Throttle position sensor
 

Apparently the throttle body on my wife's 2004 is failing. There is also a throttle position error code as well. Is the throttle positions sensor part of the throttle body, or is it a separate part?

Thanks is advance.
Greg

Might have some info here to help.

https://www.jaguarforums.com/forum/x...-2004-a-81565/

The tps (throttle position sensor) is part of the throttle body and it needs no programming. That means that you can take your bad throttle body and simply replace it (30 minutes by yourself) with a good unit. It's a really easy swap. I've had to take my throttle body off many times.

If it were me doing the repair I would buy a used part, because it's so cheap and it's such an easy part to get at. If you want a new one, they will destroy you on the price unless you buy one of these (just make sure it fits!!!!) 4x43 9F991 AA Throttle Body for Select Jaguar x Type Models | eBay

I may have a throttle body for your car if you are interested.

Thanks all. I had hoped that I wouldn't need a computer to complete the repair. I'm traveling without tools and I don't have a garage. A local repair shop said that they could put it on without difficultly, but didn't know if it would have to be programmed.

I paid $525 for this one Brand New Genuine Throttle Body for Jaguar s Type x Type | eBay and $40 overnight freight. $500 seemed cheap compared to the $2000 quoted by the dealer.

We have an S-Type that hasn't had any problems, but it appears that the trottle body is a weak link in the system.

Hopefully UPS will make the delivery Wednesday and I can this solved.

I had the same exact problem in my X. It got so bad to the point I couldn't drive it more than a block without my throttle completely cutting out and going into limp home mode, at which point I would try restarting 5 or more times or just push it home.

I was afraid of spending big $$$ on a Throttle Body so I followed this guide to clean the Throttle Position Sensor and the Throttle Body. GUIDE HERE (for an S Type but parts are either same or similar

It was pretty easy and my TPS didnt seem dirty at all but FIXED MY PROBLEM!! It has been 25,000 miles since I did this and has been knock on wood. Worth a try before shelling out big bucks.

Thanks for all the help. We got the car repaired and we're now back home. I kept the old throttle body, so I'll clean and keep it as a spare. Thanks for the link.

Do you have a TB for sale? What year of vehicle is it from

It's from a 2004. By old I meant bad. I'm going to try and clean it per the instructions and hang on to it.

I am pretty sure I have a throttle body, what year is your car?

I have a 2003 xtype 2.5, it threw a few codes, I was told it was TPS it goes into limp mode and cruise control comes on saying not available etc, so I bought the whole throttle body assembly. Do I have to get reprogramed from jaguar after installing the TB? Please let me know asap, thanks guys

Welcome to the forum Bsmokey8,

TB's are a straightforward replacement and don't need dealer programming.

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see.

In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

Bsmokey8, myself and one other member have been playing with failed throttle bodies. Atleast the ones we have played with, the problem is not the TPS unit, but the control motor for the throttlebody. This is where you will need to make a decision. You have 3 options as I see it. You can spend the $1600 roughly to get a new throttle body from the dealership and install it yourself (very easy to do, 2 plugs, a snap band, 4 bolts, and 2 hoses), you can spend $400 on a rebuilt throttlebody, but now you are going to be without a car for a few days as the throttlebody goes back and forth, or finally you can remove the throttlebody yourself and get into the control motor and tighten up the springs a little bit. If you tear into the throttlebody, you will need a set of pentalobe bits to access the motor.

In short, what is happening is the brushes that feed power to the motor are not providing sufficient contact to maintain the control motor. So, the car sees the throttle as not responding and therefore it assumes it is a TPS issue.

If you want more info, please let me know.

Thank you for the reply, I am picking up the throttle body assembly tomorrow and I will try it, if I have issues I will contact you. Thank you once again

Seems like someone has finally made an aftermarket TPS to replace the unavailable Denso 198500-3300

New Jaguar 02 04 x Type Denso Throttle Position Sensor 198500 3300 | eBay

It's about time!!!

Nearly 4 yrs old...

