It’s a Jeep Thing
Jul 20th, 2007 by C. Alexander Leigh
Driving back from Vancouver BC, about 11 miles from home the Jeep died and was no-start. MIL coded out failure on all three ignition coils, but this was (predictably) a big lie. The real problem was a known-issue with these engines (particularly 2000 build 4.0L engines, for which there is a service bulletin), where the oil drive + crankshaft assembly seizes.
The usual instinct for these kind of failures is crankshaft sensor, located (curiously?) on these vehicles on the upper transmission bell housing. On the Wrangler, also ingeniously (!) situated in such a way that you have to remove the ignition rail to get at the plug.
In this particular case you could see where it had rotated 45 degres, scraping metal all along the way. Nothing some new parts didn’t solve. Thanks to Aaron for the rescue after the rest of our loser friends didn’t answer their cellphones! (That’ll teach Aaron to answer his).
JP & Gwyn get a pass though, they were thousands of miles away on their honeymoon.
Pfft I would have rescued them.
So is this a failure of the camshaft sensor or the crankshaft sensor? I’m confused by your copy/picture combination.
You know I wasn’t really clear in the post; the failure was with the camshaft sensor (engine) not the crankshaft sensor (transmission). The picture is of the camshaft sensor assembly.
We were looking at the parts and someone observed that the takeoff drive from the oilpump is exactly the same as a distributor. In other words when they switched these engines from having a distributor to having an electronic ignition, they were left with a hole in the engine, so they put a camshaft sensor there instead. In a way I suppose that’s clever, at least from a design standpoint.