I have recently purchased a '95 XJS 4.0 with 86,000 miles. Beautiful, well cared for car. Starts the first time after sitting, but is hard to start shortly after turning it off. After five or six attempts it will fire and run smoothly, but has a very strong acrid fuel smell. It made my dogs sneeze when in the garage. A couple of times after multiple attempts it started, sputtered and died. Fuel pump is running, crank position sensor replaced 1,500 miles ago. It runs very quiet and smooth otherwise. Ideas?

 

Oxygen sensors not working well?

Fuel Filter clogged?

How does the trunk smell?

Assuming its a convertible?

 

Coolant temp sensor?
Crank position sensor?
Fuel pressure regulator?
All these can be iffy when hot.

Does flooring the throttle help?

 

Appreciate the suggestions. Will start with the easy and move from there. Will try the fuel filter first. Thank you.

 

CPS was changed recently by previous owner. Perhaps they were chasing this gremlin. Throttle position does not seem to matter. Thanks!

 

Coolant temp sender could be playing up causing overfuelling when hot on restart. Try disconnecting the plug and bridging the terminals on the plug. If that improves hot start, then change the sensor. Also try starting with accelerator held FULLY floored which will cut out pump. Again if that improves matters, if could be a indication of overfuelling.

If its potentially underfuelling through fuel evaporation / regulator valve dropping pressure, then you could try cycling the pump by turning ignition on and off a few times. (Pump will run for 2 secs on each turn of the ignition) if that improves the start, then you're looking at a drop in fuel pressure in the rail.

Another check is to open the fuel cap when hot. If you get a rush of air, you've got a vacuum building up which can restrict fuel flow. The vacuum would probably slowly release overnight hence cold starts are ok.

Good luck

Paul

 

Thank you. Will provide the results when don.