out seeing as the cells were never tuned on the low cam map which is where it will be without VTEC activation. I don't know what any of the specs are, so I don't know when full boost is acheived, but make sure you don't have a boost leak from a hose or silicone adapter somewhere. You may have an issue there.

Jason

 

the car has been dyno tuned and street tuned by the local shop and is sound in that department. I'll check for a leak. Whatever it was happened in 5 days of the car sitting. Ive been filling up with premium chevron so I'm assuming the gas is fine.

 

what map sensor are u running?

 

not sure, don't have the receipt for that from the previous owner. Ill rip it off tomorrow and have a look.
Anyone ever had an issue like this with a fuel pump going out? I know most the time they abruptly go out and its obvious. But as these symptoms began I started noticing the pump making a lot more noise and whining.

 

just looking at the fuel pump and it looks like im running the full blown dual fuel pumps. That could explain why it runs fine under low load but as soon as vtec and boost builds there is nothing. One of the two pumps might be out?

 

thats my guess is fuel related. put power to each one and see which one is working. If they are both working I would look at the fuel filter

 

I don't think its the fuel filter being that the build has less than 2000 miles on it. I think I got on it too hard with too little gas in the tank and one of the pumps didn't like it. oooops =/

 

Yup, it was the fuel pump. When they installed the double pump they used one pump which had already been used. When i tested it, it ran but sprayed gas all out the side and just barely any outta the actual hose, covered me in gas but hey no more headaches!

 

Hope you are sleeved.. otherwise. I don't see this motor lasting even with forged internals.

 

sleeved of course. The motors built from top to bottom. Built to handle 25-30 lbs of boost on race gas at 10.5k rpm. I daily drive at 14lbs and 8500 rev limiter, its soft tune put 421 whp down, makin ~350 for the street. Its reliable, same build as the local shop owners (who built mine) driver at 60K+ miles now.

 

hey sorry to thread jack, but i have a VERY similar problem on my LS/Vtec...it bogs out at 5000rpm..so did a new fuel pump solve your problem?

 

try fuel pump first then move to the dizzy and replace the coil and Ignighter. the dizzy was my problem

 

update: Installed the new fuel pump (installing the full blown unit is quite the hassle). Didn't fix the problem, then checked and noticed only one was working which turned out to be a burnt fuse. Replaced the fuse and didn't do a damn thing. I can unplug either of the two pumps and the car will run the same as it will with 2 pumps. I could give the dizzy a look now i suppose.

 

ya so im running the msd hvc-2 coil and msd dizzy, don't know how i feel about just replacing those on a whim, kinda spendy. Anyone have any other suggestions. The car has actually gotten worse now it wont even rev past 3500

 

try just going to the junk yard and getting a diffferent ICM out of another dizzy and replacing it. Since its not likely that your msd has went out, still wouldnt rule out the fuel pump. go buy a cheap jegs fuel pressure gauge that goes on the filter and see whats its reading

 

Ill try the icm idea. Would the ICM from my obd1 b16 del sol be the same as my obd2 b16 head on this build? The pumps can be ruled out. I pulled both, replaced one which tested bad and I have unplugged each and ran the car with just the one working. I've checked the fuel pressure from the fuel rail itself. Im gonna go monkey my hands in and check my fuel filter its some aftermarket (aeromotive i believe) and in a horrible inconvenient location.

 

Im am not even sure if the obd2 icm will fit obd1, but im gonna guess NO. Take it out and see and post if it worked. It would be some good knowledge for me

 

ill do that after the fuel filter and let you know

 

the icm's are the same even though the cap and rotor are different. Both are e12-303 made by hitachi. So good to know. Not so good to know is that didn't do a damn thing for my car. I've never wanted to see a cel so bad in my life this is driving me crazy taking shots in the dark.

 

heres a link to my s300 datalog if anyone knows there **** can you please glance over it for any red flags.

http://www.speedyshare.com/620630643.html

 

finally got to the fuel filter. It is using the http://www.summitracing.com/parts/SUM-230116/ "flow" filter. Well they installed it with the arrow pointing against the flow which would lead me to believe it was backwards. And after taking it apart the caps glued to each end of the filter had broken their bond and were free floating. Just ordered replacement, hopefully thats the ticket.