Last night we finished putting a new motor in '80 brat. This Brat hasn't ran since 2000, and it was kind of a mess. Anyways we put it all together and let it just run to see if the fan worked. As we let it run the cat. turned orange but the car was still fairly cool. I was wondering if this was normal. I've had a few subarus before and have changed motors but I've never seen that before. What would cause this?

Is the heat sheild in place around the cat?

 

Otherwise - I would try another Y pipe - that sounds bad to me....

 

GD

i've seen that happen with turbo engines, they will make the down pipes glow bright orange under a load, but not just ideling. Mabey (just guessing) your cats are clogged, or something along the line is clogged, restricting air flow, and causing friction and over heating your cats. Pull it and see if you can see day light through it. It shouldn't be too hard to do.

 

Dan

1 I, does the engine seem to be running rich?

Carb dumping ect? An overly rich mix will allow excess gas to pass to the cat where it will be burned if the AIS is working (which it sounds like it is) Did you have to "prime" the carb to get it fired?

my Y pipe when I had the heat shield off would glow a little in one corner... but, I would probably say that it is clogged. Spray some O2 sensor freindly cat cleaner down your exhaust manifold (generous I would suppose) and see if it doesn't kinda clean it out. Either that or weld up a new Y pipe. I made a Y pipe using exhaust putty, and alumnium exhaust tape for under $30.

 

(it's actually two pieces... a chrome exhaust Y tip and a piece to go over the end of the pipe to slip fit my cat.)

The thing is running real rich and we can't get it to run in the green on the vacume gauge. We did time it too. I had thought that there might be a chance that that thing was clogged up too.

 

 

Jeff

1 I, does the engine seem to be running rich?

Carb dumping ect? An overly rich mix will allow excess gas to pass to the cat where it will be burned if the AIS is working (which it sounds like it is) Did you have to "prime" the carb to get it fired?

 

 

Yes we did prime the pump, and its hot wired. You think that could have something to do with it? also what is the AIS.

 

 

 

Jeff

Jeff, the gas you used to prime the pump could have been burning in the cat - have you driven it yet?

Kind of to flush things out.

When you hot wired it, did you hot wire the choke also? If not maybe the choke did not open? Again looking for rich running.

 

The Air Injection System is the way an early Sube engine injects the extra air (oxygen) into the exhaust so the unburned gasses in the cat can oxidize rapidly (i.e. burn) No 02 and no oxidation.

The pipes right at the exhaust ports lead to reed valves. These are fed air from an air cleaner and this pumps air into the exhaust.

The silencer in this system is known to melt down if the reed valves fail.

I did a search for AIS* here is a sample

http://www.ultimatesubaru.org/usmb/forum/showthread.php?s=&threadid=5549&highlight=AIS%2A

Hope this helps

Oh wow. I never knew any of that stuff. The car had bad gas in it at first we dumped gas straight down the throught. That could be a helping factor for it. The choke isn't hooked up on it, and I don't know if it is staying half or full on, that's one thing we should check.

 

 

 

Jeff

Be careful when you have a new cat in your car. It can mask bad carburetion by burning off the excess fuel.

 

The problem is you will burn out your cat well before it's time. It's kind of like which comes first, the cat or the carburetor.

 

If you put a new cat in, you can have rich carburetion that is being masked by the cat working overtime.