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'87 air pump

having some problem with the air pump on my '87 f 250. took some members advice and had most of the pollution crap removed. Got through emissions test but carbon monoxide level is rather high. The air pump is still installed but when I put the belt back on it it backfires pretty fierce. A RV cam was installed before I got the truck. I more worried about next years inspection. How can I lower the carbon monoxide level? Is this related to the air pump?

Lawrence
 
having some problem with the air pump on my '87 f 250. took some members advice and had most of the pollution crap removed.
What did you remove (Catalytic Converter, EGR Valve)?
Why would you want to remove pollution devices?
You do not gain anything by doing so.
How can I lower the carbon monoxide level? Is this related to the air pump?
Yes it is.

Catalytic Converter System:

The engine exhaust consists mainly of Nitrogen (N2). However, exhaust also contains Carbon Monoxide (CO), Carbon Dioxide (CO2), Water Vapor (H2O), Oxygen (O), Nitrogen Oxides (NOx), and Hydrogen (H) as well as various unburned Hydrocarbons (HC). Three of these exhaust components--CO, NOx, and HC--are air pollutants so their emission to the atmosphere has to be controlled.

Removing the belt can also plug the Catalytic Converter and make it inoperative.
 
Well the little plastic tubes were breaking, couldn't get it to pass the inspection. It has passed the inspection but there is that back firing issue I'd like to clear up and I don't want the carbon monoxide level to rise. This truck has a carb rather than EFI. Does it have a cat? I'll check under the vehicle maybe. When I got the truck someone had "fixed" the system but most call it "buggering' it up! There was no belt on the air pump and when I put one on the back firing began.

Lawrence
 
The Catalytic Converter System is the only reason for the Air Pump. It supplies air to the Catalytic Converter to do its job.

The only thing I can think of would be you have a plugged Catalytic Converter and with the added air pressure from the pump it is backfiring.

Backfiring is caused by too lean fuel mix, valves leaking and timing most of the time. I do not see how any of the above would change by putting the belt on.
I take it the pump does turn free.

The little plastic tubes can be replaced with little rubber hoses.

I have an 85 250 351 with a Carb but I did know they made an 87 that way, is this an RV?
 
Not a RV. my mechanic advised me that all those extra bits weren't absolutely needed to pass the emission test. I was thinking about the plugged catalytic converter as well. I'm now wondering if I did replace and hooked up the air pump how much lower would my emissions be. This all relates back to whoever buggered the system in the first place.

Lawrence
 
No catalytic converter. So... why the back firing when the air pump is working? Would worn out plugs, wires be a possible cause? Timing off a tad? Would the RV cam have led to this?
 

BKW

Ford Parts Guru
[confused]

Smog pumps predated catalytic converters by ten years!
 

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