So I've decided to take on a p0171 and p0174 bank one and bank two code fix. I have changed everything from o2 sensors, crankshaft sensor, spark plugs, MAF sensor and for a few days the codes went away. I've decided to replace the manifold gaskets with the assumption theres a leak somewhere there. The only question that I have with this is has anyone here worked on the '04 Vanden Plas manifold? I can't find anything for this year make and model on youtube or anywhere! The issue I have run into is removing the manifold bolts on the driver side. The passenger was a struggle, but I already have that side removed. I cannot reach the bolts on the bottom half of the manifold on the driver's side. Is there a special tool needed or is there some other tool that I can use to reach down there? Does anyone have any tips that can help? PLEASE!

 

In the event you don't already have the X350 Workshop Manual, here is a link:

https://www.dropbox.com/s/xl1qtf4hwt...anual.pdf?dl=0

 

The inlet manifold information is contained in section 30.15.01, beginning on page 1279.

 

Thanks NBCat...maybe I didn't speak on the right area in which I am working in..I am a rookie DIYer when it comes to Jaguars, but they have sparked my interest every since purchasing my first one which is this one. I am actually replacing the valve cover gaskets. The manual however does not tell me if there are any special tools required so I'm assuming that there are none. My problem, being the rookie DIYer that I am, I can't seem to find the proper tools to be able to maneuver around on the driver's side. I can get the oil dipstick nut off and reposition, but all other bolts in line there to actually remove the valve cover are a mystery to me.

 

Hi MrVP,

what do you mean with "...but all other bolts in line there to actually remove the valve cover are a mystery to me"?

If I remember correctly from when I did the job on my SV8, and I suppose that the basic layout is the same for both n/a and supercharged engines, all bolts are 10mm heads, no special tool needed as such. The main problem was accessibility, or lack of it, as the space between the engine and the engine bay wall is very limited, so that I used different 10mm inserts (different lengths because some bolts have longish threads to attach further items) with a 1/4" ratchet.

The layout of the bolts for removing the valve covers is the same on both cylinder banks, so if you have already done the passenger side, the driver's side is basically the same.
The main issue on the driver's side, apart from lack of space, is the fixing of the dip stick. After you remove the nut fixing the dipstick eyelet, the manual says that you have to remove the dip stick tube. I did not do this because I did not want to apply too much force, so I did what other members of the forum did and cut the eyelet, bent it out of the way and then I could remove the bolt.

I am sorry that I do not have a better picture, but if you enlarge the attached one, you can make out the cut and bent eyelet of the dip stick on the right.




The following shows most of the bolts on the driver's side:




I hope that this helps a bit.

Best regards,

Thomas

 

@MrVP, use 1/4-inch drive universal sockets to reach all the bolts around the cam covers as described above by Thomas-S. Note the position of the bolts as some are different to secure other parts such as the oil level dipstick.

When removing the LH cover, DO NOT remove the dipstick from the tube or it becomes very difficult to reinsert the tube into the sump.

 

Thanks everyone for the great advice and information. I actually have not worked on the Vanden Plas since posting this as someone decided to get high and run into my Cadillac Escalade, which is my daily driver, totaling it. Not only that I am in the process of replacing the rear calipers on my sons ‘07 s-type. If that’s not enough, both my 2004 Kawasaki Zx6 and 2009 zx14 motorcycles are in the middle of fuel injector replacements and carb cleanings. All done by me so I decided to step away from the Vanden Plas beast for a moment. This weekend I am back at it. I will let you know how it’s coming along. Any more advice, please feel free to share!

 

The job had proven to be more than my daily workload would allow. I ended up putting the jag in the shop to have the manifold gaskets replaced, smoke test, and hopefully figure out the hard/no start issue. Four months later after "taking" it out I still have a check engine light and it still have difficulties starting. Whenever I spray starting fluid or carb cleaner through the intake, 8 times out of 10 or always starts. With this being said, I'm not understanding why the repair shop still hasn't been able to solve the hard/no start issue. Anyone have any advice or experience with this? PLEASE HELP!!
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Just a thought.......If the crank position sensor is faulty, the engine will require a longer cranking duration to enable the ECM to determine engine position.
It should generally start, but just takes a lot longer than normal if the sensor faulty.

 

@MrVP, use a smart phone with the Torque app to connect to the vehicle's PCM via a Bluetooth interface through the OBD port.

What is the fuel pressure with the ignition in the ON position prior to engaging the starter motor?

 

Possibly not applicable, especially after this length of time, and this does not address the hard start issue at all, but my case came to mind immediately on seeing that the thread started with trying to solve the cause of those codes.

I was getting P0171 and P0174 after repairing the broken vacuum pipe that supplies vacuum to the fuel pressure sensor and to the secondary air injection system. The codes imply a vacuum leak because the O2 sensor show the mixture as too lean, most likely from unmetered air entering the intake system. I was getting symptoms of a vacuum leak after repairing a known vacuum leak...

Initially, the codes were every time I ran the car. I'd clear them, they'd come back within a few minutes. After some time, it took them longer to come back. Eventually they stopped altogether, and I haven't seen them for weeks now. (See my Coolant Leak thread.)

