Hope some of you guys can provide more insight on my little misfire dilemma....

Two days after we picked up our 2005 S-Type 3.0 after repairs were supposedly completed from the August 3rd front-end accident when a guy in a pickup truck plowed into me, the "check engine" light came on and stayed on. According to Jaguar, the code thrown was P303 indicating a series of misfires in cylinder 3. Jaguar inspected the components, ran diagnostics and found nothing wrong, cleared the code, and then swapped coil 3 with coil 2 and spark plug 3 with spark plug 1. The theory was that if it is a recurring coil problem, it should throw a code P302 next time (since the original coil 3 is now installed as coil 2) and if it is a recurring spark plug problem, it should throw a code P301 next time (since the original spark plug 3 is now installed as spark plug 1). The car has been driven more than 1,800 miles since the coils and plugs were swapped a month ago and there have been no more issues until now.

My wife was driving home from work yesterday evening and the "check engine" light illuminated again. I took the car to Autozone this morning to get the codes read and was quite surprised to see that code P303 popped up again, exactly the same as a month ago. So the problem did not follow the coil swap and it did not follow the spark plug swap either. The problem remains with cylinder 3.

Other than faulty coils or spark plugs, what else could be causing these misfire problems in cylinder 3? I'm still scratching my head on this one. Jaguar continues to insist that the problem is not accident-related, but I remain convinced that it indeed is....

 

This looks like a time to hope the Tech(s) have ideas!

There are things specific to each cylinder: the wires going to the COP (coil), the injector as well as its wiring, the various valves and so on.

I've no idea what would be the most sensible to test/change first (or at all) - sorry!

Sometimes wiggle testing (literally wiggling wires during testing) can reveal things but access to wires, harnesses etc may not be good (it's worse on mine!).

I've also no idea what the chances are it was affected by the accident. Probably easier to figure that one out once the fault has been found and fixed.

I believe you trust your shop actually to have moved the parts as you describe, which at least rules out one fairly unlikely possibility.

 

I've done some further research on my JTIS CD and it seems to indicate that if I don't have a coil problem or a spark plug problem, I may have a problem with the number 3 cylinder fuel injector or its circuit. It could also be a weak valve spring. The problem in diagnosing this issue is that it is so intermittent and only shows up sporadically and then decides to turn on the check engine light. No degradation in performance is ever noticeable - the engine runs normally and the car drives like it always does....

Jaguar techs, if you have any additional advice please offer it. We bought this car for my wife to use to drive solo back and forth from North Carolina to Florida to visit her parents six to eight times per year. She's unwilling to use it for that purpose now due to the fact that she still doesn't fully trust the car, and I know she won't until we can find and fix this problem and therefore keep the check engine light from coming on when she's behind the wheel....

 

Hi Jon,

From what your description indicates I would lean towards an electrical or circuit problem. The fact that it is intermittant would rule out a valve spring since that is a mechanical problem and to my mind would be a constant problem. I would look at the wires going back from the coil or the injector circuit. I would welcome the expert opinion of a Jaguar tech also since I'm not an expert either.

Mike

 

Thanks for the feedback, guys. The car goes back in to Jaguar on Tuesday morning, and I'm going to compose a write-up informing the dealership that my research is pointing towards an intermittent electrical circuit problem either in the number 3 coil or the number 3 fuel injector. By now they've learned to take me seriously so I hope they'll pay close attention to the information I will be handing them along with my keys. I really need this issue found and fixed so my wife can get back to using this car for the purpose we purchased it for....

We've continued to drive the car throughout the weekend as we normally would. Performance is normal and the only non-typical sign of a problem is that the check engine light remains illuminated....

I'll update this thread after Jaguar takes another shot at their diagnostics next week. In the meantime, those of you who have pertinent information to add here, please do so....

 

If they record the freeze frame data, clear the code, wait for the fault and do this a few times they may see a pattern as to when the misfires appear.

They should be able to see pending misfire codes and/or the individual misfire counts (mode 6 data), which may speed the process up.

Another possibility is a contaminant in the #3 plug well, say from a leaking gasket.

