Engine Smog Pump Hose Routing...thinking Out Loud Here.

[Mustang5L5]

So just want to run this by you guys. I no longer need to take the sniff test, but I run cats. I plan on running a bassani catted X-pipe, featuring 2 cats.

My TFS170 heads do allow for hooking up the crossover tube, but my thought it without the two pre-cats upstream of the o2 sensors, there's no point really. So my plan was to remove the diverter valve and leave the bypass valve hooked up and run it directly to the h-pipe. I'll probably reroute it all through the fender so it's not even seen.

This way, my cats are happy and efficient, and I can eliminate this plumbing from the engine bay completely.

I'd imagine this would give me a code 44/94 since the diverter can't send o2 to the heads and the o2 sensors won't see this. Shouldn't be a big deal though...or would it?

 

[Blandnuts]

I'll be doing something similar when I go through the exhaust. I'm still debating on getting ride of everything minus the cats and dealing with the premature failure of the cats.

 

[Mustang5L5]

I'd just let it ride too...but catted H/X pipes are expensive.

If I eliminate the pipe to the heads, I can run most of that stuff inside the fender anyway...I think

 

[jrichker]

So just want to run this by you guys. I no longer need to take the sniff test, but I run cats. I plan on running a bassani catted X-pipe, featuring 2 cats.

My TFS170 heads do allow for hooking up the crossover tube, but my thought it without the two pre-cats upstream of the o2 sensors, there's no point really. So my plan was to remove the diverter valve and leave the bypass valve hooked up and run it directly to the h-pipe. I'll probably reroute it all through the fender so it's not even seen.

This way, my cats are happy and efficient, and I can eliminate this plumbing from the engine bay completely.

I'd imagine this would give me a code 44/94 since the diverter can't send o2 to the heads and the o2 sensors won't see this. Shouldn't be a big deal though...or would it?

That should work , but it may pose problems with the visual inspection.

The same bolts that bolt the accessory brackets to the front of the engine bolt the crossover tube to the ports on the back of the heads. If passing the visual inspection becomes a problem, just bolt the crossover tube in place and hook up its plumbing. It won't do anything, but it will look factory stock.

 

[Mustang5L5]

That should work , but it may pose problems with the visual inspection.

No visual here. Hood stays closed and there's no sniffer test.

I just prefer to run cats and don't want to destroy them

 

[jrichker]

No visual here. Hood stays closed and there's no sniffer test.

I just prefer to run cats and don't want to destroy them

It won't hurt the cats to do what I suggested. The crossover tube is only operational for the first 1-2 minutes. After that the airflow from the smog pump switches to feed the cats. On a properly tuned and running car, you'll never see any difference in the life and operation of the cats.

 

[kendawg73]

hmmm, I have a UPR catted x pipe, but it doesn't have a hook up for the air.... would that still be needed then? I wasn't planning on putting the smog pump back on my when the engine goes back in.

 

[General karthief]

To comply with the U.S. Environmental Protection Agency's stricter regulation of exhaust emissions, most gasoline-powered vehicles starting with the 1975model year must be equipped with catalytic converters.[1][2][3][4]These "two-way" converters combine oxygen with carbon monoxide(CO) and unburned hydrocarbons (HC) to produce carbon dioxide(CO2) and water (H2O). In 1981, two-way catalytic converters were rendered obsolete by "three-way" converters that also reduce oxides of nitrogen (NOx);[1] however, two-way converters are still used for lean-burn engines. This is because three-way-converters require either rich or stoichiometric combustion to successfully reduce NOx.
Got this from internet search, basically the modern-day cats don't need the air pump, different scientific stuff inside.

 

[Mustang5L5]

It's a little misleading. Modern cats with modern engines don't need the air pump, but our older 5.0 engines don't burn as clean and need a little help by way of air injection to aid the conversion process.

So even modern cats can foul when run on the older "dirtier" engines.


I actually don't care about passing the sniffer test. I just a) want cats, and b) don't wait to ruin my expensive cat pipe

 

[imp]

It's a little misleading. Modern cats with modern engines don't need the air pump, but our older 5.0 engines don't burn as clean and need a little help by way of air injection to aid the conversion process.

So even modern cats can foul when run on the older "dirtier" engines.


I actually don't care about passing the sniffer test. I just a) want cats, and b) don't wait to ruin my expensive cat pipe

My '94 GT, bought in May, and finally getting "caught up" had a shorter belt routed to miss the smog pump. The hose plumbing was missing altogether along with the diverter valve and bypass valves. The 2 check valves just hung there on their steel tubes. The vacuum lines for the valves were still there, plugged, and tucked inside the fender. Ripped out the inner apron, found both solenoids still hidden there, with vacuum lines running up front.

Running this way produced no codes (??). I bought the valves, the diverter came with a twisty steel bracket, which I could find no mounting place for, so the 2 valves hang supported by the hoses. Pump turns smoothly, puffs out lots of air. The valves seem to be switching airflow as expected. No different "feel" to the quality of running, fuel economy seems up a bit, but can't positively say smogware did that. imp