D16Y8 Low RPM Hesitation - Fine past 2500 RPM

[Wreckless Hype]

Stock 2000 Civic EX

When I bought it, I thought it was a little strange that it seemed hesitant in low RPMs of any gears if I give it a "sporty" amount of gas. By "sporty", I mean it's between feathering the gas so I get to 60mph by length of a Fast & Furious runway, and "Hey, check out my 60 foot". I'm not flooring it, but I'm trying to move a little bit, ya know?. I never noticed it when I test drove it and I was sure to get on it when I took it out.

From a stop, the car seems to hesitate all the way up to 2500rpm or so and it's like it snaps to life.
Second, third, etc all do the same thing. up to around 2500rpm and then it's fine.
When it "snaps to life", the best description I can give is when you're accelerating up a hill with your AC going and you then turn the AC off, the car gets a little kick in the ass almost.

So far, troubleshooting and changed parts (updated):
Feb '14
Spark Plugs - NGK ZFR5F-11 V-Power Spark Plug
Plug Wires - NGK (8034) HE76 Premium Spark Plug Wire Set
Distributor Cap - Bosch 03306 Distributor Cap
Ignition Rotor - Bosch 04278 Ignition Rotor
Oil & Filter - Penzoil Ultra 5w30 + Fram Ultra filter
May '14
Serpentine Belts - Gates K040325, K040332, K040315 Multi V-Groove Belt
Jun '14
Valve Adjustment
Mechanical Timing (No issues)
Ignition Timing Adjusted (Needed to be advanced)
Fuel Filter - Purolator
Short Ram Intake - Password:JDM - Utilized connections for IAT and PCV blowby, blocked off AASV hose
Exhaust Manifold - J2 Racing (eBay brand?)
O2 sensor disconnected, issue remains
TPS voltage tested 0.51V CT / 4.59V WOT
July '14
Distributor swap with healthy running D16Y8
ECU Swap with healthy running D16Y8
*P1033 code*
Check for exhaust leaks - none
Readjusted valves
Rechecked Mechanical timing - OK
Readjusted ignition timing
*P1033 code and stalled while cold, low idle*
Fixed AASV
SeaFoamed gas tank and intake manifold
*Next Up*
Compression test
Swap TPS with healthy running D16Y8

*Recent developments*
Slow signal on front O2 sensor - CEL
Low / dipping idle while "cold" idle (resolved)
Stalled before hitting operating temp (resolved)

*Originally*
No CEL at all.
No idle issues
No smoke that anyone following me could ever see.
No vibration or any other weird sounds or feels.
Gas mileage is unchanged - sits around 33-35 depending on how I drive.

When I changed the plugs, wires, oil and filter, it seemed to run a lot peppier, but I noticed the hesitation again.
When I pulled the plugs out (have been in a month or so), they all looked identical. They had a smooth gray burn to them, they didn't stink like oil or anything, they all looked good.

If I accelerate to around 5 or 6k and shift, it keeps me out of the 2500rpm band in the next gear so the issue never really surfaces.


The girlfriend has the same car, same engine, almost the same miles and it pulls really nice (for a D16). Reaching here, I'm not sure... I've been looking at similar topics for a couple days and it's such a broad spectrum of possible causes.

 

[XpL0d3r]

I had a very similar issue. Car ran like complete s**t below 3k, and past that ran perfectly okay. No CEL either.

The issue was with my primary o2 sensor. It was sending readings to the ECU still, but for whatever reason must have been off on lower RPMs. It was f**king with my A/F ratio. It drove me nuts for a while. Not saying that this is your issue, but it's something to look in to.

 

[Wreckless Hype]

I had a very similar issue. Car ran like complete s*** below 3k, and past that ran perfectly okay. No CEL either.

The issue was with my primary o2 sensor. It was sending readings to the ECU still, but for whatever reason must have been off on lower RPMs. It was f***ing with my A/F ratio. It drove me nuts for a while. Not saying that this is your issue, but it's something to look in to.

