O.K., I need the combined brain power and experience containedin the membership. I’ve been chasing a series of interrelated codes without awhole lot of success. It all startedsubsequent to a busted timing chain tensioner (NO RATTLE WARNING) which led toa bent valve and the need to pull the left (driver’s side) head to replace avalve and a complete chain and tensioner replacement with all of the gaskets,seals, and what nots that goes with the all of that. I also exchanged the oldplastic thermostat cover for a new aluminum one while we had everything apart.We start with the point as before I had no codes relative to fueling orignition.

Shortly after my A/C died due to a poorly reconnected pressure line and thatwas followed by a left bank cam position sensor code (P1341). Since they’recheap enough I pre-ordered a new one before starting to dismantle stuff to getat the old one figuring if it tested bad I’d have a ready replacement. Ran thepin point electrical checks and didn’t get a negative result so I installed thenew sensor, cleared the code but it came back. Since the system defaults to thecrank position sensor when that happens I’ve left that one go for now.

I then began to get this series of interrelated codes (P0171, P300, P1316) withan occasional specific cylinder being coded as well which has indicated acylinder on both banks but never both at the same time and often no specificcylinder at all.

I’ve checked all of the obvious places for unmetered air leaks from the intakerunner to the throttle body, both full and part load breathers and their orifices’,VVT seals, etc., and couldn’t find any leaks. I just replaced all the injectorsas well as both valve cover gaskets as both showed signs of oil seepage at thebottom rear of the covers which was causing a mess as well as the typical hotoil smell so there’s no air leak there. Also replaced a water pump due to afailing bearing but that had nothing to do with my fueling problems.

Since I can now feel a miss and some rough running which is actually getting worse as I’ve gonefrom an intermittent RP light to a constant one over the past several days it’snot likely to be a downstream cause like and 02 sensor or exhaust leak. Also just started getting a P0327 code whichis the knock sensor 1 low voltage input code on the right bank so something isdefinitely going south on the right side.

Since the fuel related potential problems shouldn’t be causing any of thissince fuel pressure and fuel flow problems should affect both banks dues to thepressurized manifold having only one entry with 8 equally pressurized exits ateach of the injectors I left trying to figure the next most likely step to take.

keep in mind………8 new injectors yesterday, new valve cover gaskets yesterday, noblocked part or full load breather tubes, no VVT seal leaks, new P & F loadbreather tubes, no air leaks I can find anywhere into the system, plugs haveless than 2,000 miles on them.

Most recent codes pulled yesterday after everything was done are:P1000
P1341 (CAM SENSOR)
P0171 (LEAN RIGHT BANK)
P0300 (RANDOM MISFIRE)
P0327 (KNOCK SENSOR 1 LOW VOLTAGE INPUT) Just started 2 days ago
P1316 (EXCESS EMISSIONS)

 

Quick couple of things:

From memory, there is a screw "on top" of the cam sensor. Possibly to hold the cam cover. From what some have reported, that particular screw needs to be shorter than the other ones. A long screw drives into the sensor and I suppose damages it. You might want to remove the sensor and check if the body is damaged. Again, this is my recollection, I have not done this job myself.

Also, re-check everything with a connection to the heads anf throttle body. Dip stick o-ring, PCV valve (o-rings again) and VVT seals. Generally, if you see oil, there is likely an air leak. Double check the bellows on the EGR pipe. Harbor Freight o-ring kits are great for this.

Last, keep the air flow meter on the radar, too. As usual, get some numbers, in particular fuel trims. A cheap ELM327 is great for this.

Best of luck, keep us posted.

 

I've got SDD/IDS from British Diagnostics as well as a laptop based OBDII program as I also have a 2004 XJ8 (wife's car) that I have to service and I sometimes feel that I've become a full time mechanic<G>

The cam sensor on my XK has only one screw and it passes through molded 'ring' alongside the actual sensor body instead of through it. Both the one I removed and the one I installed were externally undamaged and I could see nothing that would have blocked the sensor from "seeing" the cam as it rotated. I have to think that it is a problem in the ECM that it communicates with or somewhere in the circuit between the two. Since the fueling defaults to the crank position I've left that particular problem aside for a bit as testing the circuit for resistance really takes two people to do it properly because of the distance between it and the ECM.

I took a long hard look at both VVT seals when I had the valve covers off and they're pliable and tight with no oil seepage. Given the growing severity of the miss I'm feeling I don't think a dip stick O-ring is going to be the culprit but I'll check it again anyway since I have a ton of metric O-rings anyway.

I've used a K&N air filter for 3 years now without any problems and gave it a thorough cleaning and re-oiling about a week ago because of the oil blow-by I'm getting in the air cleaner housing so that should be passing sufficient air. Of course I'm running lean which would indicate too much air for the fuel in any case.

I've cleaned the MAF sensor but perhaps that's gone south and isn't measuring the flow correctly and the ECM is getting a wrong signal as a result. There's even a possibility that the IAT sensor mounted next to the MAF is causing problems although we seldom see problems reported with that particular sensor. In any case would a lean condition cause a "knock" sufficient to trigger the knock sensor.

Etc., etc., etc. I could have stumbled into a bad tank of gas and although I stick to Chevron high test exclusively it could still happen as the knock sensor has only been triggered since I filled it up a couple of weeks ago. If I drove the car on a daily basis it would be easier to make such connections but I don't.

It's easy to see how you can throw parts at a problem when your experience data base is pretty much limited to one car over a period of months and not an entire series of cars over many years.

