Fixed my cruise control

[gull]

Today I tackled fixing the cruise control. The Haynes manual doesn't cover it well, but it's a pretty simple vacuum-operated system, with the slight twist of having its own vacuum pump, instead of relying on manifold vacuum.

Since the actuator was in easy reach, right there on top of the valve cover, I hooked my MityVac to it and tested it first. It held vacuum fine and I could easily pull the throttle open by pumping on the MityVac's handle. I reconnected it, then removed the hose from the vacuum pump and connected that hose to the MityVac. No good; it wouldn't hold any vacuum at all. The dump valves for the brake and clutch pedals, under the dash, checked out when I tested them separately. (I think it's a good idea to check them anyway when reviving a cruise control system that's in unknown condition, since they're what ensure you'll be able to turn the thing back off.) That narrowed it down to a vacuum hose.

It didn't take long to find the culprit. The hose to the actuator had a huge hole in it. It had been lying across the braided steel fuel injector lines, which had sawed nearly halfway through it. I found a piece of fuel hose in my junk box with the same inner diameter and replaced the bad hose. A quick check on the freeway showed the cruise control to be working quite nicely.

[gull]

I spoke too soon. Last weekend it worked for about an hour, then cut out and wouldn't re-engage. It worked great while it was working, though -- rock steady, even on hills.

I haven't had time to dig in and see what happened, yet. Most likely I didn't secure one of the hoses well enough and it vibrated off.

[Briano1234]

I spoke too soon. Last weekend it worked for about an hour, then cut out and wouldn't re-engage. It worked great while it was working, though -- rock steady, even on hills.

I haven't had time to dig in and see what happened, yet. Most likely I didn't secure one of the hoses well enough and it vibrated off.

that would be my guess, there is a FAQ on the tex about diagnosising issues with the cruise control.

[tolusina]

Here's a link, cruise control electrical testing procedure....

http://reflectionsandshadows.com/cruise/

[gull]

Today I got a chance to look at it again. The new problem was pretty obvious. The rubber grommit in the linkage had disintegrated and the link rod between the servo and the throttle lever had come loose. I replaced it with a grommit I found in the bottom of my toolbox that was roughly the right size.

[Briano1234]

My first one didn't have a grommet, so I adjusted the linkage to catch at the closest part of the lever...