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Blue smoke and failed smog test

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Old 11-21-02 | 02:08 PM
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From: Aloha OR
Unhappy Blue smoke and failed smog test

Specs of car are: 1987 NA with 159,500 miles, no mods.
I have 2 problems here, I will start off with the smog.
about a week ago I took my 1987 NA to the DEQ test station here in Oregon. I had a feeling that it would fail cause it idles from 1100 to 1500. And I did fail hydrocarbons and carbonmonoxide. So I decided to change the plugs(ngk stock ones) and the oil(Castrol GTX 20w-50 w/ a Puraltor filter) The car ran a bit better for a few days, but now it is back to normal(running ok but not as good as I think it should) probably because the plugs have started to foul (edit- I check the plugs and they are fouled like a ****). I checked the TPS and it is fine 1k ohms at idle and 5k ohms at WOT. I am going to check the vacum stuff but what else should I check?
And now my smoke problem. I replaced my oil on tuesday, and yesterday (Wedensday) is started smoking, the smoke is blue. (just a little bit when it was idleing, a little bit more if I would blip the throttle). But today it is way worse, is leaves a little bit of a cloud when I tap the gas at idle, it seemed to go away after I took it for a trip around the block (got to red line it through first and send, and redlined it through 1st most of the time) but after it sat and idled for a minute it would emit blue smoke if I blipped the throttle, but not quite as bad. Here is a run down of what I think I should check
Do a compression test, to check the side seals
Check the oil metering pump (do FC's have these, and if so how do I check?)
Check the purge valve (again how do I check this?)
Is there anyting else that anyone can think of, I really need to get teh car running right

Thanks
-Justin

Last edited by j200pruf; 11-21-02 at 02:22 PM.
Old 11-21-02 | 02:11 PM
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From: College Station
Could be your oil seals going, which could mean a rebuild is in order, or it could be your OMP.
Old 11-21-02 | 02:29 PM
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87's use mechanical OMP's. My moneys on the oil control rings.
Old 11-21-02 | 02:48 PM
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whoops didnt read the 87 part
Old 11-21-02 | 02:50 PM
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Not sure if everyone who agree, but would switch to a thinner oil. I had a 79 GS that smoked at startup and high rpm using 20-50, switched to 10-40 and problem was minimized. Racing Beat tech told me to do this and the ATF trick occasionally, I ran the car for 15 years like this! Just sold and got '88 vert, '79 was still running fine.
Old 11-21-02 | 03:03 PM
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From: Hood River oregon
Re: Blue smoke and failed smog test

Originally posted by j200pruf
Specs of car are: 1987 NA with 159,500 miles, no mods.
I have 2 problems here, I will start off with the smog.
about a week ago I took my 1987 NA to the DEQ test station here in Oregon. I had a feeling that it would fail cause it idles from 1100 to 1500. And I did fail hydrocarbons and carbonmonoxide. So I decided to change the plugs(ngk stock ones) and the oil(Castrol GTX 20w-50 w/ a Puraltor filter) The car ran a bit better for a few days, but now it is back to normal(running ok but not as good as I think it should) probably because the plugs have started to foul (edit- I check the plugs and they are fouled like a ****). I checked the TPS and it is fine 1k ohms at idle and 5k ohms at WOT. I am going to check the vacum stuff but what else should I check?
And now my smoke problem. I replaced my oil on tuesday, and yesterday (Wedensday) is started smoking, the smoke is blue. (just a little bit when it was idleing, a little bit more if I would blip the throttle). But today it is way worse, is leaves a little bit of a cloud when I tap the gas at idle, it seemed to go away after I took it for a trip around the block (got to red line it through first and send, and redlined it through 1st most of the time) but after it sat and idled for a minute it would emit blue smoke if I blipped the throttle, but not quite as bad. Here is a run down of what I think I should check
Do a compression test, to check the side seals
Check the oil metering pump (do FC's have these, and if so how do I check?)
Check the purge valve (again how do I check this?)
Is there anyting else that anyone can think of, I really need to get teh car running right

Thanks
-Justin
Run your ECU codes. If you have a malfunctioning sensor, it could be causing your car to go rich.

Rat

Here is the link...
http://home.rmci.net/panther/ecu_codes.htm
Old 11-22-02 | 02:14 PM
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From: Aloha OR
Checked my ECU codes, and no codes popped up. I will hopefully do a compression test and stuff tonight or on Saturday morning. And I noticed something yesterday, when my car is warming up it idles at about 2000, then it will hunt inbetween 1300 and 1700, then after it gets really warm it stops hunting and idles at about 1200.

Last edited by j200pruf; 11-22-02 at 02:21 PM.
Old 11-23-02 | 07:29 AM
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From: just a bit north of your business
That idle is really high. Will it idle lower if you turn the idle down or will it die? Thats a lot of miles on that engine, but I've seen them go longer without oil control ring failure. How long have you owned it? If the engine has been severly overheated its possible that could've hardend or deformed the rubbers in the oil control rings. (the rings themselves are metal and ride on the side housings, the rubber o-rings seat against the rotor and the rings)

My huge street port will still stay running at 650rpm but it sure doesn't sound like it wants to. Your stock motor should be idling at 700, and it should be very happy doing so.

btw: I keep my idle just high enough to prevent the lopiness so no one knows what I've got going on under the hood. (ends up being very smooth at 750-830)
Old 11-23-02 | 10:57 AM
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From: London, Ontario, Canada
Sounds like multiple problems. The high idle is likely due to a vacuum leak or stuck throttle blades (or cold start). The rich running is more than likely due to being out of tune, or a failed sensor (water temp sensor, TPS, etc.). The smoking could be several things, but tired oil seals are more than likely the cause. Though it couldn't hurt to replace the purge valve.
Old 11-23-02 | 03:41 PM
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From: Aloha OR
Well Last night I popped my hood to check the oil, but I forgot to turn the motor off and I noticed that the ECU code for the Oxygen sensor was blinking at me (#1 long light long pause repeat #2 no light) And I took my plugs out and cleaned them, they had black build up on them.
If I turn the throttle screw down much more it will hunt really bad.
And should any of the dashpots on the throttle body leak at all, or are some of them metered?

Last edited by j200pruf; 11-23-02 at 03:44 PM.
Old 12-03-02 | 09:57 PM
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From: Aloha OR
Allright, I have an update. I did the ATF trick with Marvel's Mystery Oil and the car felt great, it stoped smoking, but I still had the idle problem. But after driving aroud for a day I climbed on it through 1st and second, and when I went to shift into third it started billowing blue smoke The smoking doesn't seem to be that bad, but when it is ideling and you blip the throttle and then blip it again it will smoke really bad. And when ever the car is stopped you can smell oil and just a small hint of gas in the exhaust (even though there is no visable smoke). I have tried a different TPS, changed the O2 sensor, I checked the AFM. It gets a little bit better everytime I tinker with it but still has the problems. And I am going through about 1 quart every 250 miles. I did a compression check and I had 85 to 90 on all 3 faces of both rotors, but that was when the motor was cold and with the wrong kind of compression tester.
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