Is the PCV valve suppose to be creating suction after i rerouted it?? I don't feel anything sucking? I even sprayed some carb cleaning up the hose, but the idle didn't change at all.
Here are some pictures of what I had done to the PCV valve. Does this look right?
We just stuck a bolt in the intake manifold vacuum port that WAS connected to the PCV valve, put some silicone on it, and hose clamped it. Think this will work?
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Hi Drew. Yup Looks good to me! Those first 2 pic's are a very good depiction of how to do this. And yes the other hose winding under the air duct looks like the passive/ breather hose. The open end connects to the air cleaner box,right? If so you are exacto-mundo!!
Done this way (the right way) there will be no vacuum signal at the PCV Valve. Not connected to a manifold Vacuum source anymore. May be a little vac. present under heavy throttle/load due to air flow through air duct (Venturi Vacuum) but you should not feel any vacuum there any more.
And your bolt/silicone block off should work OK. give it a day or two to totally cure then a short blast of cheapo carb clean on that at idle--if no idle speed reaction its good. Ya want to be sure if you do that trick again to be sparing w/ silicone don't let any get ingested into engine, probably cant hurt much(dont get it into crankcase it can foul/block the oil pick up screen bad for oil pressure!) It can foul an O2 sensor if it makes it downstream. Good creativity using galvanized fittings hadn't thought of that...but long-term corosion issue?? Ya got a lot to check out under that hood! Treat every hose/connection as suspect 'till proven OK. When I got like that I found/killed a bunch of small hose vac.leaks/potential ones! on my Subie.
Carry on, Luke, Thanks for excellent pics too!
Tracyg Gadgetman Reno
Founder and Constant Aide to Gadgetman
Gadgetman Reno, NV
So now I'm working on trouble codes and vacuum. Please, see my other post to help with my trouble codes. So I have a Mityvac pump that I started doing some tests with. I no the general idea of the system and have worked some with vacuums lines, but this is really new for me to go this deep into them. First I need to mention that i have used carb cleaner and also a propane setup to go around the manifold as well as some of the vacuum lines and components. There was absolutely no change in idle with either substance. I'm a little lost with how to use the pump to test the lines. I have read the book and ran the tests that the book mentioned. I hooked the pump on a port close the manifold. On a cold start up the pressure was just under 15 and steadily increased to a little under 17. I let the van warm up after that, but the pressure never went above a 17 at idle. No strange drops or increases either. So where should I go from here? Do I need test EVERY individual vacuum line? and how do I know that every device that a vacuum line is hooked to is not leaking vacuum? is each device suppose to hold pressure? Any tips would help. Maybe even some detailed steps that you might take when testing a vehicles vacuum system. thanks.
I am sorry you have to get hit with one of these "problem children" to start your career as a Gadgetman. But it is what it is... Perhaps you can connect with one of the family. We'll see if anyone offers, but if not, you're going to have to solve this one yourself.
With a manifold vac of only 17 at idle, that is a statement of poor integrity of your manifold. Somewhere, something's leaking. It may be almost anywhere, so you have to practice the process of elimination.
I start with the largest hoses and check them. They would be the Booster and the IAC. As you have already done the PCV (are there TWO vac lines to this? CAP THEM BOTH@ Ford is the only MFGR that uses two-SOMETIMES-of which I am aware and you gotta get them both.) then move on from there.
On the brake booster, just put your vac pump on the hose at the intake manifold. Start ALL your testing of sub-systems there and when you find a leak, trace it back to source and correct it.
On the IAC, here's a good way to see if it's closing. Remove it from the intake. Two 8mm bolts hold it in place. Cut a new gasket (you can use a business card), opening only ONE of the ports for air and reinstall it.
The engine will stumble, no doubt, but with the port closed the manifold vac should be in the range of 19" hg.
There is one other suspect connection. That is in the line that feeds the climate control for the cab. FREQUENTLY leaks develop there and no one catches them. IMHO, these are the 'silent killers' of your MPG.
So, get ready! You may find the leak right away, and you may spend a few weeks on it as you explore.
The LAST place to look at is the manifold gasket itself. The Chevy 305 and 350 series engines are notorious for leaks from exhaust gas passage directly into the intake ports on the heads. Invisible and impossible to diagnose, when all other options have been exhausted, replace the gaskets.
Several have done this and found another 20% MPG gains hiding there, so it is something to look at, even if you're already happy!
Ultrashotone has resurrected an old thread from 3 years ago. I remember this one, and, it's a really good one to read completely through for ALL the info. This old Ford van Groove job, and the thread, plus the original post referenced by a link at start of this thread, is a pretty complete study of what Gadgetmen need to be aware of. This 90's era Ford TB is typical for that OBD1 era in Ford's, and it's confusing to look at. So is the engine bay!
Looking at those pics again, 3rd one down, he's holding the hose, I see where it looks like Drew used a Ford PCV valve as a hose tee in his PCV valve re-route. I avoid that kind of thing doing custom hose work. Sometimes we need to get creative but I would have gone to the parts store and just bought new stuff.
Drew cut beautiful Grooves in this TB! But, we see that there's more to this work than just the Groove itself! I bet- if the vacuum leak issue was solved, and if Drew still comes here, we could still help him with this stubborn Ford. Heysoundude's Pre-Groove Prep tricks would be beneficial here.
So Thanks, Ultrashotone, for digging this one out of the Index, it's a good one! BTW, that pic you posted, from the Index, is that a GM TB?
Founder and Constant Aide to Gadgetman
Gadgetman Reno, NV