Are you saying to create a hatch mark along the black plastic body of the old TPS and extend the mark to the aluminum of the TB? This would help you remove and reinstall the same TPS, but how do you clock a new TPS to an old throttle body?


https://cimg5.ibsrv.net/gimg/www.jag...7e84163697.jpg

Patterson: Those elongated holes in the TPS are to position it at the proper angle for correct output / signal voltage from the pink and yellow wires. With the ignition key in the run position and engine off, here are the DC voltages specified by Jaguar:

orange / yellow wire: 5 V reference input from the ECM
black / green wire: ground
pink wire: 0.74 V at idle, 3.97 V at full throttle
yellow wire: 1.65 V at idle, 4.20 V at full throttle

As Thermo notes earlier in this thread, sometimes when you suspect a bad TPS, the real issue is worn brushes in the servomotor controlling the throttle plate. Both can cause erratic air / fuel ratio. After installing the TPS to the correct output / signal voltage, it would be good to check the fuel trims at idle and ~2.5K rpm to see if the ECM is adjusting your fuel trims properly.

Patterson: To try to make sense of your X-Type's symptoms and error codes in this thread, I need to recap them:

Baseline:
+ 150K mile 2002
+ The Jag was running great up until a few weeks ago

Prior to May 8, the symptoms were:
+ Repeat rich codes in both banks: P0172, P0175
+ MAF codes: P0101
+ significant oil in at least 1 spark plug well, likely causing misfires
+ engine stalled, "ran poopy"
+ bad sulfur smell from tailpipes

What you replaced or checked recently:
+ new throttle body with new TPS from dealer 6 years ago
+ new air filter 18 months ago, to resolve lean code
+ oil in the spark plug wells - cleaned & installed new valve cover gaskets (May 8)
+ replaced all 4 oxygen sensors (May 14)

On May 14 the symptoms were:
+ exhaust does not smell like burnt firecrackers anymore
+ now runs great at idle and up to 3K RPMs, but it is still in limp mode (haven't yet cleared the error codes)

On May 15 the symptoms were:
+ still in limp mode
+ P0172 & P0175 - rich condition both banks
+ P0101 - Mass Air Flow Sensor Circuit/Performance Malfunction
+ P0102 - Mass or Volume Air Flow Circuit Low Input
+ P0112 - Intake Air Temperature Circuit Low Input - New code

On May 16:
+ Installed new MAF sensor
+ cleared the codes
+ rev'd pass 3,000 RPMs for the first time in a month - no longer in limp mode

Followed by, also May 16:
+ Well, that didn't last long
+ P0172, P0175 rich in both banks
+ MAF codes did not return

On May 28:
+ The pattern after clearing the codes (P0172 and P0175) has been
+ Clear ‘em, dive to work (18 minute mostly fwy ). At the end of the day, they come back pretty quick as I warm up the car to dive home. By ‘they’ I mean that I have the engine icon lit up and the solid yellow light in the speedo dial.

==================
So from May 8 to 28, the consistent theme was rich conditions in both banks. However, on May 29 to June 1, the symptoms changed, now suggesting lean conditions, perhaps from a vacuum leak.
==================

On May 29:
+ won't idle
+ cleared the codes ....... got to work and in neutral I held a rev at 3K RPMs for almost a minute, the engine sounded normal, nice and tight, no misfires or coughing.
+ But, when I let off the 'air pedal' (I like that btw, more accurate than gas pedal) the engine stalled.
+ On the way home it would not idle at stop lights, just stalled and dies at every traffic light.
+ It starts right up tho, and drives at high RPMs, 4K or so. In 3rd gear at 4K RPMs I let off the accelerator and left it in gear, using the engine to slow down, the revs were fine, no stalling until back at idle

On May 30:
+ New development: Got home today and the car idled for a good 5 mins in the driveway.
+ A few blocks away from home it wouldn't idle, just conked out as it's been doing now for a couple days.
+ I pulled in the driveway just now and let off the pedal and to my surprise, it sat there idling.
+ Since the no-idle condition started I've been driving to work on the fwy in 4th gear, holding about 4K RPMs all the way, about 15 mins.
+ Engine light has not returned since yesterday. It had been returning regularly after a drive, but I've been clearing it everyday, so I know it might be taking longer to re appear, but that let me hold the high RPMs on the fwy.
+ Thing is, when it's cold in the mornings, it does idle at first, until the choke (or whatever its called now) closes, then it has gone back to stalling out if the accelerator is not pressed a little

On Jun 1:
+ CEL was out until getting home yesterday when it illuminated
+ P0306, P1316, misfire in cylinder 6
+ engine sounds good on hwy, has normal power
+ at highway speeds: plenty of power and runs smoothly - YES
+ at idle and cold: not smoothly, rough, but does idle
+ at idle and warm: stammers and stalls
+ did carb spray test and found leak in EVAP line

==================================

Am I interpreting this correctly? It seems like the rich codes P0172 & P0175 your X-Type had prior to May 28 have been replaced with lean, vacuum leak conditions. Did something occur ~May 28 to explain / help solve this?

