restoring83

OK, so I can't pass emissions in NJ even with the Guaranteed to Pass Emissions, which actually made it worse!

My mechanic thinks that my carb is shot, and it is running too lean, burning too much fuel, thus too much HC and CO. There is no adjustment left in my carb, and he thinks I might have a crack in it somewhere. Does this sound reasonable? I unfortunately don't know all that much about carbs. If I buy one from England that was from a 1984 12A engine, will it fit my 1983 12A American version, and does it have all the neccessary connections to pass 49 state emissions? PLEASE HELP!!!

BTW, I CAN smell gasoline every time the car is run, like it is escaping from somewhere. Would a cracked carb do this?

82streetracer

iTrader: (1)

What is a "gauranteed to Pass Emissions"

And if your maechanic is telling you that it is running lean and burning to much fuel and letting off too much HC then your going to one dumbass mechanic.

restoring83

Guaranteed to pass emissions is a bottle of "Add to gas" crap that you are supposed to run through your engine, then fill your engine again with fuel and go for inspection. I can't recall if he said it was running lean or rich, but he said he thinks there might be that crack in the carb which would somehow cause me to fail emissions. What do you think?

Sterling

I don't know about that! Was this a mechanic, or some tech-kid running the sniffer? I ask because the first thing a mechanic would do is say you have a vacuum leak, meaning that the gaskets have deteriorated and you carb is getting air from where it should'nt be. Or one of your hoses has a crack in it. But I've never even heard of anyone suggesting that a carb would have a crack in it.
I mean, whadya do - Hit it with that hammer once too often?!

You probably just need to join the ever growing member list of the "17-23 year old Nikki carburetor rebuilders club"!

peejay

Carbs CAN crack, but usually the gaskets shrink and allow fuel to go where it doesn't belong.

One nice thing about the Nikki - no gaskets below fuel level. Don't have to worry about gasket shrinkage like on, say, a Holley Or the Autolite/Motorcraft 4300, I had plenty of "good times" with those carbs...

It IS possible for fuel to leak into where it shouldn't... but promarily I'd first be checking for vacuum leaks. Also, dumb question, how old is the converter?

restoring83

I think the converter is probably original. The car sat for three years in Virginia before I picked it up. I already had the hoses looked at, and they seem fine according to the mazda dealer that I paid 160 to tell me that, although he reconnected a few. After he did that, my emissions got worse, not better. I can't afford to sink a ton of money into this problem, I already overpaid for the car, being that it has 151,000 miles on it and its an '83 GS that I paid $800 for. So far I have about $2200 into it including the cost of the car, and I know cats aren't cheap. What's my best bet next? I ordered a carb from an 84 12A from England, but will that pass NJ emissions?

inittab

A carb is a carb when it comes to Nikki's. When you get it just swap on your emission control "junk". Has your new carb reciently graduated from the "rebuilders club"? If not, I'd suggest doing it or having it done before installing it in your car. Good luck!

Spieder

The 1984 and 1985 carbs are different from the 83's and earlier. As far as I know (and I just went through this) the intake manifold bolt pattern is not the same as 83 and earlier. If you buy an 84 carb it will not fit on your 83. You will have to change the intake.

The 84's and 85's also use a gasket/vaccumm manifold that are mated. You will need to ge that too. When I rebuilt my 85's carb, the kit came with the gaskets for the earlier models. They would not fit over my bolt pattern. So I am extremely confident in saying 84's and 85's won't fit.

As for your smog, here's what you need to check first:

1) Cat's

2) ACV (if it's malfunctioning, it won't feed air into the cats and it will choke off your carb running rich)


My experience with mechanics is that they are stupid when it comes to anything carbureted. They always blame the carb first. I found, that my 85's problem was the ACV. Here's how the mechanic checks.

Disconnect the hose running from the air pump to the ACV. Disconnect the air hose running from the exhuast to the back of the ACV (held on by a flang with 2 bolts).

