What else could it be?

[evol90accord]

Okay, I've spent the past two weekends trying to figure out why my engine is hestitating/stumbling on acceleration. I've read as much as I could about this on these forums and tried everything I've seen mentioned including cleaning the EGR ports, the EGR valve, spark plugs/wires, distributer rotor and cap, new ground wires all around, and I even did the spark plug seals (#2 spark plug was drowning in oil). After I did all this I got a valve adjustment at the dealership and its still doing it!

It hesitates/stumbles at around 1500-2000 rpm, and on occasion backfires. After 2000 RPM it runs just fine. I've noticed its a lot worse when the A/C is on, and it only happens when the engine is hot. Can anyone else think of something that maybe I'm missing?

[starchland]

not sure if youve read my thread, but i posted hesitation during acceleration too which i still havent figured out. im thinking maybe an electrical or 02 sensor problem, maybe pgm fi for yours?

[evol90accord]

i read your post, but your problem seems a little more severe. The 9k rpm thing doesnt happen to me. I also have an Automatic tranny... the stumbling/hesitation only happens when I first accelerate from a dead stop. The only other thing I could thing of was ignition timing, but I thought that timing would affect the car throughout the rpm range, not just at acceleration. I'm having it checked regardless. I've also made sure all my vacuum hoses are okay, and they seem to be... no leaks that I could find. This is really stumping me, and whats worse is that the problem seems to be getting worse very quickly. This only started happening occasionally about 2 months ago and its gotten unbearable in the past 3 weeks.

[91hybridaccord]

Your engine could be flooding itself with fuel. The injectors may be pouring too much fuel into the throttle body. Which could cause the car to run very rich. If this were happening, you would see black smoke from the pipe. It may still stumble if the car is running lean too. If it is running lean, it is not geting enough fuel.

- Some things to consider: your O2 sensor is out or you have a clogged fuel filter. I would defintely check these two items first.

With both cases The O2 sensor tells the ECU to make the engine run more rich or more lean as you drive into different altitudes, it also tells the ECU how much air the engine needs to run smoothly. These could be a couple problems that you may have. Also, if the Fuel filter is clogged, you may not be getting the proper amount of fuel to the engine. In addition, a clogged filter will cause the fuel pump to overwork itself and the pump will wear out faster, I just figuered I would say this also.

[evol90accord]

When I pulled my spark plugs they looked normal. A buddy of mine said they looked like they were running lean because there was a light white coating over them, but my spark plugs have always looked like that.

I checked my log, I replaced the fuel filter over 60K ago... i guess its time for a new one! I dont know how long these things are supposed to last, but they're pretty cheap so I'll give it a try. I'll also try a new O2 sensor since its never been replaced. I just thought that if your O2 sensor was bad you'd throw a CEL. Also, other people have this problem and have replaced it and it didnt do anything.... I'll give it a whirl... i'm running out of options here anyway.

[91hybridaccord]

Sometimes the check engine light doesn't see that the O2 Sensor is malfunctioning. With my car, the CEL was on for a while then it turned off and never came back on. When I went through emissions, I didn't pass. So I changed out the O2 Sensor and I passed with flying colors. BTW my car ran a lot better with the new O2 Sensor!!!

[starchland]

Is there any way to check an oxygen sensor for its resistance like you would an ignition coil using a volt meter?

[evol90accord]

This might sound really stupid, but how in the hell do you use a timing light? As far as I know, you connect the positive and negative clamps to the respective posts on the battery, then clamp the plastic thing on the number one spark plug wire. Pull the trigger and the damn thing should flash, no?

Mine doesnt do that!! I've already returned one thinking it was a defective light, and now I'm beginning to get extremely frustrated with my stupidity! What am I doing wrong? Is there some kind of magic place on accords to attach the light to? HELP!

Just so you know its an Actron D.C. powered inductive timing light from autozone.

[homegrown_xt]

sounds like you have it hooked up properly, did you try to put the pick up on another wire to see if the light flashes? You may have a faulty #1 plug wire.

I just did the timing on my accord and it worked fine. I just replaced the distributlor o-ring and had to reset my timing. I have a Mac Tools advance timing light and it is about 18 years old and still works like a charm.

[evol90accord]

Yeah, I attached it to all my wires to make sure I was getting spark everywhere. So according to this light, my engine isnt firing at all when its running. Must be running on majik voodoo shit or somethin... I'm taking this one back too and getting a completely different timing light. I think maybe this one is used for a different application, because the inductive pickup looks different than most other timing lights. Its more of a metal clamp inside a plastic sleeve, like it should be attached to bare wire or something. If thats the case, then Actron needs to put a different label on these timing lights and put different instructions with them!

[evol90accord]

Its an F22a with a short ram intake.

[evol90accord]

I am a GOD!

Okay not really but I did figure out what was causing the lag so much. After returning the crappy timing light to autozone and picking up the not so crappy timing light from... uh.... autozone... I found my problem: my ignition timing was way off (if your buying a timing light from autozone make sure its the RED gun not the black one). I adjusted the distributer as far as it would go, and now have another question:

when looking through the hole in the bell housing, what angle should you be looking at the timing marks? I mean if your 7 feet tall you're looking at a totally different angle than if you were 5 feet tall. Right now I'm aligning the marks so that when looking through the hole in the housing the alignment mark on the housing aligns with the bottom of the hole. However, you could have the alignment marks on the bell housing sitting squarely in the middle of the hole and align marks that way.

Pictures speak a million words here, and I wish I had a digital camera... anyone understand what the hell I'm saying?

[homegrown_xt]

Looking down the hole in the bellhousing there is a pointer with a v notch in it, I set the red mark in the middle of the notch. and if you look at the timing specs on the hood it says 15 degrees plus or minus 2 degrees. I guess that is compensating for the angle that you are looking at the mark.
I have a advance timing light so that I can tell exactly where my timing is at. Alot of those inexspensive lights do not have that feature. I hope this helps.

Ken

[evol90accord]

thats what i'm saying, the "v-notch" timing mark on the bell housing kinda "shifts" around depending on what angle you look at it. That angle seems to me a lot more than 2 degrees. Also, what do you do if you've turned the distrubutor as far as it would go, and its still not lined up perfectly (regardless of how i look at it)?

[homegrown_xt]

That is what is nice about the timing gun that I have, I dial in 15 degrees on the back of the gun and line up the white mark in the center of the V. If you are turning the dist. and the marks still dont line up your timing belt may have jumped a tooth. If that is the case that need to be taken care of or you will run into bigger problems.

Ken