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Is your coolant always that low, or does it start out within the full lines, then get that low?
The AJ133 in my Range Rover had the blown head gasket(s), primarily bank 2 (driver's side) until I replaced the head gaskets.
Blown head gasket resulted in coolant seeping into the cylinders, not too bad but enough to cause misfires & corrupt o2 sensors & cat over time.
After replacing the head gaskets I had to replace the o2 sensors (bank 2 upstream was slow). and the cat on that side isn't as efficient as it should be, but not to the point of any misfires anymore.
And of course it doesn't consume coolant anymore.
But that said, it continued with misfires (but less) until I replaced the o2 sensors that were old & contaminated from before I replaced the head gaskets.
The engine was rebuilt because of a gasket failure. But no its not low it just sat in the coolant pipes as the car sits at an angle on the side of the road. Once the car is on it goes back to full on level ground. Of course when I removed the connection from the supercharger some came out as well and depressurized but the coolant is fine and the gasket is fresh.
[size=16px]Ocwolfy
Where are you located, i might be able to help. Need to connect to vehicle using a scanner not sdd, like an autel launch etc...
Not the first time i come across this issue after an engine rebuild or timing job. [/size]
I'm in Maryland South of Baltimore. It would be much appreciated, I need someone else who's seen a non misfiring 5.0 S/C to look at this. All the people in my area have v6.
I'm in Maryland South of Baltimore. It would be much appreciated, I need someone else who's seen a non misfiring 5.0 S/C to look at this. All the people in my area have v6.
I'm in California, i can connect remotely and check it, need to read live data but its easier to use an aftermarket scanner than using SDD. What tools do you have ?
The engine was rebuilt because of a gasket failure. But no its not low it just sat in the coolant pipes as the car sits at an angle on the side of the road. Once the car is on it goes back to full on level ground. Of course when I removed the connection from the supercharger some came out as well and depressurized but the coolant is fine and the gasket is fresh.
That's good to hear - I wouldn't want that to be an experience you have to have after all the love you're giving your XJ.
I'm just hyper-sensitive from reading about too many failed attempts at head gasket repairs by professional mechanics that turn out not as good as expected.
And after the mechanic you had to deal with did everything he could to screw you over, I have no faith in him & his garage.
And since I did do my own head gaskets & all involved including camshaft timing, I've heard many (mostly professional) mechanics say they don't deal with the AJ133 & similar engines because the timing is very complicated, I just don't get it.
Getting the camshaft system back together & in perfect time, while not a task for the average aspiring DIY'er, is not terribly complicated for someone with reasonable mechanical experience & ability (from your posts, your mechanical smarts are higher than average & are gaining experience at a high rate for your (assumed) age, so you certainly appear well-qualified) that has the right procedures (true JLR ToPix service procedures) and tools including specialty kits for R&Ring the camshafts, crankshaft pulley, torque wrenches, etc.
There are critical precision steps in reassembling, a big one I remember is that the spring-loaded camshaft sprockets have to be held/preloaded at a certain torque (35 N/Ms IIRC?) when tightening the 3 bolts that secure them to the camshafts - a very important detail for the variable valve timing system.
Last edited by 12jagmark; Apr 24, 2025 at 09:33 AM.
I'm in California, i can connect remotely and check it, need to read live data but its easier to use an aftermarket scanner than using SDD. What tools do you have ?
Other tools I have is Top Scan Pro with the full subscription with software to Jaguar on it. I can access it from phone, other tools are JLR SDD 166 and my cheap quick handheld tool you can get from china.
That's good to hear - I wouldn't want that to be an experience you have to have after all the love you're giving your XJ.
I'm just hyper-sensitive from reading about too many failed attempts at head gasket repairs by professional mechanics that turn out not as good as expected.
And after the mechanic you had to deal with did everything he could to screw you over, I have no faith in him & his garage.
And since I did do my own head gaskets & all involved including camshaft timing, I've heard many (mostly professional) mechanics say they don't deal with the AJ133 & similar engines because the timing is very complicated, I just don't get it.
Getting the camshaft system back together & in perfect time, while not a task for the average aspiring DIY'er, is not terribly complicated for someone with reasonable mechanical experience & ability (from your posts, your mechanical smarts are higher than average & are gaining experience at a high rate for your (assumed) age, so you certainly appear well-qualified) that has the right procedures (true JLR ToPix service procedures) and tools including specialty kits for R&Ring the camshafts, crankshaft pulley, torque wrenches, etc.
There are critical precision steps in reassembling, a big one I remember is that the spring-loaded camshaft sprockets have to be held/preloaded at a certain torque (35 N/Ms IIRC?) when tightening the 3 bolts that secure them to the camshafts - a very important detail for the variable valve timing system.
