Hi, I just had my 85 308 out for its once every 2 month drive(pathetic I know...), and experienced a puzzling "dropout". Here are the symptoms- 1) under freeway onramp hard acceleration, a partial engine bank dropout occurs causing severe "hesitation" 2) I could cruise at 80mph(approx 4k rpm) for extended periods without problem, then randomly would feel the "dropout/hesitation" and the tach would momentarily drop to the 0k/1k/2k range however I know the engine was still turning in the 4k range because I was in gear and barely lost speed before the engine would pick back up again. Since I believe the tach has some sort of electrical pickup, and the car would keep going after the "hesitation" moment, I suspect an electrical issue. It seems like it could also be just one engine bank dropping out... Do you guys have any insight? Thanks, Mark
Hey Mark that sounds like it could be a Digiplex problem, first I would check the grounds for the Digiplexies that is a comon problem, if that does not work you may want to have the Digis tested. Wade
It could also be the plug extenders. They will burn a hole and arch against the cam cover. Pull the spark plug extenders and look inside for white film and a blue color on the wire inside. If there is, then look on the outside of the extender and see if there is a hole. My car had a similar issue and I replaced them all and it cured the problem. Good Luck.
Your problem is almost 95% certainly the crank sensor on the digiplex that has the tach connected to it. (The tach going haywire when the bank drops out is the dead giveaway) It could be the connector from the sensor, the connector at the digiplex or the sensor itself. A new sensor is $100 and about an hour to install. To test the sensors (there are three) just use an ohmmeter. They should each be around 600-800 ohms. They usually fail internally and go open circuit. Do a search, there are several threads here with more detail. Birdman
Here's some light reading on the subject: http://www.ferrarichat.com/forum/showthread.php?t=105715 http://www.ferrarichat.com/forum/showthread.php?t=102649 Birdman
Thanks for the info everyone, this will make a great garage project when the wife/son head to Mexico to visit relatives. Mark
