Hi, my brat has a bad exhaust smell in the cab, I have no oil leaks and no oil on exhaust pipe. Had exhaust replaced new cats and pipe and muffler. Still smells. Especially bad when defrost or heater is used and when brat is first started. After it warms up seems to get a little better but usually have to have window cracked. Any ideas or similiar situations. Does not seem to have exhaust leak, but think it getting in cab from engine compartment threw firewall. Thanks Ray.......

Yes - probably one of your Air Injection System valves has died. They take in raw oxygen for the cat to do it's job. I just block them off, but they can be repaired if you are so inclined. Check the repair manual for a step by step on this. You have exhaust in the engine bay, and the heater fan is sucking it into the cab. Leaks in the exhaust pipe or the metal gaskets for the y-pipe at the heads can do this as well but you say all that is new....

 

GD

Another possible source for exhaust in the cab area, is how/where the exhaust pipe exits the BRAT. The rear area of the BRAT is hollow, from the tailgate to the B-pillar. Exhaust can enter the cab thru the sidewalls of the bed, as it's all open in there. Nothing in the cab area to seal it off, except for the trim on the B-pillar.

I had simular problem on the '86 BRAT I'm driving now. Yes it's a pieced together exhaust system on mine, so it's not ran like the stock system. I added a couple inches of pipe onto the end of the tailpipe, and no more exhaust smell in the cab.

 

Just my .02....

Thanks JD and Tom for the replies, I will try the air injection sytem valve. Hope this is it. My tail pipe has a nice crome tip so it sticks out far enough from the bed. ......

what about the seal between the the 2 sliding rear windows ?

that seal xcan kill you as well.check to make sure that your y-pipe and and tailpipe section is tightened down .this sits right below your shifter.and if it is loose it can let fumes up through your shifter boot(maybe a small tear or something.

the rear window slider seal is good, has anyone else changed a air injection sytem valve or blocked it off, GD what repair manual are you talking about. I have a chiltons. Any tips how to do this....

Blocking them is easy - just unscrew the pipe going to the valve and put a quarter (yes - $0.25) in the vavle body and screw it back together. Removal is also easy if you have access to a welder - just weld up the port in the spacer under the head - where the pipe going to the valve attaches. I cut the steel ends off the pipe, and use a washer for filler - weld it up, and then thread your new "cap" into the spacer.

 

The repair manual I was refering to is the one on this site - it's a "forum" all to itself, you just don't post there. Check it out. There's an article on the AIS valves, and how to repair the reed valve inside it.

 

Personally I wouldn't repair it, but it's your choice. Blocking them takes less time and is 100% effective. Removal requires some welding which not everyone has the ability for, and repair is more costly.... and they could still fail again in the future.

 

GD

thanks GD, blocking sounds like the way to go, I'll let you know how it goes. Ray in Seattle......

GD, thanks for the quick and easy fix. No more exhaust smell.. a quarter was was the perfect price. Thanks again Ray in Seattle.......

My pleasure - glad it worked for ya.

 

GD