Well, I knew this was going to be a problem.

Car is: 1990 305 Speed-density TPI 5-speed.
I have dual exhaust on the car. no AIR, no cats.

The first time I went with 94 octane gas running at around 215 F.
Results:
Test Driving Idle
HC(ppm) 64(89 MAX) 182(82 MAX)
CO(%) .61(.68 MAX) .57(.50 MAX)
NOx(ppm) 999(1007 MAX)

After I welded my old cat(which worked before I took it off) onto the right side. That is the only spot I can fit a cat with the duals. Also put in 87 octane because I thought it would burn more completely and lower HCs. I passed the driving test even better but at idle I got 160 HCs and .60 CO(HIGHER?!?!? )

To renew my insurance I have to pass the emissions test, by Saturday. For the next try I was going to try 10% ethanol but I'm not sure that's enough. What else can I do? Some other gas additives? Change the timing?

I have brand new coil, cap, rotor, spark plug wires, and plugs. Changed the oil and cleaned the air filter too. O2 sensor is pretty new also. I have an exhaust leak about 2' after the sensor would this affect it?

HEEEEEEEEEEEEEEEEEEELLP!!

 

use the 94 octane again. High concentrations of ethanol are found in those cheap white bottles of gas line anti freeze. Use a near empty tank, and put in as much of the booze as you can. It would run on 50% in case you were wondering. If you are lucky it will be raining and the humidity will also help you. Fill your tank up after you are done getting tested.

 

Hey man, here is a little trick I hae learned. Do you have a manual fan switch? If so, laeve the fan off, and let your car heat up, to about 240-250 dgrees. Your gas will burn more completly if the engine is really hot.... Make sure the timing is at standard and not like any advanced or anything. BTW, if you dont have a manual fan switch I cant think of anyway to heat your car up. Good luck,

 

I couldn't find any gas antifreeze but I found alcohol stove fuel. It says 100% methyl hydrate. Would that work? I know methanol is more harmful to the fuel system but if I drain it out after the test and fill up on regular gas it should be ok.

 

I would never let my car run 250* ouch, talk about risky.


I'd drive the car for about 20 mins prior and have 1/8th tank of gas and pour some rubbing alcohol in it, helped lowered my readings a tad.

 

If this helps, hobby shops sell fuel to run remote controlled cars that is I believe up to 35% nitro-methane and the rest is alcohol. I don't know if this'll help but there's the info

 

Nitro-methane? I don't know about that.

When I put the cat on I left the AIR tube hole open. Should I close it off maybe outside air is cooling the cat off too much for it too work?

 

This is BS. I failed again. With about 30% methanol everything got better except HC at idle which I was already failing

Driving
HC(ppm) 35(89 MAX)
CO(%) .24(.68 MAX)
NOx(ppm) 704(1007 MAX)

Idle
HC(ppm) 432(82 MAX)
CO(%) 0.41(.50 MAX)

The trace graph looks really wierd. HC stays at ~80 then there's a huge spike up to 476. CO also has a huge spike but it happens 10 seconds before the HC spike. In neutral, if I hold the throttle open a bit it won't stay at a constant RPM. It drops down and then comes back up at a steady rate. Maybe a misfire? It goes away at higher RPMs.

I found out I can get a 3-month insurance extension so I got some time to figure this out.