I thought about that, but I also thought it would throw off a code. I guess not always. I could just swap them both out, Denso parts they're like $115 for both.

Going to first look into fuel filter, cleaning IACV and running a bottle of injector cleaner through a tank of gas, since it's all pretty cheap and the filter / IACV cleaning could both stand to be done any way.

I don't know how old the O2 sensors are, but I've always just been one to forget about them until they light up my dash board. I've heard of people testing them by just unplugging them, but I'm not sure what kind of harm that would cause. I guess it would be like driving home on a blown sensor...

 

[RonJ]

Check the ignition timing by following the service manual procedure.

If you suspect the O2 sensor, then unplug it to see whether the problem goes away.

You also may want to compression test the cylinders.

Does your car have a manual or auto transmission? What about your girlfriends car?

 

[Wreckless Hype]

Check the ignition timing by following the service manual procedure.

If you suspect the O2 sensor, then unplug it to see whether the problem goes away.

You also may want to compression test the cylinders.

Does your car have a manual or auto transmission? What about your girlfriends car?

Have to wait until the weekend to check timing.

O2 sensor I could try, it's a simple plug to at least check.

Both cars are identical, 5 speed manual

Follow up: I was reading over the ignition timing through the service manual and checking some other sites to make sure I was reading the right information. The checks using the "UP" position on the camshaft pulley and the white indicator on the crank pulley is how I was eye balling it when I was turning the crank. Also, I was using a long skinny screw driver (shh, don't tell anyone I did that...) sitting on top of the 1st cylinder. Since I'm somewhat hard on myself trying to get the lines to level out "perfectly", I probably went through half a dozen sets of rotations to adjust the valves.

When I started, the cam pulley was at "UP", screw driver was highest point up (lol), and the single notch in the crank pulley was next to the pointer, the 3 slots to the left. When I would screw up and go slightly too far for the next cylinder, I'd spin it around so the cam pulley spins twice back to "UP" and checking the notch on the crank pulley lines up, screw driver hits a "peak" each rotation on the crank, I pull it out of the tube when the piston falls away. Am I missing something, or is that essentially how Honda says to do it? I just added the screwdriver as another check for myself...

(Dear mods, I added a response because if someone like RonJ or XpL0d3r is looking over posts for a response, the "edit" doesn't come up as a response so the information would be overlooked. Does that makes sense?)

 

[RonJ]

You are describing checking the mechanical timing, which is different than the ignition timing. See the Ignition System chapter of the service manual.

 

[Wreckless Hype]

You are describing checking the mechanical timing, which is different than the ignition timing. See the Ignition System chapter of the service manual.

Right. I'm dumb. Ok, so it's the blue connector up under the dash that you jump when you would normally try to get the "blink code" for a CEL.

So jump it, run the idle at 3k with nothing on, in Neutral until my fans kick on, then let it idle. Connect the light to the #1 plug wires and aim at the pointer on the belt cover down below.

My light has been lost so maybe I can grab another and check that tomorrow. Might as well get a fuel filter while I'm out as well.

 

[RonJ]

...so it's the blue connector up under the dash that you jump when you would normally try to get the "blink code" for a CEL.

Yes

So jump it, run the idle at 3k with nothing on, in Neutral until my fans kick on, then let it idle. Connect the light to the #1 plug wires and aim at the pointer on the belt cover down below.

Yes, but you can simply warm the engine fully by driving and then jump the service connector. The pointer has two parts and aims like the sight on a gun. It should align with the red mark on the crank pulley with the engine idling to spec.

My light has been lost so maybe I can grab another and check that tomorrow. Might as well get a fuel filter while I'm out as well.

You may be able to rent (free) the timing gun from an auto parts store that has a tool loan program.

 

[Wreckless Hype]

Yes

Yes, but you can simply warm the engine fully by driving and then jump the service connector. The pointer has two parts and aims like the sight on a gun. It should align with the red mark on the crank pulley with the engine idling to spec.

Well that's good then. I can just leave it running then when I get home from the parts store. And yeah, it's kinda like an iron sight, only plastic ha.