Visual inspection required, most likely.

 

Update:

Took the car into the Jaguar dealership this morning and had a long conversation with the service advisor as well as the lead tech who will work on the car again....

The tech admitted to me that Jaguar is experiencing a higher-than-normal rate of misfire-related issues in cylinders 1, 3, and 5 in the 3.0 V6 engines of 2004 through 2008 S-Types. Jaguar suspects electrical circuit or wiring problems in the coils or the fuel injectors due to component degradation, but they do not currently have an answer....

I immediately asked the service advisor if Jaguar would be providing financial relief to customers who experience these problems (as our car certainly is). I was told no for cars that are no longer under warranty....

I continue to argue my case that our particular issues are related to the accident suffered on August 3rd. The service advisor continues to express his opinion that he sees no evidence of that, but the tech is more open-minded and told me that he would look for evidence that could potentially confirm that our case could indeed be accident-related....

So we'll see where it goes from here. I got a 2008 X-Type loaner with 40,000 miles on it. I expect to have it the rest of this week. The transfer case whines like a sick puppy....

 

If you may recall, I had two instances of these same misfire codes within 2 months. Nothing definitive was found and I was told to use gas with Techron in it.

Eric

 

Eric,

What model year and engine do you have?

Which cylinder(s) misfired?

What sort of diagnostic procedures did your dealership use?

How much were you charged?

 

Jon89 - the dealer could read the misfire data to see how many misfires are occurring on each cylinder. If (say) cyl3 ones happen reasonably often, they could monitor them in real-time while driving, to see if any particular engine speed/load/etc increases the rate. Which may (or may not) help them figure out the likely cause.

(They can do something similar with a DSO if they're good. SOmetimes the DSO waveforms are more helpful but someone has to know how to interpret them.)

You might be interested to read this (which includes misfires):
http://www.underhoodservice.com/Arti..._it_seems.aspx

(probably split over 2 lines but just join them back together)

 

Thanks for the additional input.

Yesterday afternoon Jaguar discovered that my air filter housing was cracked. Lo and behold, they acknowledge that this happened in the August 3rd accident and had to admit that they missed it during the post-accident work they did to the car in late August and early September. This repair cost will be supplemented back to Geico.

They don't know yet if this has anything to do with the misfire issues, but they doubt it.

Went out for dinner last night on my wife's birthday. Took the loaner 2008 Jaguar X-Type. When we went to dinner, it was still light outside. Night had fallen when we left the restaurant, and I discovered that only one headlight worked, only one taillight worked, and there were no working running lights on the passenger side. Had to drive home like a 95-year-old granny with people flashing their headlights at me constantly.

My wife is ready to never get into another Jaguar again. She says she'll never set foot in the local Jaguar dealership again, either. Not even to drop off her car for service. So if we do wind up keeping our S-Type, it will be up to me to either run it back and forth from the dealership or find a good independent service shop that can handle the problems that I can't....

 

Missing the cracked airbox is not good but maybe excusable - but the faulty loaner is not!!

Unless the crack is downstream of the MAF (sounds unlikely), I don't see how it could affect anything - other than perhaps bypassing the air filter and thus potentially allowing something unwanted through, but I can't see that being the case at this stage or accounting for misfires.

Even then, I don't see how it could be just one specific cylinder.

(I don't quite see your wife's point of view but let's not get into that!)

 

I would still lean towards a coil on this count, did they swap the correct coil? cylinder 3 on your year is the middle cylinder under the intake on the passenger side of the engine. Its definitly not the first time ive seen people change wrong coils, and the problem stays. Our belief here is that the passenger bank is fed from the lower intake passages were oil tends to collect and this can lead to misfires, more so on cold starts, but can happen any time. And yes a cracked air box can cause misfires and lean enigine condition even upstream of the mass air flow. We have a bulletin right now about checking new xk's with lean engine codes for same date of manufacture stamping of the air filters! Seems they flow slightly different, enough to cause air flow balance issues and lean or rich engine codes. If this were my car, and eliminated the coils. I would pull all the injectors, send them out and have them sonic cleaned and flow checked with new screens. I have a friend that does this www.injectorrx.com
and have fixed and diagnosed many problems doing this that never would have been found or fixed without seeing what the injectors are flowing and doing through out their operating cycle. Things like injectors that stick, or flow fine until they hit a certain duty cycle and then stumble. Youde never find this without this equipment and he is very reasonable. Definitly cheaper than a new set of injectors. And while this may not be the problem, diagnosing is about eliminating what the problem is not, to find out what it is. Same thing cops do, they eliminate the usuall suspects to they come up with the one or two that are the most likely suspects