Disconnect the fresh air feed to your cat. Now run a hose from your air pump to your fresh air feed. Leave the one with the flang diconnected.

You car will probably pass now. After 5 years of being a gross poluter and having a dozen different mechanics do everything, that was my problem.

I even had new cats put on and they made no difference until I bypassed the ACV.

What it does is regulate some air into the intake and the air into the cat. If the cat doesn't get air, then it can't finish the burn cycle. This will put you HC's through the roof and give you really low nitrogen.

I went from gross polluter to better than my friends 95 Honda.

restoring83

Spieder,

You rock! I will try that tomorrow. I am getting tired of different answers from every mechanic I go to, and I almost dropped $350 on a new carb for an 84 that would not have fit. How mad would I have been!!! I'll try the ACV bypass, hopefully that will take care of it. We'll see.

restoring83

Would replacing my ACV with a "new to me" used one from Atlanta RX7 for $75 plus shipping fix my problems? And how do I know if my cats need to be replaced or not?

Spieder

Well, new, they are over 300 dollars so if you need one, then 75 bucks sounds good. What you need to do is get a haynes manual and run down their checklist for the ACV. They tell you how to take the side off (exposing a vacuum diaphram) and check to see if it's pumping. When I took mine off, it was rusted solid.

I don't recommend buying anything you don't need. The trouble is figuring out if you need it.

You can usually tell if the cats are bad by doing an exhaust prep. This is what they used to do before CA went all computerized. But you cannot do it at home. They just hook the sensor to the back of the exhaust and then plug the exhaust repeatedly with a towel. This heats the cats up a lot more than normal. If the emissions gets alot better then you probably need new cats. Also if the cats have holes or there is stuff rattling inside they need to be replaced.

I don't know what state you live in, but you might think about getting a V8 cat. They are cheaper and do a better job than the RX-7's. MY firend had a 1983 and he had his two cut out and one put in. It made a huge difference on his emissions. However, I couldn't find anyone to do it because they said it's not CA legal to modify my cat's and they wouldn't touch it. So, if you are thinking about replacing your cat's ask some local shops for advice or check this site.

restoring83

I went through the checklist in the Haynes manual, and everything seemed to check out, however, not a lot of air was flowing through the split air hose port after I disconnected the switching solenoid valve vacuum line, but there was some flow. Should there be a lot? Also, there was NO air was flowing through the spilt air hose port until I disconnected the small solenoid hose. Is this normal? How do I know if the solenoid is set or working properly. I am pretty much ready to just bypass the ACV and get it over with just to try to pass the damn test, but I still have a few questions:
1. Where is the fresh air feed to the cat?
2. What else will bypassing the ACV do? I assume the ACV was there for a reason, what will happen when it is totally bypassed? What was the reason for it in the first place?

Thanks!

82streetracer

iTrader: (1)

There was this guy at my dealership who owned like 7 FBs (he traveled some insane amount each like 80,000 a year)
Anyhoo, he said that if he ever had a problem passing emissions he would run the tank really low right before the test then he would pour a huge amount of seafoam or heat engine treatment in the tank and run on that.

Spieder

My car is an 85. You can see the metal tube running up from the cat. I am not sure where your's is at. I know the 83's are a little different.

As for the sensor keeping it closed, I am not sure if it's supposed to open up at higher RPM's or not. The mechanic where I had my car smog diagnosed the problem and told me how to bypass it.

The only problem with the ACV being disconnected is that you'll suck cold air into the intake. So it will be a problem if it's really cold. Also, sucking unfiltered air may introduce debris into the intake.

I'll tell you what though. If my other ACV doesn't work, I am going to modify and bypass my ACV so that the air air line runs to my air cleaner. I ran my car for over a year with the ACV bypassed and she hardly ever backfired (got plenty of fresh air in the cat). Now, with a ACV back on those high RPM pop's are back.