Stinky Exhaust
10-21-04, 07:28 PM
#1
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Stinky Exhaust
The exhaust on my car smells soo bad. I know this is fairly normal for rotary's but working on my car with the garage door open and idling my clothes just smell like **** when i am done. I can sit there and watch my exhaust with a faint stream of smoke come out. I don't know if this thing is running rich, or the OMP is running too much oil but it's kind of annoying.
10-21-04, 09:27 PM
#6
Airflow is my life
Air control Valve. It directs the airpump air to either the exhaust ports, or the pre cats, or the main cat as controlled by the "computer". You guys should try leaning your idle mixture a little, but without any emissions, rotaries will idle best with a richer than normal (ala piston) mixture.
10-22-04, 01:13 AM
#7
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Well i no longer have the ACV but a blockoff plate i installed the same time with my racing beat streetport exhaust. My exhaust never smelled like this before. Is this just something that i should expect without the ACV functioning? Also without the ACV is it in any way going to affect the idle quality?
Last thing is i have no idea how to properly adjust the idle mixture via the rheostat and whether i even should. I've never touched it which leads me to think i just have a stinky rotary exhaust. Any suggestions?
Last thing is i have no idea how to properly adjust the idle mixture via the rheostat and whether i even should. I've never touched it which leads me to think i just have a stinky rotary exhaust. Any suggestions?
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10-22-04, 02:13 AM
#8
Ryan
I know what it is...
I had the same problem with my SE, Headers, no acv... never found out what the problem was till I pulled the motor.
There a lil in-line filter looking thingy on a hose, that's under the Upper Intake Manifold.
When I saw it it was broken.
If some of you know the differences between 84 & 85 SE 85's have the in-line filter looking thingy on the front side of the UIM. It is like green with a arrow directional...
**** IT heres a pic....NM I just found out that that was the wrong UMI
sorry
I had the same problem with my SE, Headers, no acv... never found out what the problem was till I pulled the motor.
There a lil in-line filter looking thingy on a hose, that's under the Upper Intake Manifold.
When I saw it it was broken.
If some of you know the differences between 84 & 85 SE 85's have the in-line filter looking thingy on the front side of the UIM. It is like green with a arrow directional...
**** IT heres a pic....NM I just found out that that was the wrong UMI
sorry
10-22-04, 02:24 PM
#11
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So what would that check valve have to do with stinky exhaust? Does anyone know what the correct vacuum pressure for that line should be? I am told it works the sec throttle plates.
Last edited by GavinJuice; 10-22-04 at 02:27 PM.
10-22-04, 02:29 PM
#12
I'm 99.9% sure that works your secondary throttle plates, but I have no idea what the pressure should be. You're going to be getting extra fuel when you stomp the pedal, but your secondaries won't open up, meaning your air fuel mixture is gonna be off. The could lead to some smoking and stench I would imagine. It also would make your car pretty slow... Get that fixed if its your problem! 
10-22-04, 02:36 PM
#13
84SE-EGI helpy-helperton
Dude - did you get yourself a Digital Multi-Meter??? (j/k)
In all seriousness, the posters above talking about removed emissions and ACV's that don't work are on-track. The stink in your exhaust is unburned hydrocarbons that would normally be burned through the fresh air injection pipe from your ACV and your platinum core catalysts burning off any fuel residue - and in a rotary engine at idle THERE IS A LOT.
The green 'thingy' under the Throttle Body is actually a delay valve for the Secondary Throttles (or choke, in common parlance), that Mazda installed there so that the Thermowax Pellet attached to the left side of the TB can route vacuum pressure to the Secondary Throttle diaphragm and close down the secondaries to act as a choke during cold temperatures and cold coolant temps. This will not cause your stinky exhaust, directly, but could lead to a richer than normal idle mixture due to reduced airflow from the choke effect. The green barrel is simply a filter to ensure that the Secondaries don't 'FLAP' open when the coolant temp goes up and the Thermowax Pellet closes down vacuum pressure (Secondaries are normally OPEN, they are CLOSED under vacuum from the Thermowax Pellet and mechanism).
In essence, if you want to 'fix' the problem, reinstall your cats and airpump, get your ACV working correctly again, and change your plugs for good measure.
If you're too addicted to the performance gain that you get from a header, the welcome to the club and understand that earplugs also fit nasal orifices...
