Today was productive. The oxygen sensors are done and the cam covers are re-sealed and back on. I even found a hack job on the wires to the LH VVT solenoid and repaired that. When I separated the intake aluminum runners from the plastic plenum this is what it looked like. The presence of the oil doesn't surprise me considering the 111K miles on the engine. But the amount that has apparently traveled through the seals tells me that there has been a leak that has gone undetected thus far. Thanks to michaelh for helping me sort out the part number of the right seals.

 

Good progress, well done....

 

Today's report: Cleaned the intake and runners as well as the front cover plate, throttle body elbow and AFM. That was a messy job but it's ready for reassembly as soon as the runner seals arrive. Also replaced the vacuum hose that runs under the intake. Then spent most of the rest of today replacing the orings in the Norma connectors on the octopus hose. I'll post a few notes about that on another thread. I replaced the other small hoses to the TB and EGR and cleaned the EGR though it had almost no deposits on it. Used new gaskets on the valve and tube. I think I'm on hold til the runner seals show up. Don't want to jinx myself but I feel confident that some improvement will result from all this...Gawd I hope so!

 

Attention regarding the runner seals price from Partsgeek: My order arrived yesterday and even though their ad clearly shows 8 seals for 23 bucks, Partsgeek only gives you one. I had to call customer service three times and eventually had to demand to talk to a supervisor to get them to refund my money and take the single seal back. It was the argument from hell over 35 bucks (including shipping). So, DO NOT ORDER THESE FROM PARTSGEEK THINKING YOU'LL GET 8. YOU WON'T. I did find a full set at BritishPartsof Utah.com for 69.95 and, after that, a full set on Amazon for 65 bucks. I am assuming they will arrive as advertised. I hope nobody else ordered from Partsgeek because of my erroneous post.

 

Partsgeek has proven to be difficult to deal with and often wrong for the past decade or so. I crossed them off my reputable supplier list many years ago....

 

Update: since my last posting I have done several more tasks that I hope will improve my Jag's overall dependability. And learned a few lessons as well. I got the intake runner seals installed and put the intake back on using new gaskets of course. When I started installing the injectors a couple more tabs broke off so I replaced all the injector pigtails. Pressure tested the plastic convoluted tubes and replaced the orings with slightly larger diameter material and they fit well so I suspect they might have been too small even though the smoke tests didn't indicate a problem. Then the fun began. I had removed the dipstick tube in an effort to be thorough and it was a good thing since the oring at the block was cut. But putting it back was a major pain. After trying to remember where it had been routed I searched the forum and learned that I made a huge mistake by not reading up on that seemingly mundane task beforehand. I'll add my two cents to the correct threads about how I resolved it but it was a bitch.

Got everything together (sans engine top cover and coil covers) and did a "hard reset". It started and ran well and didn't leak any fluids and no CEL appeared. However, while it sat idling I heard a loud "clack" sound that got my attention and it repeated about every 30 seconds or so getting slightly lower in volume each time and farther between til it got maybe a couple minutes apart and was more like a click. I had a hell of a time trying to locate the area as it seemed to echo thru the engine bay but I believe it is either on the back of the engine or on the firewall. The AC was off so I turned it on and that changed nothing. I took the car on a 15 mile test drive stopping for gas and stop lights and such and didn't hear it over the road noise. It ran fine enough but I believe it should improve as the computer relearns it's data. I hope so. I'm going to let it cool overnite and hook up the reader tomorrow and check all the live data to see how well my work affected the data. That will give me an opportunity to go thru another cold to warmup cycle and listen for the weird sound again. It'll be interesting to see if it is loud again or not when it's cold.

 

Put everything back on today and started it cold and the weird clack sound appeared again. Then I hooked up the reader and looked at live data when it got up to operating temp and it looks very good so far. The fuel trims are zero and respond somewhat after revving but return to zero quickly. fuel pressure is good and everything I can discern is in range of expectation. I tried repeatedly to find the source of the weird sound but it stopped more quickly this time and I have concluded it is expansion and contraction noise from items that were repositioned during all this work. Time will tell. I'm going to attempt my first drive cycle when the damn rain stops. Next attack is changing the trans fluid to stop the ZF "squawk".

