Mike91W

Hi, i have a 94 civic si with the d16z6. i just got the car bout 3 weeks ago, my throttle was sticking so i decided to take it all apart and clean the whole assembly. also noticed that the throttle body was dirty as hell. so sprayed some cleaner in there and was seeing if that would work. well long story short, it didnt work, need a new throttle body, but after i took off the throttle body n cleaned it, my car jerks n misses when im revving around 1k-2.5k and accelerating midway. if i accelerate slowly it doesnt do this but when i try and go a little it happens. Why could this be? i messed up the throttle body cleaning it, fuel filter, dirty intake, timing?? i dont think timing because i dont hear any missing when i just rev at random rpms. some help with this problem please?

ezone

If the ONLY thing you messed with before this happened was the throttle body, then that's where to start. I'd be inspecting to see if the TPS isn't adjusted right, or if it got damaged first.
Then vacuum leaks, screws that got messed with that should NEVER be touched and need to be put back where they belong, etc.


Or you got the connectors for the MAP and TPS swapped. They WILL reach and swap on many engines, and it will run like **** if you manage to do it.
Seems like you really have to try hard to screw this one up, since the wires all lay where they were supposed to be.
Swap them back and forth anyway, it's easy and quick and if that didn't solve it, it should have only wasted a minute or two of your time.

HTH

Mike91W

If the ONLY thing you messed with before this happened was the throttle body, then that's where to start. I'd be inspecting to see if the TPS isn't adjusted right, or if it got damaged first.
Then vacuum leaks, screws that got messed with that should NEVER be touched and need to be put back where they belong, etc.


Or you got the connectors for the MAP and TPS swapped. They WILL reach and swap on many engines, and it will run like **** if you manage to do it.
Seems like you really have to try hard to screw this one up, since the wires all lay where they were supposed to be.

Ya only thing messed with was the body. its not running like crap, its just when i hit the gas a little bit at 1k-2.5k seems like its missing. but the timing is all, i guess you could say perfect. my guess is it could be a leak, fuel filter, something like that. how should i go about figuring out which it is? and its not the tps or map unless they went bad. like i said it doesnt run like crap, just skips a beat and its annoying when i need to go.

ezone

Maybe it was there before you touched the throttle body. Or it's a new problem.

True misfire is usually ignition related: Plugs, wires, cap and rotor. You should be able to duplicate it by power braking it if it is ignition secondary.

I can't tell if you have real misfire or just a hiccup of some sort.



Does it have an EGR valve? Unplug it and see if it clears up.

Mike91W

Its a stick tranny, and i read that it doesnt have a egr vavle, but somebody said look behind the intake manifold and wala theres a sensor. gona guess its the egr, didnt take a close look just a glance. so, ill try that and see what happens and also with the powerbraking. this is my first civic so don't know a whole lot about them. thanks for the help!

Mike91W

also, could it be the map or iat sensor? i did unlpug both sensors (map, tps) from the throttlebody but def. didnt mix them up lol. im just reading a lot of other posts and trying to come up with a solution.. I despise cars than don't run perfect -_-

ezone

I got to looking more, that engine shouldn't have an EGR valve according to my info. No idea what you are looking at behind the manifold. I can't see it from here.

Gonna be hard to powerbrake a manual. I was just thinking that ignition problems are usually somewhat consistent (by conditions) and easily duplicated.

I can't even begin to take a SWAG at the real problem without a LOT more data that you aren't going to get/give/have/find. Driving the car myself is what I need first, and that ain't gonna happen.
All I can do is guess from here.



By "damaged", I meant electrically damaged.


Was this problem there before you touched the engine?
Did you remove the TPS?
Did you booger up the throttle body gasket at all?
Did you recheck all of your work?
Got any codes?
Got a DVOM? Know anything about using one?
What is the TPS voltage output at closed throttle?
What does it do during a long slow throttle opening?

MrDobin

Did you solve the problem. having a random similar issue and I have a map sensor spare but i havent got around to doing the swap. Mine randomly cuts mid acceleration but higher RPM is just a champ. Only erratically when i floor from stand still.

