Mitsubishi Montero LS 1997 won't start after oil change

Starter works but does not engage/ignite engine. Had an oil change and next day car would only start intermittently. would not start, then start and run a few miles. come back, sit over night - no start : All this even after mechanic replaced fuel pump and fuel filter, Battery checked out AOk new last year, new radiator last year. Mechanic tried new Ignition connection, because no spark is getting to engine, although all spark plugs are good. (New tires of course, the day before it would not start, just pure irony, right?)
Mechanic thinks expensive to search out under engine for the drive shaft sensor. Ideas? He is referring us to another shop, Seen this before?

I think your mechanic is heading in the wrong direction.

I would rule out a alarm system that ,may disable the ignition first.

Second I would check the voltage to the Crank shaft sensor,


When did you first notice that it would crank ok, but wouldn’t catch and run? Immediately after the oil change? Or immediately after the fuel pump and fuel filter was replaced? I presume you understand that if there’s no spark, replacing the fuel pump and fuel filter won’t fix that.

If it cranks ok – that rrr rrr rrr sound – then the battery is ok. No worry about the battery condition. What usually causes a no spark is the engine computer doesn’t see that the engine crankshaft is turning. That’s probably the sensor you mention above, not the driveshaft sensor but the crankshaft position sensor. Shops with the appropriate diagnostic tools can test it very easily. I presume what you mechanic is saying is that he doesn’t have the necessary equipment. If so, that’s correct, find another shop who does have the equipment, which would be presumably a Mitsubishi scan tool.

Thanks for your reply. It failed the following morning after the oil change, then in the evening, still would not start. 1/2 hour later it did start, and worked fine.
After the fuel pump was replaced (there was not pressure coming from the fuel pump before it was replaced) it did run well, and I drove it 12 miles home. The next morning it failed again.
Thanks for the counsel, we will definitely let the new mechanic know and verify that he has the appropriate diagnostic tools, for Mitsubishi.
Thanks again.

Thanks for this reply. We will let the new shop know what you are saying.