Recently, I had new fuel pump and filter installed, it has been running perfectly no hick ups, nothing just quietly purring. I have taken her on two 120 mile road trips and around town — all has been perfect. Filled her up today for a nice Sunday drive of about 90 miles, parked her (on a slight incline) but when I restarted after lunch, she started ok but was running roughly. Backed out of the slightly inclined parking space and drove about 50 yards still running roughly and she died. No codes on the dash. Yes, it had just over 3/4 tank of gas — fresh super premium Chevron with Techron gas.

On cranking she would fire up for a second then die. Tried several times with same result. The check engine light finally came on but no engine codes.

Since this was how she acted when the fuel pump went out before it was replaced a few weeks ago I immediately assumed another had gone out again! I check the Schroeder valve and got a good strong spray ruling out the a second fuel pump failure. So I tried cranking her with the gas peddle fully down as I had read this might reset the system. The engine just turned over and over. The check engine light stayed on this time but still no codes!

Frustrated, and 90 miles from home on a Sunday afternoon I started looking for towing options and a repair shop to tow it. After about fifteen minutes of searching I tried cranking one last time before calling the tow service. This time she fired up beautifully! I cautiously put her in gear to move away from in front of the fire hydrant I was parked next to so to find a new spot to let her run for a few minutes, just in case she died again. She purred like a kitten after about five minutes, I looked at my wife and said let’s give it a try. She ran perfectly all the way home! When we got her into the carport I tuned her off then tried cranking her again. She cranked up perfectly!

As I don’t want to get stranded again any thoughts on what might be going on? Would the immobilizer have been activated on the slight inclined parking spot causing the rough start? Or Is this a sign that something more sinister is going inside one of the little computers scattered around her?

Any thoughts would be appreciated.

Bill

 

Not an expert but I think that the early XK8/R used a dual fuel pump type system. One to drive the fuel and one to suck it through. If one bit fails it will still work but will put a lot of pressure on the other pump and that will go after a while, exactly what happened to mine one time and what my mechanic explained. Sorry I might be having a senior moment and more knowledgeable members might be able to clarify.

 

If it is running roughly and cutting out it could be something as simple as spark plugs or dirty oil. Sorry to state the bloody obvious 🤣 when was it last serviced?

 

Thanks, as I understand you are correct however I should have mentioned that mine is a 2004 with the newer single pump system.

 

She is up-to-date on service since I purchased her three years ago with 65,000 miles on her — prior owner had up-to-date maintenance. But Spark plugs I have not inspected and could be the issue as she just turned 81,000 miles. Duh!

Thanks.

 

I just had a 12 month service and my mechanic removed and cleaned the plugs, no need to change them. Sometimes carbon deposits on perfectly good spark plugs can be enough to cause a misfire. Dirty plugs...little things.

Just a thought

 

Sadley you cannot find a fault that does not exist ...you need to wait till it won't start again. Sounds like changing the pump was not the cause of your initial problem. Check for air leaks in the inlet tract ( corrugated plastic pipe thing)
You only need two things to make it run fuel and spark . Next time it wont start take your stethoscope and listen to see if the injectors are clicking/check fuel pressure. If OK then its ignition.
All 8 plugs/coils do not fail at once but can be intermittent hence the rough running. Once a plug gets hot it needs less volts to fire it ...???
Dont trust your mechanic. If he is over 30 he is no good as he would have been promoted or moved on to better things.

 

A couple of things. "Dirty Oil" will not give you the symptoms you are seeing. Nor will bad plugs. Not like this. I'm not sure what dirty oil even means...

If the CEL popped there should be codes associated with the light. They should even hang around a while after light goes out.Should. These cars can be tricky. What kind of reader are you using? ---- suggest to to a local big box auto parts store hand have them read codes for free now, or next time she plays up...

There are lots of little things you can check. The car won't run (in my experience) without a good strong signal from the CTS. Check the wiring and the plug. Just because (they are under 20bucks) replace the Coolant Temp Sensor... Again, a good look at the plug.

Another is the MAF sensor and it's plug. Remove air box on RH side, and chase the wiring down into the depths to see for any chafing or broken wire covers/coat. I once had a situation where the car would not start, ran badly when it did, and hiccup all over the place. The loom from the MAF had found itself in a funny place, pinched, and slowly chaffed and one or two of the wires had become exposed. Higher resistance resulted in reporting of MUCH higher than normal air intake readings - thru everything off...

