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-   -   2001 Honda Accord, misfiring on all cylinders, losing my mind. (https://honda-tech.com/forums/honda-accord-1990-2002-2/2001-honda-accord-misfiring-all-cylinders-losing-my-mind-3335004/)

bhangmeter 03-16-2019 09:44 AM

2001 Honda Accord, misfiring on all cylinders, losing my mind.
 
2001 Honda Accord LX, 4-cylinder (F23A1), 145,000 miles.

Fault codes are P0300, P0301, P0302, P0303, P0304, and P1399. Components replaced in the past 18 months (for unrelated reasons): distributor cap, plugs, plug wires, catalytic converter, PCV valve, idle air control valve.

At idle, the misfire is nasty -- bad enough that it can heard, felt, and seen (in observing the car vibrating). Acceleration from idle is poor, but once above ~2000rpm, the misfire appears to clear up and the engine runs just the way you would expect it to.

The misfire begins immediately upon starting the engine and the problem is just as bad with the engine at operating temperature as it is when starting cold. Load conditions also do not have an effect on the misfire: in gear or in neutral, compressor on or off, etc, it stays the same.

Cylinder compression values are good and even across all cylinders. Fuel pressure test came up good. Searched for vacuum leaks (using propane) and found nothing. Can't find any evidence of arcing anywhere from the distributor cap down to the plugs or inside the distributor, itself.

I'm not a mechanic. I have some ideas, but I don't want to start blindly slinging parts. Thoughts? Is it possible that the EGR valve is stuck open? Crank position sensor? Should I set the car on fire?

Any advice appreciated. Thanks in advance.


MAD_MIKE 03-16-2019 08:41 PM

Re: 2001 Honda Accord, misfiring on all cylinders, losing my mind.
 

Originally Posted by bhangmeter (Post 51889283)
2001 Honda Accord LX, 4-cylinder (F23A1), 145,000 miles.
Is it possible that the EGR valve is stuck open?


I would suggest verifying that the valves are adjusted properly as well. If they have not been done at 90K miles they are more than due. I prefer to check them every 30Kmiles.

Possibly the EGR valve is cracked open just a tad, pull it off and make sure no carbon is keeping the valve open. Exercise the valve open and closed a few times to make sure it opens/closes smoothly.
Some folks have luck soaking the bottom half of the valve itself in WD-40, but you don't want any cleaner to get up into the electrical solenoid as this may remove the varnish on the windings and cause a dead short.
Disconnecting the electrical connector should put the engine into a limp mode. If there is a mechanical problem, and not sensor, the engine will continue to miss.
If it still runs rough then the mechanical side of the EGR valve is probably not sealing correctly anymore. Either from too much carbon/soot blocking the seat or a weak/broken return spring.
The later powered solenoid EGR valves are a bit more complicated than earlier vacuum diaphragm units.
https://www.insightcentral.net/forum...air-ideas.html
Crap shot idea.
Cut up some cardstock(cereal box cardboard) into the shape of the gasket without cutting holes for the EGR passages. Stack it a couple cards thick.
Install the valve onto the car with the new gasket and reconnect the electrical connectors. Start the car and see if the engine idles any better. If it doesn't then it is something else is probably faulty.
As for the cardboard 'gasket' I would not expect it to last too long as the exhaust gases may eventually burn through the feed side. You will also now have a misfire at part throttle cruise due to the lack of EGR flow at part throttle(1800+rpm)
So if the car runs great with the blocked off EGR valve at idle, but gradually gets worse after running for a while, pull the EGR valve back off. If the 'gasket' is burned through you have your answer.


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