Hey guys,
I've searched a number of forums and can't find anything on why my 2001 EX, 4-door, 5-spd Accord pulsates during acceleration. I thought it may be dirty injectors, so I ran 4 tanks with injector cleaner. It helped a little bit but didn't get rid of it. I've ran Sea Foam through the TB with no luck.

Any suggestions on what to try next? The car has 126K on the ODO.

Almost Jake

 

Could possibly be a blocked EGR Valve??
I have the same problem with my Euro R but only on light throttle, I found that unplugging the 02 sensor made it go away...... but the CEL stayed lit and it used lots of gas.

 

There's no indication of this at idle?
You could have a cylinder which isn't contributing as much as it could. This could be from a deficiency in compression, mixture or spark.

As a start, I'd suggest pulling the spark plugs to inspect the plug's electrodes. Do this with the engine fully warmed up and driven for a few miles. Turn it directly off (no idling) when you get to your parking area.

You should find a uniform color between all four plugs. It should resemble an extra extra light Iced Coffee from Dunkin Donuts.
If one is chalk white, that cylinder is running lean(er) than the others. (perhaps a leaking vacuum hose?)
If it is dark brown it could be rich, too cold a spark plug, a leaking injector or a low(er) compression condition.

P

 

First off, how have you kept up with the tune-up on this car?

Check the timing, it sounds like a spark and/or timing problem.

 

is it only when moving (ie if you put th car in neutral and rev up does it do the same thing)......if not it could very well be a wheel bearing on the way out or some suspension part(longshot but doesnt hurt to check)

 

sounds like timing...vtec sensor could need to be adjusted or replaced

 

4 cylinder right?
under the fuel rail, unbolt that plate and clean out the ports.

 

A pulse, or misfire would trip the MIL. Sounds like you might have a bad axle. More precise, inner joint going bad.

 

Yes it is a 4-banger.

It's been doing this for a number of years and probably 50K miles. I've learned to live with it, but it's starting to bug me. It only happens during light throttle. Over time, I realized I was subconsciously driving the car harder to avoid the pulsing.

As for maintenance, I doubt I'm as diligent as you guys. I change the plugs every 60 - 70K, but regap them every 15K. Air filter is a K&N drop-in, and the oil is regularly changed at 4K miles (dino oil). I bought the vehicle new and have never adjusted the valves.

The engine sounds great when driven hard or revved.

I'm working out of state and am not able to look at the condition of the spark plugs or able to try some of the simpler fixes mentioned. But thanks for all of your advice.

Almost Jake

 

Have you changed or altered the Throttle body? Perhaps the Throttle position sensor needs re-adjusted. You're giving it one thing, and it's thinking another.

 

it is the EGR

 

I haven't modified the car, and have done little maintenance on the vehicle other than fixing something that broke, like changing brake pads. Sad, I know. I just don't know that much about working on cars. My most adventurous maintenance task was adjusting a timing chain on an 1981 Mazda 626 (just don't ask how that turned out). As for my abilities, replacing the EGR valve should not be a problem, but adjusting the valves would be more than I'd want to do. With 125K miles, I'd probably just replace the EGR than clean it.

 

I forgot to mention that I have a slightly rough idle. I've had it since the car was 6 months old. Honda looked at it and couldn't find anything wrong. I've been living with it so long I forgot to mention it as a potential symptom.

The idle doesn't stumble, instead it feels like one cylinder is slightly "off". But again, Honda could feel it when sitting in the drivers seat, but could not find anything wrong while troubleshooting. I remember that they checked the motor mounts, harmonic balancer, and possibly the valves, but found nothing.

Almost Jake

 

if its doin it in idle to its probably the ivac valve. Its located on the back of the intake manifold try cleaning it really good and adjusting the orings on it Make sure nothing is clogged in the two hoses at the top either

Another possibility is a vac leak in the throttle body but i doubt its that

Try cleaning or just replacing the censor

 

am i not here?
you still haven't said if it is a 4 or 6.
and you can replace the EGR everyday for the rest of your life and it isn't going to fix this.


that is a 2k1, those iac's are not cleanable and would be doing something completely different.