Posting from the workshop here. We have a customer’s car with a problem and it's not an obvious one. So appealing to the forum for some sensible suggestions based on depth of knowledge you guys will have after being on here for a few years. I only post occasionally so don’t hear much about the strange ones.

The car is April 2007 MCS automatic.


When you start the engine you have to quickly dab the accelerator pedal to get the engine speed up. If you allow the engine to rev below 2500rpm it will start to misfire and it does not idle very well. If you leave it to idle it will misfire a lot and eventually stall.

I’ve had it connected to ISTA (BMW diagnostics) when it first arrived and found faults like superknock, which you see occasionally so I cleared those so I could repeat the diagnosis and hopefully see only the current fault rather than historic faults. Unfortunately whatever is causing this does not appear to be engine management related so there’s no engine light on the dash and it isn’t generating any faults.


With this in mind I decided I’d do the walnut blasting on it to clean the intake valves. Started it up again and it was exactly the same as before. Obviously after finding out what the problem is and fixing it the customer will see the benefit of clean intake valves, but for the moment it is running as badly as before so the problem is elsewhere.


I’ve done a compression test and all cylinders are close enough to be able to rule out a lack of compression.


So impress me folks. What ideas do you have? Thanks.

 

Your description is almost similar to the HPFP failure mode. Has it been replaced yet? Usual failure mode is very hard starting, and when it finally kicks in, it takes a lot of pedal-pumping to get it running by itself. I don't know how to test the HPFP, mine was a hard-core failure and the dealer took care of it. No codes, just very hard starting, and ONLY after a hard run that exercised the HPFP a lot.

And cam timing is OK? Chain stretch and chain guide failure are also common failures. Replacement history?

 

I get a nervous twitch whenever I hear the word Superknock or Superknocking.

 

Maybe a fuel system flush might help, injectors, fuel filter, and/or hpfp. Presuming its not the timing?

 

I have a spare HPFP, I could try switching that out. It wouldn't hurt. Not a long job.

I believe the superknock is a sign of carbon buildup. Really though, without actually being able to see exactly what's causing it, you're only guessing. Knock is either pre-ignition or lean running. With lots of wet oily crud built up on the backs of the valves pre-ignition is more likely.

So does anyone know what happens to these fuel pumps when they fail? Worn out impellers or snapped shafts or what?

 

Not the high pressure pump. Just changed it, no different.

 

I had a brand new motor put in my car and it still knocks.
Goodluck its a long journey ahead possibly to nowhere.

 

Turbocharged engines do knock a bit if they're pushed hard. And I don't mean driven to death, just the occasional foot to the floor acceleration is enough to get knock reports registered.


The reason this happens is that the goal for the best turbocharged engine is to advance the ignition as far as possible to give you the best performance. This means you run close to the knock threshold and to find out where that is your ECU will step over the line occasionally. If you drive a car where the engine is knocking all the time you'll certainly notice poor performance... and of course greatly increase the chances of melting a piston.


The MINI is also a fully sequential setup so knocking can be per-cylinder as well. i.e. just one cylinder knocking a bit before being adjusted.


So anyone recommend the next best course of action. I think I'm going to take the cam cover off and see if the timing marks line up. I'd hate that to be the problem though.

 

You're gonna need special tools to check / set timing --- there are no cam "timing marks" to line up. But, while you're in there, take a look at the chain and guides. Maybe check chain tension. And, your "spare HPFP" was new? When mine went, it acted like a diaphragm seal was weak or leaking --- it lost it's "prime" overnite, after a hard drive that day. Worked fine after it started and smoothed out --- got the expected performance.

Sounds like you're relatively new to the Mini internals. If you plan to get into the Mini service business, I highly suggest getting a set of Bentley Service Manuals, for torque-to-yield bolt ID and settings if no other reason. Cam timing setup is pretty well described.

Also gotta agree with JCWORKS --- knocks of any kind are scary. Best of luck.

Keep us posted?

 

I have a set of Bentley manuals ta.


Personally I've never had to look for timing marks on the Peugeot engine but presumably if you know there aren't any then you must know how to check the valve timing is correct? Fancy sharing? Haha.


I'm actually in the first instance a huge Saab turbo fan and spent many years working and tuning Saab turbos. Therefore, I know my knock.


Saab were boost control pioneers and were always ahead of the game in this field. Knock does occur on turbo engines and the APC system Saab invented fitted to Saabs from the early 80s performs the specific function of limiting boost upon detection of knock. That is done using a knock sensor on the earlier cars and then via ion sensing in the spark plug tips from the mid 90s onwards. The R56 senses knock in the same way, through the plug coils.


In fact, I even did a version of the Saab engine using the same coils from the R56 but connected to a Motec M800. That's in my track car.

 

I don’t mean to come across as a know-it-all —- I’m working on my 1st Mini, and after 4 years, doing most of it myself —- including internals. Had success early 2014 doing rods / pistons, and my last dyno showed 300 WHP and torque. Not a lot of local Mini high performance talent in Northern NV, so I’m learning the hard way —- not making the same mistakes twice.