You may be able to rent (free) the timing gun from an auto parts store that has a tool loan program.

Likely. I do seem to use it often, but I'm not going to bother buying it if I don't have to.

Thanks much, will report my findings.

 

[Wreckless Hype]

I'm going to go ahead and say my ignition timing is off. When aiming the timing light right down through the iron sight, I could hit the pointer below it and I was watching the timing marks on the outside of the pulley and it seems like the markings just can't catch up, they're a little behind. The first mark is even a little bit behind. (My timing light has no adjustment, just a power button)

Gonna go ahead and say that's an issue. I'm guessing at this point I need to rotate the distributor slightly? Or is this evidence of it being so out of whack, it may be off a tooth? It really seemed the mechanical timing was spot on, but I guess I could miss a tooth? With the TDC mark up, the "UP" is also straight up (to me, not aligned with the engine).

I took a look, the distributor looked like it was retarded a good bit (the top bolt hole was peeking out from behind the bolt - distributor pulled closer to radiator support).

I loosened up the 3 12mm bolts on the distributor and pushed it back a bit to almost center it. Timing light put the first mark just to the right of the pointer.

Loosen again and pushed it back a bit more so the top bolt hole was peeking out on the opposite side - success! Middle mark, red line hitting the pointer every time.

Cleaned up and took the loop out, went for a ride and holy s*** the power band in first and second is so damn smooth. Took it to about 3200rpms to check low end in gears and it builds rpms very smoothly.

$38 for a timing light very well spent (no one had any to rent or did not rent them)

 

[RonJ]

 

[Wreckless Hype]

So after driving the car for a few days and a fair amount of miles, it feels like it slunk back into it's weird hesitation. It still only does it at like moderate throttle. Granny driving it is fine and when I step on it, it's fine. Taking it to shy of 4k RPMs and giving it more than what I feel is half throttle, it's like there is a weird shift in power. I almost feel like something is missing, but there's no misfire code or any for that matter. Clogged injector? But that would through misfire codes I'd think...

Edit - I have also been putting Wawa gas in my car religiously, since they are everywhere. My buddy sometimes puts it in his WRX (premium obviously) and he datalogs his car on a regular basis and says when he runs on Wawa gas, he can see his car pulling timing. Am I just using s*** gas all the time? I did try a tank of Shell premium after a tune up but it didn't seem to fix the issue.

Since the timing change was done, I've replaced the exhaust manifold with an aftermarket one (it was running great with it on) and also changed the fuel filter with a purolator brand.

I do know the timing needed to be done. Obviously you can't see 100% how bad it was, but you can get a pretty good idea how off it was.

Edit again - Since the upstream O2 sensor clip is easy to get to, I'm going to pop it off before I go to work tomorrow. Work is about 4 - 5 miles away. I can always pop it back on and clear the code before I head back. I would think that distance is safe.

 

[Wreckless Hype]

I was running late for work this morning and completely spaced when it came to disconnecting the O2. It's not really a big deal, I can do it for the ride home (since I left my tablet at home also for clearing codes...).

While in my rush to work, I didn't let it idle much before leaving so I was driving it cold when I left and I noticed the hesitation is a lot less noticeable and it feels much more peppy. It also wasn't 94 degrees and humid as hell (sure was yesterday when I was on 195 for a while). Even with my WRX in Florida the heat soak wasn't that bad so I couldn't imagine it's a heat issue, unless these things are way more prone to heat issues.

So I'm currently stuck on cleaning IACV, checking O2 (for the hell of it, never know), maybe ICM?

I'm likely going to replace the distributor for this reason and also that there is a bolt broken off inside for the cap and I'm about the worst there is when it comes to luck backing them out. Honda says TD-73U (30100-P2E-A12), but everyone references them together with TD-63U (30100-P2E-A11). Is there a difference that would make a 63 not work? It all seems OBD2, 8 pin, yadda yadda. I wasn't sure if the 73 was special to the Y8 head for some reason. A completely rebuilt 63U with OEM parts sounds nice at the moment, which is why I ask.

