2005 mini s, rebuilt head and related parts 6 month ago, running great until the other day it started running ruff. Check engine light and mis fire code cylinder 1. checked compression and all 4 in the upper 140 to 150 range. installed new plugs ,wires and coil pack no change. Moved injector from 1 to 4 and cleared codes. Drove it nice for a few blocks and engine light back on, code read now shows cylinder 2 mis fire. My next task is to change the fuel filter (124k) Any other ideas?

 

Did you use OEM head gasket ?
Replace all head bolts ( stretch bolts ) with new ones ?

 

Yes and yes. Compression test confirms cylinders are equal and have proper compression. Engine misfire moving from cylinder 1 over to cylinder 2 would confirm its not a compression issue. After replacing the ignition parts and clearing the code my thought was possibly a weak injector and that's why I swapped 1 and 4 but that proved to be not the case. Now I'm thinking fuel filter first and maybe fuel pump second as low fuel pressure may cause ecu to shut down injectors? BTW I installed new injectors (Bosch) when I did the head. FYI I had the head rebuilt because of carbon build up holding a valve slightly open causing low compression on a cylinder.

 

Excellent! with respect to injectors, stock OEM or aftermarket BOSCH? If original were the O-rings replaced?

Also, theres a tiny micro screen in the Fuel Pressure Regulator.....the FPR is attached to the fuel rail. Wonder if it’s clogged ?

There’s also a vac line for it, (FPR) it’s in a really hot area and if line is bad pressure in the fuel rail will not be constant going to injectors. I had his happen right before a rally. Cylinder misfires when engine was under load....I just replaced it for 3rd time the latter being “preventative” maintenance. (234k miles)

 

Injectors were aftermarket replacement Bosch "upgrade" from reading forums and yes new o rings were installed. Vac line under intake was good when I replaced the head but as you stated they go bad, will check that. I will also check the screen on the FPR (if possible) I need to put a gauge on the rail to check FP. Under load / high RPM is when the misfire usually starts (not always) . Filter first as its original with 124k Appreciate your input so far.

 

Are the injectors you purchased a Chinese knock off ? I have seen sources from that country selling fake BOSCH brand and even using logo/part number on the product.

If you end up exhausting your options, maybe consider putting the old injectors back in and give that a go ?

One thing I noticed was that "things" changed when you rotated the injectors around....( Code moved from one cyl to another )

 

Injectors were Siemens , do not recall anything else about them except they were yellow. lol

 

i'm seeing a TON of counterfiet parts like this on ebay claiming to be; Siemens, BOSCH and even factory blue JCW injectors while bearing a portion of the factory part number on the injector.

A true copy-cat injector. But then upon further inspection, "CHINA" and 4 injector ports in lieu of factory 2.

I'm just wondering if that may be a concern.

 

Oh boy! these were ebay. top rated seller Alantaauto. rebuilt genuine modern Bosch 4 nozzle spray pattern bla bla bla. claim to be lifetime warrenty bla bla bla
Why if cylinder 1 had a misfire, but when I swapped 1 and 4 no 2 cylinder then had misfire?
What injectors do you recommend?
did have a bad review (after I bought my set) low performance and lean code

 

Just F.Y.I. There's nothing wrong with 4-port injectors. I use 4-port reman Audi TT 380cc injectors (plug & play) in my MC40 and they perform perfectly. I've also used 4-port Volvo injectors that worked well though I did swap them out when one of the wiring adaptors started misbehaving. I am of the personal opinion that 4-port injectors better atomize the fuel.

 

I have read all the posts above...I fail to see any quotes from anyone stating there was anything "wrong with 4 port injectors...."

 

No need to get your knickers in a twist. It wasn't a criticism. You mentioned copy-cat, CHINA and 4-port injectors in the same sentence. The inference was that they were inferior.

 

I'm just as stumped as you are, because you've done a marvelous job already spitballing ideas and running down any probablilties. Up to now you've done everything I would have thought of as well. But there comes a point when one has to back track on what work was done and examine the parts installed before misfires came up.