Clocking the TPS
 

Quote:

---

Originally Posted by dwclapp (Post 1906487)

Patterson: Those elongated holes in the TPS are to position it at the proper angle for correct output / signal voltage from the pink and yellow wires. With the ignition key in the run position and engine off, here are the DC voltages specified by Jaguar:

orange / yellow wire: 5 V reference input from the ECM
black / green wire: ground
pink wire: 0.74 V at idle, 3.97 V at full throttle
yellow wire: 1.65 V at idle, 4.20 V at full throttle

---

dwclapp, I am humbled, thank you very much for the detailed summary of the troubles with Rasputin. Personalized plates are too expensive, I don't have one, but that's what I call this car. The summary is spot on, I'm going to look at it closer in a minute.

This morning, I measured the TPS voltages on my existing TPS with in a couple % the Jag specs you posted. I thought I might not even remove it since it was giving the all right voltages, but I did buy a new one this week. Not a Denso, and probably not a good idea. I got the new one in and I measured the 5V ref. and 0.74V on the pink wire, but only .02V on the yellow, no matter how I probed it could not get anywhere near even 1 volt. Also, the DIC was reading ‘Engine Systems Fault’. I turned the car off and replaced my original TPS and clocked it carefully to retest the voltages. I noticed that, depending how concentric with the circlular bosses on the throttle body, where the TPS seats, many different positions will give you about the right volt readings. However, the circular motion of the lever arm that engages the TPS, won’t be concentric either. So the best position is with the screw heads about centered in the slot.

Dwclapp, thanks a lot for compiling these notable points along my almost 2 month period of trouble with the Jag. This is very helpful to track the behavior and narrow it down to a possible fix or several fixes and note the things that have been repaired and replaced. Really nice of you to take the time, Thanks bud! I entered my 2 centavos in red text. To be honest, I'm leaning towards a new throttle body and new Denso coils.

Patterson: To try to make sense of your X-Type's symptoms and error codes in this thread, I need to recap them:

Baseline:
+ 150K mile 2002 manual trans, 2.5L,
+ Battery: After a drive volts are 12.6, over night volts drop to 12.30. A few weeks ago when I was carpooling and left the Jag in the garage for 4 days straight, the volts went down to 12V even.
+ The Jag was running great up until a few weeks ago

Prior to May 8, the symptoms were:
+ Repeat rich codes in both banks: P0172, P0175
+ MAF codes: P0101
+ significant oil in at least 1 spark plug well, likely causing misfires
+ engine stalled, "ran poopy" Flashing CEL
+ bad sulfur smell from tailpipes

What you replaced or checked recently:
+ new throttle body with new TPS from dealer 6 years ago At that time I paid $1K. I think they are about $200 now. I would suspect that servo gear motor assembly well before I would suspect the TPS. The TPS is a very simple device, there is not a lot that is likely to go wrong with it.
+ new air filter 18 months ago, to resolve lean code currently have my old K&N air filter installed.
+ oil in the spark plug wells - cleaned & installed new valve cover gaskets (May 8)
+ replaced all 4 oxygen sensors (May 14) Rechecked the spark plag wells on both banks when R&R-ing all 4 oxygen sensors, the wells were dry. Pulled a spark and it looked good.