 

[RonJ]

Why do you espouse the "replacing parts" philosophy over testing when trying to identify and solve a problem? Replacing parts is acceptable for basic maintenance, such as tune ups, but not for figuring out problems.

Place the O2 sensor test at the top of your priority list because it's so damn easy and might instantly pinpoint the problem.

If you truly think the distributor is the problem, then do the service manual testing of the coil and the distributor sensors and wires. You can also test the ICM. You said that your girlfriend basically has the same car. Have you considered swapping distributors to see if any change is noticed? Think logically and use all tools available to you.

Also test the TPS.

And what's the rationale for cleaning the IACV when you don't have an idle problem?

I used the IAT sensor and the blow back hose from the valve cover;

Used them for what?

the second hose below the VTec solenoid I blocked off.

Do you know what you blocked off?

 

[Wreckless Hype]

Why do you espouse the "replacing parts" philosophy over testing when trying to identify and solve a problem? Replacing parts is acceptable for basic maintenance, such as tune ups, but not for figuring out problems.

The swapping out the distributor thing was mostly just because I broke of a bolt in the housing for the cap. I've tried drilling out a snapped IACV -> TB bolt and ended up ripping up the threads and having to replace it anyway.

Place the O2 sensor test at the top of your priority list because it's so damn easy and might instantly pinpoint the problem.

Right. I'm doing this today when I leave work. It's already number one.

If you truly think the distributor is the problem, then do the service manual testing of the coil and the distributor sensors and wires. You can also test the ICM. You said that your girlfriend basically has the same car. Have you considered swapping distributors to see if any change is noticed? Think logically and use all tools available to you.

Can do this I'm sure. The replacing thing again was an issue with a stuck bolt snapped and there not being a proper seal on the dist. cap.

Also test the TPS.

I did read "dead spots" could be an issue. I've never heard of that, but I can add that to the list for sure.

And what's the rationale for cleaning the IACV when you don't have an idle problem?

Possibly reaching here. Ran OK Cold, hesitates when it warms up. And I'm sure it could stand to be cleaned anyway. It won't hurt, am I wrong?

Used them for what?

It's an aftermarket intake with only 1 air hose port and a port for the IAT. I used those connection on the intake instead of the AAV

Do you know what you blocked off?

Air Assist Solenoid. I admit, I didn't know the name, I knew it as air valve, but s**t, any hose connected to a housing could be a damn air valve, little did I know that was pretty much the name for it, kinda. My understanding was the main function would allow for quicker warm up times and when the hose is split or the nipple is broken, will cause a vacuum leak. I capped it off and ran electrical tape around it to secure it on. Since this issue was not effected by this hose being connected or not, I didn't suspect it to be an issue. Unless you were just checking if I willy-nilly tape s**t off. I guess that a popular thing...

 

[RonJ]

The swapping out the distributor thing was mostly just because I broke of a bolt in the housing for the cap. I've tried drilling out a snapped IACV -> TB bolt and ended up ripping up the threads and having to replace it anyway.

Because you fell off the horse doesn't mean you should never get back into the saddle. Hire a mechanic if you've lost all confidence in yourself.

The replacing thing again was an issue with a stuck bolt snapped and there not being a proper seal on the dist. cap.

See my response above.

I did read "dead spots" could be an issue. I've never heard of that, but I can add that to the list for sure.

You'll need a multimeter and some confidence.

Possibly reaching here. Ran OK Cold, hesitates when it warms up. And I'm sure it could stand to be cleaned anyway. It won't hurt, am I wrong?

It also wouldn't hurt to wax your wheel lug nuts.

It's an aftermarket intake with only 1 air hose port and a port for the IAT. I used those connection on the intake instead of the AAV

AAV?

Unless you were just checking if I willy-nilly tape s*** off. I guess that a popular thing...

So Honda engineers decided to throw useless parts into the engine bay for the fun of it? Do you want to be popular or rational? It's your choice.

