I have a 1998 Jaguar XJR that smokes from the exhaust at cold start until the engine reaches operating temperature. The exhaust smells like straight fuel. I'm concerned I may have put the wrong gas in, but I'm not sure if I would mistake that.



I have been experiencing intermittent misfire issues from injector one for a while and I'm waiting for a replacement injector. Despite driving the car for a while without noticing this issue before, it recently started smoking After driving and idling the car for about 15-20 min the smoke disappeared. I checked the spark plugs and found no signs of coolant in the combustion chamber, nor was there any bubbling in the coolant reservoir.



A few days later, the car died at a grocery store. It cranked but wouldn't start, so I had it towed to a mechanic. The next day, it started right up without issues, and the mechanics found no smoke. I drove it home without any abnormal issues.



This evening, after the car had been sitting for two days, it smoked again on startup, with a strong fuel smell inside the cabin. After idling, the car died, possibly due to an empty fuel tank. When I start the car, it doesn’t rev over 1000 RPM, and it dies as soon as I press the gas pedal.



The car has exhaust modifications: no muffler and an X-pipe. My main concerns are the smoke and the strong fuel smell. Could this be related to-the fuel pump or injector completely gave out or something else? Any insights would be appreciated.

 

If there is one bad injector. There can be several leaky ones. In the video it clearly rains. The smoke you have is moisture in moist air untill exhaust pipes dries up. Strong unburnt fuel smell could be leaky injectors.

 

What are the codes? Has the car been scanned?
Is it using any coolant?
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I just replaced my fuel pumps still crank no start condition. I have checked all my fuses connections and fuel pump primming everything checks out. Still no start just cranks over I definitely have a good battery and I even jumped it as well. Could it be that one injector leaking in one cylinder or something else.

 

I think you checked your ignition coils ?

 

The first thing to check is to determine if you have spark at the coils.
Then make certain fuel is also getting there and if so, check your
compression to ensure you haven't created a bore wash situation.

 

This very much sounds like leaking injector(s), especially since you replaced your pumps which are probably holding pressure that your worn out ones weren't and your next weakest link is the injector(s).
I thus wholeheartedly agree with RandyS that you have probably created a bore wash condition.
I would pull all the injectors and check them since you'll be there for #1, and if one is leaking your odds are there is another. If you want to rebuild the rest, here's an example of what you are looking at... https://theinjectorshop.com/products...4-0l-1998-2003

96-99 was known to have a bore wash condition (Porsche had the issue as well) from use of Nikasil cylinders and when not run long enough (or leaking injectors) excess fuel winds up in the cylinders causing a flooding condition. Be sure to check your oil, smell it for fuel and look for residue, you may have to change it to prevent burning a bearing.

The solution...Totally depressing the throttle completely shuts off the fuel supply. Cranking the engine for a about 20-30 seconds several times still holding the pedal at the floor allows oil redistribution on the cylinder walls.

Here's a vid from this chap with his XK8 explaining it, its exactly the same for the XJ8...I tagged the vid to shorten it, windscreen wipers aren't our concern for this.

 

If you’re experiencing intermittent misfire #1, exchange coil and plug with cylinder #4 and see if it moves.

The early AJ26 cars can suffer ECM failure. I believe the issue can be a bad ECM. You’d have to remove the ECM from the car and open it up to see if it was a problem