Help needed. On an extended weekend drive, I suddenly lost significant power. I also lost tachometer needle movement. I could barely get the car up a hill in 1st, and top speed on a flat highway was something like 65mph. The tach came back occasionally, but at reading that was lower than I would have expected. And then if the RPMs went to any height, the tach would drop out again. I should add that there was significant water that also got splashed onto the engine bay when opening the rear lid. Any thoughts on helping to diagnose or fix on my own? Thanks! Matt Image Unavailable, Please Login
Very likely a crank position sensor. If that is a QV it will have 3. Common to fail after a certain age and (depending on which one) you will lose half your engine ignition - from an 8 to a 4, instantly. I *think* one of the three control your tach too so you could be losing two of the three but it doesn't matter, you will want to replace all three when you are in there.
This is the most likely. If it is a 2V GTSi there are still 3 sensors and all can be replaced relatively easily in car ( can only comment for 2V ) also check plugs going into the digiplex units are secure and clean. Plus make sure they have a good earth. Sent from my iPhone using FerrariChat
Thanks, gents. Two-valve 1981, I should have mentioned. Any how-tos on replacing the three crank position sensors? Is it a DIY for a semi-novice? Matt
From memory they are held in by 2 x 8mm nuts each. The plugs on the modern replacements are different from the original 81 plugs so what I did was cut the original plugs off and solder them onto the new replacements. I can take photos and post later (I’m at work) of the locations if it helps. My engine/gearbox (also 81 but euro) are out at the moment in my garage Sent from my iPhone using FerrariChat
The sensors get their signal from the ring gear/flywheel and are located in the plate between the block and bell housing this pic should give you a good indication Image Unavailable, Please Login Sent from my iPhone using FerrariChat
Same thing happened to me... I replaced the entire ignition system with a XDI Electromotive unit - SO MUCH BETTER than stock. I've kept all the original Magneti Marelli parts just in case, but the XDI system made the car much more reliable and smoother running. Relatively easy to install as well. Good luck.
I'll trouble shoot it this weekend and see if I'm getting uniform spark at each cylinder, and work back to the rotors. If those are fine, I'll look at the crank position sensors. Thanks, everyone. Matt
Don’t forget the Digiplex as one of them can also go bad very common, located in the rear left corner in the trunk space under a cover.
