94 integra with b20b transplant. my issue is any time under boost when more then 1/2 throttle the engine bogs. my gauge drops lean and engine cuts out but only if i have the throttle pressed more then 1/2 way. this car is turboed obviously. i have tried 3 different turbos to eliminate a turbo issue. i have swapped map sensors to eliminate that. i have jacked my apexi neo gen programmer to the max and still drops lean.
car insight
b20b
turbonetics thumper turbo
aem fuel rail
12:1 fmu
660 cc precision injectors
2x 255 walbro fuel pump
sleeved block
forged internals with 8.0:1 comp



any thoughts would be helpful

 

You need a proper tune!

 

1. What gauge are you using, just a crappy A/F gauge? I would get a wideband because you do not know how accurate that gauge is, acutally, it is useless and just a piece of junk! Get rid of it.

2. You need a tune, a real tune using a real management system. That will most likely be the root of your problem.

3. FMU's are junk and why are you running 2 255s and only 660 injectors?!?!?!?!?!

4. You need a tune.

5. You need a real EMS

6. You need a tune

side note, holy low compression too!!!!!




AND why would you try 3 different turbos before addressing the most logical of issues?

 

no reason not to chip your ecu and use a better ems as said above.

if you are getting a misfire your o2 sensor will read lean as it is reading the unburned oxygen, and there will be a lot of it if you misfire.

again as said above, what a/f gage are you using? a junk narrowband lightshow or a wideband?

 

Get a wideband and a real tune.

 

X2 on the wideband and use Chrome or Hondata S300

 

i can't for the life of me understand why someone spends money on this stuff when an ecu chipped for crome is $150 and a real tune about $350, that's 500 all said and done for an actual datalogged and dyno tuned car

 

I say this soo muchhhhhhhhhhhhhhhhhh!

 

sounds like u got a lot of money in parts but the best spent money is the money spent on tuning...its obviously the most imprtant aspect to any EFI vehicle

love to know wut a/f guage your using
GET A TUNE!

 

Honestly some people don't even know what a tune is.


Instead of buying go fast parts, invested into an EMS and get friendly with it. It'll be your best friend.

 

i may not have been clear in my previous statement so let me try again.
the 2 255s were on the car when i bought it. i use 660 injecotrs due to the lower flow of the aem fuel rail. anything bigger is a waste. i have a hondata s300. im not an electrical or program guy im a mechanic. so i took the car with a base map from hondata to my dyno guy after 26 hrs on the dyno it still has issues. and it has a wide band. i know the narrow bands are worthless. sry i wasnt more specific.
from all of my wrenching i cant for the life of me think of what would cause this. my dyno guy says its all good on the programing side. so it has to be something mechanical and im lost as to what it may be.

 

I'm no expert, but that deffinatly sounds like a tuning issue. If you know your running lean after 50% throttle, have the tunner add fuel to that part of the map. Also, what's the fmu for if you have an s300? I'd see a new tuner though. Sounds like yours kinda sucks.

 

and my tunner may suck that may be the issue i live in a little po dunk town and our only tunner is a diesel specialest. the fmu is to keep constant fuel pressure in my rail to keep down on fuel spike. anyways thats how it was explained to me. i dont fully understand the boost dependent fmu.

 

my biggest problem is the closest acutally gas tunner is about 18 hr drive and as you see i cant really drive the car down there nor do i trust my trailer to take it that far but maybe i need to just bite to bullet and tow it down there and leave it for a few weeks

 

What are your AFR's at that load and range?

 

Yeah, if you have an s300, there is no need for an fmu, and the fact that your tuner told you that you need one is a red flag. The only reason to use an fmu is to raise the fuel pressure in the fuel rail to squeeze more fuel through the injectors under boost when you can't actually tune for it. Bite the bullet and see a pro, you'll be way happier with the results and so will your car. What are your AFRs any way? How much boost are you running? For the short term you can turn your boost down and see if that richens it up. but I would just say **** it untill you see a real tuner.

 

The 2 225s are a nice setup however you can make more than enough power on 1 225. The 660s are just going to limit your power gains and anything bigger is not a waste, misconception there.

I would go see a new "dyno guy". I would never trust any tuner who can't/won't work on cars. I mean you have to have an inkling as to the inner workings of a motor and be very familiar with one and so forth to be able to tune one, make sense?

If he recommended an FMU while using Hondata I would def say it's time to go elsewhere! ASAP!

 

i had the same problem it was becuz a bad tune