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When I removed the entire Symposer I also found that small diameter vacuum line brittle and broken in several pieces. I had no codes because of it either.
I have circled the multiple pieces in red.
Here is all that's left on the car. I plugged the small vacuum port and left the electrical plug in place. Again I found no codes.
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Last edited by clubairth1; Apr 2, 2025 at 07:04 AM.
@Trainingdragon To be systematic I would reinstall the symposer and check all adjacent connectors and lines for trauma (like the cracked line shown above).
If the misfire codes return after clearing them I would remove the SC (again) and replace all the single-use gaskets.
Then with the greatest of care put down the SC (with an extra pair of hands) on the new gaskets and tighten slowly and carefully in a star pattern (minute 4.00 onward):
So maybe I'll revisit the symposer delete. In my case I removed the symposer, blocked off the hole in the back of the supercharger with a designed block off plate, kept the metal bracket that held it along with the little electrical connection to the device that activated the symposer. This way I didn't have an open electrical connection. I used a small rubber cap (came with the kit) to plug the small tube/port coming off of the device with the electrical connector. Is there any chance that could be my problem and maybe I did that wrong?
Nop, the deleted symposer does not give any problems. Just block off the sc hole wich you did and block the small vacuüm hose wich you also did..The connector to the valve does not matter at all according your problems..
Thanks guys again for the continued support. So a couple of new questions then:
1. Do you guys really think the metal intake gaskets, throttle body gasket, and supercharger lid gasket are one time use only??
2. I noticed that when I tried to clear the codes, the misfire codes are showing up as permanent. Forgive my ignorance but is it possible that Jaguar's ECU stores this and can only be deleted by Jaguar specific software, AND, the car will not run correctly until this super specific expensive software clears codes? Forgive my sarcasm but it wouldn't surprise me if Jaguar did this to ensure DIYs didn't do work like this so they can make their money on repair work.???
Trottle body gasket can be used more than once… low torck (10Nm) and thick rubber should be no problem as it also applies for the SC lid after a solid clean.
The intakes are 1 time use metal gaskets which forms during mounting/ torcking. It could be used again only in combinatie with good sealent paste (or whatever you call this) in case of “emergancy” as no new once are available and have to close it…. PS there is overpressure and not vacuum at the joint….
My opinion…
@Trainingdragon thanks to YOU for sharing your progress. We want you to win this battle and the war also. BTW thanks to @OzXFR and YT'ers TDC for this tragic but funny video of a "Pyrrhic Victory."
I haven't done this job yet, but I have to do it in the next few months. So I am learning through your and others' experience. AFAIK the permanent codes can't be erased and become historical. But the active codes will come right back after clearing if the problem still persists. If your engine is still running rough and has multiple misfires then an intake or vacuum leak is my best guess as it affects all the cylinders. As @pascal mentions it is a positive pressure leak so if it is the SC gasket that should be more obvious than a vacuum leak. New gaskets could be the solution. Can you perform a smoke test past the throttle body? This would be definitive for ruling out those SC gaskets.
The large top hat gasket to the blower is re-usable if not damaged.
No you just are seeing the problems of trying to fix you car without using the Jaguar SDD system.
Many times the codes will be listed as permanent but when the problem is fixed they will clear. I had the same thing for a cat failure code. Once I got a working cat it all went back to normal.
The codes don't do anything but report on what's going on. They don't stop the engine from working they only monitor it's running condition.
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Thanks everyone for the added feedback. So one new question since there was a comment about doing a smoke test past the throttle body - any suggestion how and where to do that. Also the smoke tester may not generate enough PSI but it's certainly worth a shot.
So one more piece of info that I forgot to share is that while I had the intakes off I noticed a lot of carbon some of which was pretty gewy so I took time on each valve (with the valves closed) to clean the carbon off and it wasn't perfect but I got a lot of it off using brake clean, a little pick and a vacum to suck out the debris and I let it all dry out. I was very careful NOT to let any of it fall down into the cylinders. Does that raise any flags for anyone?? A good buddy of mine who is very good with engines recommded it since I had good access to the valves and they were pretty bad.
I really appreciate all of you trying to help me sort this out.
And Jagcode3 I know you said you plan to do this job soon, so don't use my bad experience to dissuade you. So many people do this job with no issues at all. Somehow someway I must have messed something up. I'm not giving up yet.
carbuff2 thanks for the video. SO with the F type the throttle is electronic so I really cant prop open the throttle like this method since there's not easy way to open it. I've also heard that with electronic throttles it's not a good idea to manually open the throttle body plate as it can cause issues possibly with the ECU?? I don't totally understand why though if the car isn't running or if the battery is disconnected.