Basic description for timing —- lock the flywheel at 90 deg (both cams show lettering on top), then lock both cams, all with special tools. With cam gears loose, use chain tensioner to apply “proper” (I’m too lazy to look it up) tension to chain, then with new bolts, tighten to spec. Remove tools, re-assemble, and say a prayer or two. More details in the manual.

All this AFTER chain has been checked for stretching —- again, I don’t know the specs, and might not be in the manual. This is why I originally asked about previous chain replacement.

You’re obviously more experienced than I am, especially with turbos and diagnostics. I’m just sharing my experiences with the MCS. Hopefully, they relate to something you can use.

 

Have you checked the intake system for liquid oil or the exhaust for post turbo pre catalytic converter for pressure (at idle and full boost 13psi should be <.1psi)? We have seen the cats on these cars get so clogged that the they can pressurize the exhaust which will push oil int the intake. This can cause extreme knock and in some cases hydro lock (and piston, rod, and crank damage/failure). If this is the case both the turbo and catalytic will need to be replaced or refinished. Hope this helps.

 

With all due respect Emmett, with all the resources thats available to BMW/MINI...and they cant permanently fix my car I dont see how you would be able to resolve this car. There has been times they do certain things and it takes the knocking away but it comes back after about 3000 miles. There has been several PuMa cases opened on my car but not a single time has it been solved for good.
All the things everyone has mentioned has been checked and replaced on my car, not a single part wasnt changed in the motor. I can even give slight acceleration to overtake and it will knock.

 

My question to you JC would be why the knock is a problem on your car?


i.e. I say this on the basis that engines do knock. So I'm wondering if you've found a way to read codes from your own vehicle and decided that you don't want to see fault codes for knock so you're trying to get it to stop happening when really it's not a problem?


If your car drives ok I wouldn't worry about it.


Another one of my cars with an engine I'm not worried about breaking has no boost control and the wastegate is welded shut. It also has a knock indicator on the dashboard, a LED which flickers when the engine is knocking. I basically drive by that. If it starts to knock you back off the accelerator a little.


The timing chain won't have worn enough by 50k odd miles on this engine for there to be that much of a problem due to wear. I suppose if there was some problem with valve timing then it could have jumped a tooth. The nature of the fault where it performs very badly for part of the rev range but ok for the rest is reminiscent of valve timing issues. It is the last problem I want to get involved with though.

 

It's a problem because it can be felt and it's damaging to pistons.

When the car Knocks it cuts the power briefly, the car Jerks aggressively followed by a metal clicking sound from the engine.
This actually becomes dangerous when you trying to overtake or take a gap. This happens every time I drive the car. I don't have to drive like a racing driver for it to happen.

Imagine having passengers and this occurs, embarrassing to say the least.

 

That is certainly an issue. Agree with you there.


Interestingly unexpected knocking issues are extremely unlikely to be caused by the engine itself. It is surprising that an entire engine has been replaced.


Does it happen every time you accelerate foot flat to the floor or is it only occasional?


I've submitted a tech support ticket with BMW for the problem I posted this thread for originally. The problem with 'ideas' is that they tend more often than not to end up leading you on a wild goose chase. I've already done the walnut blasting and the high pressure fuel pump without fixing the problem so I'm a bit reluctant to waste time looking at other things which might not be the cause!


If I do manage to resolve this I'll post the results.

 

The '07 timing chain is notorious for early failure. Many have failed at less than 50K. Check the various threads that appear when searching for "death rattle" which is what happens when chain stretch is excessive. I'm suggesting your issue might be early symptoms of the death rattle. You might also find how much stretch is acceptable, by searching those threads.

And yes, troubleshooting someone else's problem on the web is often a waste of time, for all concerned. Too many unknowns.

Best of luck anyhow.

 

BMW suggested testing the Vanos hub and also checking the catalytic converter.

Checked the Vanos hub and that was ok.

Realised during the process that the engine runs perfectly for a few seconds after the engine has been turned over by hand! This happened twice. First time was after the walnut blasting and the second time after checking the vanos hub.

After turning over by hand something is reset and for the first few seconds you can start the engine, rev it, let it idle and it works like it should. Then leave it idling for a few seconds more and the problem returns.

I've pointed this out to BMW and asked what they think I should change first but they are really slow to respond and sometimes when it gets a bit difficult they don't reply at all. So I'll give them a little bit longer to come back with a suggestion. In the meantime, if anybody wants to guess what to go for first or has any theories that would be much appreciated.

BTW... it had a new timing chain about 5000 miles ago. But it was replaced under warranty so there's no paperwork and no way of knowing whether it was really done or whether the dealer just fobbed off the customer as they sometimes do.

 

FYI --- Bentley manual always uses CW manual rotation. CCW should be OK for troubleshooting, but never for final setup / adjustments.