Then there are other things.

With a code reader, you want to be able to SEE what kind of numbers the engine is producing while running, especially when running poorly. Look for the g/s of intake air from the MAF. The long term and short term fuel trims -

Have the OBD running on your phone while you go around under the hood (car idling) jiggling wire looms (MAF, CTS, crank sensor, and 02 sensor wires (although 02 sensor wire shouldn't have the stalling effect, exactly)... Also, the 2004 should be reporting fuel pressure. Could be the wiring AT the pump OR at the fuel pressure module in the boot.

Intermittent problems are the worst.

The picture below is of 1 or the 2 coil wire plugs on an XJS. Car left me in the side of the road til I HAPPENED to notice one of the 6 coil wires hanging by a thread. Broke off completely when I started messing around. Old car, old wires and clips, one snapped wire (and they do snap) is all it takes.

 

Chances are that your OBD tool is not being truthful, i.e. there's at least one code!

I think immo would mean no start, and likely a code flashed via the PATS light.

 

Dirty oil creates additional friction that wears away the cylinder wall. Over time, the increase in diameter of the cylinder and the existence of any irregularities in the cylinder wall also promotes blow-by. As wearing accumulates, more blow-by occurs, which accelerates the wear and allows more blow-by. Dirty oil also contributes to wear on bearing surfaces, which reduces oil pressure.

Not an expert but personally if it were me I would have an oil flush and and an oil change and have the plugs cleaned. If the problem persists at least you can rule it out and move on to other possible solutions.

 

To all, thank you for your quick responses as you are laying my roadmap. So for an update. I just move her into the garage to begin some OBD2 diagnosis. She cranked up perfectly after our drive home last night and turned off the ignition, she was running all of a minute before I turned her off.

i hooked up my OBD2 to get a read on the codes. It would not connect but I had trouble with it a month ago when the fuel pump originally quit working. So I tried my iPhone OBD2 but it too would not connect.

i decided to crank her up to see if that would help make the connection.

And ... she she refused to crank! same problem as yesterday! Would this be tied to the cylinder wash issue if you don’t let the engine properly warm up? But it seems like I read the 2004 4.2 liter engines did not have the cylinder wash issue!

Any further thoughts?

 

When you say refused to crank,,, do you mean when you turned the key to start, the starter would NOT activate, engage and spin the engine at all OR, do you mean that that the starter DID turn but the engine would start up?

You have to be able to read them codes. There kinda HAS to be some, unless you drove them out of the car on the 90mile trip home. I would guess you may still be able to have a look at them,,, even as PAST codes. Maybe. I think it's fair to guess the car WILL produce them again, if you're lucky, which may sound like a strange thing to say.

I have a cheap "torque pro" that has served me well over the years. May be able to get one at an AutoZone type store (or another), download the app to your phone and give that a shot. Best 20 something bucks I ever spent.

 

Oh and,,, I wouldn't worry too too much about cylinder wash right now. The same mystery thing that was stopping the engine from starting for a spell,,, then kinda "disappearing" temporarily, is probably what this is/is happening again.

I hate to say it but consider yourself lucky. You're in a 'safe' place and can now do the work and investigating - as opposed to being, well, 90 miles from home on the side of the road with yo Lady looking at ya funny.

The good folks here will help ya figure this out. No doubt.

 

Not cranking … meaning not starting! And yes we are fortunate in that I just tried to start her some three hours later and she will not start!

So fortunate she decided to start last night and got us home! Blessed one might say!

 

Had a similar issue that was infuriatingly hard to pin down, it would even cut out while driving, which was fun.

In my case it ultimately turned out to be poor contact in the connector for the fuel tank harness interrupting the power to the pump. Similar to yours, symptoms appeared after having the pump replaced.

To diagnose:
Start the car and let it idle
Open the boot and pull down the liner at the front that hides the fuel tank
There is a wiring harness that runs across the top of the tank from the right hand side with a connector about mid way
Wiggle the wires on either side of the connector (the larger ones are the pump power)
If you can induce the stumble and die behavior you have found your culprit

I cleaned the connections first but the symptom returned a year or so later. Ultimately I bypassed the connector for pump power and ground with posi-locks and everything has worked perfectly since.

