Samuel A. Falvo II

I'm trying to get my '86 GXL to pass smog in California. Everything on the car is bone stock, and has been tuned and retuned at least 4 times. Exhaust and intake seals have all been replaced, new plugs, yadda yadda...

When taking it to the smog shop, the car passes beautifully everything, EXCEPT the 15MPH and 25MPH HC tests, where it fails by only --><-- that much. For example, at the 15MPH test, the numbers were MAX: 141 MEAS: 215, and for 25MPH, it was MAX: 116 MEAS: 169.

I am positive that I'm not the only one who's suffered from this problem. The car has never failed a smog check before. What can cause this?

Thanks.

(PS: my '80 RX-7 died; blown apex seal while driving on the freeway. 227,056 miles!)

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Samuel A. Falvo II
86 GXL

J-Rat

iTrader: (2)

Well, there are a couple of things you can do. You can cheat the ACV into dumping air into the CAT at all times (Really easy), or you can try running some alcohol (easy but kinda dangerous).

Lets see if I remember this correctly...In order to get the car to dump air at all times to the cat, you disconnect the upper forward VAC line on the ACV, and plug it. That should do it.

damn...Where is HAILERS when you need him....

hugues

Too much HC is probably cat related. You may want to tune your car since it may be running rich.

J-rat is right.

To dump air into the split air (cat) instead of port air (exhaust port),
you've got to prevent vacuum from going to the switching valve (goes from intake to switching solenoid to ACV)

see my web page in sig under emissions->secondary air

Your cat may also be starting to fail.

hugues -

billzrx7

HC is unburnt fuel.. try the acv trick or put in new plugs.

HAILERS

J-Rat......you can pull and plug the fwd line, and that does disable the switching diaphram from keeping air from going to the split air pipe.....but to really add a large amount of air to the split air pipe, disable the split air solenoid (rear solenoid on the acv) by pulling it out and removing the poppet valve, then reinstalling it). I put the split air pipe into a bucket of water and the difference is dramatic on the flow of air without the poppet in place.

Of course you don't want to cheat, so you should put new plugs in, timing on the mark, idle at 750, new air filter, new oil and filter. Make sure the acv is not dumping overboard at any speed below 3800 (some exceptions but lets not go into that). At idle pull the large hose off the bottom of the acv. Little to no air should be dumping. Now reach over there on the left side of the engine and pull the Blue plug off the Relief solenoid. Air should dump big time now. Put the plug back on. The air should stop flowing. If this does not work as I just wrote, then write back and we'll fix it.

The idea is that you want to make sure the air pump air is going into the exaust ports(and the split air pipe under acceleration) and not dumping overboard.

Catalytic converters do wear out though.

A note here. The above only works on a fully warmed up engine. When cold, the relief valve will dump overboard. Thats normal. Also on a 86-88 there is a water temp switch at the bottom of the radiator that has to be functional or the air will dump when it normally won't.

Samuel A. Falvo II

Already done.

I haven't a clue as to what you're talking about here. I called Mazdatrix, because nobody in my local area (Oceanside) has a clue as to what's going on, and gave them my %02 numbers, and they seem to concur that the ACV needs replacing. They're down in the 0.4% and 0.2% range. CO2 numbers are pretty solid at approximately 14.6%.

Although I'm technically minded and mechanically adept, I'm NOT when it comes to cars. Something inside me says, "If you touch it, it will break." I lack some of the tools, the real-estate, the experience, and therefore, the know-how (though I wish to remedy this situation quickly, so as to not have to pay big bucks to repair shops who don't care any more for my car than anyone else's). I don't want to do anything to this car that could even remotely make the situation worse. I've considered just purchasing the ACV+gaskets myself, and installing it myself, but I'm hesitant, almost afraid even, to touch what's already there.

It's funny: when it's not your car, you're more than willing to help someone fix their car. But when it's your car, the tables turn pretty quickly. I'm not a mechanic by trade or training, so I hope you understand my hesitation with respect to this project.

I'll try to locate the ACV and the hoses you suggest today, and see what comes of it. I'll let you know if I find them, and what happens.

What do you mean by overboard? Would this just be venting the air to the outside?

It's a new cat.

Now this is nice to know. I hadn't known this before. I'll record this for later reference.

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Samuel A. Falvo II

HAILERS

Venting overboard, as in to atmosphere. As in not going into the exaust port or the split air pipe to the catalytic converter, but dumping into a silencer in the right hand bumper area then to atmosphere.

Samuel A. Falvo II

Well, I checked under the hood, and the only piece of equipment I saw that had "ACV" on it was a part on the right-hand side of the engine, which had two hoses (one on the left and one on the right) -- there were no hoses "beneath" the unit. It also had an electrical connection coming from underneath.

On the left-hand side of the engine, I did not locate any blue plugs.

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Samuel A. Falvo II

HAILERS

Your car has an air pump. The hose coming out of the airpump goes to the ACV. The ACV has another hose of approx the same size as the one going into it on the bottom, outboard side. That hose leaves the ACV and travels forward and disappears into the right hand part of the bumper.

The ACV itself has two solenoids screwed into it. One on the forward side and one on the aft outboard side.

On the left side of the engine(drivers)there should be four solenoids with colored electrical plugs. One, blue, one grey, one yellow, one orange. You have none of these????????

Go here: http://home.earthlink.net/~burntoast...xports_acv.jpg and there is a picture of the acv. Its the one circled in the middle in yellow. The yellow covers up a lot of it but that's where it is on the right side of the engine.

Edit: I could not find a picture of the solenoids. This is the best I can come up with right now
http://home.earthlink.net/~burntoast...um_diagram.jpg

HAILERS

OH! I read your post all the way thru. Ouch. I don't think the ACV is bad myself. The N/A cars acv seems to last for quite some time. The turbo one has a tendency for the diaphrams internal to it to harden and not work at all.

There are two small hose just above that make the ACV work like it should. Those two vacuum hose are operated by the ECU throught the grey and blue solenoids on the left side of the engine. If the solenoids are not there as you imply, then the acv won't work at all. It will dump the airpump air into the atmosphere instead of into the engines exaust ports like it should.

It's not hard to see it the acv is good. Get a piece of vacuum hose and attach it to one of the nipples just above the acv. Now suck on it. If the hose will hold the suction, the diaphram is good inside the acv. Now do the same to the other small vacuum nipple above the acv. Same results. If one or either does not hold the suction you put on it, then the acv is bad.

I used to post pictures....but this site won't accecpt jpgs anymore.

Samuel A. Falvo II

OK, I found the ACV, and I found the blue plug. I was assuming left when viewed from the front of the car, not the cockpit. That was my mistake.

However, I'm lacking in the equipment I need to follow your instructions. I'll just take it to a smog shop, with a print-out of your recommendations and of Mazdatrix, and will just pay the folks there to work on it. :/

I have a 60-day permit on the car, so I'm pretty confident that I can get this car smog-legal in that time frame. Even if it means breaking the law, taking it to Mazdatrix, and having THEM work on the car. **** Gov. Davis.

Thanks very much for your help. I really appreciate it.

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Samuel A. Falvo II