The car: 2000 XJ8 with 118K miles.

Suddenly running very rough at pretty much all rpms. Check engine light came on. (Might be coincidence, but just a few miles before this happened I got a full tank of gas - Shell premium)

Got home - shut it off. Connected my OBD unit (when I restarted car got Restricted Performance warning) Here are the code I got:

P0307
P1316
P1642
P1000

Any thoughts or suggestions? I'd really hate to have to take it in - hoping against hope it's something I can try to sort out.

Sure would appreciate input.

SV
San Diego, CA

 

You've got a misfire on cylinder 7 b(3) (P0307), emission danger due to misfire (P1316), restricted performance (P1642), and diagnostic cycle not complete (P1000). So, it looks like your problem is with cylinder 7, probably caused by a coil that is not functioning properly. It may be because of oil leaking into the spark plug well. That's the first thing I would check. I think the cylinder in question is on the LH side (driver's side in the USA), third one from the front. I'm not sure why your diagnostic cycle says not complete, unless you have had the codes reset recently. The other alternative is that something in the cycle is not responding and so, the cycle never completes (not good).

 

Jim, thanks.

Looking around the web I'm finding conflicting info as to which cylinder is where. Any suggestions? One source says cylinder closest to firewall on passenger side; another says closest to firewall on driver side.

Assuming I can get the location sorted out - how hard is it to get to the coils and plugs. Haven't dug that deep into this car so any pointers or links you can provide would be a big help.

 

Steve,
I got the info off of Alldata.com. It says the "A" bank is the right hand side when sitting in the car and the "B" bank is the left hand side. The cylinders are numbered 1 - 4 from front to back. Sometimes they are numbered 1 - 8 starting with front right and ending with rear left. Someone else can verify, but I'm pretty sure b(3) and 7 both refer to the third cylinder back from the front on the left hand side. To get to the coils, all you do is remove the engine cover (pulls off), then remove the screws holding the plastic cover over the coils and wires (4 8mm, I think ?), then each coil is held in by 2 screws (8mm, I think). Then the coils pull out. A 1/4" drive ratchet works best. It's really not difficult, but don't get over zealous and tighten anything too tight. It's not hard to strip, crack or break the plastic. I'd pull that coil and plug also and see what they look like. The plugs are standard size 5/8". Anybody else, please correct me if I'm wrong. It's been a while since I did this.

 

Steve, both the P0307 and the P1316 are indeed related to a miss in cylinder 7. The P1647 is likely due to the scanner itslelf and the P1000 implies that the test cycles are not complete, perhaps since a previous OBD reset?

Attached is a picture of the cylinder orientation for the XJ's. I agree that cylinder 7 (relative to the OBD error code) should be bank 2, cylinder 3. And Jimmy is correct in his description of how to get to the coils. The coil covers are simply a long rectangular plate mounted to the top of each valve cover - removal will be obvious once you remove the engine cover and can see them. Coil removal becomes just as obvious once you have access to them. When the coil is removed, look carefully for oil around the plug boot and in the plug bore. Before removing the plug, clean the bore thoroughly, as you don't want any debris that is trapped within the bore to fall down into the cylinder.

If there is evidence of oil in the bore and/or on #7's coil boot, then thorough cleaning may resolve the issue, but the source of oil will have to be dealt with - most likley by replacing the valve cover gasket and plug bore gaskets (they come as a set).

If there is no evidence of oil in the bore of #7, and the plug looks okay, I would suggest swapping coils between, say, #6 and #7, resetting the codes and driving until the CEL occurs again. Hopefully, the new message will include a P0306, telling you that the coil that was in #7 and is now in #6 is the cause. If it remains at P0307, then some more troubleshooting will be necessary.

BTW, are you the Steve Vaus (aka Buck Howdy) that I remember fondly from the 84 and 96 Padres playoffs and World Series songs ("Talkin' Number One" for example), among many others? If so, congrats on your Grammy! You and Glenn Erath did some work together, didn't you? Man, this brings back a lot of great memories! Cub busters t-shirts... Hudson and Bauer... Garvey's home run... what a great time to have been in San Diego.

 

QuadManiac, yeah I'm that same guy - long time since those great Padre years! Thanks for remembering.

I had recently reset codes - had a thermostat thing and CEL just a few days ago. I've just now pulled the coil cover - but as luck would have it my socket broke as I was loosening the #7 bolts to pull that bad boy. So now I've gotta see if a neighbor has a 8mm socket. Not my day.

I plan to swap coils - see if the error follows the coil - course I'll have to wait for the CEL to come on again (I stupidly reset the CEL - but I don't imagine it should take too many miles)

If it is the coil . . . are these cats finicky as to what brand coil or coils being matched? NAPA has one for $140 that they might be able to get today. Otherwise any suggestions?

Thanks much to all.

 

Well, as is usually the case, I edited and added a lot to my post, WHILE you were responding, LOL... It appears that you are in the middle of doing all that was suggested, glad to see you have good troubleshooting skills.

So all I can do is wish you luck and offer additional troubleshooting help if and when you need it.

I have always trusted NAPA parts, and they are close in Poway - the guys there are all good people, from my experience (lived in Penasquitos for 25 years)... I'd go for it if you prove it is the coil.

