Been noticing lately when starting the car from cold that I smell some kind of exhaust odor through the interior fan. Tried to smell around the exhaust manifold, but could not define it from there, more so from around the PGM part.

Tried removing the PCV unit, cleaning and reinstalling, but seem to smell still at start.

Not sure where to look and test after the PCV. Since it has not been an issue before I guess something is broken, cracked or clogged by something.

 

If you still have the OE Exhaust Gas Recirculation system, look for leaks from the exhaust flange back to the intake valve body.

 

Not entirely sure where the exhaust flange is located on my car, found some pictures from the repair manual if that helps.
Suspecting it is connected from the engine right before the exhaust manifold going through to bottom of 17.



t

 

Yes, 17 is the EGR. Remember a small crack can hide when cold but you can hear it faintly and of course you can smell it. Mine was cracked at the exhaust which makes sense since the metal is thin and the exhaust side is getting more heat cycles.

 

Not quite sure where this exhaust flange is located, and if visible from where it is or if something must be removed to view it.

But if it was cracked, how did you manage to repair it?

 

Mine was cracked on the weld on the flange.

I understood very thin metal to be difficult to weld, and this was about 12 years ago when I could buy another from Honda for my C27A4. If you find a cracked pipe, a welder may either hate you for asking or welcome the challenge of repairing / fabricating.

 

Sounds like a leak

 

Went out to the car today trying to find where the exhaust flange is but could not locate it. I found the EGR valve, and a hose going to the control box but not where the other two hoses or connections go. It's like a bird's nest with all the hoses and lines going everywhere. Do I need to remove something to access the exhaust flange? On the picture it seem to be connected before the exhaust manifold, but some videos seem to locate it closer to the catalyst below the engine...

 

I'm guessing 92 EX? I cannot find a good diagram of that EGR pipe. But it looks like the pipe runs to the intake below the vacuum supply to the EGR Valve. It looks like it would be easier to spot from under the engine in back below the intake manifold.

 

Yes 92 EX should be it.

Found some picture in the manual, so it seems it should be connected



before the exhaust manifold. Also browsed through parts diagrams but cant determine where the hose goes into the engine block though.

 

The EGR recycles hot exhaust gasses back into the intake, Honda's idea at the time was for any unburnt fuel to enrich the intake air instead of being wasted to the catalytic converter, and the warmer exhaust improved something with the fuel mixing. I can't remember, it was a thing for Honda since CVCC: my 87 CRX DX had a EGR-style flexible hose from the exhaust to the carburetor and my 86 Accord EX had an electrically heated mesh under the carburetor in addition to the EGR-style hose. Emissions and fuel efficiency.

Point being: Your looking for the other end of this hose on your exhaust or exhaust manifold. Not the engine block.

 

Seems there are three hoses connecting to the bottom of the EGR valve. One connected to the throttle body, another to the Fast Idle Thermo valve, then a thicker hose seem to go to the thermostat housing on the cooling system. Unless this is connected somehow to the exhaust manifold.

Could it be the thicker hose I should inspect? Or maybe I have found the wrong hose? Anyway, I might need to remove a lot of stuff to be able to remove the hose anyway.

 

Took another look, there might be a connection to the exhaust somehow, unless it is just part of the engine block. But on the backside of the EGR valve part there seem to be something. Other than that I am quite clueless until I get to check underneath the car.

 

That EGR diagram is misleading. 92 Accord doesn't run a pipe or hose like other Accords, yours is routed through the block "internally". Definitely more durable than a pipe that would experience heat cycling.


1992 Accord Exhaust side

 

If you are certain about this observation, then it is pointing to the EGR gasket or valve itself. If the Intake gasket was the point of failure (exhaust runs up through the block into the intake and then into the bottom of the EGR valve), I would suspect you would've notice symptoms of the engine running too lean.

If you've never cleaned the EGR this may be a good time to change the gasket and give it a clean.

 

Never touched the EGR during the 12 years of owning the car. Not sure if someone else have done it but could give it a go then.

Are there any other possible parts that might leak exhaust gases in the EGR system or other parts? Since there are hoses and gadgets in a mess I have no clue if there might be any other place for leakage. Removing the hoses itself just to check the metal connection might prove risky if I might damage them in the process...

 

The EGR system is the only path the exhaust would take back toward the intake and is close to the firewall. All other exhaust heads to the tail pipe. Use a smoke machine to test for exhaust leaks between the block and the tailpipe that are too small to be heard. I suggest you attach a vacuum tester to the EGR Valve during the smoke test to open the EGR Valve and see if the valve body diaphragm has failed or is leaking.

 

Doubt I will be able to hear any sound from a possible when the engine is running. I have heard a strange whining sound, but I think that is from the alternator belt being too loose (noise disappears after a few minutes).

Sounds like I might need to ask the local mechanic for help as I do not have a smoke tester available unfortunately. I will have the EGR valve cleaning in mind though.

 

So, cleaned the EGR valve and replaced the gasket (looked like it had sort of melted into the metal somehow... had to remove a lot with a screwdriver to make it clean enough.

Read something about covering the exhaust pipe with something (a rag or plastic bag), looking for possible fumes exiting somewhere.

Not sure if this could help or possibly break something if it is covered I mean, creating too much pressure in the exhaust system.

The exhaust manifold looked rather rusty (could not determine any smell from around there though), maybe it could be leaking somewhere near the catalyst, leading fumes up to the intake for the air vent...

That's the only possible places I can think of.

 

I wouldn't run it with the exhaust covered. I would check for leaks with a smoke machine, they seem to have gotten pretty cheap and avoids stalling the motor from back pressure.