It's been wicked cold in the NE all winter and my GF tried to start our 96 about a week and a half ago and she said it was running fine for a few seconds, then started to get very rough, she isn't sure if she shut it off before it died or if it died first. So far, I have tried to make sure the battery is 100% charged, cracked a fuel fitting and have lots of fuel pressure, replaced the crank position sensor with a new Lucas part, tried a noid light on an injector and get good pulses, shot some starting fluid in and still I get very little to nothing. It'll want to start for a second or two, then nothing at times, at other times it doesn't even act like it wants to start. Basically, it is acting just like it did when the crank position sensor went out a couple of years ago. Anybody have any further ideas? I've read about harmonic balancers becoming de-laminated, but I'm not sure that the tone ring that triggers the ignition via the crank sensor can loose it's orientation, I'm under the impression it is the drive for the belts that gets loose. Am I overlooking something here?

Thanks for any assistance in advance!

 

Have you checked that you have spark? Also check the plugs to make sure they aren't fouled.

I take it the starter is turning over? Have you tried starting it with the accelerator pushed all the way to the floor in case the engine is flooded?

If you have fuel and spark, you may want to check the engine for compression.

Is your check engine light on? Do you have any DTC codes set?

 

Sounds like our old friend "Cylinder Washdown" or whatever it is called has found a home in your '96. Try pulling the plugs and squirting a bit of oil in each cyl.

You are correct, a failing damper will not alter the crank timing wheel's relationship to the sensor.

 

No codes and the starter is turning fine. I pulled 2 coils and it seems like I have spark, but it is a bit iffy looking. I'll get my GF to give me a hand with it when I'm off on Tuesday and pull the plugs. I'm not familiar with the "washdown", care to elaborate? I did get it to run, poorly for a short time and managed to move it out of the way of the rest of the fleet, so maybe tomorrow's warmth will melt some ice and at least make the XK8 accessible.

Thanks!

 

Since you did get it to actually kick over & run, albeit poorly, I'm inclined to think a timing issue. Mark the position of the cam position sensor (looks like a distributor with no spark plug wires and has a small window with a bubble in it). Loosen the bolt and rotate it 1/8th inch counter-clockwise then attempt to start. If no joy then attempt the same in the clockwise direction.

 

This. It has happened to me.

 

I tried holding the pedal to the floor with no luck. It does seem like ignition or timing to me as well, I had very high hopes as I was driving back from the parts store with my new crank position sensor, since it was acting just like the last time it failed. Also, when i tried starting fluid with no luck I was leaning toward ignition, since just about anything in the neighborhood of ready to run will at least jump with some ether. I'm off from work again Tuesday and will check out the cam position sensor. I'll also take a look at Snap On's Shopkey to see if there is anything about timing the crank to the cam, etc.

Thanks to all! Any further suggestions welcome!

 

I haven't experienced it, but seems there have been a number of threads about it within the last few weeks. Firstly, since it started and ran, you don't have it. Supposedly, when you start and run the car for a short time, it is still running rich in its cold-engine fueling; open loop control and when you shut down the unburned fuel washes all the oil off the cylinder walls, preventing the rings from sealing, resulting in a loss of compression. Fast or easy cranking should accompany this condition. By squirting a bit of oil in each cylinder, you allow the rings to seal, compression returns, and you get a start. That is my understanding of it; if flawed or in err, I'm sure someone more intimately familiar with the phenomenon will happen along and correct it. Any car would theoretically be subject to this problem but the Jag inline 6 seems overly prone to it based on the posts where long-time techs have weighed-in on their past-experiences with it.


I too have made the same experience as Allan G and GatorJoe. Start, rough-running-stall - followed by no-start until you hold the pedal on the floor whilst cranking.

 

Well, I plan on pulling the plugs next time I work on it, so it can't hurt anything to give each cylinder a bit of oil. This is so frustrating since this X300 has been just about the most reliable, trouble-free car I have ever owned!

 

Well you need a few things to get an engine running.

Fuel/Air: seems you have plenty of that.

Spark: You appear to have it but think it might be a bit dodgy?

Compression: If you can, check the engine compression. At minimum check your oil and the inside go the oil cap and make sure there is no sign of milky coloured fluid.