Question for clubairth1. When you deleted your symposer and kept the electrical connection intact and capped the small plastic tube, did you keep the 3 point metal bracket for it it just elminate that too? I did the exact same thing but kept the bracket so it all had a mounting point.
So one additional question at this point, for mainly the intake bolts and possibly the lid bolts does anyone know how many times you can tighten/torque these? They aren't high torque but I'm wondering if after 2 times of torquing these, 3 including the factory installation, if at some point I need to replace these bolts? I don't think they are one time use. Anyone know?
I think you're focusing on the wrong things. Smoke test it and you can wad a soft rag to pitch the throttle body, or remove it to bypass it though that seems very unnecessary.
The bolts have a torque spec and are NOT torque to yield (meaning definitely one time use). If they are in good condition reuse them.
The gaskets listed above have a portion that are single use, others seem to have clarified this.
I didn't read the entire thread to be honest with you, it sounds like an electrical connector mismatch. Does the vehicle smell like gasoline when operating? It also could be injector related but assuming everything went back in and was reconnected with the proper connector, they should be plug and play minus the teflon seal replacement. Others have skipped this step and been fine, others have not.
dmchao thanks for the response. My interest was to ensure I wasn't creating another problem if the bolts were one time use. I didn't think they were so thanks for confirming. I'll try the smoke test later today and see how that works out. And yes it seems pretty consistent from folks on here that I should not have re-used the intake gaskets after the first installation. It's possible that's my issue but I'm struggling with it. I'm wondering if a smoke test has enough PSI to show if I don't have a good seal there. More to come and thanks for the reply.
If you can't find a helper to hold a throttle open a bit, how about a cut-to-length piece of wood between the gas pedal and seat?
There is ALWAYS a way!
So brief update. A good car buddy of mine came by today to help. He's much more well versed in this kind of stuff than I'm in general but not necessarily with Jags. So we did a smoke test from multiple places and found no leaks. He tried using several scan tools with live data and live tests but had trouble communicating with the computer. I've heard Jags computers don't like a lot of scan tools for in depth work. The codes seem to focus on misfires in several cylinders but could also simply be all cylinders. Fuel trims were inconsistent from bank 1 to bank 2 but he didn't know what it should be for this motor and our various scan tools didn't have a benchmark value to compare to. He was stumped as well and he gave a one heck of a look over. So next step, order new intake gaskets and he's going to come back and redo the job with me. Probably take a week or so to do next steps but I'll keep posting.
Any additional thoughts are welcome as this issue remains ongoing.
To answer your question about the Symposer I took off everything I could. All the parts removed are in my picture up thread. So look at that and see if the bracket you are talking about is shown.
As far as scanners go we do have a large and updated thread on which scanners guys are using.
If you have not seen it take a look if your looking to pick up another scanner.
We all have a bunch! It's a moving target and different scanners come out all the time and they all claim to read anything and everything in all cars. Which off course is just not true. It depends as always!
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Thanks Clubairth1. I took another look at your photo and it looks like you didn't keep the bracket for the symposer electrical connector. So did you just push that whole connector and tub behind the supercharger and under the giant wiring harness? BTW that wiring harness is a monster to work around - it's like in the way at every possible angle to do things behind the supercharger. I have a nice amount of space behind it but the wiring harness is right up against the back of the supercharger.
@Trainingdragon Now that we know about the valve cleaning too that must be considered. How did you keep the gunk from getting into the cylinders during the cleaning? Some of the valves had to be open, right?
It seems that any particulates like valve gunk should be burned up right away, but it is something to consider.
Great question. So while I had the intake off I could see the valves and most were pretty covered in carbon while quite a few where pretty gewey with wet carbon. With the valves in the closed position, I soaked the chamber in brake cleaner for several hours, the scraped carefully with a pick, then sucked out all liquid and debris with a shop vac and a small diameter hose so it could fit into the port. Once I cleaned all that out, I continued to scrape away until I had the valves much cleaner (not perfect) and made shure I sucked out all debris before considering it done. Then I rotated the crank to close the valves I needed to get to and confirmed they were closed before starting. I feel pretty confident that should not be my issue but it's a good question to ask. So with all that said, do you see any issues with what I did?
I"ll be checking the MAF today and trying to short the pos/neg cables to clear misfire codes today and see if that does anything.
One last thing, my car buddy suggested I just drive it and it might clear itself. He's had some luck with that with cars he's worked but I'm a bit concerned about doing that considering how rough it's running.
While you are at it, install an oil catch can. That will save you some valve cleaning in the future. I did this on my S the moment I got it a year ago, with 18000 miles on the clock, and I'm pretty confident the valves will be relatively clean when I tackle the same job next week.