Ok, I've posted a couple times before about what could be wrong now I have more info. Took today off work to try to get the car fixed but I'm getting nowhere. 1991 Accord 5sp 202k miles

Symptoms:
- Idles very rough, tries to stall at times but never does seems to be missing but I'm not sure of that
- Runs smoother the higher the RPM, seems to run just fine 2000RPM+
- Runs well when cold, I'm starting to believe just because of the fast idle though.
- This problem all started suddenly...not like it was kinda rough then got worse...I was at the bank came out to start it and it ran like crap, ran great when I went in

Already checked:
- The obvious, plugs, wires, etc...all of this is probably only a year old and appears to be fine
- Fuel filter is brand new, just replaced
- Fast Idle Thermo Valve...opened the cover and tightened the yellow plastic piece down, was loose by several full turns
- Disconnected EGR Valve vacuum line and it makes no difference

What else I'm thinking of:

- Injectors...deserthonda suggested this I'm still working out how to check them because I'm not hearing anything when I put a screwdriver on them...I've got the service manual instructions but am in the process...gotta figure out the best way to get the connectors loose

- Maybe EGR valve is stuck in whatever position? I've read about using a vacuum pump to check it but I'm not sure exactly how the system works so any help there would be great...I do have a vacuum pump

- Removed distributor cap--theres a slight oil leak around there which I've read about...I'm going to go clean it out and reassemble now theres very very little oil inside I think it might have just gotten there from me opening it and I'm pretty sure whatever leak is not on the inside of it...so I can fix that later once I get the car running well

- Intake Air Control Valve? I guess this is a possibility but when I disconnect it it won't idle but if I hold it at 800-1200rpm manually it still runs like crap


EDIT: I forgot to mention no CEL light is lit.


Please give any help or suggestions you can....I'll be working all day until I find a solution and hopefully I can find that solution today and not have to work on it this weekend

 

Definitely sounds like a symptom of clogged EGR ports and possibly a clogged IACV.

Disconnecting the IACV, it should idle.

 

Ok, a little update.

- I got the distributor back together, and all (I just opened it to check things out)....car still runs terrible
- Replaced speed sensor, unrelated issue I knew the speedo wasn't working just killing time
- Took a little test drive and it was running awful no power, etc...probably running worse than it was.

I disconnected the IACV (EACV is same thing right, thats what the Honda book calls it) and was going to let it die. It WILL idle with the EACV disconnected, albeit like 250rpm its barely running at this point but it did not die.

I am dreading it being clogged EGR ports, on this 1991 I have to drill and tap out some plugs, etc...I really don't want to have to tackle that. Is there any surefire way to test to make sure this is the problem? I would assume that when the system is not trying to put in exhaust gas it would run ok? Maybe there is some way to force the system to run a certain way for diagnostic purposes?

Thanks for your help.....lets hope I can get this worked out.

 

More info yet again:

from service bulletin 98-074 (which talks about how to clean the EGR ports)....the diagnosis section reads: (sorry I lost the link)

DIAGNOSIS

1. Disconnect the vacuum line from the EGR valve. Connect a vacuum pump/gauge.

2. With the engine idling, apply 10 inches of vacuum.
- If the engine does not stall continue to step 3.
- If the engine stalls, troubleshoot other causes.

3. Leave the EGR valve disconnected, and plug the vacuum line. Test-drive the car.
- If the hesistation or stumbling is gone, continue to REPAIR PROCEDURE.
- If the symptoms still exist, troubleshoot other causes.

The repair procedure then describes pulling the plugs out and cleaning the ports.

So, it did stall the first time I put 10in of vacuum to the EGR valve...I started it up and tried it again and it never would stall again...come close but not stall. So I am going to assume that the engine does not stall. Now for step 3, the EGR valve is still disconnected and I could tell just from revving the engine that is the symptoms still exist...

From this I am going to guess that the EGR ports are ok, does this seem right to you all?

EDIT: Just listened to the injectors, all are making a steady ticking noise. Sometimes at a slower rate but I'm pretty sure that's because the idle speed isn't stable. But they all do sound the same.

 

Have you checked the compression on each cylinder? Check it with the fuel pump fuse pulled, and the distributor unplugged. Make sure that you have the gas pedal to the floor when trying to start.

Check the fuel pressure. I wrote up how to make a fuel pressure gauge. https://www.hondaaccordforum.com/for...ad.php?t=17408

Remove the EVAC and clean out the inside using throttle body cleaner. Carbon tends to build up in there and can block air flow.

 

LET THIS BE A TESTAMENT TO NOT BUYING CRAPPY PARTS!

I got it running wonderfully now...I just went on a hunch and bought a new set of plug wires and spark plugs. The old wires were the crappy autozone brand ones, less than a year old. I know I should have not bought them but I was really broke at the time. My old plugs were NGKs, I won't even think about anything else.

Bought some new Bosch wires and NGK plugs, swapped them out and the car runs smoother than it has in a long time.

So, the next time you are looking at buying some off-brand aftermarket parts be it known...they suck. I usually buy all Honda parts or quality stuff (like my rotors are Brembo ones, they wanted a ridiculous price for the Honda ones)...so learn from my bad experience.

 

Well, Brembo makes nice rotors. I've been using them for years.

Honda certainly doesn't actually manufacture everything, so whatever you get from the dealer, you should theoretically be able to get elsewhere. IF only you knew who actually makes the stuff.

 

I'm going to remember now that AutoZone spark plug wires suck =) I'm just glad to have my car back...