smog guru's
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Junior User
Joined: Mar 2004
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From: california
smog guru's
Ok gentlemen I'm having a problem passing the smog test here in Cali.
1979 F350 2wd 460/auto
calibration
-97J-R10 I believe
The problem is the EGR system is not working, no vacuum to the EGR?
How do you test the system?
I've replaced the VCV like the shop said and still nothing.I don't want to keep throwing money at this.
It's getting venturi vacuum to the VVA.
Any suggestions?
Thank you Vince
1979 F350 2wd 460/auto
calibration
-97J-R10 I believe The problem is the EGR system is not working, no vacuum to the EGR?
How do you test the system?
I've replaced the VCV like the shop said and still nothing.I don't want to keep throwing money at this.
It's getting venturi vacuum to the VVA.
Any suggestions?
Thank you Vince
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Joined: Jan 2003
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From: Addison,Texas
The way to test the VCV is to warm the engine up and then see if you can suck air through it. The way to test the EGR is the same (plugging lines as you go). Hook a hose up to the EGR and suck on it. Are you sucking air or does it hold vac? Is it moving? Does the engine idle rougher?
In your setup you need to check the vacuum can the same way (is it leaking?) and you need to see if the the delay valve delays is it dead.
If that all works, put a tee in the line next to the EGR and hook up a vacuum guage and rev the engine and see what you get. Then disconnect the venturi line from the carb and suck on that. Any movement on the guage?
If not, the amplifier is fried.
ash
['I'd replace the EGR if it's more than a few years old anyways.']
In your setup you need to check the vacuum can the same way (is it leaking?) and you need to see if the the delay valve delays is it dead.
If that all works, put a tee in the line next to the EGR and hook up a vacuum guage and rev the engine and see what you get. Then disconnect the venturi line from the carb and suck on that. Any movement on the guage?
If not, the amplifier is fried.
ash
['I'd replace the EGR if it's more than a few years old anyways.']
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From: california
Thanks ashvalentine
It turned out to have vacuum line crossed and now the system is working.
But, it still doesn't pass the sniffer.
Know the tech tells me the smog pump is no good.
So now I'm thinking to myself here we go again!
I pulled the hose off the smog pump and it didn't seem to be pumping a lot of air,so I change it.Did not help!
If anything I think all the changes made it worse.
Here are the readings before the changes.
HC ppm CO% NO ppm
max mea max mea max mea
15mph 256 425 2.61 2.52 2383 542
25mph 139 302 2.41 1.27 2533 522
After changes
mea mea mea
15mph 450 4.83 228
25mph 346 3.68 224
The only thing that came down was the NO everything else went up.
Now one tech says to lean the other says to rich.
Any ideas?
Thank you, Vince
It turned out to have vacuum line crossed and now the system is working.
But, it still doesn't pass the sniffer.
Know the tech tells me the smog pump is no good.
So now I'm thinking to myself here we go again!
I pulled the hose off the smog pump and it didn't seem to be pumping a lot of air,so I change it.Did not help!
If anything I think all the changes made it worse.
Here are the readings before the changes.
HC ppm CO% NO ppm
max mea max mea max mea
15mph 256 425 2.61 2.52 2383 542
25mph 139 302 2.41 1.27 2533 522
After changes
mea mea mea
15mph 450 4.83 228
25mph 346 3.68 224
The only thing that came down was the NO everything else went up.
Now one tech says to lean the other says to rich.
Any ideas?
Thank you, Vince
Last edited by fordtime; Apr 8, 2004 at 09:25 PM.
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Joined: Jun 2003
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From: Santa Rosa, Ca
I dunno about the mph, mine is measured at rpm here in ca, but I have a 351m in my 79 250 that passes with flying colors at 123000k A coil made by accel is cheap which will boost the spark to help burn the crud a bit better, how is your cat? temp is often the cause of not passing the test. Retard the timing and lean it out, rebuild the carb yourself if you can (saves money) and put some octane boost in it. Has it been tuned up lately? These suggestions should do it without a doubt. Seriously lean it out, this raises temp as well the other dude doesnt know what he is talking about. If you have many k on the engine, the compression is lower causing less heat, you need the heat to burn all the crud out. Only in this application is heat better. The smog pump is vital, it pumps the fresh air needed, and you should be able to tell if this is working anyways, I found out mine went bad one day at about 98000 when I heard loud chirping when I started my engine. Its ok to drive it if you cut the belt, but when smog time rolls around, its time to shell out the 50 bucks. Hope this reply helps.
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Joined: Oct 2003
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From: Central Coast, CA
I think you should find another shop. Your mixture is probably off and requires adjustment which should be easy to do with a competent mechanic that is familiar with SMOG and has the correct equipment. One very helpful thing to do is change the oil and bring it in for pre-test immediately afterwards. Oil works well to help absorb some of the HC's - especially if it's fresh. Sorry to read your stuck in an area where they have you on a dyno.
Last edited by tetraruby300; Apr 8, 2004 at 09:38 PM.
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From: Louisville,Ky.
High C/O's = too lean
High H/C's = too rich
This is a good rule of thumb anyway.
