Well, I tried a high concentration of Seafoam in the tank but still no luck...

I was going to borrow a compression tester from AutoZone, but the ones they lend don't have a 12mm adapter. And since at this point it seems like I've tried all the things that I can readily do myself, I suppose it's time to take it to a professional...

I remain open to any other ideas, and either way, I'll keep you all posted on how I make out!

 

try to take all spark plugs out and have someone start the car. You should be able to see puffs of gas coming out of each cylinder. that way you can visually see the injectors working
Note, don't stick your head on top of the engine. standing in front of it should be fine.

you can also while the plugs are remove, shine some light in the holes and see what is down there.

 

arb63, I was going to update my situation after the initial Seaform process sooner, but the situation changed a bit. So I waited a bit to make sure of the changes. Here is what happened to me. I did perform the Seafoam on my mini last week after reading 20+ pages of the relative threads how to and other's experience. I only put the Seaform on the PVC about 5 oz. of it first time last Tuesday. The thread recommended to do 3 times or so. So I did again the next day. The error code P0304 continued to come up and the shaking didn't stop after about 20 min. of driving. I tried to drive a bit slower than normal the next day and fortunately no shaking.. I continued to drive like that for another day and the error code disappeared by itself… I did Seaform again last night and drove like normal this morning and didn't experience rough after 20-30 min. of driving.
I will continue to monitor the situation, but the Seaform definitely helped to resolve my issue.. Hope you'd find yours soon.

Thanks, everyone for great ideas.

jh

 

Great idea, thank you!

 

jh, that's great news, and I'll definitely give that a try! I only put Seafoam in the tank, but after reading about sucking it through the PCV, it sounds like that's definitely worth trying! Thanks for sharing your experience... I'll keep you posted (probably next weekend)...

 

Well, I did 3 Seafoam treatments (through the PCV) and no significant difference... Interestingly, the first two treatments did not generate the smoke show that I've read about, but the third one did... I took that as a good sign (for no scientific reason), but in the end, the problem remained.

Does anyone think that additional Seafoam treatments will make a difference? If not, I guess I'll take it to the professionals...

 

Did you try my suggestion?

 

Sorry, I didn't yet but I will... I've been focusing on the Seafoam since carbon buildup seemed to be a more likely culprit than a failed injector, but I will do this!

 

It is less effort than seafoaming and driving and then waiting to see the results. Checking the puffs will take 5 minutes and you will know for sure if it is operable. Did you also check compression by any chance?

 

I didn't... I went to borrow a compression tester from Autozone, but the one they loan does not have a 12mm adapter... And then I figured that I was nearing the end of the things that I can do myself anyway!

 

That kinda sounds like HPFP issue....but would not go that route w/o checking the individual coils....maybe you have more than one bad one ?
Seen these needing to get replaced anywhere from 45K miles up to 80K.
I think the HPFP are around $1400.00 now

 

Seafoam in the gas tank for a R56 will help with crappy fuel, but do little or nothing for carbon buildup issue in a direct injection engine. And unless it is allowed to soak in the upper cylinder head for a bit against the valves, carbon buildup will not dissolve all that well.

 

I tried your suggestion, but to be honest, I didn't see any puffs at all... :/

rAvEn, I seriously hope it's not the HPFP, but thanks for the feedback nonetheless... The fact that the symptoms started suddenly, plus no change in the misfiring cylinder code when I move the coil packs around would seem to suggest that it's not one (or multiple) coil packs, but I guess ya never know...

Do you think it's worth trying more treatments of Seafoam through the PCV? Would it help to let it sit for more than 30 min?

 

Check puffs on another cylinder so we can compare apples to apples. If you see puffs on the other cylinder then you know it is an injector either not working or perhaps cover with carbon residue.

 

I looked for puffs at all cylinders, but didn't see anything... (Perhaps the lighting conditions have to be "just right" to see them? I did it under fairly good indoor lighting...)

For what it's worth (and maybe nothing), I gave each cylinder a "sniff test" (especially #4) after cranking the engine, and it seemed like they were all getting gas... Hardly conclusive, I know, but I guess it's something...

 

Get your compression checked to make sure you aren't fixing a symptom instead of the root cause. It's worth buying the 12mm adapter or going to an indy shop that specializes in MINIs...trust me.

https://www.northamericanmotoring.co...inder-2-a.html

 

Makes complete sense--and I've been debating (with myself) if I should buy a compression tester--but then I wonder if there's anything else I can do by myself anyway... If it IS the compression, I'm not sure that I'm prepared/qualified to further explore the root cause... If it's NOT the compression, it appears that it would be a fuel delivery issue, and again, I'm not quite sure I'm prepared/qualified to further explore the root cause...

