I'll start off with my setup.
450cc injectors, VAFC with -38 fuel cut throughout the high throttle, Walbro 255lph intank pump, Tial Wwastegate at 8psi, B&M FPR, and a Garrett T3/T04e 57 trim w/ .63 A/R turbine.

I'm having a really bad problem with the car missing under boost around 5500-8200. I got brand new NGK pulgs and wires and that didnt solve the problem. The car will run perfect if you just have say 50% throttle and take it to redline, but when its close to WOT it misses.
I'm aware that the B&M cant return enough fuel with a Walbro and the stock bottom end and I'm getting that problem where the idle pressure is at 42psi (and it idles kinda rough and backfires sometimes when reving in neutral) and it doesnt change more than 2psi when I pull the vacuume line off.

Also interestingly enough sometimes the car will work perfect and pull hard as **** through 1st and 2nd gears, but then at 3rd it'll pop and miss.

Any ideas? I'm going to throw the AEM on today since it's a 1:1 so maybe that'll solve the problem, but I'm kinda in the dark on this since my buddies havent seen this before in a car.

Thanks

 

What is your plugs gapped at? they could be getting blown out....or you might be running to rich with the fpr and pump and injectors...that will make it run like junk up top if your to rich....Also if your to lean it will run like crap also, do you have a wideband or access to a wideband? Check you plug gap, and also look at them for signs of detonation and running lean, if they are black i would say your rich and lean out 1-2% on top and see if it helps.....those are your 3 possibilities, now u just need to narrow it down

 

THe plugs are one step colder and pre-gapped at 0.028" which is pretty much the lowest I've heard you should use with a stock ignition in a turbo'd car. I tried playing with the VAFC and it still missfired a lot regardless of if I gave it more fuel or less fuel so I believe theres a problem with the fuel system somewhere. Could it perhaps be the filter? I replaced it about a year ago.

Thanks for the replys guys

 

check your timing..

 

Hey did you ever get this thing to a dyno?? I know you told me you were gonna do that. I have the same problem with my car at top end. And when i get on it during 1st and 2nd it tears up the pavement but in the top of third when getting full boost i get the "hesitation" too. At first I though it was running to lean so I threw more fuel into it via VAFC II and then it ran fine for a few minutes and the problem came back. Guessing with no knowledge on what's goin on get old real quick, doesn't it. I'll tell you what you need to do. Give me a call and both get our asses to that dyno to see what's up!!!!

 

wow thats a pretty low gap, i gap my plugs at .040....that could be part of your problem, I run 1 step colder bosh coppers

 

I'll give you a call in a bit Rob, I'm gonna pick my AEM FPR from the post office and see if it makes any difference. I was with justin all last night and we couldnt get the car to stop missing, and Kurt didnt know what was up besides changing out the B&M.

Interesting about the plug gap, I'll try 0.035" and see if it makes a difference.

 

Well ... Got the car to a dyno yesterday and it was running at 14:1 a/f and made 133 hp and ~150 tq (at 8psi) on the first run since it'd only rev to about 4500 before missing. We disconnected the MSD BTM and hooked up the knock sensor and the problem seems to have vanished. I'm guessing it was the BTM since the car would run perfect up to 8200 as long as it wasnt boosting, but perhaps the knock sensor might have had some impact on the car running poor?

 

Now you have to go back and get the real dyno numbers for that beast of a motor that you have.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dainteg &raquo;</TD></TR><TR><TD CLASS="quote">Now you have to go back and get the real dyno numbers for that beast of a motor that you have. </TD></TR></TABLE>

Im shooting for maybe next Thursday or Friday, I'm kinda iffy about it since I'd rather spend $50 more bucks than the cost of 3 dyno pulls and get a wideband and barrow a laptop from a buddy and tune it myself, then use Dynotuned for timing changes and maybe get some adjustable cam gears ... idk though moneys kinda tight since I wont have a job for about 2 weeks.
Gonna buy a set of GSR cams off someone here on H-T, so that's sposed to give about 10hp on boosted B16's... we'll see.

 

I also had another fuel problem last night comming home from someones house around 2am, I was boostn through the gears and all the sudden it went rich as **** and sounded really loud and deep. Through all the gears and rpm's the A/F gauge was stuck on the furthest green light but after I got home I shut the car off and started it up again and it ran normal.... damn B&M FPR ******* up heh

 

Ok now your getting the same problem as me....Your cutting out problem was alot worse than mine. But the problem that you got last night with the fuel is what happens to me. Did it feel ok when it went thru all of the rpms? Cause my car feels just like you explained except for it has these wierd hesitations going into higer rpms. If you find out what's up, let me know. Any body else got suggestions?

 

Yeah! I forgot to mention that power loss in the high rpms (that 18'er was almost gone when it happened ). Once the new problem started up I could floor it in 4th and 5th gear and there would be ZERO power, but like I said the car idled fine after I turned it off and back on, and ran great today.

Its GOTTA have something to do with the FPR, since we are running the same restrictive bottom half of the stock one. I'm gonna try to get the AEM one working today and see whats up, but I've never gotten this problem before. How often does it happen to you?

