On my 1990 5.8L E40D Bronco I had the Engine replaced due to Head Gasket failure and wanting a higher torque motor. I got a Ford Motorsports Sportsman block and a Lightning mass air kit. It now has about 75k miles on the engine and sounds abrupt idling at times. Generally it has much power going up hills. On the last Smog Test it just barely passed the HC emissions test. NOx and CO were way low, since I replaced the EGR valve and the Air Idle device on the TB.

I'm looking to replace the Catalytic Converter so that it will pass the smog test here in CA. Every time I go there they lower the HC number, thus making it harder to pass.

According to the Ford dealer information, it is suppose to have both the air tube that goes into the exhaust manifold (from the EGR valve) and the CAT Air injection Tube that goes into the CAT (via a tube from a check valve that is connected to the Air Bypass / Air control Valve 9F491)

My problem is that when the engine was replaced, the Air Injection tube #5F235 was not installed.

I would like to put this CAT air injection tube back in when I get the Cat replaced with a #94416 Magnaflow Catalytic converter with tube. It is suppose to help improve the vacuum which is at 13-14 in. now.

Question is how to do this job since the Air Control valve tree is between the firewall and the upper intake manifold right near the PCV valve. It looks like a bitch to get the pre-bent tube in there either from the top or blindly from the bottom.

How does the tube connect to the hot CAT?

I had the problem before the engine replacement when the tube was making a screeching noise due to clearance problem with some sheet metal part.

Can I use any kind of high temp rubber tube, like silicon? Or any way of using a flexible tube? How do I get to the air valve to connect it. Should it have been blocked off if not used? Can this work w/o an air injection tube and still pass smog?

Any help on this is mucho appreciated.

Ron

 

your gonna need to remove the upper intake to get to that check valve. all there is to it. once thats off you should be able to drop the proper metal tube down from the top and connect it with clamps. Are you installing a hi flow cat?

 

The tube can be attached with a section of high-temp "emissions" hose that will withstand the temp of the CAT. Its not cheap but you should need less than two feet of it. Only the section that is metal tubing really needs this type of hose if you are going to replace it with something flexible. The Bassani Y-pipe uses a short section of this hose (they provide it) to perform this function when their Y-pipe is installed. Most parts houses and major chains will carry it.

 

You can get to the valve from underneath with the catalytic converter off if you're going to be replacing that anyway. I just capped mine when I replaced the cat

 

I don't know if I'm getting a high flow cat. All I know is that Magnaflow makes converters here in CA and most of them are not CARB compliant, so it may not pass smog test. Big brother in Sacramento has data base on all smog station activity. The Magnaflow # 94416 is CA CARB compliant according to the vendor I got it from.

I don't want to cap the air injection on the cat because it will screw up the vacuum and the mpg consumption. I know, because that's the way it is now.

I will get the air tube and re-connect it, probably from the top by removing upper intake manifold, unless the muffler guy will help me put it in when he removes the old cat. One good thing if I do remove upper manifold, I can fix the leaky gasket on the valve cover that is under the big casting. I just hate scraping gaskets too! This will be the 3rd time.

The problem is getting the right air tube for my bronco. Went to the ford dealer parts manager and the tube has several suffix letters -A to -D and hey don't know which is the correct one. Still calling around to find this info. If any of you know where to get the correct p/n, I'd appreciate it! Right now I think it is a E6TZ 5F235-B & e8dz-9A487-A Check Valve or a E9VZ 9A487-A Chk Valve if its the screw-on type. I'm getting them from PCI Inc up in St Paul MN. Great help & prices there http://www.pciinc.com See p/n pc-53, pc-39 and pc-37. Prices are ~1/3 of the dealer price!!

I checked the price of the high temp silicone hose, it cost more than the damm CAT!! It was ~$71 . Got it from Full line exhaust in 'bama. www.fle-online.com
ron