help Colorado failed emissions
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help Colorado failed emissions
Ok I have an 86 f250 with the 460 and my hc is triple the allowed I have not seen a cat on this truck it is carbed so no o2 sensors and no computer to speak of closest thing to a computer is the ignition control module and I had it tested and it passed did this truck come with a cat and if not would it fix the problem if I put a universal on it?
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Joined: Jun 2012
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From: Albuquerque
I picked up a '86 F150 with a straight six and a one barrel carb. It failed the New Mexico emissions test the first time I took it thru even though it had a cat in place.
The problem was the carb (dreaded feedback carb) needed rebuilding and I'm not sure what condition the cat was in.
I replaced the carb and ignition system with a Duraspark II system and a 600cfm vacuum secondary Holley carb. Then added a dual exhaust with two universal cats.
Even without rejetting hte carb for our higher altitude, the truck passed on both idle and cruise.
I think that I was nearly 10x over the limit on idle the first test and several times over the limit on cruise.
The air pump on mine had been previously disconnected and I removed it completely, so there is no additional air pumped into the cats.
TR
The problem was the carb (dreaded feedback carb) needed rebuilding and I'm not sure what condition the cat was in.
I replaced the carb and ignition system with a Duraspark II system and a 600cfm vacuum secondary Holley carb. Then added a dual exhaust with two universal cats.
Even without rejetting hte carb for our higher altitude, the truck passed on both idle and cruise.
I think that I was nearly 10x over the limit on idle the first test and several times over the limit on cruise.
The air pump on mine had been previously disconnected and I removed it completely, so there is no additional air pumped into the cats.
TR
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
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From: Exmore, VA
help Colorado failed emissions
Ok I have an 86 f250 with the 460 and my hc is triple the allowed I have not seen a cat on this truck it is carbed so no o2 sensors and no computer to speak of closest thing to a computer is the ignition control module and I had it tested and it passed did this truck come with a cat and if not would it fix the problem if I put a universal on it?
Old School Hot Rodder
Joined: Feb 2006
Posts: 6,472
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From: Exmore, VA
dragonisfury, does your truck have the Thermactor system (air pumps) installed and functioning correctly? I am pretty sure that is what Ford used to clean up the exhaust on these. Also be sure it is being tested for the correct weight class. I seem to remember the idle mixture setting on these was a royal PITA to do according to Ford's procedure. I can't find a copy, but I seem to recall it used a propane enrichment. If I can find my 86 emissions manual I will try to scan and post the procedure.
Post Fiend
Joined: Jul 2004
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From: Northern California
Also be sure it is being tested for the correct weight class. I seem to remember the idle mixture setting on these was a royal PITA to do according to Ford's procedure. I can't find a copy, but I seem to recall it used a propane enrichment. If I can find my 86 emissions manual I will try to scan and post the procedure.
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Old School Hot Rodder
Joined: Feb 2006
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From: Exmore, VA
Mine had the two "smoke grinders" on it, one fed 6 of the 8 exhaust ports (ones at the crossover had undrilled "nozzles"). The other one fed all 8 at the manifolds through a stainless steel "spider". If one or both are missing you probably will have high hc.
Is everything in your distributor, vacuum and centrifugal advance working correctly, these engines use a complex set of vacuum plumbing, the end result though is warm you have vacuum on the distributor advance all the time. If they are doing a run up type check rather than just at idle that will kill you. Since I don't have emission testing here, I don't know what the procedure is.
Setting the mixture by vacuum will give you too rich a mixture which will cause high hc. One trick the Turbo Mopar bunch used to do to get some of the T2 engines through and I have seen it used other places too, fresh oil change, new PCV valve and take it right in for testing.
Does your truck have the electric pumps or an engine mounted mechanical one? If the mechanical one make sure it isn't leaking into the engine, that will kill the hc test as the PCV system is sucking gas fumes.
Is everything in your distributor, vacuum and centrifugal advance working correctly, these engines use a complex set of vacuum plumbing, the end result though is warm you have vacuum on the distributor advance all the time. If they are doing a run up type check rather than just at idle that will kill you. Since I don't have emission testing here, I don't know what the procedure is.
Setting the mixture by vacuum will give you too rich a mixture which will cause high hc. One trick the Turbo Mopar bunch used to do to get some of the T2 engines through and I have seen it used other places too, fresh oil change, new PCV valve and take it right in for testing.
Does your truck have the electric pumps or an engine mounted mechanical one? If the mechanical one make sure it isn't leaking into the engine, that will kill the hc test as the PCV system is sucking gas fumes.
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Post Fiend
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From: Northern California
One trick the Turbo Mopar bunch used to do to get some of the T2 engines through and I have seen it used other places too, fresh oil change, new PCV valve and take it right in for testing.
Does your truck have the electric pumps or an engine mounted mechanical one? If the mechanical one make sure it isn't leaking into the engine, that will kill the hc test as the PCV system is sucking gas fumes.
Old School Hot Rodder
Joined: Feb 2006
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From: Exmore, VA
I have never seen a factory system with both types of pumps. My timing cover had the hole but no pump from what I remember. One of the fuel pump bolts held the lines to the timing cover.
Post Fiend
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From: Northern California
The 460 and the 400 could have both. In-tank pumps to circulate the fuel, and a mechanical pump to bring it up to the carb.
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From: Virginia
1st I have heard of this too. The ones I am familiar with had one pump in each tank, and the orifice return thing at the carb. But knowing Ford and the wacky stuff they did, who knows what could be on these trucks.
Post Fiend
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From: Northern California
Here is a thread that discusses a few variations etc...
There are some weird variants, I agree...
https://www.ford-trucks.com/forums/1...me-please.html
There are some weird variants, I agree...
https://www.ford-trucks.com/forums/1...me-please.html
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