 

Dont be surprised if all that you need to do is change the ecu relay or the crank position relay. Ecu relay is located on the passenger side of the engine compartment behind the headlight. there is a set of three in a row, its the one closest to you. Just swap it with one of the other three. Now if that dont work change the relay in the small fuse box also on the passenger side of the engine compartment. this relay should be blue or black. Easy fix and very common with are cars.

 

I haven't done a compression check, but it cranks like it has compression, not abnormally fast. No gunk under the oil cap either. With the coil on plug setup it's hard to get spark by yourself. I'm going to get an old plug, make ground lead, and I'm thinking use a hose clamp to hold it into the coils to see if I get a good blue spark. With my spark tester I was getting some spark, but the connections are not very good since there is nothing to hold it into the coil.

I'll swap those relays around too, it would be great if it was something that easy!

Again, thanks to all for your suggestions and if you think of anything else, please chime in!

 

Couple of suggestions:
1) You seem to have had fuel pressure. Is it still good?
2) Does the tach read about 200 rpm or so when you crank? If not, suspect the CKPS. Yeah, I know it is new, but at least one other poster has reported early failure!
3) Use an extra plug and just ground the threaded part with the coil pulled from the well and slid onto the extra plug.
4) Introducint a little unburnt propane while cranking (unlit torch) can identify a fueling issue.

Compression (seldom an issue on an X-300), fuel, air, spark- thats what it takes! Easy to say, but not always so easy to figure out, right?

 

OK guys, I'm back with the following to report:

Tried the easy relay swap as suggested, no luck.
Checked cam position sensor and it is spot on with the crank, also tried moving both directions with no luck.
Pulled the plugs and I have spark at each plug, but I'm not to wild about it. they are all reddish-orange, not much blue-white.
Ran a compression check and have 210-250 on all 6 cylinders.

Got it to run briefly again after much cranking and it ran badly. Struggled to rev and backfired into the intake a couple of times.
I pulled the mass air flow sensor and there is not much to see there.

I did notice a lot of raw fuel in the cylinders while doing the compression check and it was misting out of the cylinders not being checked, So I suspect something on the fuel side might be amiss.

I'm also not wild about the spark. I would expect to see a blue spark, so I am wondering if I have sufficient voltage getting to the coils. Anyone know if one side of the coil is always +12V with the key on? Any idea which wire if so? All 6 coils are the original black sticker, made in Japan coils. Car has 105K miles, so they could be weak, but all of them going at the same time?

Another oddity I noticed, the interlock between the brake and shifter seems to be faulted; it won't come out of park unless I pull the little cap off an depress the button.

Well, that is where I am at. Anyone have any further input? Any insight is appreciated!

Good news is the XK8 and Z3 are both now free of ice and snow and are ready to roam, so the fleet is getting back up to strength. Hate to have the XJ6 down, it is our everyday favorite.

Again, thanks in advance for any input!

 

Having checked the X300 electrical schematic for a friend on another forum in the not-too-distant past, I can confirm that the coils should have 12V at all times when the ignition is on. The GEMS ECM switches each coil to ground and can control the timing and dwell of each coil individually. I think I recall that the 12V was delivered on the White wires with Pink tracers, and the ground wires were Light Green with different colored tracers for each coil. If you don't have the X300 electrical manual it may be available as a download at this forum or I would be happy to send it to you - just PM me.

Cheers,

Don

 

Thanks for the manual and tip. I checked and have almost battery voltage at the coil, drop of .02V. Also tried a band new battery, have heard these cars are picky about voltage with no luck.

 

On the X300 the ECM refers to the Camshaft Position Sensor (CMPS) at startup to establish initial engine timing. Once the engine starts, the ECM refers only to the Crankshaft Position Sensor (CPS or CKPS). Suede has already suggested adjusting it but that hasn't solved your problem. It seems possible that the sensor has failed. Perhaps someone on this forum knows how to test it.

Cheers,

Don

 

To be more clear, it seems possible that the Camshaft Position Sensor has failed, and possibly someone on this forum knows how to test it.

 

My name ain't Ripley, BUT, Believe it or Don't!, the X-300 will start without the CPS connected. I cannot say that it will start with a bad or severely mistimed CPS.

The manual is explicit. If the ECU does not detect a CPS signal, it will "try" both orientations of the crank to cam timing until one fires. This causes an extended crank until start, and is a diagnostic hint that the CPS might have failed.

 

Hmmm, so if I disconnect it, it shouldn't sense anything. Worth a try to see if it improves.