Much appreciation for those compliments, I'm the son of a Nigerian Mechanic/Engineer who's tinkered and rebuilt engines since he was 9 back in the country and its hard to impress him so only compliments I ever hear is from my peers or my own subconscious, he's handicap now so I handle all the repairs when it comes to cars and motorcycles in my house hold (till we split ways in 2 months). When it comes to my cars I see it more as a healthy hobby to exercise the brain rather than a chore.
As for the AJ133 I agree, when I originally seeked a mechanic to do the rebuild while I was off studying for computer science at my uni, 7/10 wouldn't do the job and said its too expensive/complicated and costly for the shop and would take too long. But mostly they had no Jaguar/Range Rover tech to handle it. If I was available at the time I would've taken my time and had fun while dailying my XK8 after replacing it's valve body but times were different upon decision making.
As of now I'm making time to do another smoke test but at my buddies shop with more extensive tests including through the throttle body to test manifold gaskets(anything that can cause imbalance that was overlooked). I also swapped the igntion coils from bank 1 to 2 just to make sure the ones I bought weren't bad and nope, no change,
Other tools I have is Top Scan Pro with the full subscription with software to Jaguar on it. I can access it from phone, other tools are JLR SDD 166 and my cheap quick handheld tool you can get from china.
Ocwolfy,
I got around performing the exhaust back pressure test on bank #2; I Oxygen Sensor Socket Set Preferred socket used for this procedure due to very limited access. Have to unplug the B2S1 AFR sensor harness connector before removing the sensor. Had to use these welding gloves to do this work, the exhaust was HOT! Backpressure test kit At idle speed less than 3psi at 1500 to 2500 RPM throttle snaps
plan on doing bank #1 in a couple of days from now.
My results indicate no restriction on bank 2.
I have posted picture of the equipment I used to do the test.
Ocwolfy,
I got around performing the exhaust back pressure test on bank #2; I Oxygen Sensor Socket Set Preferred socket used for this procedure due to very limited access. Have to unplug the B2S1 AFR sensor harness connector before removing the sensor. Had to use these welding gloves to do this work, the exhaust was HOT! Backpressure test kit At idle speed less than 3psi at 1500 to 2500 RPM throttle snaps
plan on doing bank #1 in a couple of days from now.
My results indicate no restriction on bank 2.
I have posted picture of the equipment I used to do the test.
Awesome job! So I suppose no clogged cat in your case. Hopefully another smoke test for me will reveal maybe a missed vaccum leak. Times you wished the coil was the reason for a misfire.
I have noticed if you unplugged a vaccum line no codes are given and when I plugged a ventilation hose misfire increased and spreads to cylinder 7 with no other additional codes.. So I'm more keen maybe there's something vaccum related thing im missing which is why I'm digging further into that on Friday.
Have you done a full extensive vacuum test? Like throttle body to manifold, brake booster, purge valve, pcv etc? Or the maf sensors and comparing both data to make sure they're correct?
britechie thanks for the information and the great pictures. I have heard of these testers but never have used one. What kind of cost are we talking about?
Do you have a recommendation?
.
.
.
I would recommend doing an online search for the tool and you'll find that they are all at about the same price point. The kit I used a bit more expensive due to the adapters and the quality of the hose.
Main thing to remember - when doing the back pressure test is to snap the throttle several times with the engine at normal operating temperature.
Ocwolfy,
I did all of what you mentioned previously.
Bank 1 and 2 MAF numbers are relatively equal -
both banks are between 8-10K grams/hour at idle.
as engine rpm increases, both MAFs numbers increase evenly.
Manifold vacuum measures are good - idles at about 21 inHg and snap throttle returns quickly to same number.
So, I went ahead and swapped out the fuel injectors related to the bank 2 cylinders that were misfiring - #2, #4, and #6 with new OEM spec Bosch units.
I found that the old injector tips where thoroughly coated with carbon.
The end result?
No real notable changes.
I did a short drive and found that there are still few bank 2 misfires present on cylinders #2 and #6, although much fewer than before replacing the fuel injectors.
I did notice one thing though: bank 2 long term fuel trims have began to improve after one drive cycle-they have adjusted closer to 0, (they're at -6% now) whereas previously they were would adjust out to -9% or more.
I will keep searching for the root cause(s) of these misfires at idle speed----
Not giving up on this kitty yet, more to come.
Keep us posted on the progress with yours.
Last edited by britechie; Apr 28, 2025 at 10:32 PM.
Reason: typo
Ocwolfy,
I did all of what you mentioned previously.
Bank 1 and 2 MAF numbers are relatively equal -
both banks are between 8-10K grams/hour at idle.
as engine rpm increases, both MAFs numbers increase evenly.
Manifold vacuum measures are good - idles at about 21 inHg and snap throttle returns quickly to same number.
So, I went ahead and swapped out the fuel injectors related to the bank 2 cylinders that were misfiring - #2, #4, and #6 with new OEM spec Bosch units.
I found that the old injector tips where thoroughly coated with carbon.
The end result?
No real notable changes.
