A few basic questions
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New User
Joined: Apr 2005
Posts: 15
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A few basic questions
Hello, the 1981 300 2bbl carb ford f100 did not go through inspection. The main reason being was emissions. The max was 200, something, and it was at 700. I recently did a tune up, and had the truck out on a long trip. The guy I bought the truck from took it through inspection 3 months earlier and it went right through.
Here are my questions on this topic:
I gapped the plugs to .35, is this too small for this engine?
Should i try "gauranteed to pass"?
Would running high test, greatly help emissions?
If i added another catalyitc converter on the exhaust, would it make a difference, the one already on there is fairly new.?
I hope I didnt buy another money pit.
Here are my questions on this topic:
I gapped the plugs to .35, is this too small for this engine?
Should i try "gauranteed to pass"?
Would running high test, greatly help emissions?
If i added another catalyitc converter on the exhaust, would it make a difference, the one already on there is fairly new.?
I hope I didnt buy another money pit.
Elder User
Joined: Dec 2003
Posts: 633
Likes: 1
This is where the newer trucks with computers are nice. I'd ask the last owner where he took it. I really doubt much has changed in 3 months and they probably passed it for him (wink, wink). If the cc is fairly new I wouldn't think adding another would help.
Is the emsission light on - does it come on?
Was there a problem with the truck that you gave it a tune up? (if so what)
Did you check your timing afterwards?
Also which test did it fail? (assuming they look for more than 1 thing)
After I gave my truck a tune up and fixed a few vac leaks, I had to adjust my carb because it had been messed with to make up for zero maintenance. If the truck is in reasonably good shape and runs decent, I'd think you'd be OK -not a big $ fix.
Try and give a few more details and I'm sure someone will help out.
Is the emsission light on - does it come on?
Was there a problem with the truck that you gave it a tune up? (if so what)
Did you check your timing afterwards?
Also which test did it fail? (assuming they look for more than 1 thing)
After I gave my truck a tune up and fixed a few vac leaks, I had to adjust my carb because it had been messed with to make up for zero maintenance. If the truck is in reasonably good shape and runs decent, I'd think you'd be OK -not a big $ fix.
Try and give a few more details and I'm sure someone will help out.
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New User
Joined: Apr 2005
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The truck failed for hydrocarbons. The max regualtions was 200 something, the truck was putting out over 700. The tune up consitsted of breather, pcv, air filter, belts, power steering flush, coolant flush. I check the distributor cap and rotor button. both looked fairly new. I also regaped the plugs, details already posted.
This is a 1981 so there is no emission light. There did not appear to be any vacuum leaks, although i do not have a vacuum gauge.
As far as the timing, would advancing or retarding help it? Not sure what the factory spec is, i want to say 29 past tdc. I think i will also try leaning out the enige by adjusting the carb.
Anyone else have any idears or tricks to get this beast through emissions??
This is a 1981 so there is no emission light. There did not appear to be any vacuum leaks, although i do not have a vacuum gauge.
As far as the timing, would advancing or retarding help it? Not sure what the factory spec is, i want to say 29 past tdc. I think i will also try leaning out the enige by adjusting the carb.
Anyone else have any idears or tricks to get this beast through emissions??
New User
Joined: Feb 2005
Posts: 8
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When I had a 85 E 150 van with a 300ci, 1 bbl. it would fail emission testing. I would put 1/2 tank of high test & a can of slick 50 fuel treatment in it. It would pass with better numbers than my 5.0 mustang. Make sure choke is opening all the way & the idle is set right, alittle high will help sometimes.
Posting Guru
Joined: Sep 2003
Posts: 1,192
Likes: 1
From: lino lakes, mn
hydro carbons are unburnt fuel could be a plug ,plug wire, bad cap,float to hi or a rich idle mixture try adjusting the idle mixture on the card do a lean roll adjust the idle to say 700 rpm the adjust the mixture screw until you achieve the highest idle do not adjust the curb idle just with the mixture screw once you atain that turn the mixture screw back in until the idle drops 20 rpm that way you know youir at the leanest idle you can get then check all the other stuff also make sure the choke is completly open a reading of 700ppm sounds like a cylinder missfire or really screwed up choke .adjust and check everything then check it again then poor a can of heet gas line deicer or two into the tank before you retest
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Post Fiend
Joined: Jan 2000
Posts: 5,330
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From: Dryden, ON, Canada
Plugs should be .040-.045, timing spec is between 8 and 14 degrees BTDC, varies by gear ratio, emissions equipment, GVWR and transmission, it's on the emissions tag on the radiator support. 10-12 should run well.
I second the lean adjust on the idle mixture, assuming that the failure was with it at idle.
I second the lean adjust on the idle mixture, assuming that the failure was with it at idle.
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Lead Driver
Joined: Dec 2002
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From: Kuna ID
Running quality gas is good, but don't go with a higher octane rating. The higher the octane, the slower the gas burns which means more raw fuel is coming out the tailpipe, which will cause you to fail a smog test. I learned this by reading the back of a box of that Guaranteed to Pass. I had failed the test 5 times with my mustang, running 91 octane, played with the carb, the timing, tuned it up, nothing. I switched to 87 octane and it passed no problem. If you are already running low octane you don't have to worry about this then, but I am just letting you know, higher octane will only make it worse. When I smogged my truck earlier this year and it failed, I got lazy and paid a shop $60 to adjust it for me. You need a special tool to adjust a 4bbl on an 85 460 anyhow.
Cargo Master
Joined: Jun 2005
Posts: 3,045
Likes: 21
From: The Ole' North State.
HC's or hdydrocarbons are unburnt gasoline. measured in ppm, or parts per million. There are some basic ways to bring it down, for emissions passing. First, change the oil. YES. Exhaust gasses build up in the crankcase, and cause more unburnt fuel. Second lean the mixture out as much as possible. The tests are usually not done under load, so if you have to lean in out in the parking lot the more the better. Make sure your coil is good. the hotter the spark, and the more complete combustion the less HC's you get. EGR valves are big things in this area, make sure it is WORKING. pull it off and check for carbon deposits. They can be cleaned with brake clean if necassary. If you still don't pass then, make a new friend.. .because it's going to start getting expensive.
-josh
-josh
