Hello, been reading alot lately as my 04MC is about to be paid off. I am not afraid to take anything apart, I just don't have much experience other than an 88 RX-7(wankel) and 76 vette. Did some searches and thought the forum had solved it, but new troubles arose. The car has been slow to start, but other than that seems to run ok. SES light came on with the following codes:

P2097 - O2 bank 2 too rich, haven't addressed yet.

P0445, P0031, P0037, P0340 - This set are all related to the F03 fuse, and sure enough it was blown. I replaced it, but now the engine runs real rough and get a new code P0304 (cylinder 4 misfire). When I pull the fuse, the original codes come back, but the cars runs fine.

Any ideas where to start would be awesome.

 

Check your plugs, plug wires, and coil terminals(especially cylinder #4).

Jeremy

 

I replaced all 4 plugs (#4 was a bit fried down), checked all wires for damage and solid connections. I also verified spark pulse with an inductive timing light. With the fuse installed (rough runnning) the strobe was erratic on cyl. 4. With the fuse pulled, strobe was even on all plugs.

 

check the nipple on the coil for corrosion for the #4 cylinder - the rear nipples ( #3,#4 ) are prone to corrosion.

as for code p2097 - that a fauty rear 02 sensor ( Bank 1 Sensor 2 ) not bank 2 .

P0445 - cannister purge valve

P0031 sensor 1 oxygen sensor malfunction

P0037 sensor 2 oxygen sensor malfunction

P0340 Camshaft position sensor - no signal

 

The Engine is running in open loop! (without feedback from the o2 sensor)

Open loop will use the stored LTFT cells for all the load and RPM variations.

Normally this is what happens when the Engine is cold.

F03 provides the needed B+ to:
The canister purge valve
B1S1 heater, B1S2 heater
The Cam Position Sensor
The Engine Fan
A/C compressor Relay

With this fuse blown, the o2 heaters will not function and the car never goes into closed loop.

The Cam Sensor is a hall effect type sensor (three wires) it requires power in order to produce a signal...no signal forces the ECU into semi-sequential mode.

This means that the ECU fires all the injectors at the same time! At least under all these conditions the engine will run......

With the fuse in place...the o2 sensors come online and the ECU responds to feedback from the o2

It the o2 is feeding bogus data to the ECU...the ECU will not command the correct amount of fuel and the car runs like crap!

Now regarding the coil and wires and plugs...

The MINI uses a waste spark system...this means that two plugs are fired at the same time by the same coil

In fact, these two plugs and wires are in series! If there is resistance is any of the electrical connections for either of the two companion plugs, both will misfire!...not just one due to the series arrangement.

It appears that this is not the case since the error is P0304 and not P0300.

Based on this logic I am thinking the entire ignition system is OK.

So whats left...fuel injectors and compression...Also look at B1S1 to see what the o2 is reporting to the ECU.

Good luck and I hope this helps.

 

damn.....you lost me at THE. lol

 

frenchie is my hero.

 

Having similar issues. P0445, P0340, P0031, and P0037.
Replaced O2 sensor and that didn't help. Still had same codes.
Getting very bad mileage and it takes two tries to start.
Bought a camshaft sensor, but am hesitant to have installed since changing the o2 sensor did nothing.
:(

 

Is your fuse blown too, a bad fuse will cause no power at the cam sensor, o2 heaters and purge valve; which will cause the codes you reported.

 

Your the bestest Frenchie...And i always thought nothing good came out of Jersey. lol

 

wow i always assumed the plugs were in parallel . what a stupid design . thx i think .

 

The plugs are in series, the current that gets to the second plug has to pass through the first plug.

This is why one plug fires from the center electrode to the ground tab and the other fires from the side tab to the center electrode

It takes more energy to fire from the side to the center, you may have noticed that of the two companion plugs one is always worn more that the other

This is why MINI uses a four side electrode plug...I can only imagine a single side electrode plug would get worn pretty fast

It certainly is a cheaper design than having individual coils; however it does have several diagnostic advantages.

 

very informative Frenchie, thanks....I think i get it.

does the ECU need to be "reset" to get out of sequential mode, or assuming all systems are otherwise ok, will it just adapt to the new data?

from a fuel and compression standpoint, everything checks out as far as i can tell which would follow suit since it runs smoothly (though not efficently) when the fuse is out...problems there I would assume would lead to stumble and significant loss of power....

in reference to the plugs, my stock plugs were the NGK "standard" plug with a single arm and v-cut center electrode. Should I replace these with the 4-arm "performance" plugs? Or am i missing the boat on that one....

 

The ECU does not need to be reset. The failure you have is detected when the key is turned on even before the engine starts. The ECU checks to make sure all the relevant players are present. So if the players have power turn the key on and the ECU should be happy again.

The reason it is not efficient is because the ECU does not know when to fire the injectors (due to cam position signal missing) to get around this problem the ECU fires all the injectors and whichever piston is on the intake stroke will pull in the fuel.

If you have a weak injector on a normal running engine it will be masked if the engine starts firing all the injectors at the same time.

If an injector is weak and the ECU fires the injectors one at a time as it should the o2 will detect a lean mixture (1 of 4 injectors holding back fuel)

The ECU will respond by increasing the fuel to all 4 injectors until it no longer detects the lean condition!

In the process of doing this, injectors that delivered ok will deliver even more fuel until the one that delivers the most misfires! even though that's not the one with the problem.

I would suggest to have someone take a look at the spark using an ignition oscilloscope. The waveform will reveal exactly what is happening inside the combustion chamber without taking anything apart. Many independent repair shops use the SnapOn Modis is an example of one such diagnostic tool.

About the plugs...I thought all MINIs used a plug with four ground electrodes. if this is not true then I recommend using the original plugs.

Note: the firing Kv for the plugs should be 7-9Kv (compression stroke) and 3-5Kv (waste spark)

 

I second the compression test, there has been a rash of worn valve seats that cause compression leaks. The compression should be between 3.5 and 5 bar or 175 and 220 psi can't remember 100% off the top of my head but somewhere around there. There should only be at most 15% difference between cylinders.

I would make sure you get the factory plugs, there is a reason for the 4 prong plugs that came with the car.

 

so the ngk two prong aren't as good?

 

Frenchie saved my life. Thank you.

 

thanks for this post. I had the same four codes, replaced fuse F3 underhood, all is well. I love the internet sometimes.

 

i'm back again. had the fuse last for about a week, then popped again. replaced one more time and it popped the next day. now i have to troubleshoot.

i'm thinking it's one or both of the o2 sensor heating circuits, as i can't really see the cam timing or DTS causing that much of a load to pop a fuse. and i have 110k on the car, so it might be time anyway.

thoughts?

 

got it. i had to drop the exhaust last winter to change the shifter cables, and the o2 sensor cable had rubbed thru and the insulation on 2 of the wires was gone. some cloth tape and and it's good to go!

this was the o2 sensor under the car next to the catalytic convertor.

 

time to revive an old thread... i just swaped out my entire exhaust systme. obx header, 2.5" in/out magnaflow cat, and alta catback, and two brand new 02 sensors.. when i started the car it had a hard time starting and i had those 4 same codes. cam/o2 frona and rear/ ac relay....

i did have a blown F3 fuse unde the hood, replaced it but it did not go away. it has yet to blow again. i have rest the ecu mulitple times with my BacTech scanner. and nothing... im reading the post above and if the wires on the rear sensor were rubed throguh and where touching the heatsheidling. would this cause a short and make this whole systme get messed up?

im going to try disconecting the rear o2 from the plug and start it up to see if anything chnages when i get home from work. if i thats it i wil be one happy camper.