Mike91W

Still havent figured it out. replaced my fuel filter, cap and rotor, and now its worse. same issues as you MrDobin. when trying to accelerate at low rpms it hesitates and misses/sputters. but once i get past 2.5k its all gravy from there with the occasional sputter. don't think its the timing since if that were to be it would be running like hell.. so next ima go buy a new throttle body since mine is crap anyway. this all started since i touched that damned thing >.< and my civic isnt throwing any cel's except the srs light is on... let me know if ya figured it out.

Mike91W

Still trying to figure this out. replaced plugs/wires, fuel filter, cap n rotor. Was told by a local to try the tps sensor. So im gona try that one next... any other ideas?? and also when you punch the gas at idle the engine hesitates some but then revs just fine. and i can floor it and not have it jerk on me but gotta be at the right rpm's

ezone

Didn't go back to read the whole thread....

What about sparkplugs and plug wires?

Mike91W

Yup thats new also. it was much worse till I put the plugs n wires on. But it still does it like before, just not as often. Possibly dirty injector? tps sensor? What shall my next step be?

ezone

If it were in front of me at the shop on Monday morning, I would diagnose it properly and be able to fix the problem.... but I can't do that for you over the internet.
All I can do from here is guess, and that gets more expensive with every wrong guess.


Here's a wild guess:
Were the plugs and wires both replaced at the same time?
NGK plugs? (Just say NO to Botch Platinum!)
Did any of the old plugs have carbon tracking on the porcelain like this?


When this happens, the plug(s) AND wire(s) must be changed at the same time. Leaving one in place will ruin the other in a very short time (sometimes as quick as later the same day).



HTH

Mike91W

Yeah only if I could lol. Wish I knew a honda guy around here, but haven't ran into one yet. But No to bosch platinum, I chose the v-power ngk's. Replaced both at same time. Basically I just want to know the next thing you would look at.

G.C. BANDIT

mine is doing the same thing. did you guys come up with a fix?

9Hatch4

Anybody find a fix?? My problem started out as idling high til it warms up then jumps from 1.5k to 2k rpms so I cleaned my Iacv and that really screwed things up. Now when I start my car cold it'll go to 1.5k and jump back and forth really fast to 1.6-1.7k and when it gets warm it idles pretty normal. (800/900) I took of my throttle body and cheavjed everything there and was good, didn't mess up plugs putting it together but I've got a vel for my egr but I don't have an egr on the d16z6? Let me know if anybody finds a fix! About to give up on this car.

Digitalism

Hello,

I had the same issue, spent hours tonight and might have fixed it. Here's a breakdown of my process:

1. Unscrew the throttle plate from the throttle body by removing the two screws holding the plate to the throttle rod. Clean the hell out of it with some brake cleaner, and use a wire brush to remove the stubborn carbon deposits. Take extra care to clean around all edges of the plate as I believe this was making my throttle catch at times.

2. Clean the ENTIRE throttle body, including all the intake terminals and outtake terminals. Yes, it's a pain in the *** to get in there but I think it really helps.

3. Remove the idle control screw and clean the hell out of that as well, making sure you clean the air flow port where the screw sits.

4. Remove the Idle Control Valve and take the whole thing apart, cleaning the housing that contains the Air Control Valve. This for me was dirty as all heck, so make sure you pool the cleaner within the housing and let it sit for a good amount of time. After it soaks, go through and wipe up the deposits with a clean shop towel (I used a small-headed screwdriver to get into the valve). Lubricate the valve with a small squirt of your preferred lube. Make sure you remove the excess lube. When you reinstall the Air Control Valve magnetic motor, make sure that the outside of the valve is visible in the housing. If its seated at the bottom, it won't work and will give you a P0505 code! The best way to test this out is by screwing the motor back onto the ICV and reinstall that round plastic piece on the opposite side of the housing without screwing it in. Now, simply rotate that plastic piece a full 180 degrees, and you should feel the valve spin around and see it visibly through the housing. Once it's set properly, screw that plastic piece on.