Thoughts? Are there other "DIY-level" things that I could do, based on the results of a compression test?

Thanks!

 

Couple of easy things to start with...

1) Condition of the plug in cylinder #4. The color of the tip can show if you are lean or rich.

2) Quantity of soot in exhaust. When my injector failed (stuck open) there was massive amounts of soot on the tips and it got so bad it would shoot out onto the garage floor at startup. (Exhaust also had the smell of unburned gasoline.)

3) Monitor fuel pressure on the rail. When my HPFP was starting to fail, I could see large drops in fuel pressure at idle which triggered a P0302 and P0300 codes. I used the ScanTool OBDLink LX. (Its an easy DIY job to replace it, unfortunately the price of the pump is high.)

4) Monitor fuel pressure on the injector. The OBDLink LX scanner can't do this, but my indy was able to which lead them to replace the injector. (There are a bunch of great vendors and indy shop guys on this board so I'm sure someone can suggest the proper tool.)

I wish you the best of luck and let us know how things go!

 

Atlas, thank you for the detailed response! Perhaps buying that compression tester would make sense... I'll let you know how I make out!

 

OK, I bought a compression tester... Now, I know I didn't do this right because I was rushing (my wife needed to go to work) and I forgot to warm up the car and to depress the accelerator while cranking the engine, but here are the results I got:

Cylinder 1: 190
Cylinder 2: 190
Cylinder 3: 170
Cylinder 4: 170

The fact that there was no significant difference between cylinder 4 and the others seems promising, but do I need to run this test again while the car is warm and the throttle is open to be sure?

 

Just to wrap up this thread, the problem has been solved...

As you'll recall, the car was exhibiting symptoms of a misfire--rough idle and loss of power. Error codes included misfire of cylinder 4, random/multiple misfires, and an oxygen sensor issue. Moving around coil packs and spark plugs did not change the errors. I changed all the spark plugs, Seafoamed the fuel, and did three Seafoam treatments through the PCV. No significant improvement. Compression test results were all good.

Thinking that a fuel delivery issue was a likely culprit, I took it to a highly reputable indy mechanic, who said that the problem is very likely to be carbon build-up--he sees it all the time--and recommended that I just take it do the dealer for walnut blasting (as he doesn't have the equipment to do it himself).

I took it to the dealer, who later left a message saying that it needs four new coils and a new post-cat oxygen sensor, all for just $1,100 and change, plus tax. I went down there and explained that it was hard to imagine that all four coils plus an O2 sensor all suddenly failed at the same time. They explained that it was actually just the #2 coil that failed, but that they recommend changing them all at the same time (though they could not provide a good reason for why they would make that recommendation). They also said that the post cat O2 sensor was completely fried--some kind of electrical issue.

I took the car, picked up a new coil, popped it in, and the problem was solved. Runs like new, CEL disappeared, no codes are thrown.

Some take-aways from this experience:

-- This is the second time that an error code indicated a problem with one cylinder and the problem was with another. (And this happened with two different code readers!) It's a bit frustrating that I can't rely on diagnostic equipment to provide accurate info, but I suppose that in itself is helpful to know.

-- In retrospect, and in light of the above, I should have picked up a coil pack early on and tried it on each cylinder. That would have been a quick/cheap fix.

-- I don't know what the deal is with the O2 sensor, but if the car's running perfectly with the new coil pack and with no errors, I suppose I don't need to worry about it. (True?)

-- I am always cautious about dealer service recommendations, but I now know that I positively cannot trust my local dealer's service department. They proposed $1,100+ for parts and labor, to fix a problem that I fixed in literally minutes for a tiny fraction of the cost. Oh, and get this: they were going to charge one and a half hours of labor to change the coil packs, and another hour and a half to change the O2 sensor. It's infuriating to think that they probably do this day in and day out, and most people would not know to question anything.


Anyway, thanks again to everyone for all your help!!!

 

That's awesome! Glad it was something simple you were able to resolve for a reasonable price. I've replaced and the post-cat O2 sensor and it was a very simple fix so don't pay their prices for the part or labor.

 

Thanks man, good to know... I've never replaced an O2 sensor but I couldn't imagine it would take 1½ hours... And the idea of charging 1½ hours to replace the coils--a job that takes literally 5 minutes--is absolutely criminal...

 

Really good stuff on this thread. I just got the P0300, P0302 and P0304 codes, and swapping my existing coil packs did not change the cylinders referenced on my DashCommand app. Since I did a walnut blast within the last 2K miles (not a typo), I'm going to replace all four coils and see how it goes. My MINI has 91K miles.

 

I replaced the coils and spark plugs but the rough idle is still there. Any suggestions?
My GoPoint and DadhCommand apps are not clearing the codes either.