 

Very good and interesting posts with great information, keep them coming 👍
Thanks 😊🇬🇧

 

OMG! Something is terribly wrong! I've been working on the Jag for several weeks now and got it together finally but the weird thing is: I have now driven it to town and back three times and no CEL...! Could this be possible?! (My doctor told me that if my first car is a Jag my second car should be a wrecker!) It's hard to drive safely while glancing down every few minutes to see if there is a light or message on the DIC. I cleaned it up and am almost scared to drive it again...the odds are increasing.

Oh and BTW, I figured out what the clacking noise is by laying under the car after a hot shutoff. It's the exhaust system expansion/contraction. It pops so significantly that the tubing rings after each hard one. that is just gonna have to resolve itself over time. I'm not touching it!

 

Update: Well, I made it just over 300 miles before another CEL appeared. This time it coded for high fuel rail pressure (AGAIN) and misfire on cylinder 6. Reader says rail pressure was 60 psi and I know the last time I looked it had been 55. I am pretty certain that I had put a bottle of Techron in the fuel that was in it but I added a bottle, filled with non-ethanol 91 octane and hoped for the best there. (The FP sensor is new) I can detect a very slight engine imbalance upon completely cold starts that last until it idles down but after that it is basically smooth as silk. Question: does anyone know if the high FP can affect injector function to the point of contributing to a misfire? I have other priorities right now so I can't address it right away but soon I'll re-check the FP and move injectors and/or coils around in an attempt to narrow this down.

 

Well, after adding the Techron and clearing the codes I have been driving the Jag regularly and have racked up about a thousand miles with no more CEL. In addition, the transmission (after the fluid and filter change-see other thread) seems to be getting better at the 1-2 shift. The slippage and flare are significantly less and the ZF "squawk" is gone as far as I can tell. I theorize that the computers are adjusting to my driving after the hard reset and the whole driving experience is improving little by little. Overall, I think the work done thus far has netted the desired result. Soon I will tackle the expensive and somewhat complicated task of replacing the oil cooler hoses as suggested prior. But for now, I recommend my approach to anyone having the same repeated issues with an aging XK8. It wasn't that expensive and I am happy with the results. Thanks to all you "old timers" for the help and encouragement.

 

Now it's near the end of summer weather and I have driven the Jag all summer with zero issues and CEL problems. I don't usually drive it much during winter but I will do so a few times to help keep it in practice. What happens in Spring will be an interesting study in longevity but I am very happy with the improvement in performance this summer. The wife and I enjoyed the convertible cruise in nice weather and the lack of problems has been satisfying to say the least. I still intend to change out the oil cooler hoses and I do have a very minor coolant leak at one of the hose o-rings to deal with. I also think the front seal has been leaking a bit for quite some time so I'll tackle that when I do the hoses. The car isn't perfect but it has been dependable and that's awesome improvement!

 

Aaaaannnnddd...it is now the start of winter weather and to humble myself in the presence of the Jag experts herein I have to tell you: The car made me proud this summer overall. Still no CEL BUT all of the warnings about the oil cooler hoses being too old were absolutely spot on. As I was putting the car in the storage garage after my last intended drive of the year, I noticed a significant oil leak and rushed it in and shut it down. And, sure enough, one of the cooler hoses had begun leaking around the crimp. I should also say that these hoses showed no signs of ballooning or swelling or even of hardening to any extent but that was the issue. I made my own hoses and replaced them all and will post a new set of pics in a new thread when I get a minute. Just goes to show that you guys really know your stuff about these wonderful old cars.

 

Just an update on the Jag's behavior since I did all that work last year. I have driven it several thousand miles and on a couple of trips down to the southern part of the state with no issues at all. Zero. Zilch. And I am beginning to be concerned that I am dreaming. The thing seems to run a little better each time I get in it, possibly due to the computer getting a chance to do some uninterrupted adjustments. In any event, it's doing great and the effort was well worth the results. My DIY oil cooler hoses are doing fine as well. They look great and show no signs of distress or leaks or movement. I am convinced that my approach was sound. Others think not, I know, but I am. I would like to do another set if I can find some cores as I think I could tweak the results a little bit but I'm not the least bit concerned that they will fail, at least not as a result of inferior design or workmanship. That's just my approach. As the saying goes, to each his own.