One of those broken vacuum pipes that I'd fixed applies vacuum to one side of a diaphragm in the fuel pressure sensor. That sensor had not had vacuum on it for who know how many years. Now that it did, the reading from that sensor changed. With vacuum on one side instead of atmosphere, the ECU would see "higher" fuel pressure, and it would do what it's supposed to do, reduce flow at the injectors. The O2 sensors saw that reduced flow as excessively lean combustion.

What had happened with the broken vacuum pipe is the ECU had learned a fuel mixture based primarily on the O2 sensor, and when the fuel pressure sensor suddenly showed "higher" fuel pressure after the vacuum pipe was repaired, it took the ECU some driving cycles to converge on the correct balance between airflow, fuel pressure, and O2 rich/lean status. The O2 sensor always rules as far as the result goes, so the ECU adjusts its behavior on how it responds to airflow and fuel pressure, and eventually corrected itself, no more "System too lean" codes.

That explains why after repairing an obvious vacuum lake, I got codes implying I have a vacuum leak. The ECU was suddenly not being lied to about the fuel pressure any more, and had to adjust its responses accordingly.

 

I’ve replaced the crank position sensor, nothing. It barely even turns over now. When I m try to crank it, I just get clicking and thumping sounds. Every light on the dash flashes with the clicks and thumps. I thought maybe the starter, relays or fuses were bad but the ONE shop that would attempt to help said they were all good.

 

@NBCat This is the next on the list. Going to try and tackle this today.

 

Hey guys! My apologies for the long hiatus...I am an Army vet if I didn't mention it earlier so I've been battling with the VA with my disability rating and after a LONG fought battle I have made it to the finish line! So one weight off of my shoulders and now to my baby...my Vanden Plas. I was able to complete a smoke test and found that the rocker cover o-rings were leaking and had that fixed. It doesn't entirely fix the hard start but I had the battery tested, which I have been doing very, very, frequently and found that all the batteries I have gone through have been good. After doing a more in depth diagnostic, I did however find that something in the vehicle is draining the battery at a very rapid pace. So after using my most frequent resource, (YouTube) I decided to preform a parasitic battery draw. My findings....a bad fuse for the rear cigarette lighter, but that was pulling low volts, like less than .003 or what I've learned, 3 millivolts BUT I also found that my fuse labeled F8 which is the heater circuit water pump is reading 1.673 millivolts which can't be good! That's some heavy current flowing across that fuse when the car isn't running. My question to all of you enthusiasts, what exactly is the heater circuit water pump? Does that deal with the actual water pump or possibly my headlight or windshield pump? I think I may see the light at the end of the tunnel with this 6 year small rebuild, so any additional information will be accepted graciously! Thank you all thus far for sticking around with me!

 

Congratulations for being able to solve the bureaucratic issues you had!

I suppose that with the battery draw you are talking amps (ampere) or milliamps, not volts.

The heater circuit water pump is an electric pump that is in the cooling circuit and boosts the flow of water in the cooling circuit at low rpm of the engine to help the heating system work better and is situated on the passenger side of the radiator.
It is item no. 3 in the following picture:


Additionally, here's the flow diagram of the cooling circuit on the N/A V8 engine, the electric pump in this case is item no. 11:


The actual water pump is mechanically driven by a belt and as such subject to the rpm of the engine. The headlight washer and windshield washer pumps are exactly what the names say, they are fully dedicated to those jobs. Water-circuit wise, they are completely separate.

Best regards,

Thomas

 

I am no expert but have measured current drain in the past and


got 8mA.

I seem to remember that up to 50 mA is ok.

 

8mA when the vehicle is not running? Hhhmm...I am def no expert, but that seems to be very high. From what I have researched all fuses should be reading very close o.oomA when tested when the car is not running at all. I just know that something is draining my battery thus causing little to no start at all. After doing a parasitic draw on every single fuse in each of the fuse boxes (engine, cabin and trunk) this is the only fuse that spiked noticeably. Anything I could be possibly missing? Man, 50 milliamps sounds excessive, but again I'm still learning. Thanks for the info

 

@Thomas-S. Thank you for the correction, I did indeed mean milliamps! Very thankful for the diagrams as well. I do recall seeing it at one point when I removes my radiator to replace the bumper reinforcement bar. I am replacing the radiator also, so this will be a great time to replace the heater circuit pump as well.

 

With all the electronics in our cars, 8mA is actually on the low side for when the car is not running. As Meirion1 said, anything up to 50 mA is to be considered as normal, on some cars this might even go up to 70 mA.
You have to consider that for the example the clock, the memory of the radio, the alarm,etc., all need power to be able to operate. In the case of the Jag, also the air suspension will drain the battery a bit, because the car tries to compensate for air losses from time to time until the reservoir is empty.
Best regards,
Thomas

 

Also it is worth remembering that it can take a number of minutes after you have shut the car off for the various systems to finish their communications updates and go into hibernation.
Even then things like the suspension controller will reactivate regularly to check vehicle height and try to maintain the vehicle's stance.