 

Q. What model year and engine do you have?
A. 2005, S-Type 3.0

Q. Which cylinder(s) misfired?
A. There were mis-fires on 1, 3, and 5.

Q. What sort of diagnostic procedures did your dealership use?
A. Don't know but they claimed an air filter was the problem the second time. I produced the receipt where they had replaced the air filter just 45 days and less than a thousand miles earlier. Then they asked me about the gas I used. I pointed out that I was using the octane called for (91). They they suggested I use gas with Techron.

Q. How much were you charged?
A. $0...the second time. The first time I had a routine service done at the same time. That's what sort of had me P.O.ed as it cost something like $800.

Eric

 

Jon89 - excellent help from Brutal. As he says, they could have swapped the wrong coil and plug. I've read several times about injector clean/test but never knew where to go to get it done. You're probably not going to be able to get the insurance to agree to do it but it's DIY to take them out I think. If needed.

 

Thanks very much for your input, Brutal. It is much appreciated, and I have passed it on to the service advisor. Whether any of it is heeded remains to be seen....

I have asked several times if the tech did indeed swap the correct coils. Each time I ask, I'm assured that he did. I have no way of truly knowing, though.

But in thinking it through I have my doubts, and here's why. My understanding is that cylinders 1,3,and 5 are on the passenger side of the engine and are accessible without removing the intake manifold. Cylinders 2,4,and 6 are on the drivers side of the engine and the intake manifold must be removed to be able to access them. So to actually swap coil 3 with coil 2, the intake manifold would have to be removed - correct?

When I dropped off the car again on Tuesday morning and met with the tech, I specifically asked him if he had removed the intake manifold when the car was in the shop during the first week of September for the initial round of trying to figure out what is causing these misfires in cylinder 3. He told me that he did NOT remove the intake manifold. So how could he have swapped coil 3 with coil 2?

If I'm being lied to, I really need to know that. Otherwise I'm just going to continue to get smoke blown up my butt every time I go into this dealership....

 

Hi Jon,

I found this regarding the 3.0 V6 firing order from WIKI:


1-4-2-5-3-6 Firing order S Type 3.0 engine 123 left bank 456 right bank (facing engine from front of vehicle). Maybe the first step is to really nail down what is the numbering scheme for the cylinders since that is different from what your understanding is.

I took a look at my S-Type and seems that unless the tech had fingers like ET I don't see how he could have swapped out the coils for cylinders 2 and 3 without removing the intake manifold. You might be able to get an articulated socket wrench in there, but not sure how you get the coil in and out.

Good luck,

Mike

 

It may be more of a false statement than a lie (eek), but it does sound like he thinks (or did at the time) that 1,2,3 are one bank. You're right, however, I believe (and yes passenger side i.e. right side).

However, with the wrong numbering, he would still have moved part of the correct plug/coil (unless as you wonder he's lying).

If you were there in person you could point and say "so you swapped THIS coil and plug with THAT ..." type of thing, to trap him. Then point out the correct numbering. Not sure they'll love you......

He could try some more swapping LOL

 

carelm - The numbering depends on what you read

But this is an OBD code so we need jag's OBD numbering. Jon89 has it correctly as per jtis, I believe.

 

3.0 liter DOHC V-6 (AJV6)

Got this from another source. Looks to be some confusion between JTIS and other sources. I would recommend getting with the tech and have him identify the cylinder numbering as he understands it so everybody is operating off the same sheet of music.

Mike