 

It occurs to me that since P0171 code identifies a lean condition on one bank only that you should be able to eliminate certain potential problems from the start. Let me explain my thinking and tell me when I go wrong.


Here's the list of potentials from the manual:



 Air intake leak between MAF sensor and throttle


Fuel filter system blockage


Fuel injector blockage


Fuel pressure regulator failure (low fuel pressure)


Low fuel pump output


H02S harness wiring fault


Exhaust leak (before catalyst)


ECM receiving incorrect signal from one or more of the following sensors - ECT, MAF, IAT, TP


Wouldn't it make sense that to go lean, or rich, on only one side that the problem has to be more local to that side? A faulty MAF sensor or intake air temp sensor would affect both sides would it not? The same with a fouled fuel filter, a bum fuel pressure regulator, or low output fuel pump since the fuel injector rail is a pressurized closed loop system affecting all injectors equally.

If that's right than a lean condition on one bank would be mostly likely confined to one or more blocked injectors on that same side in which case I would almost expect a misfire code to show as well although it might not. Also if there's an air leak it too would be confined to just that side either through the full or part load breather depending on which code you got; or one of the valve covers leaking, etc.

I would also think that the ECM wouldn't be the problem as it derives its signals, I think, from sensors that can't discriminate one side from another...TP, MAF, IAT, and ECT

If I'm right....and that's the question.... wouldn't a lean code from only one side be primarily caused by one of the following?

1) Faulty or blocked injector
2) H02S harness wiring fault
3) Exhaust leak before catalyst
4) Unmetered air intake on the side of the block that sets the code

If I'm wrong...and I may well be because of the way these systems are interrelated....please point me in the right direction.

I started with 7 codes and have whittled it down to just 3 and that includes the P1000. I've now got just the P1000, P0171, and P1341 (cam sensor) so I can almost detect the tunnel if not the light at the end.

 

I would encourage you again to check the long term fuel trims especially at idle. Codes are triggered by fuel trims over 25. For argument's sake, one bank could be triggering a code, and the other could be at right up there at 23, with no code, meaning there could be a "common path" leak anyway. No code doesn't mean things are where they need to be. My trims were in the teens a while back and the engine was pinging. Bringing the trims back down to single digits (one leak at a time) brought a lot of jaguarness back into the ride, believe it or not.

Best of luck, keep us posted.

 

^^ What Fred said....

 

I had a persistent and intermittent P0171 on my '07 (same basic drive train). I looked everywhere for air leaks. Finally, I had a "smoke test" done (about $100), which uncovered several small leaks in the intake tract. After all this, I think a smoke test is the best and may be the only definitive way to locate air leaks.

 

Is this an AJ26 or AJ27? AJ26 has 2 leads to the coil pack and the AJ27 has 4.

 

AJ27 with 4 leads per pack.

 

Yes, my fuel trims are probably off but what I'm trying to do is minimize the false trails the svc. manual suggests might be a cause.

The problem, according to the svc. manual can be either a specific physical cause, air leak, fuel blockage, etc., or an electrical problem such as a failing pump, H02S sensor with internal shorts, and so on. Some of these would (or should) affect both sides equally and if severe enough do so with some consistency.

In my case it has always been just the right bank and only at very low speed and even then over varying periods. I may, or may not, get an RP light at a stop light or school zone, and upon getting into clear traffic the light will go off within 1/4 to1/2 a mile and stay that way the rest of the trip. The next time out it may not happen at all but if it does it will always go off again as soon as I get above 25-20mph and full power is again available.

I've checked all the intake air channels for air leaks...part and full load, entire intake system from air cleaner to TB, VVT seals, part load breather with a 3/32 drill bit, but I still need to check for an exhaust leak before the cats. I've replaced all 8 injectors, put new valve cover gaskets due to slight oil seepage, replaced a suspect coil on the #4 cylinder on the left side due to a P0300 & P306.

The iridium plugs have less than 2000 miles on them and when I checked #4 looked solid with good color.

I've also replaced, for different reasons, both the coolant expansion tank and a failing water pump. Oh, and when I replaced the tensioners I also replaced the thermo housing.

For almost a year now I have consistently gotten a P0171 (never a P0172). I can clear it after each attempt to locate the problem but within 2 or 3 drive cycles it has always returned.

 

I didn't see mention of an intake manifold gasket leak or possible crack in the manifold. I think a smoke test could save a lot of time, no matter what the cause.

 

RD Minor where abouts in the manual is the list of DTC's?

I have just purchased an icarsoft i930 scanner and have a list of DTC's the downloaded manual is divided into
1. General info
2. Chassis
3. Powertain
4. Electrical
5. Body

This is the download manual for the 2004 XJ8 are the DTC's the same?
Where do you download the manual for the 2001 XK8?

Many thanks for your help, David

 

From the bottom of the second post in this sticky https://www.jaguarforums.com/forum/x...ts-data-29800/

 

Engine related DTC's will be in the powertrain section. For instance, those associated with fuel issues will be in powertrain under fueling Suspension issues will be in the chassis section, and so on.


The 2004 XJ8 MAY share some of the same DTC's but it's not only a different year but also a different body and different engine than a 2001 XK8 so I wouldn't go by them except as a very last resort.

Go here for a pretty good collection of links to a most of the things you may need for starters including the second edition svc. manual that covers 4.0 XK8's

https://www.jaguarforums.com/forum/x...ts-data-29800/

And here for a list of almost anything you might need relative to Jags...at least for now<G>

JagRepair.com - Jaguar Repair Information Resource

Hope these help get you started