OK, this may sound like a stupid question, but would the effects of a bad coil pack appear more pronounced if it were the cylinder 1 coil pack rather than one of the other cylinders? Theory being that since the cam position sensor is keyed to cyl one position, misfires there might cause more confusion to the ecm. Car is a 1996 XJ6.

Stupid concept, or possibly a real thing?

 

The Cam position sensor is a hall effect sensor different then the inductance crankshaft position sensor

With the 6 windows of different widths the Cam position sensor sees each cylinder on TDC

The Cam position sensor is only used in the starting sequence and then the ECU reverts to the Crankshaft position sensor by design

With the Crankshaft position sensor with the Cam position sensor unplugged the ECU must learn if the Crankshaft single target is actually on the # 1 TDC or 360 degrees out or one revolution

It has to try firing the coils and if a unsuccessful light off the ECU will electronically pic the signal back up on the 2nd revolution and keep that 2nd revolution during the cource of your drive

This require a couple of rotations before the ECU tries a change

There are no stupid questions

 

Hi cathammer,

Welcome to the Jaguar Forums! It's great to have you with us.

What are the symptoms you are trying to diagnose? If your engine is misfiring, you will have one or more Diagnostic Trouble Codes stored in the memory of the Engine Control Module which may help point to the cylinder that is misbehaving, either due to a problem with the ignition coil, damaged to the coil wiring, fuel injector, spark plug, low compression, or some other cause. Most auto parts stores will scan for DTCs for free. If you will post them here exactly as they appear, knowledgeable members like Parker will be glad to help.

P.S. Your post count may be high enough now that you can use your User Control Panel to edit your signature and add the year, model and engine details of your granddaughter's Jag to your signature line so they appear in all of your posts.

Cheers,

Don

 

Thanks, Don,

More exploration of the problem to hopefully occur today, but here is a rundown:
Car started running a little rough, and randomly stalling (or trying to). Code set was P0302 (cylinder 2 misfire ). My first suspicion was the coil pack, so I cleared the code, and swapped the coil packs on cylinders 1 and 2, the idea being that if it gave a new code of P0301 (cylinder 1 misfire), that would easily confirm that the coil was the issue. The spark plug looked good...no indication of oiling or damage.

That didn't seem to help, but in the short time I had to drive it around (G'daughter needed to use it), it didn't set another code. It would stumble, and the CE light would flash, but not remain lit. The "transmission" icon lit up, but, as I understand it from posts on the forum, that is likely an effect of the misfire causing the tranny to see a mismatch with engine speed. The reason I asked about cylinder one, was that I wondered if it had a sort of "special relationship" with the control system, and that maybe I should have done the trial swap with another cylinder.

While the GD was driving it, it stalled while coming to a stop. She sort of panicked and became afraid to use it, so her dad and I took her another car and brought the Jag back. He drove it...said it stumbled some along the way (about 10 miles). When we got it back, it did have the CE light on. The codes, however were P0727 and P1775 (which, again, seem likely to just be the transmission reacting to the erratic engine). No misfire code was set...????
BTW, I do have an OBDII reader (Ancel AD410...Amazon had a sale ), but it's the first one I've ever used, so I'm at the bottom of the learning curve on it right now.

I plan to go at it again today or tomorrow, so any suggestions on other avenues of approach would be more than welcome.

Cheers,
Bill

 

Thanks, LP...Although, according to Mr. Garrison, “Remember there are no stupid questions, just stupid people.” Maybe I fall into there, somewhere

So, you're saying that if there were any unique problems with a cylinder 1 coil pack gone bad, they should maybe evidence only at initial start-up?

Cheers,
Bill

 

Thinking

 

Hi Bill,

Thanks for giving us "The Rest of the Story." My first question is whether your granddaughter may have refueled recently and if so, is it possible she got some gas contaminated with water?

If the problems persist but you don't get any consistent codes, one suspect is the Crankshaft Position Sensor (CKPS), mounted on the right front of the engine near the crank pulley (right side as viewed from the driver's seat). It's worth removing the sensor and cleaning it and its electrical connector, but an even better idea is to replace it with a new one and put the old one in the trunk as an emergency spare. The CKPS is a known failure point that can cause difficult-to-diagnose gremlins, stalling, and eventually a no-start. The sensor is held on a bracket by a single screw (8mm head, I think), and the electrical connector is usually clipped near the right front corner of the engine.