On May 14 the symptoms were:
+ exhaust does not smell like burnt firecrackers anymore
+ now runs great at idle and up to 3K RPMs, but it is still in limp mode (haven't yet cleared the error codes)

On May 15 the symptoms were:
+ still in limp mode
+ P0172 & P0175 - rich condition both banks
+ P0101 - Mass Air Flow Sensor Circuit/Performance Malfunction
+ P0102 - Mass or Volume Air Flow Circuit Low Input
+ P0112 - Intake Air Temperature Circuit Low Input - New code

On May 16:
+ Installed new MAF sensor also installed new PCV at this time
+ cleared the codes
+ rev'd pass 3,000 RPMs for the first time in a month - no longer in limp mode

Followed by, also May 16:
+ Well, that didn't last long
+ P0172, P0175 rich in both banks Revs good up to 4,500 RPMs or so, but gets a little rough sounding past that, I can tell not a good time to go much higher with the RPMs.
+ MAF codes did not return

On May 28:
+ The pattern after clearing the codes (P0172 and P0175) has been
+ Clear ‘em, dive to work (18 minute mostly fwy ). At the end of the day, they come back pretty quick as I warm up the car to dive home. By ‘they’ I mean that I have the engine icon lit up and the solid yellow light in the speedo dial.

==================
So from May 8 to 28, the consistent theme was rich conditions in both banks. However, on May 29 to June 1, the symptoms changed, now suggesting lean conditions, perhaps from a vacuum leak. On this I am waiting for CEL and OBD codes. I drove the car today for about 20 mins each way to the store. The misfire is more apparent, will idle sometimes, but is very sluggish and not a stable firm idle, sounds like it’s struggling. This 40 minute drive did not produce a CEL or pending codes. I'm sure they'll show up soon. For vacumm leaks I have hit all the usual suspects: Two ports on top of manifold, IMTs, one way valve to brake booster and at brake booster connection, TB interface to intake manifold, There’s a vac line that runs under the intake manifold, that and the brake booster lines were replaced 2 yrsa ago.
==================

On May 29:
+ won't idle – It had been idling fine until now. First appearance of the no idle condition.
+ cleared the codes ....... got to work and in neutral I held a rev at 3K RPMs for almost a minute, the engine sounded normal, nice and tight, no misfires or coughing.
+ But, when I let off the 'air pedal' (I like that btw, more accurate than gas pedal) the engine stalled.
+ On the way home it would not idle at stop lights, just stalled and dies at every traffic light.
+ It starts right up tho, and drives at high RPMs, 4K or so. In 3rd gear at 4K RPMs I let off the accelerator and left it in gear, using the engine to slow down, the revs were fine, no stalling until back at idle

On May 30:
+ New development: Got home today and the car idled for a good 5 mins in the driveway.
+ A few blocks away from home it wouldn't idle, just conked out as it's been doing now for a couple days. So, the problem of holding idle appears to be somewhat intermittent, but mostly failing to idle, here and there it has decided to hold the idle, but 8 out of 10 times it won’t idle.
+ I pulled in the driveway just now and let off the pedal and to my surprise, it sat there idling.
+ Since the no-idle condition started I've been driving to work on the fwy in 4th gear, holding about 4K RPMs all the way, about 15 mins.
+ Engine light has not returned since yesterday. It had been returning regularly after a drive, but I've been clearing it everyday, so I know it might be taking longer to re appear, but that let me hold the high RPMs on the fwy.
+ Thing is, when it's cold in the mornings, it does idle at first, until the choke (or whatever its called now) closes, then it has gone back to stalling out if the accelerator is not pressed a little

On Jun 1:
+ CEL was out until getting home yesterday when it illuminated
+ P0306, P1316, misfire in cylinder I swapped coils 4 & 6. Waiting for codes to come back. Also, at idle, I do believe I hear the misfire. It is a faint hicup in the sound of the idling motor that is periodic. I’ll admit I bought bargain coils, lol. I couldn’t find Densos. These were $88 for all 6 coils.
+ engine sounds good on hwy, has normal power check
+ at highway speeds: plenty of power and runs smoothly - YES
+ at idle and cold: not smoothly, rough, but does idle check
+ at idle and warm: stammers and stalls
+ did carb spray test and found leak in EVAP line Sealed this

==================================

Am I interpreting this correctly? It seems like the rich codes P0172 & P0175 your X-Type had prior to May 28 have been replaced with lean, vacuum leak conditions. Did something occur ~May 28 to explain / help solve this? Well, if vacuum leak conditions are consistent with failing to hold idle, yes, something occured in my vacuum mgmt. but I'm pretty sure I'vre been thru of those vacuum checks. Other than that, I'm thinking I'll buy Denso coils next and that should fix the misfire. I could spring for a throttle body and see what happens to the idle. After that, I'm putting this car on the next SpaceX rocket so it can be flung out to interstellar space and catch up with Starman.
https://cimg0.ibsrv.net/gimg/www.jag...c1a63009bf.jpg

Patterson: My pleasure.

