well, in lower gears, when i hit WOT, after about a half second of normal FAST, it begins to misfire so badly it won't accelerate at all. this is in first and second. in higher gears, the misfiring begins instantly when the ECU turns to closed loop engine control. new plugs, TPS is PERFECT, and i've been having **** like this bug me for a while. please help.

 

bumpity bump bump

 

It is possible your plugs aren't gapped correctly, that happened to me before.

 

nope, plugs are gapped perfectly. did it myself. it was doing this on my old plugs (4000mi old), so i changed them out, and it solved it until the first time i floored second all the way up. then, about 6500rpm, it started happening again. plugs look fine, no tell-tales, no burning oil. also, no air/fuel reading when the misfiring occurs. like the O2 goes stupid, too. it just doesn't read anything, almost 0V.

 

geez guys, come on

 

is it always reading 0 volts?? or just when it misfires?

 

just while it's misfiring. when i release the gas pedal, and it comes out of closed loop, the misfiring stops, and the oxygen sensor reads like it normally does again.

 

ok heres a few ideas. First check your tps voltage with the car in the on position but not running. Just go through the whole range and see if there are any flat spots. I know you said its fine but just check it again. Second check your throttle cable, make sure its not too tight. Third make sure your fuel pump isnt fried. At higher revs it might be struggling to maintain pressure. Check all that and hit us back. Im just firing out ideas as they come to me, its hard to diagnose a car on the internet.
Tyler

 

i checked the tps a few days ago for full range of readings, and it's perfect. i was so disappointed b/c that would have been a perfect solution, but it was perfect. .44V closed and like 4.46 open and very linear everywhere in between. as for fuel pump, that runs the same whether at WOT or idle. and i've got a fuel pressure gauge under hood; it's fine at idle. when the fuel pump runs, it runs the same for all conditions, and runs long enough to keep pressure in the system, then shuts off. i mean, maybe it's not able to keep pressure in the system or something? i guess that's possible, but it runs fine cruising around and idling, so this shouldn't be an issue. just thoughts. but anyways, the fuel pump only has 1 speed, so WOT shouldn't make a difference to it. my fuel pressure is 48psi and the max pump pressure on hondas is 75psi. no prob, no?

 

i've seen both gummed up injectors, and a weak coil cause this same problem

 

Have you checked your valve adjustment? I've seen instances where if they are too tight, the car will run and drive fine untill you get on it then it will float the valves. Also it could be the distributor, alot of times they will malfunction at high rpms.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rfeigley &raquo;</TD></TR><TR><TD CLASS="quote">i've seen both gummed up injectors, and a weak coil cause this same problem</TD></TR></TABLE>
well, i tried cleaning the injectors in clean gasoline. don't know if that did the job, but i tried. left them for at least a couple hours each. as for the coil, it checked out on the resistance like the manual says, but i'm not sure whether or not it could still be bad even though it checked out on the multimeter. please, do tell.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bealziboost &raquo;</TD></TR><TR><TD CLASS="quote">Have you checked your valve adjustment? I've seen instances where if they are too tight, the car will run and drive fine untill you get on it then it will float the valves. Also it could be the distributor, alot of times they will malfunction at high rpms.</TD></TR></TABLE>
first, i do valve adjustments every 5000 miles b/c i get bored and feel like it. only takes 30-45min, and it's free, so why not, right? second, Crane valve springs and retainers rated (by Crane, not by sane human beings) for 10,000rpm. i doubt they could deal with 10k, but they aren't a whole lot looser than Crower duals, and i'll never EVER see 10k, so i really think i'm way past all right. oh yeah, professionally built.

on a side note, i noticed that the timing belt has a little slack between the two cams. just a little bit. but i think it should be flat across there. i might try turning the intake cam back a little (the direction it seems to want to go to tighten the belt) and use the tensioner to suck up the slack. this might be the culprit? autozone timing belt, stretch, i know, i know. but please keep the ideas coming. this has been pissing me off for so long, and WOT is sooo much fun!

 

**** i had nightmares trying to diagnose your car last night haha. The reason i said fuel pump could be that its just not holding pressure at wot. Sure it reads fine at idle but as soon as you tromp on it the pump just cant keep up.
I think i have it figured. Pull your dizzy cap off and see if there is any oil. Maybe your seal is shot and its misfiring due to oil being in there. Check that, make sure everything is clean in there.
Let us know, Tyler

 

I vote dizzy related as well. Have you tested the coil and ignitor? I would start with that. Honda coils are known to go, but your symptom's are wired though. (I'm just biast since i had coil problems though... )

 

ya could be that too. I still vote blown seal though.