 

Thats interesting. B/c I am only 2 weeks into boost, and I am having similar issues. When I hit the higher Rpms, my engine wants to "hesitate" also. I am thinking I am way rich, and need to visit the dyno too. Can't wait. I stepped down to some colder plugs and heard that .032 was the best for Ngk's. I have dsm 450's, walbro 255 intank, and the Vafc controlling the whole mess....

Good luck...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ExVtec &raquo;</TD></TR><TR><TD CLASS="quote">Thats interesting. B/c I am only 2 weeks into boost, and I am having similar issues. When I hit the higher Rpms, my engine wants to "hesitate" also. I am thinking I am way rich, and need to visit the dyno too. Can't wait. I stepped down to some colder plugs and heard that .032 was the best for Ngk's. I have dsm 450's, walbro 255 intank, and the Vafc controlling the whole mess....

Good luck... </TD></TR></TABLE>

Interesting. Thats the identical fuel setup that dainteg and myself are running. I'm using NGK 1 step colder plugs and they're pre-gapped at 0.028, but if your running less than ~10psi you shouldnt have any problem with the boost blowing out spark at 0.032. What do you have your VAFC set to? Mine was at -38 to VTEC and -36 on up and I was running super lean at 15.1:1 a/f
somethings really fucked up though because to bring it back to 12:1 where it should be, the VAFC is in the mid-20's which is adding way too much fuel.

The thing i dont get is that a ton of ppl are running turbo'd cars with a 255, 450's, and a VAFC and are using the stock FPR or a B&M modded one and they're not having trouble.

 

Are they not having trouble or are they not saying anthing about there problems. Now in my setup which is also the DSM 450s, 255, and VAFC. I'm running the 14B turbo and i've heard that when you use this smaller turbo you have to watch out for boost spikes. Is that something that could be the problem?? Especially since i'm not running a fuel pressure regulator or a boost controller too.

 

I have never had any problems at all....I gap at .040, -30 acorss the board from 4500-7000 wot just to be safe on 10psi...450's, stock 90 fpr, and dsm pump..I use ghetto dyne to pull timing in boost and I have never once expereinced anything like what is happening to you guys...Its somethin really dumb and its the dumb things u cant find and they really **** you off......

 

Well it funny that you say that you fun so rich on top end cause i noticed less of a problem when i ran it at -34 across the board from 4000-8000rpm. But according to the dyno i was running at a way to rich enviroment and they set it back to 12:1 which is -38 accross the board starting at 4000rpm. Hmmm...trust the actual dyno or your butt dyno??

Edit: here's someone that's had the same problem:
https://honda-tech.com/zerothread?id=410323

 

not sure check the housing connecting to the comprssor housing it could be that air is leakin out and u might have to clamp the housing tighter so the air doesnt leak hope that helps but i could be wrong

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bgsxyguy &raquo;</TD></TR><TR><TD CLASS="quote">not sure check the housing connecting to the comprssor housing it could be that air is leakin out and u might have to clamp the housing tighter so the air doesnt leak hope that helps but i could be wrong </TD></TR></TABLE>

How do you figure that'd cause a missfire?

 

I went to tighten my BOV yesterday and as i turned it about a a little bit the bolt and nut just flies off! I looked at the hole and it's striped. This could've been my problem all along. Dammit. I think i'm gonna find a stock 1st gen eclipse BOV now. Hey Cracka- hows the car running now? I can't boost past 5psi and 4000rpm cause of the leak in the BOV now. If its not one thing than it's the other.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dainteg &raquo;</TD></TR><TR><TD CLASS="quote">I went to tighten my BOV yesterday and as i turned it about a a little bit the bolt and nut just flies off! I looked at the hole and it's striped. This could've been my problem all along. Dammit. I think i'm gonna find a stock 1st gen eclipse BOV now. Hey Cracka- hows the car running now? I can't boost past 5psi and 4000rpm cause of the leak in the BOV now. If its not one thing than it's the other.</TD></TR></TABLE>

Damn man that sucks! Did you loosen the nut before turning the stud thing with an allen wrench? My car seem's to be running good, but for some reason today I was boostn and the the VAFC wasnt reading it so idk what did that, because it worked fine after that, but I also discovered a check valve Dynotuned put inline with the MAP sensor that they didnt notify me of! That boost leak in the BOV could've very well been the problem all along, you should've tried running your car when we switched BOV's or if you dont have a substitute next week we could give it a shot and swap em again, I'm back Tuesday, let me know!

 

Well I got the BOV changed over to a stock 1st gen DSM BOV. Now i have a problem with my ignition. The so called "hesitation" could have been this all along. I was driving on the highway and the rpms dropped like 2000rpm in like a agressive pause about 4 times then the car dies and wouldn't start back up right away. I eventually was able the start up the car again and it DIED again. I got it home alright and the next morning it started up ok and then after 15 miles or so it DIED for the last time. Now i can't even get it to start anymore! I swapped out a couple different ignitors and still no spark. What do you think it could be? It could be as small as a distributor cap or dizzy. but who knows.