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

The chain is the original 130,000miles but the tensioner and guides are 2 years old but saying that the tensioner could be defective. Last night I changed the injectors, plugs and cam sensor. The cam sensor came out with some black grunge on it which I was surprised to see. I'm taking off the cam cover tonight weather permitting. I did some more data logging and found the ignition timing to be all over the place at idle and a constant 34.5 at 4000rpm. If the engine had a distributor I would have said it was that.

what's nice about the data log is I can see what changed after swapping a part. The short term fuel trim went from -7.8 to -14.6 to -21.4 to -29.9 % after changing the injectors. I need to check if this is good or bad.

Looks like the engine is running rich(as the dealer mentioned) based on this article on fuel trims.

http://www.obd-codes.com/faq/fuel-trims.php

 

Last night I took off the cam cover to find the cam/rockers etc in good order. When I built the engine I timed the chain to the gold links and gear wheel marks. So to check the timing I turned the engine over to find the top gold link 2 teeth out from the cam wheel mark! Ah ha I thought the timing had jumped 2 teeth but after cranking the engine over several times I noticed the gold link and timing mark moved away from each other. After several cranks over the gold link and timing mark where 16 teeth out. Based on this I think the 130,000mile timing chain is stretched. Maybe the when the engine was going through the misfire this stretched the chain more and now the valve to piston timing is out so much the ECU cannot compensate? I did some checking online and a worn chain can trip the SES light and cause a misfire.

http://www.agcoauto.com/content/news/p2_articleid/339

Seeing as the chain has done 130,000 miles it would not harm to replace it. Looking at the engine to chassis clearance I presume this is an engine out task?

 

The guides/seals and tensioner have around 3000miles on them so I'm good in that area.

Yeah we were with the same conclusion at work today that the valves should hit the pistons but if the chain was way too long wouldn't the gold link slowly creep away from the timing mark? although the crank and cam gear would be in the same position. The cam would be retarded quite a bit but not enough to hit the pistons. When I looked down at the chain in the guides I can see one side of the chain about 2" from the other. Also I was thinking if the chain was past the length of the tensioner the chain would be slightly loose which would account for the erratic ignition timing. The ignition timing is very erratic at idle (less chain tension) and at 4000rpm (more tension) the timing remains steady at 34.5 . Another thing is the fault only happens if I hold the rpm at a set point for about 30 seconds. blipping the throttle never brings on the fault.

Another thing is I have this strange rattle/vibration that was not there before which could point to the chain resonating. either way I'm going to change it next week and start the strip down tonight. Exciting stuff!

 

Yes I'm with you on that idea Goldsmithy. I did check the sprocket for wear but they looked ok, the bottom one is 132,000 miles and the top 23,000 miles . Actually the Bentley manual says the chain and sprockets should be changed together but I didn't see that until after I'd ordered the chain. DUH! but saying that the chain is longer than spec and needs replacing to eliminate that as a possible cause.

 

It will be just a process of elimination and time. It's funny because I'm having similar issue at work which basically started the same time so I'm in deep with both issues with no solution in sight. LOL

 

Thanks. my worse fear is the roll started a potential wiring fault. Finding that would be pretty much impossible without replacing the whole wiring loom....I live in hope.

 

Last night I took off the cat and woke up the locals! Going up to 3500 rpm sounded interesting! The cat looked ok and the fault was still there. So I fitted the cat back on and pulled the plug on the downstream 02 sensor and got a P0036 error. I cleared the code fitted the plug and did the same with the upstream 02 sensor but no code came up which was interesting. Another thing is the fault rpm range has narrowed. The fault is now from 2800-3500rpm and takes around 30 seconds at a constant rpm for the fault. Before it was almost instant from 1500-3500rpm…..some improvement I think. I’m going to swap the 02 sensor next.

 

Didn't do so much at the weekend as the weather was nice. I was working my way through the grounds and wiring but found nothing that looked suspect. I suppose in the end the issue could be the engine ECU.

 

Yesterday I got an email from UK BMW tech who told me the issue is not the ECU. He told me to reset the ECU with the odo button. Then go drive the Mini so the ECU can learn new data. This was a new path to follow so I reset the ECU per his instructions and set off up the road. Ah so nice to back in the driving seat and the reason I love to drive this car........until bah bah bah the SES was back on and the fault was still there. I did a few runs and found the issue happens anywhere above 2000rpm while driving.

Boooo hoooo as I drove home. I do have a chance of a original JCW R53 ECU....see other thread.

 

me too! I thought that an ECU reset might work. Now I have 3 options.

1/ buy a complete used ECU set to test in the ECU is bad and then get the ECU tuned. (most time)

2/ send my ECU for repair.(quickest)

3/ buy the Vi-Pec ECU from Jan( expensive)

The first 2 are in budget and the last is the best nice to have.