At idle the 'old' TPS had a voltage of 0.74V on the pink wire (which is on spec) and 0.02V on the yellow wire (well below 1.65V spec). After you installed the 'new' TPS, at idle did the yellow wire have a voltage of ~0V like the 'old' TPS, or ~1.65V per Jaguar's spec?

I ask because Jaguar's spec for the yellow wire 1.65V at idle and 4.20V at full throttle, but you seem to be seeing a different result. So I checked other automakers who also use a 4 wire TPS's and learned that they call the yellow lead an "idle switch" which at idle has a voltage of 0V and is an open / high resistance circuit to the 5V reference lead, and for all other positions, i.e., not at idle has a voltage of ~4-5V and is a closed / low resistance circuit to the 5V reference lead.

If you test your now loose TPS, the resistance between the pink lead and the orange / yellow reference lead should change smoothly as you rotate the TPS. It's a variable resistor, aka potentiometer whose resistance changes smoothly as you rotate it. If you check the resistance between the yellow "idle switch" lead and the orange / yellow reference lead, does it also have a smooth transition in resistance, or a step change from low resistance to high resistance at idle?

If anyone can lend clarity, please do.

Hi dwclapp, Before I removed the old TPS it had good readings on all 3 wires (exclude ground), that were spot on with the Jag spec.

Like I said, I almost didn't take it out bc it had good voltages. The new off brand TPS gave .02V at the yellow wire and seems to have triggered an error message "Engine System Fault". I removed this new TPS, will return it to Amazon.

I re-installed the old one and set that (rotated and clocked it) to get the Jag spec voltages you posted on all 3 wires. Funny thing is now the car is idling, albeit a rough idle, but it is not stalling at stop lights as it has been for a week.

I think I essentially adjusted the TPS by removing it and re-installing it. The adjustment seems to have quelled the non idle condition, but the car is still not happy. I don't think there is anything wrong with the original TPS, but I'll check that resistance as you mentioned here "If you test your now loose TPS, the resistance between the pink lead and the orange / yellow reference lead should change smoothly as you rotate the TPS. It's a variable resistor, aka potentiometer whose resistance changes smoothly as you rotate it. If you check the resistance between the yellow "idle switch" lead and the orange / yellow reference lead, does it also have a smooth transition in resistance, or a step change from low resistance to high resistance at idle?" I'd rather not loosen it in order to turn the lever are, can I just have someone push the gas pedal smoothly to perform this test, or does it have to come out?

I drove to work today, but no CEL yet. I can hear the misfire. I should just buy new Denso coils and put them in, but I'm waiting to see if the misfire moves to cylinder 4 from 6, where it was first discovered. If it doesn't, then the coils aren't causing the misfire.

Also, now when driving at very low speed, first gear in a parking lot, getting some jerking while trying to apply very light pressure to the gas pedal, or slowly remove pressure from the pedal to slow down. This reminds me of when my throttle body was bad 6 years ago and I had to replace it. Herk and jerk!

Quoting dwclapp "At idle the 'old' TPS had a voltage of 0.74V on the pink wire (which is on spec) and 0.02V on the yellow wire (well below 1.65V spec). After you installed the 'new' TPS, at idle did the yellow wire have a voltage of ~0V like the 'old' TPS, or ~1.65V per Jaguar's spec?"


The old TPS had good voltages on all 3 wires. The new one gave only .02V at the yellow wire.

Okay, the CEL returned today on the way home. I have 2 codes return, P0306 and P1316, cylinder 6 misfire detected. I had these codes last week, and swapped the 4 and 6 cylinder coil packs. I was expecting the misfire to move bc I did buy cheaper, but new, coil packs when I did the tune up and cam cover gaskets last month.

So, what else besides the coil pack, or the spark plug, could cause a misfire? Any advice on how to proceed is greatly appreciated :)

I found this table on Jag specific OBD codes. The easy thing is to check the spark plug gap. Next I suspect a problem with the fuel injector to cylinder no. 6.