 

I agree with the dizzy thought. Buy one from a local parts store swap and test. If its not the dizzy return it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tmack &raquo;</TD></TR><TR><TD CLASS="quote">ya could be that too. I still vote blown seal though.</TD></TR></TABLE>
well, i was in there testing the coil and ignitor about a month ago. both checked out fine on the multimeter, and i didn't notice anything unusual like oil, or any sings of wear on the dizzy cap or rotor. and i'm not losing any noticeable amount of oil. but i will check that out for sure. any chance the coil and/or ignitor is bad even though it checked out?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tmack &raquo;</TD></TR><TR><TD CLASS="quote">**** i had nightmares trying to diagnose your car last night haha. The reason i said fuel pump could be that its just not holding pressure at wot. Sure it reads fine at idle but as soon as you tromp on it the pump just cant keep up.</TD></TR></TABLE>
how exactly would i test this? i have fuel pressure gauge under hood, and i don't have a bunch of money to throw around.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by projectxspeed &raquo;</TD></TR><TR><TD CLASS="quote">I agree with the dizzy thought. Buy one from a local parts store swap and test. If its not the dizzy return it.</TD></TR></TABLE>
would they let me return it? i thought to test dizzy i'd have to borrow one from somebody. by the way, anybody got one? i can send you $$$ as deposit until i return it to you. also, this is my favorite one. this problem intuitively seems like an ignition problem to me. especially since new plugs helped the problem for a short time, before i slammed the gas all the way through second, and at the top of second, it started coming back.

anybody vote for a little timing belt slack?

 

The best way to find out is ask, and explain your situation. Most auto parts store will allow you to return the dizzy if you keep the box and receipt.

 

well to check if your pump is holdiong pressure pop the hood and pull up on the cable at a high rev. Just watch the gauge, it will drop a few pounds but if you notice it continuing to drop your pump may be bad.
Have you replaced your o2 sensor?? Maybe the backfire is becuase your faulty sensor is reading lean (0volts) and the ecu is dumping a ton of fuel in there.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tmack &raquo;</TD></TR><TR><TD CLASS="quote">well to check if your pump is holdiong pressure pop the hood and pull up on the cable at a high rev. Just watch the gauge, it will drop a few pounds but if you notice it continuing to drop your pump may be bad.
Have you replaced your o2 sensor?? Maybe the backfire is becuase your faulty sensor is reading lean (0volts) and the ecu is dumping a ton of fuel in there. </TD></TR></TABLE>
O2 sensor is fine. it works perfectly the rest of the time. and the fuel pressure goes down a bit when i gas it from under the hood. never get to floor it. it's already revving high by the time it's floored for a sec. but when i pull the vacuum hose off the fuel pressure regulator, pressure goes from 48 to like 56 or something. not sure how much more, but something significantly higher, and it will stay there as long as i leave the hose off or put my finger over the FPR's vacuum port.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by projectxspeed &raquo;</TD></TR><TR><TD CLASS="quote">The best way to find out is ask, and explain your situation. Most auto parts store will allow you to return the dizzy if you keep the box and receipt.</TD></TR></TABLE>
thanks.

anyone know if the coil or ignitor could be bad even though they checked out on the multimeter? also, i remind you guys (and gals) here that there is just a little bit of slack on the timing belt between the two cam gears. i'll cinch it up next time i'm home, since it won't take long a i guess could be the problem. the intake cam drives the dizzy, so maybe that's a threat?

 

ya it definatley could be, it all depends on how much slack there is.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">... and the fuel pressure goes down a bit when i gas it from under the hood.</TD></TR></TABLE>It should go up, as the manifold pressure goes up. (less vacuum = higher pressure)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 95lstegman &raquo;</TD></TR><TR><TD CLASS="quote">...but when i pull the vacuum hose off the fuel pressure regulator, pressure goes from 48 to like 56 or something...</TD></TR></TABLE>That part is right.

When you blip the throttle, the fuel pressure should go up for as long as you hold the throttle open. Then when you close it, the rpms are high so the vacuum is stronger. Fuel pressure should then go down a little lower than normal, & return to normal as the idle settles.

Your coil can be bad even when the resistances measure OK. You're using a multimeter to measure resistance thru the primary & secondary. What you're missing is how to measure whether the insulation is breaking down at high voltage.

I don't think the timing belt slack is related. Some small amount of that is normal, the belt ISN'T supposed to be tight like an alternator belt. Without seeing it firsthand it's hard to say whether yours is too loose...

 

coil can break down under a load. when you check it with a multimeter there is no resistance from the rest of the ignition system, so you're not really checking the potential output.

 

thanks guys. i'm going to pick up a dizzy and install it this weekend and see if that works. i really can't wait to be back to haulin' @$$ again. i'm rebuilding and LSD'ing my tranny soon, too, and i can't have a LSD and not be able to hang above 4 grand for a while. mwahahaha