 

[Wreckless Hype]

Because you fell off the horse doesn't mean you should never get back in the saddle. Hire a mechanic if you've lost all confidence in yourself.



See my response above.

It's $75 for a rebuilt OEM distributor. Around the cost of an hour of labor for most mechanics. The trade off seemed worth it. And since it's my only means of transportation, if I do happen to fall off the horse again, which I admit, I'm not at all worried about (I ripped apart my DX block and rebuilt the top end when I had 0 prior knowledge), but I won't have a vehicle to drive while I wait for a replacement part.

You'll need a multimeter and some confidence.

Got those and beer.

It also wouldn't hurt to wax your wheel lug nuts.

Did that last week.

AAV?

Awkward Annoying Verruca

So Honda engineers decided to throw useless parts into the engine bay for the fun of it? Do you want to be popular or logical? It's your choice.

I'm not looking to be the coolest kid in high school, nothing about my car is to win the hearts of everyone on the internet. Popularity through a car really is just never spending enough money. Was there anything wrong with my stock box, no. The intake I put in was a decent part, it was very cheap for me, the added benefit is minimal as with any aftermarket intake, but I put it on.

The question came down to, do I run the hose for crank case air flow or for the air assist solenoid? Weighing the options and doing some reading I made a choice, not based on popularity. I could switch the connections and put a sweet breather filter on the valve cover and hope I'm popular enough that Lisa will want to take me to the prom.
I decided it would be best to use the connection for the positive crank case pressure and keep the PCV system in check.
Air Assist Solenoid, I literally cannot find anything more relating to its function other than warm up assist. Is it a useless function, absolutely not. Apparently this was such an issue 96-98 that Honda spent countless resources and came up with this part to install on the 99-00 D16Y8s. Then I buy an aftermarket intake and like an a*****e, tell Honda to shove it right back up their ass.

Can I easily drill a hole into the intake and put a rubber grommet / hose connection in? Sure. Will I? Maybe, but it's not top priority at the moment.

 

[RonJ]

Awkward Annoying Verruca

Nice, try. This^ is actually your embarrassing skin lesion.

And I take back what I wrote earlier. You're on the right track by randomly unplugging and capping things off in your engine bay. Those Honda engineers were just clowning around with silly things they threw under the hood.

 

[Wreckless Hype]

Nice, try. This^ is actually your embarrassing skin lesion.

And I take back what I wrote earlier. You're on the right track by randomly unplugging and capping things off in your engine bay. Those Honda engineers were just clowning around with things they threw under the hood.

Ron, you're my favorite, no homo. Now that we got our sarcastic antics out of the way,

I'll continue with my O2 sensor test today.
I'll read into checking the TPS ( I think I may have actually done this on my D15 when the idle was fluctuating).
I'll look into getting a grommet drilled into my intake for the AASV (not my gross lesion) so that will function correctly.
The distributor I'll leave well enough alone for now and work on the bolt when I have some time and I know the autoparts store can get me one next day. <- What the hell am I saying; the bolt is f**king broke now, so if I blow the threads on it, the cap still won't be bolted down and I'll be in the same boat so what the hell is the difference at this point.
If you don't think the ICM is an issue, I won't mess with it. I am trying to research and search and get as much info together as possible and ask specifics instead of "Help, my car is sick".

Ron, if you continue to follow up, cool, if not, I really appreciate your help and sense of humor. Hopefully I can get it hammered out and post a positive end result that helps other people.

 

[RonJ]

Now that we got our sarcastic antics out of the way,

That was a fun diversion. Now I have both you and connie pissed at me. Oh well, the interwebs is a complicated place to navigate.

The distributor I'll leave well enough alone for now and work on the bolt when I have some time and I know the autoparts store can get me one next day.

Wouldn't hurt to swap in your girlfriend's known good distributor. Just buy her a new Honda O ring for the courtesy.

If you don't think the ICM is an issue, I won't mess with it.

You or an auto parts store could test it, but the distributor swap would cover everything distributor.

Post pictures of your broken distributor bolt.