What's this vacuum port go to? (1 Viewer)

[muelbeedle]

My truck is running like a top, idling smoothly at ~650 rpm, but after doing the 'lean drop' method I've got the idle mixture screw turned nearly all the way out. Doesn't seem right. I have to believe this open vacuum port on the intake manifold, next to the brake booster line, is to blame. Tireless searching online doesn't show where this connects to.

I imagine I have many other vacuum routing issues, but let's start with this one.

Vacuum port on intake manifold

• muelbeedle
• Mar 1, 2016
• 1

 

[Joe_E]

Trying to remember off top of my head but it may go over to A/C idle up vacuum solenoid on fender.
Either way if you have nothing on there, it needs to be capped or it's a vacuum leak.

 

[FJ40Jim]

What Joe said: AC idle up VSV, located on wall of fender, separate from rack of emissions gear.

 

[muelbeedle]

Awesome, thanks guys. Really clears things up. Now I finally understand how pressing the "ac" button activates the ac idle on the carb. Beautiful.

 

[LittleRedWgon]

My truck is running like a top, idling smoothly at ~650 rpm, but after doing the 'lean drop' method I've got the idle mixture screw turned nearly all the way out. Doesn't seem right. I have to believe this open vacuum port on the intake manifold, next to the brake booster line, is to blame. Tireless searching online doesn't show where this connects to.

I imagine I have many other vacuum routing issues, but let's start with this one.

Vacuum port on intake manifold

• muelbeedle
• Mar 1, 2016
• 1

@muelbeedle Any chance you can post the image of the connection to the AC Idle up VSV connection??
I am having a hard time identifying it. Thanks!!

 

[Spike Strip]

 

[LittleRedWgon]

Thanks, @Spike Strip ! I have a few other questions...you got a minute? hahah.

BELOW______Is this Right???

BELOW____This connects here, correct??

 

[Spike Strip]

All those diagrams are in the Emissions FSM, which show much better than I can explain. May take a bit of study, though, but worth it for understanding. Emissions FSM has big pix.

pdf copy in my sig line.

 

[LittleRedWgon]

Also, a few questions about the VSV's...
The spec sheet that I looked at said that the Distributor VSV is a Brown, The Carb is a Green and the other is a Blue...

When I purchased the New VSV per the part for the Distributor one..it came like this...Is it correct? or as I saw in forums..that maybe this should be a green or blue??

 

[LittleRedWgon]

Thanks, I went off of this, but had a few unanswered questions... some things not showing. Will keep working on it. Much appreciated.

 

[LittleRedWgon]

sorry...but I Also had a few questions about the VSV's...
The spec sheet that I looked at said that the Distributor VSV is a Brown, The Carb is a Green and the other is a Blue...

When I purchased the New VSV per the part for the Distributor one..it came like this...Is it correct? or as I saw in forums..that maybe this should be a green or blue?? Not clear per the Forum or the spec sheet..any thoughts would be helpful.
Thanks!

 

[Spike Strip]

Those are Vacuum Transmitting Valves - They delay the vacuum slightly.

I don't think there's supposed to be anything between the EGR valve and the EGR Vacuum valve...

The others look correct, but those new VCVs may be superseded parts that replace the older one. Not sure.