i have a turbo f22a1 1995 prelude.

the car has a miss at idle i need help so bad i cant figure this out and i have experienced ppl helping me all the time, i mean turbo rhd welding 10 plus car tuning guys. we cant figure this out.

the car, like i said, idles wierd. it idles right at 900 rpm, but it sounds and feels like there is a miss in it, you can pull the #3 plug wire (from passenger side) and no difference in idle.

the miss seems to disappear when you give it some gas and load going down the road. the engine has a vibration to it and seems unhealthy at 4500+ rpms or under 2000 rpms...

its spewing 3 CELs : 5, 7, 41..

5 is map sensor
7 is tps
41 O2 sensor heater

when you take the car out of gear it revs 500 rpms up from whatever rpm you was at (when cruising low rpms)

checked rotor, cap, changed plugs to iridium, use 93 gas all the time..
the cap was busted at one time, changed to new one.

the engine's grounds were SO BAD we grounded the hell out of it now that shouldnt be a problem anymore.

i really need some help here guys i dont ask a question very often and have been a member for a long time.. i've built this prelude from bottom to top over the past 9 months.

And the fmu that was on here, the diaphrams were destroyed inside of it so when i took it off i stopped leaking mass fuel and it runs good enough to drive daily.

please help i need to know what this idle problem is. Could it be the Timing?
maybe the coil or something? is there a common problem that could cause it to throw those 3 CEL at the same time?

please please help thank you so much in advance.

 

This is on another thread today! But 9 out of 10, if you have a tps and map codes. The connectors are criss-crossed! Check it out and get back.

 

is the car tuned? and if you pull of the wire for #3 and no chane then it is something to do with that cylinder. maybe the sparkplug wire. maybe something internal

 

which connectors? the plug to the tps? god i hope thats it, i just changed the plugs, wires and cap, cleaned the rotor button. looks all good. still misfiring

 

sounds like you could have a couple problems here. you didnt gap those plugs did you? i know its a dumb question, but youre not supposed to gap those iridium/platinum plugs. if they are bosch plugs id go ahead and replace that number 3 cylinder again (preferably with something that isnt bosch). compression test that cylinder too.

hook a voltmeter up to the signal wire of the tps and see if youre getting a steady voltage increase/decrease while opening and closing the throttle. also see where it sits at at idle, someone on here im sure knows the specification on that.

 

oh no they're iridium ngk's, i know bout the bosch's... didnt gap them either,, the cylinder was running fine a while back btw.
and i know my TPS is trash but would that cause the cylinder to not fire?

and at one time the rotor cap was busted and shocked the **** out of me. replaced it lol.

can the coil be a problem? i have another one at a friend's house, its external coil btw f22a1

but what are these connectors that could be crossed up?

 

The map and tps. the connectors are the same. Easy to cross. Happens alot!

 

coil is definitly a possibility...mine got heated and had a miss at idle and hesitation when driving

did u clean the FITV and the IACV?? ive heard of ppl getting misses at idle because of cloged IACV witch makes perfect sense

 

should i just run seafoam thru this i have a freind that is wanting me to do this, he swears it cleans EVERYTHING out of the motor.

well my idle isnt all stupid, but it does get stuck i think my throttle plate needs cleaning, it'll idle to 3k when i start it until i rev it a little then it goes to normal. so i dont think my FITV fast idle thermo valve is dirty, that would make it search for idle all the time, I'll clean it anyways!!!

but the IACV is supposed to have the same problems right? would that make it miss alot? it misses completely on the 3rd cyl at idle, you can take the plug wire out, no change..

im really about to change my distributor and my coil. just to see if it'll fix it. already changed plugs, wires, cap. cleaned button and the little things on the cap with wire brush.

 

technically it shouldnt cause a miss but i wouldnt count it out, it happened on my buddies grandam. id say replace the known bad part(s) first and see how it acts after the new tps. how are you tuning your fuel/air?

i would have to say probably not on the coil. if your coil is bad its gonna effect every cylinder and youre gonna have a major lack of power. its something individual to that cylinder. maybe check to see if the injector is pulsing as well. before you start throwing parts at it id say replace the tps and if its still acting up check the compression and make sure that cylinder is getting fuel.

 

can you verify spark at the end of the plug wire? you can buy a cheap spark tester for like...10 bucks at murrays/oreillys/meijer basically anywhere. if you have spark at the end of the wire i think its safe to assume the dizzy/coil isnt the cause of the miss. if you dont, you can hook it up between the dizzy and the wire. if you dont have it there, then id maybe start thinking about replacing the dizzy. how are the contacts on the cap? file that cylinders contact down a little and see if it runs better.

 

i did spark test it after installing the other dizzy and coil.
all the contacts are good. verified that this is not a wire/plug/dizzy/coil problem..

maybe its the injector? timing? or dropped compression......

im leaning towards timing the more things i run thru.

my friend thinks its off just a tooth.