Onset of symptoms 05 Cooper S w/ 162K miles

Symptoms began with hard starting first thing in morning (SoCal, so temp isn't the issue). cranked maybe a little slow but mostly it was just slow to "catch". Subsequent restarts were fine all day long

We may have had an occasional CEL misfire engine code pop up while driving as well but self-corrected/cleared

Transitioned into even harder to start, stumble at startup like it was only running on 2 cylinders and then fire all all 4 and run smoothly after a moment of struggle. Again, later startups were fine.

By this point we definitely were getting cylinder misfire codes but they weren't the same cylinder/code each time.

Swapped out plugs w/ ngk new ones, new plug wires, and even tried a coil pack from another Cooper I have sitting dormant. No real change. Hard cold start continued. I thought I noticed that if I waited a little longer with key on (fuel pump prime) position that it would start more easily, but that may be misperception.

Wife bought another MINI so this Cooper S has just sat. Been sitting maybe 2 months. Finally changed the fuel filter out as a "maybe it's this" deal. I went to start it and the battery was weak as the car / starter made a pathetic clicking/grinding noise.

Charged the battery fully and came back after several hours-- cranks over beautifully but there's no start. Nothing. Like it's not even trying to start.

I can still hear the fuel pump turn on like it is pressuring up and then it clicks off. But motor just cranks and cranks and cranks and nothing.

Could this be fuel pump? Could this be me screwing up something when replacing the fuel filter? Could this be the car jumped timing because of no pressure on the timing chain tensioner after drainback from it sitting so long?

How can I check if the timing may have jumped a tooth? Is there a cam position vs crank tdc position I can use to confirm it's still good?

Is there only 1 pump in the MINI Cooper S? I keep reading terms like "High Pressure Pump" which makes me wonder if there is also maybe a low pressure lift pump somewhere??

Thanks for any help. I'm familiar with classic original minis, but this fuel injection stuff is new to me.

 

Going to move you to the Stock Problems/Issues area.

What codes did you get? Have you checked the hose connections around the throttle body and the BPV? You have pulled the plugs and verified you are getting spark?

On the chain tensioner, I am thinking there are marks that should line up with the cam gear at TDC. I also may be incorrect, but I am thinking the tensioner is not going to close due to loss of oil from sitting.

 

I do not remember the code numbers exactly. They were "misfire, cyl 3" and then misfire in some other cylinder. When cleared they were fine for a while. Then we also had a "misfire multiple cylinders" I believe.

That is all.

I borrowed a friend's fuel pressure tester. I'll remove the intercooler and see if I can check pressure at the schrader valve

 

Update: I replaced the fuel pump with a used one. it too turns on and off at KOEO as it should, just like the other one. Crank and no start, just like the other one.

Interesting note: The return line wasn't dumping into the fuel pump holder as it was supposed to be clipped in but wasn't. The pump I removed was a Valeo and was apparently replaced not that long ago. Both the lockrings on the filter and pump were paint marked, and the pump housing is bright white and not yellowed at all.

I put a fuel pressure tester on the end of the fuel rail-- nothing registering, but then again it's a borrowed harbor freight tester so...

I also found a snail shell that could POSSIBLY have been pinching off the elbow on the vacuum line that attaches to the fuel rail pressure regulator, but I'll cal that a red herring right now. It broke when I was feeling for the hose.

There is no evidence of fuel leaving the filter housing and into the fuel hose that feeds the car.

Something else I found interesting is that there does not appear to be a return fuel line on the MINI. At the base of the in-tank fuel filter housing is what appears to be a fuel pressure regulator.

https://tinyurl.com/yab2g84s

I've found one thread that seems to give me hope of finding my solution. I offer these links for others to who in the future may find themselves with similar symptoms.

https://tinyurl.com/y6w237sy

https://tinyurl.com/ybm5lmff

I'll report back my findings once I go pick up a replacement fuel filter housing setup (from the same car I got the fuel pump) and then pull out my whole filter housing assembly (which looks like a real bear to do).

 

Since I like having conversations with myself, I'll continue on here in public.

I replaced the filter housing, which requires that the fuel pump side be opened up again as well because the fuel lines go from the pump to the filter and then bypas and back to the pump. The float on the filter side is also fed it's power through a connector on the fuel pump. So all of that needs to be disconnected at the fuel pump before you can pull it out with the filter housing on the filter housing (passenger) side.

I realized at this point why the instructions for replacing the filter don't have you removing the housing completely-- because it would require the fuel pump side to be opened up as well or else risk screwing up the feed or return / bypass line.

When I replaced the filter housing, I used the new filter I had put in the original housing.

When I hooked it all back up-- replacement filter housing and replacement used fuel pump-- I also made sure to prime the filter housing. Turning the key and the auto prime didn't seem to really do much or run long enough, so I paid attention to which prongs on the fuel pump connector were hot and ground, and I jumper wired them to a battery until I could hear the filter housing fill up completely and I finally got a pressure reading at the fuel rail according to the gauge.

First crank, it fired right up. Test drive was great. Car felt wonderful.

Fingers crossed it lasts!

 

Hey did this solve your issue? I have the same exact symptoms. Also do you think it was a bad pump or filter?