Car's running superbly, zero issues,battery's @ 100% & kept on a maintainer when not in use. Tonight I go to start it catches then stumbles & shudders off,no codes. A couple more tries, same result, then I manually give it gas via pedal it fires up. I have noticed a sort of delay in starting & was thinking the starter @ times maybe going out. During the fouled start though I hear the starter fire as normal. I cut it back off & restarted it w/ no issue, but I don't want any unknown glitches lurking w/ this car.

Fuel pump failure ?!
Starter ?!

 

King Charles....sounds like a fuel delivery problem.

 

Yes fuel pumps are on my suspect list.

 

There is a check proceedure in the JTIS....and considering that an XJR has two compounds the problem.
What sort of mileage has this car done and how stale is the fuel?
Modern fuels seem to have the propensity to go 'off' very quickly.

 

I for one can vouch that KC is very meticulous about his Jag. So I would not think it to be a fuel situation, he drives it often, ...unless its the delivery system as is suspected?
What I might be suspect of also would be the plugs. Its a simple check and they can tell you loads of what is giving the car an issue.
Another simple item, the fuel filter, its a cheap replacement if it hasn't been done in awhile.
Also, check the cam cover breather line to the air intake tube for any blockage or excess oil. If you see oil, check the TB for residue, it could be sucking it in.
Here's a fuel pressure check pdf from NBCat...and I've attached a couple other pdf.'s for starting issues for review.
Here's a link to the Workshop Manual (its too large to attach)... https://www.dropbox.com/s/vujkjrxklu...anual.pdf?dl=0

 

I'm on it.

 

KC, difficult to isolate this early, as per others, it could be several things, but regarding the fuel pump mine gave me several weeks of warning with perfect running combined with intermittent stumbling, stalling and refusals to run. I found with mine it performed fine when cold, but would/could give the symptoms when warm. The only way I could pin-point it was to check the fuel pressure at the rail when it was acting up. Harbor Freight has an economic fuel pressure gauge set. CK

 

Roger that,
Sunday is now Jag diagnostics day will update accordingly. I for one can't have any grey matter with this car.

 

Car just came (last week) from an 820 mile round trip to & from Snowshoe West. Va. & did so flawlessly.
Ok plugs are new(March 2019),MAF's clean as is air filter & no visual trauma in that region. I'm going to get fuel trims in the coming days but I'm going to tackle the fuel filter even if not the culprit It's due anyways.

Hindsight being 20/20 on that rough start, it did seem like the fuel flow was compromised but not stopped. I'll gather trim data & knock out the filter then see what develops.

 

Sure is looking more and more like the fuel pump, my own experience is that they don't always just suddenly quit on you, rather they can begin to operate intermittently. I would have a car that ran flawlessly, then I would come out of a store, start the car, pull away, and then suddenly stumbling and wondering if I was going to make it home. Once cold the car would run flawlessly again, until the next time, and the intervals got shorter and shorter. Once it became a "repeatable offense" I could accurately check the fuel pressure at the fuel rail Schrader valve when it was acting up, it then became obvious that the fuel pump was not pumping fuel.

 

Yeah I'm going to test @ the rail soon. It's about time for an oil change & tire rotation so I'll likely just get them to knock out pump & filter while it's there. This is the first episode so there's that.

 

Since this was a cold start problem, as winter comes on, you might also have a bad temperature sensor. When the ECT sticks it will cause insufficient enriching at cold start (or in summer, flooding if too rich).

 

You have a part# for that I want to have all part #s ready @ hand if needed, thanks.

 

Hey Jim, are you speaking Ambient or Coolant temp sensor?

 

I've had this problem recently. In my case I'm pretty sure it's due to worn valve seats dripping oil into the chambers. Steady oil consumption plus possible blue smoke once you have finally got it turning over initially. My situation is worsened according to parking uphill or downhill too. I'm also wondering if colder winter temps make it worse.

My own oil consumption is steady and I've got the seats ready to go in, it's not ideal timing in the middle of winter though so it'll be delayed. I've 200k miles btw.

 

My car loses zero oil so it's fuel delivery or temp. sensor fouling of fuel delivery in my scenario.

 

There are two different CPS-s: for AJ26 it is LNA1600AA and for AJ27 (after VIN 878717) it is LRA1600AA.

LNA1600AA


LRA1600AA

 

Ok 1st round of addressing this is going in for oil change,tire rotation this week & get the fuel filter changed while the tires are off & in there.

In midst of setting up Torque Pro to record fuel trims so I can monitor if/when the issue resurfaces, albeit I'm not having much luck setting up the app.

 

I've had issues with getting the app to link of late myself. Whether it be the Jag or my work truck. I'm looking for another system.

 

Coolant sensor that is in the cross over pipe and wires to the MAF sensor connector.