I've read where others have had the HPFP and / or vacuum pump get very hard to turn. Both are driven directly by the cams, and might throw off the timing. Cranking manually might be "resetting" them. Your replaced HPFP should eliminate it from the list, leaving the vacuum pump as a possibility.

Chances are the owner noticed the "death rattle", causing him to get the chain replaced. If no replacement --- rattle persists, so it probably was replaced. I don't believe there was an actual "recall", just authorized warranty repair. Is this when the owner first noticed the current problem, after chain replacement? Dealer couldn't fix it, so he brought it to you?

 

I don't think if it were a mechanical problem that you'd get as much good runtime. I'm getting at least 3 seconds of good runtime. I've not timed it as these smooth running events were unexpected. It is enough to start the engine normally, watch it seem ok at idle, rev it up to 3 or 4k, watch it settle back to idle where it will sit and idle well for a period before gradually returning to the state of very poor running. It will actually stall as well if you leave it long enough.

 

I have a similar issue as JCW0RKS. Although to a lesser degree. Its still not resolved either. I'm sure what I'm about to share will not help directly, but at least add to the discussion with my trouble shooting.

Most of my troubles have been outlined in THIS thread. And I have even gone as far as to take pictures of my TURBO. Feel free to read these as well, but I will give a brief run down.

After switching out to a Catless DP and running DNA tune I noticed, what I would later find out to be super knock, that when I would go WOT under a load (such as a hill) but while in a high gear (5th or 6th) I would get the hesitation, clicking and a puff of smoke out the back. This would only happen if not going particularly fast (like 50mph) in the higher gears. So I started switching things out.

I changed plugs; coils; reinstalled stock intake box; put my stock cat back on; changed my tune to serveral different levels, including stock (what I'm running right now); walnut shell blasted intake valves; and even ran fuel cleaner (desparate move here).

Nothing has changed. Now this winter when its dropped below 0 ambient temperature it did stuggle at times to keep running without pedal work with the accelerator. One time it would hardly accelerate at all until the engine warmed up some more. So with all that said, I am suspicious of the HPFP. No codes have ever been thrown (excluding the P0420 for when I ran catless). From what I understand the '07 models and even some '08s may not through codes as easily for the HPFP than the later model years (I don't remember where I read this).

Needless to say I'm very interested in what, if anything, you find out. I've tried nearly all the littler, more inexpensive things to resolve this. Now that I'm getting to more expensive things I'm a little more apprehensive to just throw parts at all the guessing out there.

I hope I've given at least some insight into a problem that may be related. I will be standing by...




EDIT: I also forgot to mention this vehicle has had 3 different timing chains. One of which was within 10,000 miles of the concern starting.

 

Sounds like a bad tune to me. Even the original MINI tune could have faults.


When you're climbing hills in a high gear on boost that is the time when a poor tune is most likely to show itself. That's because the boost map is very rarely capable of reducing boost for conditions similar to a hill climb as it just isn't programed for it. At the same time the engine is under greater load and can't use up the boost being supplied. So you have high boost and no matching fuel or ignition map.


This is where Saab genius comes in. Within the Saab ECU you have secondary and tertiary maps which the ECU will switch to when the engine starts to knock and the ECU can't adapt around it. These are the knock map and then the emergency map. Each being more conservative than the last. In other words, 3 lines of defence against knock. Adaption, knock map, emergency map. This can disguise bad programming and protect you from it. Ideally it wouldn't be there, but not everything is ideal all the time.


Turbocharged engines also perform differently (as do all engines) according to air temperature and altitude. Then on top of that you've got fuel economy, emissions regulations, reliability and driveability to account for when making maps.


Ideally what you would do to resolve your issues would be to have a laptop connected to your ECU and drive it up the hill to replicate the fault and see where the ECU is struggling. Either visualising it in real time or preferably via logging so the map can be analysed.


Anyway, with my problem with the car in question right now, I've taken out the timing chain tensioner and it seems like all the others I've taken out so I'm ruling that out.


So what's left after that? Just the solenoid? Maybe I didn't test the Vanos hub properly and it has actually failed? I'm convinced by this stage that it's something to do with the adjustment of the timing rather than anything mechanical. Maybe I could try updating the ECU. Has anyone ever heard of that resolving a fault like this? The engine's clearly capable of running properly so it can't be anything too complicated.

 

I've got an old spare tensioner taken off another MINI. The spare one I have is an earlier revision of the part and it is noticeably easier to compress compared with the one I've removed. As this car had a timing chain replacement recently I'd guess it would have had the later tensioner fitted at the same time.


I'm going to try the earlier tensioner just to see if there is any difference... and if I get a short period of smooth running. Or hopefully a long period of smooth running.


Will report back.

 

I think it runs smoother more often with the earlier tensioner in place. But it's far from fixed.


So anyone recommend changing the solenoid. Has that ever been known to make any difference?

 

Local BMW dealer keeps Vanos solenoids on the shelf in stock. So you know what that means...