Should I replace the whole fuel rail?



https://www.jaguarforums.com/forum/a...code-p1314.jpg

I'm curious about the OBD codes, P0306 vs P1316. The first one with a P0 prefix reports a misfire in cyl 6. The P1 prefix reports the same message, but with something appended to it by Jag.

Could the difference be that if you get a P0306 code you have a misfire. And, if you get the P1316 code, the fuel injector to that cylinder has been shut off? Just guessing...as I am figuring out a ride to work tomorrow, ha ha, fun :)

Your laws require 2 trips (as also shown in the Jaguar codes info).

No. Don't guess.

Much better to read the Jaguar explanation of codes - free download after all!

I would never do that. I prefer to guess :)

If you scan the 'Causes' of P0306 vs P1316, I imagine you will see one thing in particular. The P1316 code warns of fuel injector trouble with restricted or leaking flow, or even continuous open injector. This code also warns of a bad electrical wire connection to the injector (fuel injector circuit fault).

The P0306 code does not mention fuel injectors, it's more along the lines of vacuum leaks and the MAF or worn out coils and plugs.

Of course, this doesn't mean the injector is turned off, as I 'guessed' earlier. Just that the Jag specific code P1316 focuses in on the injectors as the likely problem. good take away.

Since my swap of the 4 & 6 coils didn't change the misfire, I'm looking to swap fuel injectors and follow the codes. I found the picture below tonight on JF. I've never messed with fuel injectors, I hope they are the level of 'easy' that is associated with replacing the coils.

I hate driving the car like this, it coughs and puffs while it plays around with the idle on a search for equilibrium. But honestly, it doesn't stall and die at stop lights anymore. It just hates being a car, kind of like when a person gets the influenza. Cant regulate my body temperature, no energy or power, coughing and not breathing right.

In any case, I'm putting her up in the garage for the wknd when I can swap the fuel injectors, and drive her again to recreate the misfire.

Question: I'm wondering if I should clear the codes as I do this injector swap btwn dead cylinder 6 and live cylinder 4.

Or, should I leave the current P0306 and P1316 codes as they are and swap injectors, drive the car, and wait for the code to change to the good cylinder having a misfire?


https://www.jaguarforums.com/forum/a...change-4-1.jpg

Patterson: After you remove the fuel injectors, for a modest fee an independent mechanic can clean and test them for leaks and consistent flow rates. www.mrinjector.us does this by mail for $17.50 per injector plus postage. The video below shows how.

I clear error codes during a repair to see if they return, for quick confirmation the repair was successful.

Thanks again Mr. Clapp. After noticing that the injectors are underneath the intake manifold, swapping injectors to identify a bad one is surely a lot of work considering that I'd be removing and re-installing the manifold at least twice!

I watched the video you posted, very nice work. Gives me faith in remanufactured injectors. I found a set on Amazon and ordered them. They come out to about $24 each. They won't get here until Tuesday, but I'll pull everything apart this wknd and be ready to install them when they arrive.

Do you know if they are easy to remove and replace? I've not worked with fuel injectors.

Patterson: Yes, removing and replacing the fuel injectors is relatively easy....... compared to removing & reinstalling the intake manifold to access them.

Some tips and caveats:
+ disconnect the battery so the fuel pump can't accidently energize while the fuel rail is disassembled
+ release any residual pressure via the schrader valve in the fuel rail
+ take care not to break the electrical connectors when unplugging them. The release mechanism prevents them from vibrating loose.
+ Disconnect the electrical connector for the fuel pressure sensor - at the fuel rail end near the battery - so you can flip the fuel rail up and out of the way without disconnecting the flexible fuel line
+ the fuel injectors have O-rings - a dab of motor oil will help them seat during installation
+ don't over-tighten the small nuts that secure the fuel rail. The torque spec is only 10 Nm / 7 Ft-Lbs

Great tips man, thank you! That's a lot of info I didn't have :)

I have a sweet torque wrench that goes from 20 to 200 inch lbs. If I multiply your 7 ft-lbs by 12, we get 84 In-lbs. And back around to about 10 Nm. I just want to be clear that we all understand the calc. bc I've seen engineers get it wrong and that is when you snap bolt heads off.

