3.0 distibutor vacuum connection help, please?

MotoSook · 04-10-2002, 08:40 PM

I need help with my 3.0 transplant. I bought a 3.0 from a well know Rennlister, and I trust him; but everyone can make a mistake. He disassembled the motor and may have the vaccum connected to the wrong place on the throttle body.

Should there be vacuum on the distributor at idle? Where does the line go /where is the distributor's vacuum source?

I found a vacuum source under the atmospheric connection to the WUR. The line to the WUR was hidding this from me until tonight. And it was sucking air upt o now. I plugged it, but the motor ran with the same stumble and shaking at low throttle. The two stubs are on the rear of the throttle body (toward the back of the car) at aproximately the 7 o'clock position. The top one is atmospheric presure for the WUR, but the lower one is ??

This is where my 2.7 motor gets it's vacuum from. Should the 3.0 distributor connect here? I think the two motor types are different set ups (retard vs advance), but I'm not 100% sure.

I think the result of this error is my stumble and shaking at very low throttle input (just above idle).

Help???

makaio · 04-10-2002, 08:45 PM

What year 3.0 is it? 78-79's are different than 80-83's.

MotoSook · 04-10-2002, 08:46 PM

The motor came from a '78 SC.

MotoSook · 04-10-2002, 09:32 PM

I know it's late, but where are all the SCWDP guys at? I need help, it's going to be a great weekend for the bastard SC, if she runs well enough.

makaio · 04-11-2002, 08:41 AM

Ok sorry, my wife kicked me off the computer last night!

Anyways, the vacum line should go to the port off the throttle body ( I think that's what is called). It's under the boot that connects the throttle body and the mixture control unit.

I would post a pic, but my camerea is being a P.O.S.

Do you have the Bentley manual? If you do there is a pic on page 240-29.

Good Luck!

Get her running

wckrause · wckrause's Garage

It's a vacuum advance system, therefore there should not be a vacuum on the line at idle.

I'll have to check my car to tell you exactly where the vacuum line goes. From memory, I think it goes to the front top side of the throttle body. I believe the two ports on the back side are for the WUR.

RarlyL8 · RarlyL8's Garage

You might have an open vacuum port somewhere.

My '78 has no vacuum hoses attatched. They were eliminated when the SSIs were added and all the smog crap removed. Is your engine still in full smog dress?

wckrause · wckrause's Garage

Rarly8 - Do you set your timing a little advanced to compensate for not having the vacuum advance hooked up? Does it ever knock?

I checked my car. The ignition distributor vacuum line connects to the front side of the throttle body on the top.

RarlyL8 · RarlyL8's Garage

Bill - you know I can't honestly remember. The timing was set three or four years ago when all the engine upgrades were done. I'll have to check my notes.
No detonation that I have ever noticed. Run it on 87 octane fuel as well. I'm sure that we set it on the conservative side, I always do that.

MotoSook · 04-13-2002, 05:36 AM

Thank you all for the in out. It looks like there should be no vacuum at idle, but vacuum should develop as RPM's increase.

I'll have to find my running problems somewhere else. Back to the garage for some more head skratching.

Have a good weekend.