I specifically made this video to start this thread and save me a large amount of explaining. Long story short. the technician only has suspicion of the misfire issue on cylinders 7, and 8 and he didn't even check out all the things that the shop manual says but just said i need a new motor. LIKE REALLY DUDE! However i do know that my bank 2 Cat is destroyed (assuming the misfire happened first and then caused the cat to fail). The dealer said it would be 3k to replace 1. I said H, E, double Hockey sticks NO and just ordered the cats from VAP as well as the pulleys and tune for the same amount during VAPs end of year sale.im still awaiting the downpipes to come in. and will update as soon as i get them put in.

Heres the full explanation

 

Austin,

Sorry to hear about your experience. Unless you have warranty work or a tec bulletin item I would stay clear of the dealership. I am in Hampton roads Virginia and our jaguar dealership is known to not be a place to take your car form various conversations had with other Jag owners. Mechanics at dealers make poverty wages so they have very little incentive to offer quality service, and this is from personal experience gained from working at Acura through my college years.

Unless you have starved the engine of oil, had the engine overheat, sever timing issues, or detonation due to running nitrous etc., there is no reason to require a new engine. Are you throwing engine codes? This is what I would look into.

Fuel injectors. I changed my injectores at 16K and there was significant carbon build up. I paid $800 PN BS62120 through Parts Geek for a full set. While replacing the injectors you can also clean the around the valves. Sticking valves can be another cause for misfire and with our engines being GDI they are susceptible.

Other common causes for misfire are O2 sensors, mass airflow, or vacuum leaks. A code reader will help with this but the fact that the car runs strong unless under extreme load would lead me to think it’s a fuel issue.

I would also have the car compression checked just to make sure the head gaskets are good although failed head gaskets from my personal research is uncommon. This would also lead to coolant oil mixture and would be visible by changing the oil.

Bottom line is to find an independent shop you can trust or download the manual, by a scanner, invest in some tooling and conduct your own maintenance/upkeep.

 

To add a bit, I run bg 44k engine cleaner for the valves/injectors/o2 sensors/cats every 1-3 months and it has kept my "fueling" normal - original valves and such at 55k (V6S). The V6 is at higher compression I think too.

https://www.quora.com/Can-a-fuel-inj...-fix-a-misfire

I have nothing to do with BG - the local shops with mechanics I know and trust say it is the real deal even though it is marketed quite well. I'd run two bottles in a full tank of the best gas you can find...around here I think that is 93 shell nitro....and see what happens.. Don't run full tilt but say do over 3k rpm for a bit. Have no idea how long to wait and see but say 1/2 a tank and then see how she goes is a guess.

I generally run "top tier 93" too - that matters in my opinion too. I am not a mechanic and this is just what I would do - I cannot vouch for this as a good idea and take no responsibility if it doesn't work or causes other issues. But for me, this has been my years and years approach and it has kept my engine happy.

Good luck. Please update us.

 

So this stuff works even though my V6 is direct injection?

 

It works for me. I think we have the same engine.

BFG 44K instructions with a lot of GDI engines: https://www.bgprod.com/platref/

It is super easy...I get the plastic bottles with the longish necks so it is easier to put into the tank....just my preference. They have cans too and you sort of need a funnel for those.

 

The cleaners like BFG will aid in maintaining the injectors however, from my research it will not really do much for an injector that has severe carbon buildup and is causing engine performance issues. As far as the valves go at 16K I had a thin but complete layer of gummy like carbon buildup present. I had to soak rags in carb cleaner and stuff them into the intake overnight then use a combination of rags, toothbrushes and gun barrel brushes to clean the areas out. It was a significant, time consuming and nasty job. At higher milage where there is more carbon buildup that has become hardened the engine would have to be manually turned so that each valve is seated and sealed before cleaning can be accomplished because if pieces of the hardened carbon fall into the block it could create scarring and damage the engine.

High quality fuel is a must as well as oil. I have used Amsoil 0W-20 full race synthetic at change intervals of 5K and the oil removed is similar to the new oil going in the car. This may be overkill but if it keeps the internals clean and well lubricated than the cost is well worth it.

Direct injection engines in my opinion are problematic in design due to the back of the valves not being washed by fuel. Although there are benefits by the car manufactures being able to reach higher fuel efficiency it’s the owners of GDI that have to deal with carbon build up issues.

Other alternatives are running an oil catch can, and or methanol as a valve cleaner. One member that I am aware of (Rock 88) has a great thread on installation of both items.

 

Good stuff, but more of a preventative cleaner than a cure. Those using it to improve gas mileage are apt to be disappointed.

 

C'mon you guys, stop calling it BFG, it is BG with no F!
Yes I reckon it helps, I use it alternately with Redline SI-1 Fuel System Cleaner.
Some JLR dealerships chuck a bottle/can in as part of a routine service.

