To make a long story short:

-Back in March I had just filled my tank with gas and stopped at my first stoplight when my MINI rough idled and died.
-I had just changed my spark plugs, wires, and coil pack about 3-4 weeks prior in February
-CEL codes are: P0036 (post-cat O2 sensor) and P0138;
-Changed Post-cat O2 sensor to a Bosch last week on 9/2. (Pelican parts states post-cat is ok for Bosch but NTK/OEM is best for pre-cat)
-I can still start my car from time to time, however, it will rough idle and die within a minute or so.

My best guess is:
-Fuel Pump and/or Fuel Filter are done
-Bosch sensor is crap (I have an NTK on hand)

Since it still starts it’s not the starter/alternator

Any help and insight would be appreciated.

Thanks in advance!

 

Sounds like the post cat sensors. Was the car running well before the change?

 

It wasn’t running before the change, though I could still start it up and it would rough idle and die.

I’ve already swapped out the old sensor (Post-cat) but it doesn’t run. I’ve already cleared the codes as well.

Gonna change the sensor hopefully tomorrow (it’s too smokey out due to the California fires) to the NTK and switch out the Bosch.

Was talking to a buddy of mine and he also thinks there’s an issue with fuel delivery. Gonna try the Fonzie method and hit the tank before I change the sensor to see if that help. If it works I’m almost sure it’s the fuel pump.

 

When my pump was dying I could hit the back seat to get it going for a little.

You should be able to hear it when you turn the key to position 2.

 

So I installed the NTK sensor today and it started, but died about 5 minutes later (with the orange sky and ash falling creating an ominous setting). This time the code that came up was P0171 which means that the car is running lean on gas. Researched that it could be due to the upstream 02 sensor, so I ordered another NTK and it should be here by the 11th.

I’d also like to add that I did the Fonzie method with no luck, so I know for sure it’s not the fuel pump!

Hopefully the O2 sensor replacements fix this issue!

 

Keep us updated if you would

 

Ok, so my 2nd O2 sensor came today and I got to work right away. Changing the upstream sensor was much easier than the downstream one for some reason. I went to start my mini and....it was the same result.

I’m gonna try starting it tomorrow and see what that does, since it also starts randomly.

Up next:

-Fuel pump/filter
-Bypass Valve
-Throttle body

However, tomorrow I’m going to pull my spark plugs to see if there’s any oil. In that case, it may be my head gasket.

Getting all my sources for issues here:

 

If there is oil on the sparks, its the valve cover gasket, not the head gasket I basically followed this guide

https://www.pelicanparts.com/techart...eplacement.htm

 

Just a little update:

My friend came over and diagnosed it. Fuel pump is dead. Didn’t even notice it doesn’t prime anymore.

He also checked the fuel relay and swapped it with another to see if it would work with no response.

I’m in the process of selecting a new fuel pump. Thinking of Walbro or DW rather than replacing the entire unit. Walbro would need some modification whereas the DW is a bit more expensive but is a drop in replacement.

 

Well done, great call. Been lurking on this thread all week. Just curious, do you happen to know how many miles are on this pump, and/or if it's the original factory one?

 

I’m the 3rd owner and got it with 75K~ miles in 2012. It now has 160K miles, and as far as i know it’s still the stock unit.

I’ll be changing the fuel filter as well. Really curious as to how that’ll look!

 

I'd be interested to know if the pump was the actual fix. Fingers crossed.....I think when I last had this code it was 1) unmetered air entering the system from bad green jam gasket for duct horn. The xtra air in the system created this lean code to pre-cat o2 sensor which regulates air/fuel mixture. 2) Rough idle bad running when engine under load = turned out to be the vac line from FPR to plenum on right side supercharger horn under the intercooler.....lots of times its where owners tap into for a boost gauge.

 

it’s possibly the issues you’ve listed, however, my fuel pump straight up doesn’t prime anymore, as stated above a few replies ago. I’ve also changed those gaskets about 60k miles ago, so I’m sure they’re alright. I’ll see when I change the fuel filter. Sneed4Speed hasn’t fulfilled my order yet...

 

It's been discussed at length......For me, it did not go away until after replacing injectors......I installed factory JCW 380's and ran it that way for a while before MINI tech loaded the JCW software .......Maybe, it was the fact that the old rubber injector O'rings were hard as stone.....maybe...... https://www.northamericanmotoring.co...-starting.html

 

Not sure you will "hear" the fuel pump prime if fuel rail is already up to pressured to deliver the fuel.....There is a fitting where one can check to the FP at the rail.....

 

Alright, so my car is running now! So it was the fuel pump. Purchased a walbro 255lph from Sneed. Required a bit of modification to get it to fit into the stock fuel pump housing, but it wasn’t too bad.

Gonna clean my car up inside and out and take it for a ride so everything can get moving.

I didn’t change the fuel filter, but plan on doing it once I get the fuel level down.

Next maintenance and mods are an oil change, rear seat delete cover, rerouting my battery tie down, and replacing my engine mounts.