I did a short drive and found that there are still few bank 2 misfires present on cylinders #2 and #6, although much fewer than before replacing the fuel injectors.
I did notice one thing though: bank 2 long term fuel trims have began to improve after one drive cycle-they have adjusted closer to 0, (they're at -6% now) whereas previously they were would adjust out to -9% or more.
I will keep searching for the root cause(s) of these misfires at idle speed----
Not giving up on this kitty yet, more to come.
Keep us posted on the progress with yours.
Wow, awesome job! That's exactly what happened when I installed my new Bosch ones as well. Friday I'm doing smoke test and today I will have a remote session with a forum member to continue the investigation on this
I have another, hopefully useful update for you: I went to the local BP station and put about $30 worth of premium gasoline (93 octane) in the tank...guess what? - no misfires logged in Mode $06 for the trip home. Yoohoo! - but not so fast, I'm thinking to myself.
Still not convinced that the problem is solved completely and here is why:
During cold start ups -
engine high idles as usual (900 to 950 rpm).
as the idle speed settles down to 800-700rpm, the idle quality is not good - shudders a bit too much to me, especially for a low mileage V8; the engine has about 65K miles on it.
once warm and normal engine temp has been achieved while idling at 600rpm, - it feels mostly, a bit better, I guess?--.that is the best way I can describe it.
I am so used to V8 engines idling smooth as silk
I have an old Dodge Ram 1500 5.7L Hemi with more than 180K miles and it idles like butter consistently.
I have a '95 Mercedes 300D 3.0L inline 6 cylinder and the idle is comfortably smooth to me, at least for an old school diesel.
I'll certainly keep ya posted though. I think I am going to need more drive time on XJ to be convinced that it's really just down to premium gas, we'll see!
Last edited by britechie; Apr 30, 2025 at 10:00 PM.
Reason: add to comment
I have another, hopefully useful update for you: I went to the local BP station and put about $30 worth of premium gasoline (93 octane) in the tank...guess what? - no misfires logged in Mode $06 for the trip home. Yoohoo! - but not so fast, I'm thinking to myself.
Still not convinced that the problem is solved completely and here is why:
During cold start ups -
engine high idles as usual (900 to 950 rpm).
as the idle speed settles down to 800-700rpm, the idle quality is not good - shudders a bit too much to me, especially for a low mileage V8; the engine has about 65K miles on it.
once warm and normal engine temp has been achieved while idling at 600rpm, - it feels mostly, a bit better, I guess?--.that is the best way I can describe it.
I am so used to V8 engines idling smooth as silk
I have an old Dodge Ram 1500 5.7L Hemi with more than 180K miles and it idles like butter consistently.
I have a '95 Mercedes 300D 3.0L inline 6 cylinder and the idle is comfortably smooth to me, at least for an old school diesel.
I'll certainly keep ya posted though. I think I am going to need more drive time on XJ to be convinced that it's really just down to premium gas, we'll see!
Sounds like what happened when I combined half a tank of 93 octane with Lucas fuel system cleaner. Forgot how much I used but it was quite a bit, and it ran smooth. Barely felt misfires until after a while I went back to just 93 octane and it got worse.
I wouldn't say get your hopes up unless you always did use 93 Octane but if you didn't there may be a chance it was just the quality of gas.
Mark,
I normally use mid-grade, top tier 89 octane. Thanks for asking.
What octane do you use in yours?
I had an '03 Range Rover with the BMW 4.4L and ran 89 octane regularly with no idle quality issues whatsoever. I kind of miss that truck and all of its quirks.
Mark,
I normally use mid-grade, top tier 89 octane. Thanks for asking.
What octane do you use in yours?
I had an '03 Range Rover with the BMW 4.4L and ran 89 octane regularly with no idle quality issues whatsoever. I kind of miss that truck and all of its quirks.
Not gonna lie, any V8 or high performance engine i always use 93, when it comes to cars I can't ever cheap out. In the long run it has it's flaws.
Even my older vehicles like the 07 xj8 or my 01 xk8 I used 93 octane (US Rating)
Last time I put 89 in a V8 was 2 years ago when my dad had a Ford pickup I drove an hour with. He told me specifically put 89 when I told I would put 93 but whatever... Truck didn't really feel much different other than maybe slower.
Try using some bg44k with 93. And then see what's happens long term
A higher-octane rating means the fuel is better balanced and stabilized against spontaneous ignition on combustion, which can cause knocking and damage to the engine.
In other words: The higher combustion pressure = Higher octane needed.
So, adding low octane fuel in high output supercharged engine is for sure looking all kind of troubles.
You just cant compare NATURALLY aspired engine from 2003 to supercharged high output AJ133 engine.
By modern engine control the ECU is able to benefit the higher octane rating (turbo- or supercharged engines) so you will get your bucks back, because you will cover bit more distance with higher octane. (ECU will rise the boost)
There is no reason to "save" by using low octane fuel on charged engines.
