!!!Exhaust is burning my eyes

[bryand2]

Hey everyone, my 77, which is bone stock, burns my eyes on deceleration while in gear. The exhaust fumes are so bad that they burn my eyes, but this is only with the drivers side window down and only while decelerating in gear. Anyone have thoughts as to what may be causing this?

[bryand2]

Sorry guys, it is stock except for a Borla muffler

[siteunseen]

It could be coming from your gear shifter boot. Under the leather one there's a rubber one that can get loose and open up a big hole. I don't remember but you might have to remove the console, but it's easy, few screws in the armrest compartment and some more up front in the foot wells. I just remembered, after a swig of coffee, you will have to remove it. The leather boot is held down with some metal clips under the console. Good luck finding that leak, it could be dangerous as was pointed out to me by a fellow member who said a late night drive with the fumes could turn into more than a stinking problem.

More coffee; you could use a flashlight to shine up or down around the boot then climb under your car and look for the light shining through. Just a thought.

Edited May 7, 2013 by siteunseen

[hr369]

Hey everyone, my 77, which is bone stock, burns my eyes on deceleration while in gear. The exhaust fumes are so bad that they burn my eyes, but this is only with the drivers side window down and only while decelerating in gear. Anyone have thoughts as to what may be causing this?

Easiest is to keep the windows rolled up and the fresh air vents on each side open.

extend the tip of the muffler past the back of the bumper.

replace the back hatch inner weatherstrip.

replace the tail lite to body gaskets.

check/replace the rubber body plugs near the muffler on the underside of the cars quarter panel.

take the hatch upholstery panel off and tape/silicone a plastic over the opening. then replace the

panel. lots of gasses come in thru the hatch lock.

install a rear spoiler some people say it helps a little.

[Captain Obvious]

Occurs when you have high manifold vacuum. That's why it only happens when decelerating in gear.

Higher the RPM the worse it is, right?

How's your compression? Do you use oil?

Is your BCDD working properly?

[madkaw]

EGR working? I'm with Mr. Obvious, somethings not working with your EVAP or emissions controls.

[bryand2]

that was my thought, maybe egr malfunctioning, I did discover today that the little vacuum delay valve is not working properly, its supposed to be easier to blow in one side than the other and was equally easy on both sides, im not sure i that would make the egr stay open all the time or closed all the time? As to the other comment about having high manifold vacuum, I was running a bit rich and I dont rem where I read that improper mixture affects the manifold vacuum, is it rich=higher vacuum or rich=lower vacuum?

[bryand2]

Occurs when you have high manifold vacuum. That's why it only happens when decelerating in gear.

Higher the RPM the worse it is, right?

How's your compression? Do you use oil?

Is your BCDD working properly?

Yes its worse the higher the rpm is, my compression is good, do I use oil? and i know the bcdd is working, but I am not sure if it is adjusted properly, the douche at the smog station messed with it about a year ago and despite reading the FSM, I am not sure how to adjust properly

[Captain Obvious]

Well it sounds like you run very, very rich when you coast at high RPM. So rich, in fact, that you're beyond a mixture that will ignite and you're pushing clouds of atomized gasoline mixed with motor oil out the tailpipe. So you should look for things that would add fuel or oil to the party.

Worn rings, valve seals, and maybe a specific kind of head gasket failure could all offer oil.

Non-functioning or improperly adjusted BCDD or AFM could encourage extra fuel. So could a faulty FPR, leaky cold start valve, or injectors.

But of all the items listed above, the BCDD is the one that is supposed to help with exactly that kind of "extra rich mixture at high manifold vacuum" emissions, so that's where I would start.

You familiar with the carbs used on the earlier Z's? If so, think of the BCDD as the fuel injection equivalent of the older throttle opener servo that pulled the throttle open when you coasted. The BCDD essentially does the same thing.

[Z_lis]

I am having this problem... what is BCDD?

[EuroDat]

I would be more concerned about the fumes getting into the car, not what is causing it. You dont want carbon monoxide poisioning.

When you have the window down it changes the air flow through the car and actually can cause negative pressure. This will draw air in from all places that are not sealing.

I would check the hatch seal and sealing around the taillights etc. Then move onto the rich running problem.

[siteunseen]

Z_lis, 240s won't have BoostControledDecelerationDevice, BCDD, unless you have EFI for fuel delivery. Google it.