As far as my suggestion that we look at the injectors goes....Think of it this way. You have an air pump run off of tens of thousands of controlled miniature explosions, the only thing from turning the W11's engine valves/pistons from being turned into molten lava are the fuel injectors supplying properly atomized fuel at the back of the intake valves. On a forced induction engine like a supercharged one, where heat cycles can spike in a 10th of a second. Proper fuel supply is critical to keeping things cooled down...and why the R53's run a little rich from the factory.

Other than injector(s) being faulty, I am wondering if there's any possibility carbon has build up....carbon can heat up to a point where it will actually trigger the fuel and unspent fuel just like a spark plug while not in proper sequence with timing, hence a misfire.

 

Well since you brought it up, yes. When it comes to autoparts about everything which comes from China is inferior, a cheap imitation, a faux copy comprised of inexepensive materials more often than not assembled by 10yr old kids working 16hr shifts all done in violation of intellectual property rights.....so with respect to something as ctitical as a fuel injectors and China? Yes, forgive me if I seem a bit skeptical about the bootleg injectors.

 

I know for a fact there is no carbon build up. The reason I pulled the head was to remove carbon and have a valve job done since it was off and that was maybe 8k ago. Like I first posted the car ran great until a few days ago when the misfire started out of the blue. I still had the original wires and coil (124k) so logically those were the first parts to replace. The 8k old plugs looked good, slightly lean in my opinion so I changed them too. Moving injector 1 to cylinder 4 was a test to see if the misfire code would follow, it did not as the code moved to cylinder 2 instead. That made me think about the original fuel filter being the issue. Once the filter comes in and if the misfire does not go away I will check the vacuum line and fuel rail pressure. Fuel pump or injectors my be needed, we shall see. I appreciate the help so far.

 

Doesnt take very long for carbon to build up in the proper environment.....the fact engine running lean will contribute to this in no time.

Well, at the onset one would conclude that this code change sounds like unequal fuel rail pressures but why would that vary from one cylinder to another when injectors are 3 inches apart ? Which brings me right back to the injectors. There was a documented "change" with the codes after fussing with them.

While the change did not meet your expectations, the only thing you did was fuss around with the injectors.....focus there.

 

10-4

 

I contacted the seller off ebay that sold me the injectors and they claim they are not "China" injectors and are willing to test and replace any iffy ones. I also changed the fuel filter last night but now my mini won't start...….ARG!! Possibly air in the line? I will pull charge air cooler to bleed fuel rail this afternoon.

 

It won't start prob due to the top line fuel connector not being snapped in properly. While it hasn't happen to me in the 4 times I've done mine, that connector will not fully seat w/o a lot of muscle behind it. After replacing the filter and sealing it all up. I would typically just turn the key to pos 2 several times before cranking and always had pressure to start.

 

I removed it 2x to check and it appears to lock in place as it should, I do hear the pump cycling. I was surprised how easily everything came apart and back together, not my first rodeo when it comes to repairs. I handle all my engine, suspension and brake repairs along with body and paint. 35+ years in the biz/hobby

my current rides include
BMW 535i E61 with JB4 tune
GTS Viper exhaust and suspension upgrades
Range Rover Sport air bag and suspension replacement
BMW M3 SMG removal to manual conversion
Mercedes Sport m272 4 cam engine overhaul
C6 Vette LS3... to much to list
05 Mini S head and suspension replacement...……...misfire driving me nuts.

 

Just makes no sense it won't start now after filter replacement.
Back track all the work...check the electrical connector, it has to be there somewhere...

 

+1 on Eurothrasher's comments about the filter housing top seating. It's happened to me and I've also removed and replaced it multiple times after the car would not start before it finally seated properly. I, like you, believed it was seated when it was not.

 

 

There was no electrical connector on the filter. What am I missing here?

 

No was thinking pump side.....