'78 150 Ranger Lariet, 351m, (?) 72 11 calibration

I want to find ORIGINAL, FORD info on my vacuum diagram if it exists? I have the faded, hard to see copy of the original diagram. I can't see what I need to see on it. I want to read about my set up and understand why Ford did it on this truck.

I know there are multiple vacuum system arrangements for the 78 351m, but surely Ford provided the original info on each set up to somebody, i.e. new owners, dealers, ect.

Purchased entire volume of service manuals on eBay. They have nothing specific on my vacuum set up. Any ideas?

http://i649.photobucket.com/albums/u...0/7-72-R11.jpg

 

yeah, that's what i have found too. I have two sets of shop manuals for my 70's Fords, complete, but the emission sections are scant. I think early 1980's you started seeing more detail in vacuum line routing, in these manuals. I had a set of GM manuals for a 1987 Buick T-Type and there was no vacuum diagram. I had to buy a cheapo Chiltons to find out proper routing. and that was back in the day when you had miles and miles of vacuum lines in motors.

 

Hey Mike,

I am afraid you won't find that info. I looked for a long time and found the same diagram you have - the only one that works with my truck. The factory diagram under the hood on mine is long gone.

I decided to try a different carb so I made a drawing of the vacuum lines just in case and installed the new carb. The new carb DID NOT WORK! So, I went back to the 2150 - unfortunately I lost my drawing. I spent countless hours trying different vacuum set ups, looking for diagrams on the internet (I've seen about 20 different ones) and nothing worked until I found the Ford diagram we are talking about. I Googled it and that is what brought me to FTE.

In your other thread you were calling the ports on the pvs hot and cold. I'm not sure where you got that. So, forget hot and cold as you had labeled them. As I told you before the pvs selects the vacuum source. It has two options ported and manifold depending on temp. If you don't have other emissions equipment on your truck then this diagram works.

If you don't have Photoshop (or similar) to sharpen the image so you can read the info maybe you could have it done by a friend or local print shop.

Mark

 

Thanks for response guys. D24x4, I was just using hot/cold reference to explain that the port on PVS closest to thermostat is closed while engine is cold w far port open; and at fully hot engine far port closes and other opens. Center port staying open always. Think we're saying same thing?

 

Mike,

Yep, we are on the same page - almost. Cold start you are right. Now, let's say the passenger side port (ported vac) is normal operating temp - not hot - pvs switches to that at normal operating temp. If the engine gets above normal operating temp the pvs will switch back to drivers side port (manifold vac) to increase RPM to help cool the engine. This has never happened to me but it is the way I understand it is supposed to work.

Glad I could help.

Mark

 

Agreed. But here's what I don't get that prompted my original thread: If it ever does get that hot and needs cooled down, the driver's side port, closest to thermostat, opens and now requires manifold vacuum to advance timing, but the "hot" port runs to spark port, then onto vacuum amplifier. Where's manifold vacuum coming from? Everything you read about the 3 ported PVS says that port was intended to run to manifold vacuum for this very purpose. Mike

 

Hi guys, I'm no expert on emissions, but have you seen this publication (it's listed on eBay and I bought a set a couple of weeks ago).
78 Ford Service Highlights

Not sure it has what you're looking for, but I thought I'd toss it out there anyway.

 

memoryman does it contain vacuum diagrams?

 

here is a list of calibration codes, not sure if it will help or not...

Calibration Coding & Tune-up Specs

 

Thank you. Appreciate it.

 

Mike,

Your desire to learn everything about this is great. You are just getting confused a little. So, you just need to take a deep breath, clear your mind, get a cold one if you need to and look at things from a different angle.

Mind clear? Good to go? OK, you said above the drivers side port was closest to the thermostat - I think you meant farthest from the thermostat. Right? So, lets go through this again.

You have the answer - look at the drawing again. We already went over the passenger side (ported vacuum) port on the pvs. Line goes back to the carb, T to pick up the spark port on the carb, and back to the vac amplifier. This is one vacuum source - Right? Center port on the pvs goes to the distributor vacuum advance - OK? The driver side (manifold vacuum) port on the pvs, line goes back and Ts into a vacuum line coming from the intake manifold (MANIFOLD VACUUM) and continues to the bottom of the vac reservoir. This is the second vacuum source. The drawing clearly shows this. Right?

Based on this you have two different, independent vacuum sources. They are separate and DO NOT work together at the same time. So, since you like to refer to these ports as cold and hot, we could say driver side (MANIFOLD VACUUM) port on the pvs is open when the engine is both cold and hot. While the passenger side (ported vacuum) port on the pvs is open when the engine is at normal operating temp. The PVS selects which source is needed from coolant temp and continues to the distributor through the center port on the PVS. Are we on the same page?

Two separate vacuum sources, ported and manifold, only one is used depending on temperature. Does this help?

Mark

 

I made one mistake in last post saying port closest to thermostat was on drivers side. FORGIVE me. But my basic question remains unanswered. I don't think your focusing on the question. The technical name, and typically labled as such, for ports on 3 port PVS are manifold (closest to thermostat) distributor (center) and Carb (last/end/farthest from thermostat) MUST understand this to understand my question. Now, you're sitting at stop light on a hot day and your engine EXCEEDS normal operating temp. Your carb port now closes leaving dist and mani ports open. You now need MANIFOLD vacuum to advance the timing and lower eng temp. With me? The open PVS port your counting on to provide manifold vacuum is hooked up to THE VACUUM AMPLIFIER. Where's the beef? Somebody help me here.

 

Mike,

WOW! I AM focused on the question - YOU are not focused on the answer. Unbelievable. I completely understand your question - I have tried to help you and you have the original Ford drawing - what else do you need?

Passenger side port on the PVS = Ported vacuum and comes from the vacuum amplifier, picks up the S (Spark) port on the carb and continues to the passenger side port on the PVS. Center port on the PVS = distributor. Driver side port on the PVS = Manifold vacuum and comes from the vacuum line coming from the intake manifold at a T and then continues to the vacuum reservoir. I don't know where you got your info on the PVS and I don't care what you call the ports. You did not clear your mind and you did not answer any of my questions. You are just stuck on this where does the manifold vacuum come from when you already have the answer.

Your last post does not make sense - "Now, you're sitting at stop light on a hot day and your engine EXCEEDS normal operating temp. Your carb port now closes leaving dist and mani ports open." Your ported vacuum port closes and yes the distributor and manifold ports are open - see above! "You now need MANIFOLD vacuum to advance the timing and lower eng temp." Yes - driver side port - manifold vacuum is open! "The open PVS port your counting on to provide manifold vacuum is hooked up to THE VACUUM AMPLIFIER." NO IT IS NOT!!!!

So, I am done with this conversation. Good luck with your truck.

Mark

 

Mark, don't be so sensitive. I was just giving you a taste of your own medicine. You were starting to beat me up a little bit there. If you understood my question from the beginning you would of simply said that the PVS port farthest from the thermostat opens at above average operating temp and provides manifold vacuum in our set up. And that my understanding of the PVS was wrong. Unfortunately, I think your wrong and I'm right. I'm going to call the manufacturer and find out. Do you know anyone on this forum that could jump on this thread and settle this?