I am having an issue with my 1983 Firebird 305cid V8 4bbl Vin:H Cruise Control. Here is a breif history:

I have replaced the signal/cruise/wiper lever (with the correct one after a parts place gave me the wrong one twice) and have replaced my vacuum canister on my firewall.

When I set the cruise at 65 mph it either speeds up gradually to around 80 mph or gradually slows down to 60 mph and holds. If I press accel, it does accelerate correctly, and if I press coast then let off it will coast and set... once. If I press coast again it will turn off and not turn back on again. Accel also only works once or twice, then stops.

My speedometer needle has also started to bounce pretty heavily. A few years ago this started and I put some luberplate on the speedo cable on the end that connects to the dash and on the end that connecs to the cruise control transducer, which fixed the issue. When it started to bounce recently, I pulled out the speedometer cable and it was still lubricated, but I did it again just to make sure... made it better for a short period of time, but didn't fix it.

I am thinking it is the cruise control transducer, but that's like $120 so I want some input before I commit to that kind of money since it's a "special order takes a week" type part. I also cannot find a Resume solenoid anywhere (it's connected directly to the cruise control transducer, but it isn't included with a new transducer).

I have placed vacuum on the lines dealing with the cruise control and the vacuum bulb connected to it as well, they seem to hold but I was honestly using my mouth and tounge to pull and hold vacuum... not a vacuum hand pump with gauge

Any input is very appreciated

Thanks, guys!

 

The standard approach is to verify all vacuum hoses are good and that the throttle linkage cable is not binding at the CARB connection point. The symptoms you note above seem to imply that the transducer is close to death. Three quick electrial tests you can try:

1. make sure you have a good ground connection. Visually inspect the ground wire on bolted to the transducer. Is the wire broken at the end of the terminal lug? Disconnect teh ground wire and clean both the terminal and the connection point on the transducer. After you clean the ground connection, take the car out and see if you still have the same problems.

2. while you are looking at the ground connector, put the connector off the transducer. Measure the resistance from the HOLD terminal to ground. It should be between 5 and 6 ohms. If it is less than 4 ohms or greater than 7 ohms the solenoid in the transducer is bad and the transducer will have to be replaced. The HOLD terminal is the horizontal terminal on the enginne side of the transducer when looking from the front of the car. The ENGAGE terminal is the vertical terminal on the fender side of the transducer.

3. At the base of the steering wheel disconnect the connector for the curise circuit from the wire running up the column to the crusie switch. ON the connector out t the transducer measure the resistance between the Dark Green wire and ground. (Use the ground point up by the dash - if you don't know where this is, search this forum for G200 and my user name. You will find a photo in that thread. It was posted some time in 2009) The resistance reading should be between 29 and 36 ohms. If it is outside this range, disconnect the connector at the transducer and measure the resistance on the Dark Green wire between the two connectors. It should read 23 ohms + or - 1 ohm. So if it is not reading between 22 and 24 ohms the "main wiring harness" should be replaced. Note that you need a good ground connection at the transducer for the first part of this test to get a good result. The service manual does not define if the "main wiring harness" is from the C100 connector on the engine bay side of the fire wall to the transducer or if it also includes that portion of the harness from the connector at the base of the steering column to in inside part of the C100 connector.

Did you check both speedo cables? Your description implies you only checked the cable from the transducer to the speedometer. How is the cable from the transmission to the transducer? Is it tightly connected at both ends? I also wonder if the speed gear in the transmission is still good?

As for the resume solenoid, I don't think it is available anymore. I haven't seen one listed on any of the parts stores web pages in 3-4 years (that is when I started looking to see if they were still available). You could take the one off your transducer and put it on the new one if you replace the transducer, or you could hunt around in junk yards until you find one.


I will try to scan several pages from the 1982 Camaro Service Manual this weekend and post them for you. You car has the same cruise control as the 82 cars did.

Good luck with the tests I listed above.

 

Thank you for the incredibly detailed and accurate posting! I did end up replacing the transducer, which did fix the speedometer wobble completely. That unit had been malfunctioning for quite a while and wasn't reliably setting even when the needle wasn't wobbling. Of course I also replaced a vacuum switch and electrical switch for my climate controls, of which the vacuum switch was defective... oh well can't win them all

Thanks again! No need to search for any more articles

 

OK

Good to hear that you got it taken care of.