One other bit of pedantic info to add to your Jaguar knowledebase: the term "coil pack" is used generically by many folks, even professional mechanics, but technically it refers to a component that contains two or more ignition coils in one package that serves two or more cylinders. Jags use a coil-on-plug (COP) ignition system with individual on-plug-coils (OPCs) for each cylinder, which Jaguar calls "ignition coils," or simply, "coils."

Cheers,

Don

 

Sometimes the Crankshaft sensor can get metallic particals on the face of the sensor other then the connector

This sensor does not always throw a code

Crankshaft code P0335 , Camshaft P0340

On the transmission codes the transmission has 2 rotation speed sensors that feed the transmission ECU which in turn talks to the Engine ECU effecting the engine

There is a history of the transmission connector getting dirty stalling the engine out at low RPMs as you shift into drive

This connector is on the left rear and can be gotten to without jacking

It is not a twist off connector but more like a air hose push on / push off referred to as a bayonet , spray penetrate oil and a couple of days soaking will help get it off if stuck

The sleeve pulls straight back

On the missfire have you tried a fuel injector cleaner if the injectors are sticking underfueling at idle

a recommended brand is the Chevron product

 

Light at the end of the tunnel, maybe...

Thanks for bringing us the gas question, Don. Actually, I had asked her about the gas, but she said she had not filled up since I gave the car back to her after installing the new timing chain tensioner, and thought it was some time in May when she had last bought gas. Thinking back on that, I realized the car had sat for about a month (maybe more) between the time I told her to park it, and the time I actually got around to doing the tensioner (retired, travel a lot). I thought I remembered seeing the tank at about 1/2 full when she started to have the current problems, but wondering about the possible state of the fuel, because of your question, I went out to it and looked again, and found the gauge in the red zone in the last 1/8 tank segment...hmmmm.

I did three things yesterday: Swapped the suspect coil pack from cylinder 1 to cylinder 4 (remember this, for later). Wired the breather hose from the valve cover so its little bell-shaped fitting stayed snug to the hose that runs to the intake ducts (just something I noticed that didn't seem properly connected), and went and got a half tank of gas and added a bottle of injector cleaner. After driving it just a little, it ran noticeably smoother, although it still had the occasional hiccup at idle (worse when in gear), and was hesitant when coming off a stop, especially if uphill or with the pedal to the floor. Cruising seemed smooth enough.

Today, hoping that moisture/crud in the gas might be the sole culprit, and that maybe the system needed some help to work that out, I had planned to give it an "Italian tune-up" on the interstate, but didn't get out early enough to avoid evening rush hour. I cleaned off the crank position sensor (though it didn't look bad), and then just ran the car up and down nearby roads for a bit. Still better than when she brought it back to me, but not really improving. When I got near the house, it seemed to get better (maybe it was glad to be home ), and idled smoothly when I came to a stop in the driveway, left it in gear, and sat for a minute...but it had set a CE code!

Pulled the code and it was P0304 (misfire cylinder 4). Hurrah! Remember now, that's the coil pack that was originally on cylinder 2 when I got the first error code P0302 a few days ago, and the one I had swapped to Cylinder 1 on my first try at diagnosing its functionality (and the reason for my original question in this thread).

I'm taking all this as hopefully indicating that that particular coil is failing, and those symptoms were possibly exacerbated by less-than-pure gasoline.

I had already ordered a new coil. Figuring it would't hurt, I've also gone ahead & ordered a fuel filter & fuel pump, and may get the crank sensor as well now, just in case.

We'll see what happens next.....

Cheers,
Bill

 

Thanks for that; I'll check those connections as well. See my answer to Don, above, for updates so far.

Cheers,
Bill

 

Good work, Bill!

We'll look forward to your next update!

One thing that comes to mind is to check the drain tube in the fuel filler box, part 6 in the diagram below. The drain tends to become clogged with seeds and leaves, which allows water to pool up around the fuel filler neck when it rains. If the fuel cap gasket doesn't seal perfectly, water can make its way into the tank. It's simple to clean the drain tube with a combination of string trimmer line, a vacuum cleaner and compressed air. Just take care with the air pressure so you don't blow the tube off of the fitting on the bottom of the fuel filler box and create more work for yourself:




Cheers,

Don

 

I'm always baffled with american cars actually displaying coil misfire errors. I had so many random misfires in my ownership of a few x300 and never seen such code, even when the coil was clearly bad.