5. Ok, so here is what I believe was causing all my issues. The small screw and bolt that holds the throttle plate open within the throttle body might be out of adjustment ever so slightly. This is where it takes some patience:

-Close your idle adjustment screw so that no air is passing through the hole.

-Remove the bracket that holds your throttle cable up, should have two 10MM bolts at the bottom of it. It sits right next to the throttle body, just follow the cable up over your engine where you will see the bracket and adjusting nuts.

-Remove the throttle cable from the throttle cable plate attached to the throttle body.

-You should see a small headless screw locked into the throttle body by a small nut. Unscrew this nut slightly, it should be 7MM.

-Now here is the hard part. Do this when your car is hot (radiator fan has run through at least two cycles). You can do this alone or with someone else, probably a lot easier if you can get someone in the driver seat to report your RPM.

-Loosen the screw to the point where your engine reads roughly 500 RPM. It might even sound like it's about stall, or at least mine did. The adjustment here must be minuscule, the tiniest turn can make it jump from 500-1000 very easily. You don't want that!

-Once you have it set at 500, use your finger to very gently tighten the nut on the screw, just tight enough so that it touches the throttle body metal. To double check that the throttle plate in the throttle body is seated correctly, just blip the throttle cable plate hard enough for it to slap back down so that it reseats to the screw.

-Now, grab your 7MM wrench and tighten that sucker down. You'll notice that your RPM will slowly increase, which is what you want. Tighten it so that it is very tight, while also making sure your RPM does not go beyond 650. This might take many tries, took me about 20!

-Bolt the throttle cable bracket back on, reinstall the cable to the throttle cable plate, and make sure you have about a 1/2" of slack on the throttle cable. Too tight and it will leave the throttle plate open or won't sit correctly on the screw you just adjusted.

-Lastly, adjust your idle screw just enough to bump the RPM's into the 700 range. It took me less than 1/2 turn, it was about 2/5 a turn.

Hopefully this helps! And if all this fails, clean the throttle cable plate spring by unscrewing the 10MM nut on the front of it and removing the whole thing. Make sure you lube the spring when you reinstall it. I used a little bit of clean motor oil. And for God's sake, replace the gasket between your throttle body and intake manifold!!!!

This is what put me back at specifications and idle hasn't fluctuated like crazy anymore. No more CEL too! Good luck!

ezone

Glad you got yours figured out and working, but I can't keep quiet on these 2 points......
If one of those screws manages to fall out and gets swallowed by the engine, ingested into a cylinder, how much damage do you think may happen?

Some manufacturers stake the screws so they can't back out, some may use Loctite or some other method of securing them. (IDK what Honda uses to secure the screws, I've never taken one apart like that.)


The cleaning in #1 can be done well with a bottle brush or toothbrush and a spray can of carb and throttle cleaner, and shop towel......without taking the throttle blade off of the shaft.

This is something that nobody should ever have to touch ---- unless someone else messed it up before you.


Adjusting the throttle stop in #5 changes the TPS reading (I have mentioned before just how consistent Hondas TPS readings are on a scanner), and alters the (calibrated) air volume that is allowed around the throttle plate when closed. Pretty drastic effects can happen with minimal changes and since nobody is supposed to ever mess with the setting, it can be tough to figure out and get corrected.

Digitalism

As far as adjusting the throttle plate, I had no other alternative. I believe it was the whole reason behind the problem to begin with, and the plate would at times literally stick in the throttle body. It would take a good force on the pedal to get it to move, but of course that would mean a surge in power when I was trying to shift, which in turn created violent shifts. So I did quite a bit of research, many sites state that for most D16Y7 engines, the throttle plate needs to be adjusted to 10% capacity if you have a diagnostic tool. Many claimed that with new plugs, this should be roughly around 450-550 RPM. I adjusted accordingly, then adjusted the idle screw, and haven't had an issue since. I always use Loc-Tite on my screws, I made sure to use it on the throttle plate. I could only imagine what damage it may bring if I didn't...