Hec's 79 gs

Hello, like the title says the car did not pass .Its a 93 stock except for down pipe, had the car for a year put about 3k miles on it. Everything pass except for CO% at idle, just need some opinions on what the problem is.I have to add that the car was not driven for about three months fixing oil pan leak and motor mounts.Thanks for any input.

moconnor

iTrader: (14)

Do you have an airpump? Is it working?

Change the plugs and wires and oil and make sure the car is well warmed up when it is tested and try again.

Hec's 79 gs

Yes it does have the air pump and the original cat. Does the pump works? Looking at the results it seems to be working inthe high speed results

Hec's 79 gs

Need to add that oil change was done ,fuel filter was replaced and plugs were in good condition. The inpector told me since that since it was not driven for a while to run some injector cleaner and bring the car back.

TRISPEEDFD3S

iTrader: (26)

and some good ol' bottle of "guaranteed to pass". Should be able to get it at your local kragen/checkers....

Hec's 79 gs

Hum! I heard of this miracle bottles but no luck got a brand name or pictures

t-von

iTrader: (8)

Must suck to live in Houston. They don't smog test in west Texas.

Steam cleaning your exhaust will help keep the cat clean so it performs better. FYI the Fd runs more rich in it's fuel/air mixture when compared to the average car. This causes the cat to receive more deposits from the engine. These deposits get even worse if the car was granny driven all the time. Since your stock, there's a few water steam cleaning threads around here that will help you. All you do is run a vacuum line to one of the upper vacuum nipples on the passenger side of the upper intake and submerge the opposite end into a liter of water. Make sure the engine is reved to about 3k so that it doesn't die when it starts sucking in water. When done repeat the same thing for the other nipple. The front nipple goes to the front rotor while the back one goes to the rear. This procedure will not harm your engine in any way (promise). The only side effect is it will create a huge white steam cloud of smoke out the exhaust. It's less embarrassing doing this away from your neighborhood. I personally do this twice a year on both my Rx7's. I know this cleans the exhaust well because I removed the cat from my Fd (when performing a modification to my ppf) and took a peak into the cat to look at the honeycomb structure. It was a very light color and not all carboned up. Keep in mind my cat had nearly 100k on it at the time.

Using the soo called magic potion will only hind the problem temporarily. The steam cleaning free so give it a try.

Trexthe3rd

The air pump should be on when the engine is below 3K rpm. You can hear the clutch engage and disengage when you rev the engine above 3K.

Hec's 79 gs

Hey, thanks for the infomation guys! t-von, do you recomend doing the sea foam treatment before the steam?Iask because I do the sea foam on my 79 sa, never done the steam. I dont know why but Im scare to do anything to the FD, the SA I just abuse that poor thing

Hec's 79 gs

Trexthe3rd are you saying that the air pump works just like the a/c compressor with a clutch? Never took a good look at it to notice

smog-guy707

iTrader: (11)

hey... what you should do is scope your oxygen sensor beacuse if its stuck lean your ECU will try to richen it up (and fail for CO%... the rich indicator) . i work at a smog test and repair and youd be surprised how many cars have bad oxygen sensors... especially single wire oxygen sensors

but just like the other guys said make sure your aipump is working and warm up your car before the smog

rx7will

iTrader: (6)

My old fc did the same thing. It pass the high speed easily, it pass the idle test in the beginning but not long enought for it to pass the test. When the car stayed at idle the hc and co started to rise and the car failed. The guy at the smog station raised the idle with the throttle and the readings started to drop and stabilize within the pass range.

Try to find out the highest the idle can be for the idle test. And then set your idle to that. Or if you know the guy at the smog station, ask him to give the car a little throttle to raise the idle. And it should pass, of course make sure the cat is really hot.

Hec's 79 gs

smog-guy, thanks ill keep that in mind. I have no idea how old the oxygen sensor is but it is a 1 wire sensor,any recomendations on replacement ?

Delicious

Time to break out the methanol....ha.

TRISPEEDFD3S

iTrader: (26)

Here you go:

http://www.autobarn.net/ch05063.html

smog-guy707

iTrader: (11)

you have to scope it first... an oxygen sensor range is between 0-1 volt and should switch back and fourth... if you scope it and it is near 0 volts... a new oxygen sensor will do it

bosch usually makes the best oem replacement oxygen sensor

Hec's 79 gs

^ thank you

TRISPEEDFD3S

iTrader: (26)

Oxygen Sensor (I use this one, and I pass with HKS racing suction intakes, HKS DP, A`PEX-i cat-back, and Power FC:

http://rx7.com/store/rx7/fdengine_maintenance.html

Hec's 79 gs

trispeed I meant to thank you also Tomorrow Im going to check air pump, change plugs, check oxygen sensor, sea foam & steam clean then drive it like I stole the sob, Im missing something?

TRISPEEDFD3S

iTrader: (26)

Buy a burger also...HAHA!

rx7will

iTrader: (6)

You passed the high speed test easily, i am pretty sure your air pump and oxygen sensor is working. But if you are going to check the air pump, you have to check it at the hose by the catalytic converter. If the air control valve does not divert the air to the cat then its useless.

You can use a regular digital volt meter to check the o2 sensor. I would not replace the oxygen sensor if its working properly and if you have not notice any decrease in gas mileage. I personally like the denso or ntk sensors. I would skip the sea foam, steam clean or any additive. I dont think it will help in your case.

Your car pass the cruise test, and in crusie the car runs leaner, thats why you have a lower HC and CO reading. At idle the car runs richer, if the catalytic converter can not efficiently clean up the exhaust then the tail pipe reading will be higher. Which your reading shows. You passed the HC idle test but not the CO. Which shows the conveter is working but not enough. But by opening the throttle a little it promotes better combustion, leaner mixture and will help the catalytic converter. I have seen this done many times, and it usually works if the car failed by a little. If you dont know the smog tech, i would just set the idle higher and see if they can do a pretest and only test the idle part. I dont know how much a smog test in Texas cost or if they give a free re-test. But adjusting the idle cost you nothing.

This is assuming that your car is in good order, no vaccum leaks or anything weird.

nocomply24

i thought everyone on here passed the way i did....illegally. i think if your car passes smog then you are restricting it way to much....

ranchan02

iTrader: (4)

Have u tried just putting the Precat back in? Thats what I did to pass here in Illinois. My car is also pretty stock (at that time) except for a downpipe. We put back the stock pre-cat and I was able to "Fast pass". You can always remove the pre-cat and re-install the downpipe once you pass.

Hec's 79 gs

First thanks to everyone for the great information.Last thrusday I checked the air pump, oxygen sensor and just about everything related to the emissions and everything checked out. Talked to a friend thats got an inspection shop and told me to bring it ever.I was there yesterday morning and found out that the test they did was wrong.I was not able to scan the new results but the last test was an idle test that is only done to 4x4.all wheel drive or traction control vehicles, they were supouse to do a dyno test.Brought the car back to them did the dyno test and guess what it pass.Here in Houston we get another test for free within 15 days.Just wanted to thank everyone and to advice to make sure they do the right test. Merry Christmas to me and everyone in this wonderfull fo rum

Rx7_Nut13B

iTrader: (1)

Denatured Alcohol

About a gallon to about a gallon of 89 octane gas and it will pass

1gallon Denatured Alcohol + 1gallon 89 octane gas = 2gallons of passing juice.

DON'T RUN IT UNDER BOOST

Glad you got it to pass, I have to get my HBP motor to pass in Jan