Just bought a 1993 Accord LX with Auto Transmission, has 161,000 miles. I noticed it had a misfire/stumble at idle but bought it thinking a simple tune up would help. My check engine light is NOT on..

This weekend, I changed the Plugs, Wires, Cap and Rotor. Didn’t help at all.

I has a pretty bad miss/stumble at idle and one around 2500 rpm’s, then it clears up in the higher rpm’s. It seems the miss is worse while in reverse. Might be my imagination but thought it would be worth mentioning.

Anything big that I’m missing?

 

FYI, it idles around 800 rpm's.

 

Off the top of my head without seeing or hearing it, I would guess that your EGR ports are clogged up. That stumble is symtomatic with those ports which are located under the fuel rail, being clogged or blocked with carbon looking gunk. There is an Eric the car guy video on how to do that job which might be found in the FAQ section?

 

EGR or IAC Valve problems would be a good start.

 

I was screwing around this morning and I unplugged the Hose going to the EGR Valve, no change in idle. I also unplugged the electrical connector going to the EGR Valve. Still no change.

What else should I check with that EGR Valve?

 

I've had IAC problems on other cars before, wouldn't that just cause surging and idle dropping when accesories are on?

 

EGR ports.

http://home.comcast.net/~em-engineering/T2T013.pdf

 

So, how would a EGR cause the engine to run like ***?

 

I'm not saying it may be the actual reason your car is running like the way it is; but, posters were referring to the EGR ports as a possible cause instead of the EGR valve.

Quote from link:

"Some, or all of the 4 EGR runners in the intake manifold clog up. The rough running apparently comes from some ports clogging and all the exhaust gas being fed to the working ports and causing them to have too much exhaust and consequentially cause them to misfire."

http://home.comcast.net/~em-engineering/T2T013.pdf

 

is the check engine light on? if it is you can jump it from a 2wire plug thats behind the kick panel in the passenger side. a blue plug with two wires. jump it and turn on the key to II and watch the check engine light flash. shoud give you a code. check youtube on how to do it. when you get the code post it here. so we can help you. remember a code doesnt tell you whats wrong with it. it just help find where the problem is futher diagnosis will help find the problem

 

The Check Engine Light is NOT on.

 

Still worth a shot it might have came on one time and you never noticed. It,would be stored in the ecu. So jump it and see what it gives you. Never know.

 

One more important thing, when I pull the drivers side plug wire. There is no change in idle.

 

That helps isolate it to one cylinder however it could just be that that egr port is clogged up.

 

Bingo!

 

So, what is the easiest way to check my EGR Ports?

Thanks ya'll.

 

Check under the FAQ section of this forum. I believe there is a step by step how to do this job. In short, it requires removing the fuel rail. The ports are located under it. I found it. Here ya go.

http://home.comcast.net/~em-engineering/T2T013.pdf

 

I wouldn't think that the EGR ports being clogged is causing a misfire at idle, not to say they aren't clogged. The basic reason cylinders misfire when the EGR ports are clogged during EGR operation is the fact that instead of the gases being distributed evenly to all cylinders, the gases are then dumped into 1 or 2 of the cylinders causing a Lean Misfire. There are a few ways to check for port clogging. One, you can use a vaccuum gauge and pull a vaccuum on the EGR valve to open it and allow full flow to the intake through the valve. If the engine doesn't stall or run really rough then the ports are fine. Another way, is put the car in gear with your foot on the brake and raise the RPM's to about 1500. This should cause the EGR valve to open. If the engine sputters while you have the RPM's raised then the ports are clogged and need to be cleared. If I were you, I would focus on the #1 cylinder which would be the plug wire closest to the timing belt/driver's side.

 

Good post and makes good sense. He did state that he changed the plugs and wires, cap and rotor, so possibly that plug wire is defective or (like some new wires sets) he needs to make sure that the wire is pushed all the way into the long connector and getting spark on that plug.

 

The wire is good, I swapped them with no change.

 

Have you pull the spark plug out to make sure the tip isn't bent or distorted in any way? It sounds simple, but I've seen it many times. If it's only #1 cylinder causing problems you need to figure out what's missing in #1. Is it spark (probably not being that you replaced the ignition parts), Fuel, or compression? Have you run a compression test on the cylinders? Try taking a long screwdriver and putting the tip of it to the base of the injector where it mates to the intake. Once you've done that, listen to all the rest and see if you notice a change in sound of the injector pintle opening and closing.

 

The plug is good, so was the old one. It's getting spark. I haven't checked for compression or injectors although when I pulled the plug out, it was noticably drier than the rest. I'll try the injector trick.

Will the clocked egr port cause a change in compression?

 

No becuz your at idle the egr doesnt open until 30mph I believe. So no it doesnt. Im leaning more towards the injector. If it was the rings that were gone on that cylinder your spark plug would be soaked in oil. So just check out the injector. Try hitting it with a screw driver gently to see if you can get it to budge. If it doesnt I would recommend changing your fuel pump strainer clean out your gas tank new fuel filter new injectors and clean out your fuel lines

 

If there is low compression it doesn't necessarily mean that the rings are worn. He could have carbon build up on the intake valve(s), I've seen that many times. He could also have intake/exhaust valves not sealing either because they're burnt or bent. I would definitely try a basic compression check.

 

exactly if seals are worn on valve or damaged seals at the valves it would throw blue smoke out the pipe due to it burning oil. And if valves were burn or bent it would misfire alot bit in his case it doesnt make ANY diff when he disconnects that plug