I have an 1989 XJS V12 that I have been updating, the car is orginal and mechanic's have said in very good condition and care.  My last bug to find is:  When I take out for drive on interstate 40 miles round trip, when I stop at a store the car is hard to start, won't stay started, rpm hard to keep up to 600 without stalling.  I have had the fuel filter and fuel pump replaced and have returned twice.  Couldn't find problem.  Sounded like a pinched or restricted vent hose.  No find.  This last time I drove out about 20 miles on the interstate, stopped for 20 minutes and bank on the interstate the car shut down.  I opened gas cap and tried to start, I waited about 20 minutes and the car starts right up and drives like normal.  when it does it thats what I have to do wait 20min and start. Any idea's?

Submitted by jfwwrepair@att.net on Wed, 04/22/2015 - 14:20

Todd

 

I had this same problem last year as well.  There are 2  crankshaft sensors on the 5.3 liter (part #DBC12507,  replaces part #DAC4606 per Engel Imports).  One of them mounts on the bell housing right next to the  exhaust pipe.  The heat generated from a longer,drive shorts out the sensor.  Mine also had a very small heat shield missing.  Designed I'm sure to minimalize this problem.  I replaced this sensor, fabricated and installed a new heat shield.  No problems since.  The part was $55.00.  The installatioin is easy if you can get under the car.  Hope this helps.

 

Jeff Ford, 91 XJS convt.