 

Okay pulled the #7 coil - for one thing there is a very obvious crack in the rubber boot. Could that be effecting anything? I'd much rather replace a boot than a coil! Swapped coil 7 and 6. Now will drive and wait for CEL. No sign of oil or fouling at the bottom of the well

 

Yes, a crack in the rubber boot over the plug could allow the spark to jump directly to the head instead of through the plug - this would cause the miss you are experiencing. If you look carefully with a bright flashlight, down in the bore adjacent to where the crack is, do you see any evidence of carbon tracks? This would prove that the spark has been bypassing to the head.

 

Does it make any difference where the crack/tear is? This is up near the top of the boot.

Thanks for your help in this adventure!

 

As stated above, swapped ignition coil #7 with #6 (third from the front on driver's side and second from the front on driver's side)

Drove around a little. CEL finally illuminated (along with a random off and on Restricted performance light.) Ran the codes again - here's what I got:

P0307
P1314
P1642
P0307 (pending)
P1316 (pending)

So, best as I can tell the issue remains with #7 even though I switched ignition coils (glad I didn't go buy a new coil!)

What's next to check gents? Anything else I can do myself?

 

As I said above - I think I've ruled out the coil being the root of the problem.

Sure would appreciate any input. Can't help but wonder if maybe it's as simple/stupid as a plug gone bad or fouled. Trying like crazy to avoid a big bill - especially in these times.

Fuel injector? How hard are they to get to? Clean? Replace?

Thanks

 

Steve:
Here are the possibilities according to JTIS:
(don't panic!)
Cylinder compression low
Worn camshaft / broken valve spring(s)
Fuel delivery pressure (low / high)
Fuel injector(s) blocked / leaking
Fuel injector(s) continuously open
Fuel contamination
Fuel injector circuit fault(s)
(Injector DTCs also flagged)
Spark plug failure / fouled / incorrect gap
ECM to ignition module primary circuit fault(s)
(Cylinder misfire detected DTC also flagged)
Ignition module ground circuit:
open circuit, high resistance
Ignition module / coil failure

I would apply Occum's razor (Google that!) and have a good look at the spark plug.

 

Are you positive that the codes were cleared - I just had a similar situation on our Lexus.

I know I cleared the codes and it read the same when I tested it after doing a coil switch. So I reset everything again .....started it up and quickly turned it off and checked for no codes.

Then ......I started it up and ran the car around to get the CEL-- sure enough it came back on the cylinder I had switched the suspect coil to.


Before I started playing with the injectors - I would double check the coil and pull the plug -- pray that a weak coil has fouled the plug!

 

Occum's razor is one of my mantras, spark - yes, Steve, pull the plug and see what it looks like.

Next, if that wasn't it, I'd check the injector connector for #7 - I had one get slightly corroded pins which caused a miss and a CEL, but It also caused a limp mode, which you have not described as of yet. Regardless, it's easy to pop the connector off, clean contacts on both sides with some contact cleaner/lubricant (like from Radio Shack), put some dielectric grease on the o-ring and plug it back together. 5 minute job.

HEY, also, ANYBODY with absolute knowledge of cylinder locations - can you go back up and see if we told Steve where #7 is correctly? It just dawned on me that if we made a mistake, he may have swapped the wrong coil.

 

No absolute knowledge.

(removed previous guess)

"Misfire detected – cylinder B3 (7)"

Gotta go with JimmyL.

Of course, you could remove all four plugs towards the back of the engine. One of them is going to look dirtier than the others.

Is there any oil down one of the sparkplug wells? Usually the first thing to be suggested in similar threads.

edit:
AHAH! check out the picture on the left in Quadmaniacs post. B3 we understand. Now, look at the firing order, and count over 7. It is 2(3) = B3

second from the windshield, driver side (LHD)

 

Thanks for all the input - at least I feel like I've got the cavalry backing me up.

I have been working on the correct cylinder - whew.

Have had occasional random LIMP modes in the past but they always clear with a shut down and restart. (All prior to the CEL - since the CEL only have had on again off again Restricted performance in which case the CEL flashes - but even the Restricted Perf goes away and the CEL stops flashing)

So I shall follow the consensus this AM and replace plug and check injector connectors as soon as it's light outside and the auto parts store opens. Any plug suggestions? Strongly prefer something that's "plug and play" - don't even wanna have to get into gapping etc.

 

I had the EXACT same problem with my number 8 cylinder, same codes, same symptoms.

My problem is that I had a bad fuel injector. I replaced it and all problems went away. To test it, you can try swapping the fuel injectors between cylinders and see if the problem follows.

However, I will warn you that when you try to remove injector the metal cap on the injector tends to get "left" behind in the port. Which happend to me and no amount of pulling with needle nose pliers would get it out. I had to run a screw down through it and then pulled it out. If this happens the injector is toast and your commited to $100-$150 repair.

I also took all of my injectors out and sent them off to be cleaned and tested. Made a big difference.

 

Thanks Ronmexico

Hoping it's the spark plugs. Will know in a bit this morning as soon as stores open. In the meantime, how difficult is it to get to the fuel injectors? I did a quick search online but didn't see any how-to instructions.

 

Wasn't too hard... there are little metal clips that hold the electronic rail (for lack of a better word) you have to take off and then there are little clips that hold the fuel rail onto the injector...

They can be a little tricky to get off/on (even downright pain in the a$$).

You will have to take all of the off on the side you are working on.

I tried plugs 1st also, gotta try the simple stuff....

Hopefully, it is not low compression due to the infamous nikasil problem. My nikasil cylinders are actually damaged, but the car runs pretty good.... doesn't have the power it once did.... (did a compression and blow-by test on all cylinders). You 2000 might be safe though, I think around that time is when they stopped making the nikasil engines.