Instaboost Posted July 14, 2012 Report Share Posted July 14, 2012 Car June 1986 Magna MPI 5 Speed Both pedal cancel button tabs are goodVac Hose Routing is good 87 Factory service manual says pre-87's require the speed control computer with the blue label. The one in the car is a yellow label part number MB509089. With this ecu the car can only be set by the resume switch and not the set switch. Once its on it then changes the speed into up and down issues "surging". Friend sent another speed control computer for a later year part number MB510816, car doesnt even respond to that but the diagnotics plug for the cruise shows a constant steady signal which means everything is normal which it isn't. Anyone have any thoughts or suggestions, even a part number and picture of the blue label speed controller would help. If you have an extra you would like to sell please let me know. Google shows the yellow label is for 85/5-86 Link to comment Share on other sites More sharing options...
Instaboost Posted July 25, 2012 Author Report Share Posted July 25, 2012 Bump Link to comment Share on other sites More sharing options...
Caliber308 Posted July 25, 2012 Report Share Posted July 25, 2012 (edited) Bump Automatic Speed Control troubleshooting: 1987 Starion FSM vol.1 Section 14-113.Troubleshooting symptom chart: Set speed deviates much toward high or low speed idle.Hunting occurs when speed is set (acceleration and deceleration are repeated) Probable cause: Vehicle speed sensor circuit faulty.Speedometer cable or speedometer driven gear faulty.Actuator circuit poor contact.Actuator faulty.Vacuum circuit faulty.ECU faulty. Bill Edited July 25, 2012 by Caliber308 Link to comment Share on other sites More sharing options...
DMNDSTAR87 Posted July 25, 2012 Report Share Posted July 25, 2012 (edited) Bumppulled mine out of my 08/86 starion during the winter----all parts are together in a box in attic----i will look at it when i get home from work and get a pic maybe---u can have mine for cost of shipping if needed-----gig out Edited July 25, 2012 by DMNDSTAR87 Link to comment Share on other sites More sharing options...
Instaboost Posted August 22, 2012 Author Report Share Posted August 22, 2012 Ill take you up on that offer. Thank you 308. Still work in progress. Link to comment Share on other sites More sharing options...
Shelby Posted August 26, 2012 Report Share Posted August 26, 2012 is the surgeing at all speeds or only lower speeds ,, speeds close to 45 mph or so can be up and down due to miss adjust'd mps , tpsalso the speed sensor is nothing more then a low voltage generator you can test it's operation for a clean signal with a volt meter ,durring a road test , the vacuum pump motor can be monitor'd the same way , a flaky signal swt to power up the pump can cause problems with holding steady speedsboth petal swt's are only off on swts,, both on with petal up,, its the same wire going to both swts excessive cable slack is not good eather Link to comment Share on other sites More sharing options...
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