Full Size Bronco, 1988, 302, Automatic.

On the back of the motor there is a ?Part? that looks like emission thingy. It is a canister directly in the middle of the motor with two hoses running from the center of the canister to each cylinder head.

Now here is the problem, the canister part is missing; the hoses are there with the base of the canister. I noticed this when I was replacing my solenoid and did the usual start test and noticed there was exhaust or gas fumes running up my hood at a pretty good rate. It was also -17c(-5F) and it was really puffing out the smoke/fumes from where the canister used to be. I also stuck my finger in the hole of what was left from the canister and noticed that there was a lot of carbon on it.(?)

I have noticed that when I put my heater fan on high I will notice an exhaust smell from in the cab. This is, I can assume, where the smell is coming from as it is very close to the intake for my heater.

I have searched my Haynes manual and found nothing except a diagram of the engine with the complete unit.

Does anyone know what this is and what it does? I was thinking some sort of cylinder head pressure balancer, but not sure.

Please help.

 

It's part of the smog air injection system. It sounds as if the check valve has rusted off. Mine did this, and I had to go to Ford to get a new one. Best I remember it was around $20. Check the pipes before you get a new one just to make sure that the threaded part pointing upwards is still in tact so that a new one can be screwed on. There should be a rubber hose nearby that would be pointing downward, perpendicular to the pipes going to the heads.

 

I'm sure other guys will chime in who know exactly what that thing is. I know that it is an air tube that is part of your emissions system that should eventually be plumbed to the smog pump. When the pump is running, air is being forced into the heads through this tube. Where it goes and how it actually works I do not know. I know from reading these forums though that you can remove this tube by taking out the two bolts that hold it to the heads and buy replacement plugs from the parts store. This, of course, is messing with your factory emissions equipment so you have to know about the inspection rules in your state. Hope it helps
Tom

 

Sweet, so what you are saying is that I can.

1. Just plug the holes, I do not have emmission tests up here in the great white north.

2. Cheap fix from Ford by replacing the damaged parts.

Thanks guys.

 

Yep, I plugged them off too. The ones that attatch to the back of the heads, two bolts to remove, saw the pipes off, flip the little tear-drop looking pieces over, presto-chango, you have block off plates. The one going to the converter I used a spent co2 cartridge, a 4" piece of hose and 2 hose clamps to make nice plug. The next thing to do is get the belt to bypass the smog pump.
The draw backs: you probably won't pass emissions after bypassing the smog pump. And because to function of the air pump is to introduce oxygen into the exaust after initial combustion to help the catlytic converter burn unspent fuel, the chances of clogging up a converter are alot higher.
I had to replace the tube on the back of the motor once, could only find it at the dealership, but it was pretty cheap.
Good luck with what you do.

'85 F150, low 1st 4spd,
B&B 5.0, P&P stock heads, Crane roller cam, Edelbrock RPM intake w/1'spacer, Holley 600,
dual exhaust w/ crossover, H/D radiator w/ electric fan

 

it is an air pump check valve designed to let fresh air one way and not let exhaust flow to the air pump

 

Thanks guys for all the help. I changed the AIR check valve and I no longer have fumes coming in the cab from the heater intake.

 

That "Thingy" is called the Air Injection Pipe and it's part of the thermactor system. There should be a hose from it connected to the thermactor pump (smog pump), which should be on the serpentine belt on the bottom left of the engine, if it wasn't removed. Someone probably unhooked it when they were cleaning out "unnecessary" components. The thermactor system injects fresh air into the exhaust stream to aid in oxidizing pollutants to reduce emissions. It would't hurt anything to just plug the hole, since the pipe won't drawn any air without the pump anyway. The only problem you might have is the truck won't pass an emissions test.

 

In some vehicles it actually makes the engine run better by keeping that cat cool so it doesn't plug up.

 

That's a good point, pfogle, but from a power standpoint hot gas is less dense than cool gas, so it moves easier through the exhaust system. They actually make insulating tape to wrap the exhaust pipe to prevent heat escape. I wouldn't worry about it either way personally, I doubt it makes much difference.