It's not ideal to replace the fuel injectors when all I really know is that the coil is not causing the misfire on 6, the spark plug looks fine (will check the gap), and the spark plug wells are dry. So the fuel injector on 6 is the next culprit, and I'm just going to replace them all.

I've been trying not to just throw parts at the car, or take it to a mechanic bc I've probably had 65-70% bad experience rip-off mode fake repairs with shops. I'm somewhat happy to be my own mechanic, a reluctant journeyman. I've yet to figure out pulling fuel trims from the Torque app. but I have given thought to the way fuel trims work. I like the Torque app, for one thing, it shows fuel pressure in real time. What psi is the Jag X supposed to be at when you turn the key to On? From what I've gathered it should be around 55 psi.

I find myself removing the upper intake too often to buy new gaskets every time, So, I plan to reseal the lower and upper intake manifolds with a Permatex high temp gasket maker. I'll reuse the existing gaskets which have been in the car for a few weeks, but add a small bead of gasket sealer and let it sit and cure overnight.

I used this gasket maker on the cam cover gasket job. But, not along the length of the gaskets, just at the points where the seating planes didn't line up (timing chain cover to engine block). It'll seal up nice, and, I hope I don't have to take it apart again until I'm well past 200K miles and then I'm rebuilding this thing as a 500 HP project car.


https://cimg5.ibsrv.net/gimg/www.jag...4c3fba4811.jpg

Patterson: Yes, 10 Nm is 7.4 ft-lbs = 89 inch-lbs.

For the intake manifold gaskets, you can re-use the FelPro gaskets when they're relatively new, as yours are. Gasket seal is good for irregular shapes like the valve cover gaskets, but not necessary for the intake manifold's flat, polished surfaces.

Faulty or dirty fuel injectors can cause misfires. If replacing them does not resolve the misfires, then check the fuel trims.

update: NN Auto at Amazon sent the wrong injectors. They have Siemens printed on them and a Chrysler logo. The Amazon ad promised OEM Denso fuel injectors, green in color as their pics showed. So bummer, these are going back. Meanwhile, I found a shop that does exactly what Mr. Clapp relayed in his video post above; clean and service fuel injectors, measure flow and operation, so I'm going to contact them tomorrow, figure I'll just bring them a bag of 6 fuel injectors. I already pulled them and broke all the plastic clips on the plugs.

https://cimg4.ibsrv.net/gimg/www.jag...42d0c578e2.jpg

Notice the Denso fuel injector on the left has 12 ports vs 4 ports on the Seimens injector. The Siemens does fit into the lower intake manifold fine and the power plugs look like they would fit together, even tho I broke the plastic clips, but of course I'm not putting these in. I'll get my OEM injectors cleaned and some new grommets. The tiny servo motors in these things are pretty robust, I'm gonna see if this shop can flush the gunk out and rebuild my OEMs.


ADM in Chandler AZ. down the street from where I work. https://automotivediagnosticspecialt...linjection.htm

Patterson: The shop that cleans your fuel injectors hopefully can provide a report of the flow rates before and after cleaning. Before cleaning, the flow rates will likely be inconsistent across the 6 injectors. After cleaning, the flow rates should be more consistent. If the flow rates were inconsistent when dirty, and the misfiring stops with clean injectors, then the dirty injectors were causing misfires. If the misfires continue after cleaning the injectors, let's check the fuel trims.

Tiny bit of good news, the Amazon vendor refunded the full price paid, so after an extra week, free fuel injectors! In addition I get to keep a set of 6 Chrysler fuel injectors, I may hook them up to the drip system in the yard.

I actually have a confession. I found this when I pulled everything off to replace the fuel injectors. What I found is that I had nicked and scraped the lower intake manifold gasket upon re-assembly. I unknowingly created a gasket leak on cylinder 6 right near the fuel injector. Not good, but good to at least know what happened. A leaky gasket is not mentioned in the causes of P0306 or P1316, but it can happen and trigger those codes.
Having now taken the fuel rail apart from the lower intake, I find that the lower intake is actually two pieces. When I was assembling the lower intake the last time, a few weeks ago, I had not disconnected the fuel rail, or even considered it. It was very unweildly trying to position the whole lower intake manifold as one piece while connected to the fuel rail and working with all those constraints in space. So, I must screwed it up!
https://cimg3.ibsrv.net/gimg/www.jag...f540752862.jpg