1st Gen R50 Cooper Most liked posts in thread: Urgent help needed!

It would be but the supplier of the battery is not playing ball. So I might have the borrow one to test the theory.

 

Ah yes the drama continues! I bought a valve spring compressor to remove the valves with the head on. I had to modify it slightly to work with the Mini head but in the end I got it to work. Anyway taking out 16 valves, checking and replacing them takes about a day. I didn't find anything bad, some exhaust valves had a slight resistance but nothing bad. I didn't find any wear, nothing to make me thing the valves were bad.

Once I had everything back together I tried the 3000rpm test and sure enough the fault is still there.

A while back I bought a cheap scan tool from China, never used it as it could not cancel codes but there is a nice little feature to monitor smooth running and misfire detection. I thought I'd run the misfire monitor. I get 0 for #1 #2 but #3 misfires per 200 cycles around 126 and #4 around 6 before going on 3 cylinders. So looking at that data my misfire cylinders are #3 #4 as noted in the error codes P0303 and P0304 and sometimes P0300. I changed the injectors over from 1,2 to 3,4 hoping to make the fault move. The misfire remained at 3 ,4 one strange thing is the engine went onto 3 cylinders at idle with #2 having the misfire just once after changing the injectors. Not being an electronics expert does not help me figure this out. I'll keep at it.

 

The part that frustrates me is changing the V belt changing the range of the misfire. Why? and the misfire only happens at 2900 to 3600rpm?

If the valves were bad the popping through the exhaust would be through idle and up but the popping starts at 2900 and finishes at 3600, The popping is blow out and not suck in as I first thought. Compression is good so we can assume the cylinders are good. Interesting is the crank sensor is by #4 but I changed that sensor.

I will take off the intake again and see if there is some issue between #3 and #4. I'm also looking for a more powerful software to run more tests.

never give up!

 

Thanks Crashton. I'm getting there. With this being a rally car I suppose certain factors related to rallying play a part in creating issues. I feel the issue is something vibration or wiring related.

 

Ah yes after 6 months crazy does not sum it up!

Last night I swapped the A/C (I don't have one) relay for the main relay and fixed the relay power issue but of course that didn't fix the issue. I mean it wouldn't be that simple. As I think the issue is something related to the crank sensor I pulled off the intake(got it down to 3 1/2 minutes) then swapped the sensor for the original crank sensor. Then ran the engine, either I'm crazy as suggested or did the fault range change? before the sensor change the fault range was from 3200 to 3700 and took around a minute to happen. Now the range moved below 3000 and happened in an instant. So it is quite possible my new sensor is a duff one? or the Donkey holes at the ECU repair shop didn't fix my ECU.

I'm going to check the range again and swap the other sensor back in, meanwhile I'll order another sensor and send the ECU back to the donkeys. Which means nothing is going to happen until next month.

 

Thanks, I'm a little skeptical regarding the sensor but it is worth a try. Ultimately I believe the ECU is the issue and as you say I have to believe that they know what they are doing.

At least I have this weekend to do more testing because I love that! not.

Reading the crank sensor issues I have most of those.

The crankshaft position sensor records how fast the crankshaft is spinning. This speed is then used by the car's internal computer for proper fuel injection and ignition. There are actually two parts to the sensor: a disc that rotates and the sensor which remains in place. The most typical type of sensor works off of the Hall Effect which uses a magnet. Many of the failure symptoms are similar to issues that other parts will have when they fail, so often times it can take several tries to uncover whether it is sensor that is the problem.

1 - Check Engine Light

This can be frustrating as the check engine light can obviously turn on for many different things. Your mechanic will need to hook up to your car's internal computer to determine that it is the sensor failing. Many times this light may go off when the car is running, but when you start the car again after it has been off for a while, the light has turned off. This occurs when the sensor stops working due to high heat levels. Once the vehicle cools down it will function again.

2 - Cylinder Misfiring

Only one of the cylinders needs to misfire to cause a problem. Many times misfiring is due to issues with the spark plug, but if the sensor fails then the computer is not getting the correct information on piston position. Many people will not check the sensor, but if you have fixed everything else and there are still problems, checking it should be next on the list.

3 - Acceleration Hesitation

This is also similar to the cylinder misfiring. If there is some type of hesitation in acceleration, then the computer is not getting the correct information on the position of the cylinders when the car is running. There is a lag between the computer receiving data from the crankshaft position sensor and applying it, so it takes the car that little bit of time to accelerate.

4 - Intermittent Starting

This is the most serious of the symptoms that could occur. When the sensor completely fails then the internal computer will have a malfunction code. If the car continues to have difficulty starting and you do not have it fixed, then one day it will not start at all. Many times this type of failure is because there is a problem with the electrical connection. There may be a problem with the circuit. If the signal to the computer begins to fail then this can cause the spark plugs to fail and eventually damage the engine.

5 - Engine Vibrations

Once the sensor fails then the position is not monitored, so you may find that the engine starts to have very strong vibrations. This will in turn affect the engine power and can also stop the mileage from recording properly.

6 - Backfiring and Stalling

Your car may stall from time to time. It can stall a few seconds after starting or quite some time after starting, and the same goes for backfiring. You will also notice that the car keeps backfiring frequently, not just every so often.

7 - Irregular Car Function

Basically you will notice that regular engine workings will start to become irregular, such as speed fluctuations, irregular acceleration, idling fluctuations, and more. If you start to notice a lot of odd and irregular workings then have your crankshaft position sensor checked.