ddub

Straight out of the FAQ at the top of the 2nd gen section.

I don't want to buy a shop manual for my car, is there a place where I can still find out the information from one
Shop manuals for both series can be found on-line at:
http://www.cochran-racing.com/FSM/index.html
http://slackerware.dynu.com/fsm/
http://208.62.166.66:82/guest/shop_manuals/
or (86-88)
http://www.teamfc3s.org/main/factor...nual/1986_1988/
and (89-91)
http://www.teamfc3s.org/main/factor...nual/1989_1991/

gordonrick

dDub -
Just tried the air rig and dropped my HC's from about 550 ppm to 8 ppm on the high rpm test for a few minutes work and a few dollars. Still failed by a little on the low rpm test for CO but by now I've spent the requisite amount of money and shown enough improvement to qualify for a waiver. I didn't try to lean it out so that might have gotten the CO down enough. Now I have all year to figure out what is blocking the air to the cat in the first place.

BTW - the emissions guy seemed to at least know a little about rotaries. Wonders never cease

Thanks much!

Charlie

HI,
There's a good write up on the emissions system here:
http://www.geocities.com/huguesdc1/index.html
Read the section on secondary air injection.
Basically what Ddub has done is bypassed the Air Control Valve (ACV) so that split air is always being delivered to the cat. This is actually one of modes in which the ACV is supposed to operate. Car warm, medium load, the ACV should be sending air to the cat. These are the same conditions under which the 15 and 25 mph testd are done. If you have a bad ACV or vacuum leak or bad solenoid valves the air to cat trick will help.
If you have another problem say a bad set of oil control rings and you're blowing white smoke like a pope was just elected, this most likely will not help.

I had a dead cat and couldn't pass even with the air being sent directly to the cat and denatured in the tank.
I checked TPS, timing and searched for vacuum leaks and replaced the O2 sensor and plugs before breaking down and buying a new cat.
My results after the new cat with everything else legit:
@ 15mph, limit reading , @25 mph limit reading
HC PPM 135, 2 , 130, 1
CO% .76, 0, .8 , 0
NO PPM 1052, 850 957, 164

The problem with emissions troubleshooting is that without specialized equipment to quantify what's coming out the back, you can't tell if your tweeks are helping or hurting. If you start throwing money at the problem and just replace things that aren't broke you're wasting your money.

ddub

Glad to hear it

WallyHojo

Yea I wish i could install my air pump again. I took it out since I installed my new turbo. It will not fit back on now. I failed before, becuase I had only one cat on.

ddub

That sucks. You should get an electric pump maybe from a different car then and just mount it wherever you can fit it. That should work similarly.

RXSevenSymphonies

iTrader: (2)

Here's one writeup on electric air pumps

http://www.cabrio7.org/mods/airpump/airpump.html

RoadRaceJosh

Simple. In many states the inspection is run by a state agency and not local yokels. Most state employees couldn't give a rats *** if you pass or fail. Whatever your car spits out the computer records. In Oregon you roll up, they put your VIN in the computer and for a 2nd Gen they drive it on the dyno along with every other 2WD 1981-1994 vehicle. 1980 and older only get a 2 speed idle and 2500 RPM test and the 1995+ OBD II cars get snitched on my their own electronics.

You can tell by his emissions numbers he has oxidized nearly all the CO (partially burned fuel from a rich mixture) into CO2, but the HC are still high due to the oil burning nature of the rotary. Since there is no O2 number like I'm used to seeing it's hard to say if there is too much air. Many states have an O2 limit as well so one might have to bypass some of the air from the air pump to get the balance right.

What kills cats is misfiring. Dump a lot of unburned fuel and air into the cat and it will burn and burn up the cat. The extra air is only going to be a problem for the cat if there is a lot of extra unburned fuel.

RoadRaceJosh

Retarding the timing acually lowers NOX as it reduces the peak combustion temperatures that form NOX, but helps light off a cat as it leaves more heat in the exhaust gas. Rotaries don't have a problem with cold exhaust so this trick probably won't get you very far with an RX. With the high surface area of the rotary combustion chamber (lots of relatively cold metal) HC is much more of a problem than NOX. EGR is strictly to reduce NOX as it dilutes the mixture with inert gas so it burns more slowly and has a lower peak temperature. Diesels are hell for NOX due to the high combustion pressures and temperatures involved which is why the new stuff is coming out with cooled EGR. Heck, even GM 5.7 diesels had EGR.

Marcus_F

If you run any car (piston or rotary engine) on a dyno with an EGT probe, and retard the timing, you will find that exhaust temperatures increase dramatically. This is because when the timing is retarded combustion chamber pressures are lowered. Lower combustion chamber pressure slows the burning. The fuel is more completely burned in the slower burning, lower pressure environment. HC is unburned fuel. Since the fuel is more completely burned, the HC levels will be reduced (this is before entering the catalytic converter). The problem with running retarded timing is more of the fuel is consumed outside of the combustion chamber. Although technically cleaner, this additional consumption of fuel outside the combustion chamber does nothing to increase power.

This isn’t theoretical, I’ve done it. I t took five passes through a California Test Only station before I could get my last smog certificate. Retard the timing on an S5 NA and the sniffer will show that the HC levels have fallen and the NOx will increase.

Lastly, I specifically said an S5. S5’s don’t have an EGR.

ddub

I could've sworn that advancing timing creates higher EGT's, not retarding...