HTH,
In all seriousness, the posters above talking about removed emissions and ACV's that don't work are on-track. The stink in your exhaust is unburned hydrocarbons that would normally be burned through the fresh air injection pipe from your ACV and your platinum core catalysts burning off any fuel residue - and in a rotary engine at idle THERE IS A LOT.
The green 'thingy' under the Throttle Body is actually a delay valve for the Secondary Throttles (or choke, in common parlance), that Mazda installed there so that the Thermowax Pellet attached to the left side of the TB can route vacuum pressure to the Secondary Throttle diaphragm and close down the secondaries to act as a choke during cold temperatures and cold coolant temps. This will not cause your stinky exhaust, directly, but could lead to a richer than normal idle mixture due to reduced airflow from the choke effect. The green barrel is simply a filter to ensure that the Secondaries don't 'FLAP' open when the coolant temp goes up and the Thermowax Pellet closes down vacuum pressure (Secondaries are normally OPEN, they are CLOSED under vacuum from the Thermowax Pellet and mechanism).
In essence, if you want to 'fix' the problem, reinstall your cats and airpump, get your ACV working correctly again, and change your plugs for good measure.
If you're too addicted to the performance gain that you get from a header, the welcome to the club and understand that earplugs also fit nasal orifices...
HTH,
10-22-04, 02:59 PM
#15
Gavin,
That is the vacuum delay valve that we discussed before. It should only have vacuum present when the engine is cold. The vacuum causes the outer secondary plates to close. The purpose of the delay valve is that it holds the vacuum for a specified amount of time even though the manifold vacuum is changing.
For example: If you were to go WOT when the engine is cold (which I don't recommend), the manifold vacuum goes to atmospheric pressure (no vacuum). The plates need to have atleast 120 mmHg (4.7 inHg) vacuum to keep them closed. (If the delay valve was not there, the outer secondary plates would immediately open. Mazda wants to keep them closed while the engine is cold (I believe to limit people from running the engine hard when cold (without the secondaries, you will be way down on power)). With the delay valve, the vacuum is held for like 12 seconds, so as long as you didn't go WOT for more the 12 - 15 seconds (at one time) while the engine is cold, the vacuum will remain on the diaphram and keep the outer secondary plates closed. Once the engine is warm, the water thermo valve cuts the vacuum to that line and after about 12 sec, the outer secondary plates open allowing you to be able to use the secondaries.
This assumes that the engine vacuum goes under 4.7 inHg when WOT with the outer secondary plates closed. I am not sure if this is the case or not (probably is), but I am not about to run a WOT with a cold engine to find out.
I am not sure what is causing the exhaust smell. Have you checked ignition (coils, plugs, wires, etc.)? How is your timing? If these check out, I would check your sensors (AFM, TPS, Coolant temp, etc.).
Kent
That is the vacuum delay valve that we discussed before. It should only have vacuum present when the engine is cold. The vacuum causes the outer secondary plates to close. The purpose of the delay valve is that it holds the vacuum for a specified amount of time even though the manifold vacuum is changing.
For example: If you were to go WOT when the engine is cold (which I don't recommend), the manifold vacuum goes to atmospheric pressure (no vacuum). The plates need to have atleast 120 mmHg (4.7 inHg) vacuum to keep them closed. (If the delay valve was not there, the outer secondary plates would immediately open. Mazda wants to keep them closed while the engine is cold (I believe to limit people from running the engine hard when cold (without the secondaries, you will be way down on power)). With the delay valve, the vacuum is held for like 12 seconds, so as long as you didn't go WOT for more the 12 - 15 seconds (at one time) while the engine is cold, the vacuum will remain on the diaphram and keep the outer secondary plates closed. Once the engine is warm, the water thermo valve cuts the vacuum to that line and after about 12 sec, the outer secondary plates open allowing you to be able to use the secondaries.
This assumes that the engine vacuum goes under 4.7 inHg when WOT with the outer secondary plates closed. I am not sure if this is the case or not (probably is), but I am not about to run a WOT with a cold engine to find out.
I am not sure what is causing the exhaust smell. Have you checked ignition (coils, plugs, wires, etc.)? How is your timing? If these check out, I would check your sensors (AFM, TPS, Coolant temp, etc.).
Kent
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