My B16 is so slow!

Hey everybody, I have a 93 cx hatchback with an obd1 b16a with a gsr transmission. i have dc sports 4-2-1 headers, 2.25 inch catback exhaust to a dynomax turbo muffler, aem short ram intake, and an apexi vafc.

sometimes when i drive at wot the car feels so sluggish no matter what rpm range it's in. it doesn't matter if the car is warmed up or not but this problem tends to occur more often when the car is warmed up. like today i was driving around and at wot my car just wouldn't accelerate much for like 5 seconds at 3k rpm in 3rd gear and then it would accelerate and then just sort of hesitate.

i bought a new distributor, got new 8mm accel wires, ngk vpower spark plugs and made sure my gap settings were right, cleaned my injectors with that injector cleaner stuff you can get at autozone, i checked my vafc settings with some other guys with vafc's with a b16 as well and their settings were very similar to mine, and i got a new air filter.

i honestly don't know what's up with my car. i did every basic tune-up i could do to it and my car is extremely sluggish right off the line especially. it accelerates for like 500-1000 rpms perfectly fine and then this sluggish problem kicks in. it sort of feels like it runs on all 4 cylinders perfectly fine and then just decides to run on 3 cylinders for a little and on and off like that. however, it has a healthy idle and doesn't really sputter like crazy. i have run single cam vtec civics and they were even with me almost the whole way until i would hit vtec.

when i turn on my car, if i try to lightly rev it up but with 100% throttle, it sputters a little on the rev up until it passes around 2k rpms. and this only happens when i turn the car on right away whether the engine is cold or a little warm.

the only other problem i think this could be is either bad injectors, a possible timing issue, or a compression problem... but i'm not sure.


any suggestions???

could be the VAFC

i know a bunch of ppl who tried to use those vfac's. they hated 'em. they all sold them and everything went back to normal

i really honestly don't think it's the vafc that's giving me problems. basically all it does is sort of trick the map sensor from what i know. and i know that my settings are fine just because i know of a few others who have almost the exact same settings for regular bolt-on mods to the engine and they have no problems at all.

when i drive at wot, or even at half throttle sometimes, it feels like my car just won't accelerate, it just stays at a certain rpm and then sometimes accelerates and then just stays at that same rpm and so on. it sucks.

could it be that my catalyctic converter is clogged? the new cat was installed last year so that's why i think that's not the problem, but i'm not completely sure until i check it out.

anybody else have this problem?

do you have the right ecu?

ok... i still think its your VAFC... every car and motor is different... so even though your setting are similar, this may be off enought to affect your car.. unless your running rich or lean the cat should be good... what exactly did you replace with your tune up? you may have missed something that could also cause this.

+1 for the vafc

How is your fuel pressure? Is the engine recieving an adequate amount of fuel?

well today i met up with one of my buddies who works on hondas alot and we checked everything out in my car. we checked the ecu and found that the knock sensor wire was completely detached from the ecu, but that wasn't the reason the motor was running so slow.

we double-checked all of the vafc connections and they were all fine. we took the car out for a spin and noticed that the car only ran slow when it was totally warmed up.

well another buddy of ours told me that my engine was extremely hot. it was running very lean and when it was running so hot, the car would run like crap.

we ended up taking off my vafc and rewiring everything back to stock to my pr3 ecu. and then we got a code 21, 10, and 41 from the cel. i think it was code 21 that would turn on around when vtec would normally engage and so something must be up with the vtec solenoid. our digital multimeter was dead so we have to recharge it to check the voltages on everything this weekend.

we checked the timing with the timing light and the timing was off just by a little bit, so this is going to be another thing we need to fix this weekend.

the only thing is though.... why is my dash temperature gauge reading normal temperature when the car is obviously running ridiculously hot? that is probably one of the reasons why i'm getting a code 10 and 41.

other than that, i have no clue as to why my car would be running so lean. tomorrow i'm taking off the coolant hoses from the front and back of the throttle body and connecting the two hoses to keep the intake manifold running cooler without having hot coolant running through the throttle body.

do you have a low temp thermostat and a regular fan switch? i had that problem.

10 is IAT sensor and 41 is primary o2 sensor heater... both those will F*** up your A/F ratio if not good. check there

today what i did was jump the switch for my radiator fan to keep it running at all times when my car is on to cool the engine a little bit. that seemed to have gotten rid of codes 10 and 41. i'm pretty sure i was getting code 10 because my intake manifold was getting ridiculously hot. the temp sensor that is on the intake manifold was changed yesterday and that really didn't change much.

but anyway, as for code 21, which i guess is the vtec spool switch or something like that, was pretty puzzling. we checked out the wiring again and it turned out that we accidentally switched the vtm signal wire and the vtec solenoid pressure wires when running them to the ecu. after doing this, code 21 was gone as well.

so now i have no codes. my ignition timing is advanced because my car is obviously running lean because the motor is getting so hot and then once the motor even gets remotely hot the way it does, the motor just doesn't pull like it's supposed to. do you guys think i should maybe change the o2 sensor even though it's not tripping an o2 sensor code anymore on the ecu? we are doing the timing on the motor on monday and maybe that will help some.

retarding the timing will help a little.. but i think you have cooling problems else where... i would suggest doing a flush to get rid of any gunk buidup that could be hindering you collant heat exchange efficiancy.. change the thermostat... make sure your water pump is working properly.. etc..

yeah does kinda sound like you got a block somewhere. when was the last time you changed the pump.

well i ran some cooling system cleaner and that seemed to have done the trick somewhat but it still seems a tad bit sluggish. it runs alot cooler now though.

yeah does kinda sound like you got a block somewhere. when was the last time you changed the pump.

when should i have changed the fuel pump? i don't think the fuel pump has been changed at all, even after the swap.

i was talking bout your water pump.

nope, i haven't changed that. i will go ahead and do it within the next couple days and see if that improves anything

i can't really think of anything else that would make your car seem slow to you. have you taken it to a track to see what the 1/4 mile is?

try replacing your cat converter to a high flow one, my car was sluggish and turned out it was a clogged converter.

if you don't have emissions testing just punch your cat out. lol no don't do that.

well i finally figured out what my problem was. the cat was not clogged because it's only a year old and it is a high flow cat after all. and also, if the cat was clogged, wouldn't the car run crazy rich since it wouldn't be getting much airflow through the exhaust?

well anyway.... we checked my coolant and stuff and it was really really dirty. like it had dirt in it and kind of like a sandy substance. it was really weird. so i drained the coolant. cleaned it with this cooling system cleaner and then changed the coolant and my car has been running like a dream ever since and it has been running very cool.

thanks for the help everybody.

we do what we can. glad to here everything is good.