Maybe the cat converter has just quit working as it should. I have seen this happen, no rattles, guts still intact, but it wasn't reducing emissions as it should. Just an idea.
Jimmy
High H/C's = too rich
This is a good rule of thumb anyway.
Maybe the cat converter has just quit working as it should. I have seen this happen, no rattles, guts still intact, but it wasn't reducing emissions as it should. Just an idea.
Jimmy
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Junior User
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From: california
Thanks guys.
This truck does not use a converter, the exhaust is hotter than **** though.
I've been using the "search" on here and there is just too much, my brain hurts!
This place is great,so much info.
Vince
This truck does not use a converter, the exhaust is hotter than **** though.
I've been using the "search" on here and there is just too much, my brain hurts!
This place is great,so much info.
Vince
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Postmaster
Joined: Mar 2003
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From: Spokane WA
good lord, why do you even have to have 79 tested, whats your year for exemption there?
thats silly.
thats silly.
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Senior User
Joined: Aug 2003
Posts: 236
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From: Santa Barbara
I notice high HC, which is un-burned gas. I'm new to the Fords so I don't know about the carb a 460 comes with. 2150's like my 302 has have power valves that are prone to blow which then dump tons of gas down the carb and cause very high readings.
'75's are exempt this year. Our 79's will be exempt in 4 more years.
'75's are exempt this year. Our 79's will be exempt in 4 more years.
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Junior User
Joined: Mar 2004
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From: california
Ya, 2 more times through the ringer.
They will change the law again just like they did before!
I remember a bunch of guys that pulled off the smog last time around when anything 20years or older was exempt.Not getting caught by that game,I'm leaving everything the way it comes from the factory.
Anyways todays # are
15mph 364 3.48 258
25mph 317 3.11 263
After setting the timing at 6 degrees and playing with mixture screws while hooked up to the "sniffer" thats the best it will do.
They will change the law again just like they did before!
I remember a bunch of guys that pulled off the smog last time around when anything 20years or older was exempt.Not getting caught by that game,I'm leaving everything the way it comes from the factory.
Anyways todays # are
15mph 364 3.48 258
25mph 317 3.11 263
After setting the timing at 6 degrees and playing with mixture screws while hooked up to the "sniffer" thats the best it will do.
Postmaster
Joined: Aug 2000
Posts: 3,312
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From: Eldorado Ca. USA
ive been told that advancing timing to the max spec. allowed helps. Run chevron fuel. Oil change, plugs, cap, rotor, make sure the truck is completly warm. I dont know if the smog test in a bottle stuff works, ive heard it does... maybe it only works on cats, I dunno
I think you might need to go and do/have the carb rebuilt, or "borrow" one from a truck that passes. A good carb makes a world of difference. Id get a holley and YES, a Holley will pass the visual inspection, assuming you get the right model. Thats what I did on my '74 F250. The motor was so worn out that it leaked about 5 oz's of oil while being tested, but the carb (once jetted correctly) allowed the truck to pass smog.
I think you might need to go and do/have the carb rebuilt, or "borrow" one from a truck that passes. A good carb makes a world of difference. Id get a holley and YES, a Holley will pass the visual inspection, assuming you get the right model. Thats what I did on my '74 F250. The motor was so worn out that it leaked about 5 oz's of oil while being tested, but the carb (once jetted correctly) allowed the truck to pass smog.
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From: california
masterbeavis....you might be on to something there.
I've been thinking of swicthing the carb,I just happen to have a Holley 750 w/ vacuum secondaries and the kick down for the tranny somewhere out in the garage.
I brought the truck back home to go over some stuff.Well today I had the air cleaner off and noticed after I shut the truck off there was steam "gas vapors" coming out of the carb?
I climbed up and looked down the carb the butterflies were wet and there seems to be fuel dripping out of the boosters?
So I started the truck and checked the float bowl levels,they are set right.
So now I'm thinking rebuild this carb or change it to the 750 that I have if I can find it.
I've been thinking of swicthing the carb,I just happen to have a Holley 750 w/ vacuum secondaries and the kick down for the tranny somewhere out in the garage.
I brought the truck back home to go over some stuff.Well today I had the air cleaner off and noticed after I shut the truck off there was steam "gas vapors" coming out of the carb?
I climbed up and looked down the carb the butterflies were wet and there seems to be fuel dripping out of the boosters?
So I started the truck and checked the float bowl levels,they are set right.
So now I'm thinking rebuild this carb or change it to the 750 that I have if I can find it.
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Junior User
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From: california
You are probably right again about the 750 being to big.
I don't know anybody that uses anything smaller than 750 out here in the hood.
I'm thinking rebuild the stock carb would be the easiest way out at this point.
Don't really want to deal with setting up the 750 to run right,jetting,power valve,pump shot,ect...
Just want to pass the sniffer,I've got other projects I need to be working on at the moment.
I don't know anybody that uses anything smaller than 750 out here in the hood.
I'm thinking rebuild the stock carb would be the easiest way out at this point.
Don't really want to deal with setting up the 750 to run right,jetting,power valve,pump shot,ect...
Just want to pass the sniffer,I've got other projects I need to be working on at the moment.