Hi all. I just got a 1987 F250 with 460 - Carbureted. Almost ALL of the vacuum lines under the hood have beeen broken or disconnected or rerouted. Not a big deal, still have the diagram under the hood and printed one out from this forum to work with. It seems the only thing I am missing is the vacuum restrictor going to the distributor. I even found a resource for that from this forum (thanks numberdummy!).

Anyway, I do not have the proper routing for the vacuum lines serving the cruise control or heater controls. There are the remnants of three vacuum hoses going to a junction block on the passenger side firewall just under the cowel. I'd like to ask if anyone has a diagram for those systems.

Also, while i'm replacing all these miles of vacuum hoses and other repair work, I would like to remove the TWO smog pumps just for easier access to everything I do intend to put them back on when I'm done. As long as the check valves are functional and the vacuum lines to the diverters are capped, is that sufficient to run the truck for troubleshooting/setting timing/etc. I figure once I get the bugs worked out and the truck running well, I can put the pumps back on and hook of the hoses again and be on my way.

Thanks!

 

Yes disconnecting and capping the vacuum lines on the smog system is sufficient and safe for your purposes, but also consider the following..

Does the truck still have a cat and/or do you need to use one for emissions purposes? If one isn't required and won't be used then there's no point having the air pumping system on the motor at all because feeding the cat is it's only purpose in life.

 

Thanks for the info. I do have emissions testing in Texas. They don't do a visual, but its all there so I may as well get it hooked up correctly. There is current talk of the Federal Clean Air emissions regulations act being forced upon every state. If that passes, I'l eventually be stuck with a non-compliant vehicle. When I was a teenager, the first thing we did was rip out all the emissions control stuff. But that's only because we lacked the patience to troubleshoot what was actually wrong with the system.

Anyone with the additional vacuum diagram?

Thanks.

 

I have a similar truck without cruise.

On my truck the three port junction block on the firewall has one line going to manifold vacuum at the same point on the intake manifold as the brake booster.
Another port passes into the cab through the blower box just beneath the heater hoses.
The third port is capped.

If the truck is over 8500GVW it should never have come w/ cats and this would be stated on the compliance sticker on the underside of the hood. "NON-CATALYST"

The only vacuum diagram I have is for emissions controls, so I am subscribing to this thread to see what turns up.

 

First of all, the port on the firewall port does in fact go to cruise control. I found a vacuum diagram on the autozone webiste - believe it or not.

THe vacuum hose repair went better than expected. Small vacuum hose fits perfectly over the hard line stuff. This allowed me to patch together and use the existing color codes at least for the very ends of the lines. The only part of the system I have capped off now are the lines for the air cleaner that go to the cold weather modulator and the bi-metal.

ArdWrknTrk, you are absolutely right about "non-catalyst" on the underhood label! I just assumed all vehicles of this age were required to have cats.

It started raining before I could get much further. I took a beer break and decided to brave the rain and start the truck to see the effects of the vacuum leak repairs. Then my starter hung up and just started spinning non stop. Brand new solenoid too! Pulled the wire off the start terminal and still kept spinning. Guess I will be hunting electrical problems today!

 

I did not mean to say that there was not a vacuum line going to your cruise control.
I said I did *not have cruise* and the third port *on my truck* was capped.

New starter solenoids often fail right out of the box, now that they're being made in China.
I went through 5 (three of these from different Ford dealers- Genuine Motorcraft -) before giving up and going to the junkyard to find one that worked.
If you can give it a whack and it stops cranking the contacts inside are welding together.
The small red wire at the top is the trigger wire. If you find 12V there with the key in run as well as start position then you may need to adjust the electrical portion of your ignition switch.

Hope this helps.

 

Wow, I read my last reply/post and it really sounded like I was being rude! Hope no one took it that way. I was just reaffirming that the the other vacuum port was for the cruise control as you had suggested. Was not at all meant to sound snotty, so apologies in advance. Teach me to try and write stuff at 6 in the morning!

The brand new solenoid was internally welded together as well. Getting continuity across the big terminals - no 12V on the start terminal.

Ok - enough on this thread. I'm starting another one on everyones favorite topic - dual fuel tanks. Thanks for all the help!

 

I didn't mean to sound pissy either.
Sorry if I came off that way.
I was just trying to affirm that I don't know where the cruise would hook up.

CU on the new thread....

 

i have the same truck, 1987 F250 with 460 carbed, and i wanted to know what vacuum lines i can plug to get rid of the emissions/smog stuff.
i think i have a vacuum leak and cant find it , i have to pass visual inspection so i need to leave the pumps on and just plug the lines.

 

Welcome 460-F250!

You need to keep the vacuum for brake booster and heater controls. This comes off the rear of the intake manifold.
You also need to keep the vacuum that goes to the yellow valve on top of the thermostat housing and then on to the distributor.
The other vacuum lines that control the EGR, Charcoal Canister purge, and A.I.R. pump check valves are not strictly required for operation.

 

ok thanks.

 

Try spraying some carb cleaner around the base flange of the carburetor and the edges of the intake manifold while it's running.
If the idle picks up you have located your vacuum leak.
If you've never done much work on it, it's a good idea to look at the gaskets on either side of the EGR plate under the carb.
These see a lot of heat and burn through after time.