DavidE

Hi Folks,

I have had a 84 GSL needing a rebuild(parked) for the last 3 years. Well I finaly got the engine rebuilt and put back in. I seem to have it running ok now, it idles and rev's fiine .
But of course to get it registered, I have to pass smog. Well took it in and had a test only done and it failed even though I only have to pass the old idle & 2500 rpm test.
Measured Results:
%co2 %O2 HC (PPM) CO%
idle 7.3 4.0 1217 8.57 - Failed HC & CO%
2500 rpm 11.0 5.8 89 0.00 - passed!

This is bone stock with Air pump, & all cats .
When I reinstalled the motor I replaced all vac & cooling hoses, new water pump, thermostat(180) and had radiator recored. I put in new plugs, but cap & wires are 3 years old, but only have about 1k on them & look fine.
So reading over the last week, it sounds like possibilites are ACV, cat or carb adj?
I did follow the carb adjustments found here, and does look like I was running rich? at the time. I also pulled the ACV in the hopes I would find a stuck valve or something obvious, nothing obvious. What concerns me is the car seems to run cool and I am wondering if that is the real problem? By cool I mean running, the temp gauge rarely goes past 1/4 mrk near 2nd large bar. Not at the 1/3 I would expect a warmed up car to run. So any ideas, is it my ACV? or what would be causing it to run cool? If it is ACV, where can I find one at a decent price, the new ones are quite expenisive

Thanks to all, so much great info here, so little tiime

81gsl12a

iTrader: (1)

did you run your car long b4 you took the test.....if not drive around and get the cat nice and hot........also i know of a few guys around here than wate till the gas tank is almost on Eand poor a bottle of high proof alcohol in with the gas it makes the car run leaner so it burns cleaner....i dont know if any of this will help you

RXDad

iTrader: (2)

1217 HC at idle indicates Cat is not functioning at idle. 89 HC at 2500 indicates it is functional, so it's not blocked.

Either the Cat is too cold at idle as the previous post indicates or it is not getting air. Check the ACV and try to adjust the carb to see if it improves.

RXDad

DavidE

Yes, car was run for 30 min on the freeway before the test. - Thanks!

Rob.W

If it passes cruise then the carbeurator is not tuned properly, it's running too lean at idle (lean enough = high CO, high HC), try fuel filter, can of BG44K, anything you think really.

Either that or it's running too rich... but I doubt it with 7.4% CO, that's a LOT of CO being pumped out.

What state are you in? If you're in WA I can help you pass. We could meet up in Renton, if you've got a car that passes (new model), and I'll talk to the dudes there, usually they'll ghost cars for $40. My '85 RX7 with no cat, no rat tails, etc. passed with 0% CO, 0 HC... lol.

PS, alcohol only makes the testers gag at your assy ******* exhaust. Doesn't help emissions. Don't do it.

I worked at Emissions for 8 months, know the ins and outs on passing... generally it's just a lot ******* easier to ghost the car.

j9fd3s

iTrader: (3)

nah it takes 15 minutes to pull apart the acv and make it blow air into the exhaust ports all the time. high hc's at idle might mean it needs a cat though.

any missing is gonna make the car fail, no matter how lean it is, its actually better to be a little rich, cat works better, less misfire etc

DavidE

I am in Northern CA & replaced the Fuel Filter as well, but thanks for the info & offer.

DavidE

Any ideas why it would run cool? Or maybe this is Normal for Rx7's in the winter. Sorry been 3 years & I don't remember it running so cool before. Since at 2500RPM everything smog wise seems to be working, thought cat was ok? But I guess a weak cat would show up more at idle? When you say make ACV blow into exhaust ports, you mean into the Reactor or into the Cat air tube? Thanks again!

j9fd3s

iTrader: (3)

make it go to the reactor. emissions are worse@ low rpms, the efi cars sometimes pass the high rpm test with no cat, but it will fail @idle

misterstyx69

iTrader: (142)

you have an engine that has just been rebuilt ..not an expert but i'm assuming that the emissions will be a little "funky " ..it's not broke in..the best advice I can give you is to make sure that you have your carb adjusted adequately and new plugs,wires,fuel filter,oil and filter..and just before you take the car in for testing ..Make sure that the car has been out for a good run..that way you have the catalytic hot (a good catalytic is key too)..that way it will absorb the crap in the exhaust..better emissions reading..good luck

andrewlevitt257

I have the identical problem on my '85 12a GS. At 2,500 RPM passed the test with flying colors:

%CO2: 11.8
%O2: 3.9
HC(PPM): 12 (MAX: 150)
CO(%): .01 (MAX: 1.2)

Then failed HC miserably at idle (756RPM):

%CO2: 9.0
%O2: 0.0
HC(PPM): 538 (MAX: 150)
CO(%): 8.72 (MAX: 1.2)

Another test with idle at 967RPM shows less bad results:

%CO2: 12.9
%O2: 0.1
HC(PPM): 52 (MAX: 150)
CO(%): 3.01 (MAX: 1.2)

It seems the ACV kicks in at 1300 RPM--does that account for the big difference in emissions between the idle and 2500 rpm tests?

steve84GS TII

Adjust the idle mixture while the car is on a gas anylizer.
The mixture screw and idle speed screw will let you fine tune the CO level,then reset the idle speed.Your either way too lean and its misfiring,or your just pig rich and its dumping unburned HC's.If you go to a station thats not "test only" then it should be a simple proceedure for them to set the idle mixture.Your cat and air injection system is working awesome,the HC levels at cruise are superb.

BlackWorksInc

I adjusted the idle mixture a little and poured a whole seafoam bottle before sending her off to get smogged, passed fine and I live in Hayward.

But it does sound like your carb is tweaked wrong...

Ilum

DemonSpawn67: I am sorry to ask a stupid question but what did you mean by "poured a whole seafoam bottle?" I have heard some say that rubbing alcohol will help the engine pass smog, but what is "seafoam" (other than the obvious)?

Vashner

It's an 84 isn't it exempt?...

djessence

Vashner, they are all in cali, is anything exempt there? Or might be in 09 becuase where there are strict emissions laws, its usually 25 years or older before they are exempt becuase the laws have changed.

Ilum

I remember reading on another thread here one of Cali guys was saying that they don't have a rolling exemption year law, it is strictly anything made before 1976 that is exempt. Hopefully one of the Cali guys will chime in and confirm if that is true. I am sure one of the guys will be up to speed what the CARB laws are there in regards to our cars...

I'll see if I can find that thread.

Ilum

OK, I found the thread: https://www.rx7club.com/showthread.p...t=smog+rolling

post #12 states:

"Our state suspended the rolling 25 year smog rule a while back precisely for this reason....."

justint5387

iTrader: (1)

That is true, very sad.

lfd75

It might be your air pump

Vashner

It's a fuel system cleaner. But when used in concentrate it's poured into the chamber to burn off old carbon deposits. So you drive it with the goop and it burns the stuff off after a hard drive. They use it for stuck engines sometimes.

Ilum

Vanisher: Thank you for the explanation. I thought about going down to the local parts store and look for it, but this used less gas. You said it is poured into the chamber ? Directly and not in the gas tank?

BlackWorksInc

Sorry I didn't notice your question until it was too late...

But yeah, what Vanisher said... Great stuff really ^.^

But I am not sure it would help your situation...