 

[QUOTE=OzXFR;2591504]C'mon you guys, stop calling it BFG, it is BG with no F![/QOUTE]

Yes! Get the 'F' out!

I don't use extra additives but always fill up at my local Chevron with premium. Yeah, I could get cheaper gas, but the Techron additive seems to be well-regarded and I've had no issues.

As a side note, when I read about the Subaru/Toyota cars that used a combination of conventional and direct injection and the rationale for doing so, I thought that made a great deal of sense.

 

F in fixed. Too much F-typing.

 

An F-Typo then

 

QUICK UPDATE!
- Pressure checked all cylinders. all are at 185psi (by dealer)
- checked battery, battery was low. changed it out with brand new battery i already had in my shop. still misfired.
- im running my first can of BG 44K through the fuel system im down to a half a tank as of now. i gave the pedal a little test tap. and yup the misfire is sill there.

next step is to change out the downpipes with the ones from VAP. and yes my tuner and pulleys have came in as well. i plan to put the downpipes on first without introducing the tune yet. my goal is to see if the car still misfires once i get rid of the bad cat or cats.
@Stuart@VelocityAP or anyone else if you have any input it would be greatly appreciated.

heres the list of codes:
P0430
P0300
P0308
P0307
P1315

 

You say you know the bank 2 cat is destroyed but don't say how you know that; you just mention it separately from the dealership diagnoses. The P0430 could be a bad sensor. That's a known weakness. There was a software update to reduce the sensitivity of the fault detection, but sensors still do fail with some frequency.

The codes indicate misfires on 7 and 8, and the P1315 might be a malfunction in the ignition.

If it were my car I'd resolve the misfire before putting on new cat, just in case the existing cat was damaged by the misfire.

 

this is why i suspect the bank 2 cat is bad

1.) the same dealer told me that
2.) the fault codes that i listed in the previous post shows the possibility
3.) the long term negative fuel trim points to it
4.) o2 sensors don't cause misfires (unless I'm mistaken) but bad cats do.
5.) a blinking check engine light misfire is destroying the cat.

 

You were questioning the dealer's diagnosis, so I'll call #1 inconclusive. It's possible that #2 indicates a bad cat but it could also indicate a bad sensor, which is a common complaint. I think #3 and #4 overlook that there are other potential causes, possibly indicated by the P1315 code.

My biggest concern would be that #5 should be a sign to not put a new cat on until you've figured out if there are conditions that destroyed the old one. It'd be a shame to damage a new set.

 

Have you looked at fuel trims yet? This will help indicate if one side is running rich or leak and then you can route a plan of action. For example, if bank 1 is always -15%, you know there's too much fuel in that mix, which could be a leaking injector or too much back pressure from clogged cats. To confirm clogged cats which could cause a misfire, either take them down and visually inspect or pull the upstream O2's and compare pressures between bank 1 and bank 2, often these tests are really easy if using a scope. But if you have access to a scope (just like the dealer), this would help pin point the concerned part. Doing a compression test is great but if running with something like picoscope, the tech can verify if it's on intake/exhaust cam/valves issue, compression, spark, injectors, backpressure..etc.

 

It is your injectors dude. I spent 10 grand fixing my injectors, it was first intermittent, then it was all the time. When the injectors go bad (at least in my case) it sputtered here and there until the injectors were fully stuck. GOOD LUCK getting the injectors out, they will likely snap off.

I had to have the entire engine torn apart and head pulled to punch out my injectors. They get rusty because of the hood bonnet it allows water in and then you are screwed because your engine is probably rusty even tho the body isnt.

 

did you get any injector codes or just multiple misfire codes, as the ones i mentioned?

 

yes at first it was just misfire codes.. the shop couldn’t recreate the issue.. weeks later they totally went out and it was dumping fuel big time and barely ran…

I decided to replace coils, injectors, and spark plugs while I was at it… this destroyed my catalytic converter too in the process …

I wouldn’t take it to a dealer, I was basically told it would take half a year to fix, they don’t give a **** about fixing it …. I took it to a mechanic that was willing to work on it in Wisconsin not sure where you live …

there is a special tool to take the injectors off and you can’t pull too hard or they will snap off… but if they are rusted which they most likely are you have to take the heads off ….. my car had zero rust it was a Florida car with 30k miles and it didn’t matter the engine was rusty even tho the body wasn’t …


Multiple head bolts needed to be replaced they were completely rusted off …

 

Thanks for the detailed info! I have been driving it as it trying to run some BGK( or whatever ya call it) performs well without going above 75-80% throttle. but this past weekend at about 40% throttle (first time its happened this low) i started getting the blinking light. so i went in a store and when i came back out and started it back up it was back to normal. So then i just took it home. my assumption is that the misfire is starting to happen at a lower threshold now.