Gross Polluter help (3 Viewers)

[Terry Lindsey]

Oops, I did notice that my VSV port that goes to the EGR port seemed stuck. It’s a 78 carb on a 76 truck. The 78 has a mount with with brackets holding the idle circuit connections. Several ports are the but I plugged them because the 76 emissions don’t use them. There is an Egr port the that then loops up to the EGR port on the carb just below the throttle valve. So I hooked the VSV directly to that port. Here is a pic. The blue caps are the ports I bypassed.

 

[Terry Lindsey]

A little more info...3rd valve adjustment cuz..... when I first adjusted them I was reading the feeler gauge wrong. Then I did it cold. Once finished it ran strong but I could really hear lifter clatter. I did it again cold but added .002. No clatter, idles smoothly, but noticeable loss of power pulling a hill. Hmmm. I’m thinking one or more might be a smudge tight hence the smell of rich fuel at idle. I will try it again but this time do with the engine at operating temp.

 

[thebigredrocker]

The method of using "go no-go" feelers with the engine running is useful if you haven't tried it. Pin_head has posted about go no-go's. Had my video camera rolling and called out the valve #'s and their behavior. Then transfered my findings to paper and did a static adjustment with the engine hot. I did a couple rounds of adjustments and found writing stuff down helpful.

 

[Terry Lindsey]

After reading more and more threads on 2f valve adjustment, it appears that if you can’t hear a bit of valve lash clatter then it’s too tight. Dang! I’ll just keep trying as I refuse to have someone else do it

 

[FJ40Jim]

The carb is a 78 cali-spec. What wiring harness & ECU is in the truck?

 

[Terry Lindsey]

It’s is a 1/76 Fed specs. I have the vacuum maxed at 15, and now have it running pretty good. The vacuum retard dizzy is ported to the VSV. The only vac ports used in the carburetor is the TP and EGR. All others are capped

 

[FJ40Jim]

This pic shows a vac hose connected to the '78 HIC port on the front of the air horn. The 76 chassis has no connection for that.

 

[Terry Lindsey]

Hmmmmm, I’m confused. The top vacuum port on the air horn, if correct, is the power valve and is connected to the #8 position on the VSV (to Power Valve). The port directly beneath the PV port on the air horn (which I thought was the EGR port) is connected to #5 on the VSV labled ( to EGR port). Apparently I must be wrong on this but unsure. Can you elaborate a bit more? Thanks

 

[Terry Lindsey]

Hmmmmm, I’m confused. The top vacuum port on the air horn, if correct, is the power valve and is connected to the #8 position on the VSV (to Power Valve). The port directly beneath the PV port on the air horn (which I thought was the EGR port) is connected to #5 on the VSV labled ( to EGR port). Apparently I must be wrong on this but unsure. Can you elaborate a bit more? Thanks

FJ40 JIM, The more I thought about your reply the more it made sense. I’m definitely not a carb guy but always trying to learn. Sooo, since the 78 carb is different from a 76, and the emissions equipment are different (ie no VCV), I started comparing the two differences in vacuum piping. So now I’ve capped the lower port on the air horn (which I originally thought was the EGR port) and re-routed that vacuum line to the front passenger side carb base port (assuming that is the correct EGR port). Obviously I had to do a bit of adjustment to the fuel and idle mixture screws but it did smooth out and my vacuum actually went up a bit. I had my timing advance a bit too much (pinging) but I backed it off a bit which solved that issue. Hope I got it correct.