Your misfire can be a multitude of things but generally, when you get misfire its:
1. Coils
2. Coils
3. Coils again.
4. Still coils.
5. Only now maybe something else

Are you still running original coils? 5 of mine failed within 2 weeks few years back and since then I went through gazilion of different coils. Generally any cheap coil will only last ~12 months and might cause more issues than it suppose to fix. I did however eventually purchased QYL coils(Amazon US) which are highly recommended here and indeed work very well.
Your misfire can also be caused by a failing MAF, coolant temp sensor and air leak, fuel pressure issues, even lambdas. I suggest looking at live OBD data, if you're not familiar with OBD, post results here and someone will translate it for you

 

Will check that out, too. Thanks, Don.

 

Granddaughter bought the car (well) used, so no idea on the age of the coils other than that she's had it for a couple of years or so. Five of the six have a sort of black bar on the composite that composes their top surfaces, and one is plain.

I hope it's not the MAF; that's pricey. I've ordered a fuel pump & filter. Don't know the current ones ages, could be contributors to the overall issue, and cheap enough to just throw in as "maintenance" rather than wait for possible problems from them.

Cheers,
Bill

 

The first year OBDII compliance was mandatory in the U.S. was 1996, so the X300 OBD system is somewhat primitive. Now that katar83 mentions it, I recall working on a friend's X300 that had P0303 stored, indicating a misfire in cylinder 3. After swapping coils around, changing the spark plugs, then changing the camshaft cover gaskets due to oil in the spark plug wells, I finally tracked down the problem. It was a crack in the wire for the coil to cylinder 6 that had created an intermittent disconnection. Repairing the wire solved the problem. Why it was triggering a cylinder 3 misfire code is still a mystery.

Cheers,

Don

 

Its most likely the coil. These cars are very reluctant to dole out codes. Your story does not surprise me.

 

I'm assuming standard MAF cleaner is safe on this model? I've heard a few types of MAF sensors on some makes are not compatible with the standard cleaner.

 

I've been using standard CRC MAF cleaner spray on Jaguar MAFS for probably a couple of decades now with no problems, so you should be fine. Clean the terminals in the electrical connector halves also.

 

Sorry for the delay in updates. Partly due to mini-vacations, and partly to the evil of Fedex (don't trust in good performance from certain of their employees, or the accuracy of their shipment tracking).

Of the parts I ordered, last part to arrive was, of course, the new coil. Before I got it, I cleaned the MAF sensor, checked the fuel filler box drain, and installed a new fuel filter... with little to no change in performance (maybe a very slight improvement with the filter, but maybe just imagination). I held off on the larger job of installing the new fuel pump, and held back on the new crank position sensor as well.

Put in the new coil on cylinder 4 (where the originally suspect coil had last been migrated) and it was immediately evident that the problem had been cleared. So, seems that the issue was a bad coil, as initially suspected, possibly exacerbated by bad fuel.

Of course, not content to behave for long, the car now has its ABS warning light on....

 

On the last version of the inline 6 , they changed the order of the cylinders with the # 1 up front and # 6 in back

http://www.jagrepair.com/images/Training%20Guides/801S%20-%202000.pdf

The early AJ16 engine had idle problems and they changed the cams with a stamp on it to identify the mod

http://www.jagrepair.com/images/TSB/...%20Changes.pdf

The plugs by TSB whent back to the old school copper Champions and no exotics

The gap also came out to X dim mention ( to prolong coil life in my opinion ) and they can be regapped to the closer original Y dimmention to ensure you have a spark of some sort at least

The easiest first step on the ABS is to remove and clean each wheel sensors as metallic debris builds up on the face of the sensor

These sensors are brittle and can break if tried too hard to pry out

There was a change in part #s in X300 production and lefts do not work on rights I think on the early sets #s but do swap on later sets , I can be wrong on this

The sensors will read 1300 ohms as a " fundamental " reading as the wire pairs in different colors on the pic

As a " functional " reading if you spin the wheel in the correct direction it will read about 1.0 volts AC

There is some fuses and a different brake switch other then the one dedicated to the brake lights