Good hunting.

 

Finally had opportunity to get that codes read at Advance Auto — only one popped up P-1000. My icarsoft OBD2 reader still refuses to connect!

i do think the issue is in the electrical connectors in the engine compartment as JayJagJay suggested. I quickly giggled all connectors I could find due to needing to quickly move the car. Low and behold she cranked! Later on I did run my iPhone OBD2 while giggling the wires but no gurgles or gulps by the engine.

As suggested by ccfulton I opened the boot and giggled the fuel pump wires with her running but again no gurgles or gulps!

Right now she is running perfectly — in the garage!

So she is playing coy with me and undoubtedly she will throw up the issue at the most inopportune time!

Question, should I find a loose wire in a connector what is the best way to tighten or correct? Can you easily replace a connector​​​​​​?

Again thanks to all all and feel free to suggest possible solutions.

Bill

 

Not always easy to replace but if it does not have too many wires can be removed and soldered instead. Otherwise pull on each wire and see if it wants to come out .If not contact cleaner and insert and remove a few times . Obviously check for corrosion

 

Yeah Man... Intermittent problems are no no fun. I've had situations where I HOPED the damn car would just break down or show me something bad...

Did the stall EVER correspond with a check engine light?

New connectors are not hard to find. It's basically Ford stuff. If you figure out what's playing up, even if you are not sure what it is, photograph it, post it up, and folks here can figure it out and even help chase the new connector. There is a GREAT "portable" soldering set on Amazon, and believe it or not soldering wire ends together gets super easy, although a little time consuming.

If it in fact IS an electrical gremlin, a wiring issue, this sort of thing CC's approach makes all kinds of sense to me as well. On some weekend day put the car in a good spot in the drive, hood and trunk open, car started and idling, just go around and start poking at any and all wiring looms you can find in the engine bay.

I'm not clear at how familiar you are with all the different operating systems, but there are important harnesses on both sides of the engine running back to front front to back. I mean, it'll take an hour or two. Bring a drink. Uncover all the fuse boxes in the engine bay, wiggle fuses, relays, ANYTHING you see that is "electrical". There are import wire sets clipped to both cam covers. The Mass Air Flow Sensor wire set. The looms for the plugs. The list goes on and on. Eyeball stuff. The coolant temp sensor. Get a new CTS if you never have. If you have the courage REACH under the car and jiggle around the crank position sensor. There are a lot of bits and pieces.

If you have a coupe can you get to the top of the gas tank? Connector there. Connections INSIDE of the tank, believe it or not. Then, fuel pump relays in the trunk fuse box. Then all kinds of fuses and stuff under the hood. Man, you just really got to get in there. You're going to get to KNOW the car better AND find your issue. Time will tell.

Folks will help out!

 

You need to rule the fuel pump (and regulation) in or out permanently. Best would be a fuel gauge. It seems like there was fuel pressure when it happened once before, evidenced by the shrader valve check you mentioned. Second best would be to read it from the fuel pressure sensor. It should read 55psi pretty much all the time. This is standard OBDII, a cheap ELM327 should be able to read it.

For your code reader, check if you can "force" the protocol to ISO-9141. Our cars have active SCP and CAN buses as well, but OBDII is only available on the older ISO-9141 bus. IOW, make sure your reader is not reading just CAN. As others have pointed out, there is at least one code available at all times (Either OBD monitors completed P1111 or not completed P1000). If you have a JLR code reader, maybe start with the OBDII function.

FWIW, if you have P1000, it means the power to the ECU was interrupted and the monitors have to be re-run. It is consistent with disconnecting the battery for the replacement of the fuel pump, but maybe it's been too long. I'd say check that power distribution block in the trunk. It's been know to loosen up and cause frustrating sometimes problems like this one. Also check the battery cables for warmth, indicative of internal resistance/damage. Last, check the voltage at the power post in the engine compartment when you crank. If it dips too low, the control modules will not work. Are you getting any TRAC/ABS errors in the message center?

Best of luck, keep us posted.

 

Should there be any play in a wire? I did find the white wire on the fuel pump connector that was slightly loose while the others tight. I pulled on it while car was running but no change in engine noticed.