It's a good thing you are in CR and not holed up in some snowbound and isolated cabin with only your non-functioning, drama queen MINI to keep you company! Talk about the "consequences" of cabin fever...or might we call this "The Revenant, Part II"?:arf:
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, I love a good puzzle! I did some lunchtime reading: 2 cylinders misfiring together could mean the head gasket or a rare case of the camshaft snapped in the middle bearing but surely both of these issues would give me issues through the whole RPM range......worth a check on a summers night, might even light a candle to make it more romantic....LOL
Not being a mechanical marvel but wouldn't a bad head gasket show up with a compression/leak down test ?? The only reason I ask is because you have done compression test and you have been satisfied with the results. Good luck !!
I thought about that. The PSI was the same on all 4 cylinders. I thought to pump air into #3 plug hole and see if air comes out #4. Should have done that yesterday with the valve train off.....DUH! should have/could have
Last night I pulled the cam cover off, checked the cam(not broken), changed the cam followers/arms for another set and tired again. Still the same fault so I put back the original followers. I took off the intake, all looked good but I did notice #3 and #4 wet with fuel. I put everything back tried again checking the misfire detection values. 0 for all cylinders until around 2000rpm where #3 starts logging faults and increases to 300 just before 3000rpm. #4 has a value of 5 just before the misfire is detected. Going from 4000rpm and up there no cylinder misfire detection. Reducing down to 3600 #3 increases the value and #4 goes to 5 then #4 is deactivated. I now have a long list of what the issue is not. Reading back I had multi-cylinder misfire on any of the cylinders except #1. Changing the harmonic balancer, V belt and alternator resulted in only #4 being deactivated. Since the change of the latter this has been the case. #4 is now the only cylinder with the error code. I've changed: fuel pump, filter, 02 sensors, T-map, crank/camshaft sensor, Knock sensor,injectors, leads, coil pack, plugs, alternator, pulley, V belt, timing chain and engine loom. Checked: the compression, fuel pressure, valves, cam, cam followers, cat, fuel vacuum leaks. Removing the plug from the T-map removes the 3 cylinder issue but the popping gets worse at 3000rpm I think removing this plug some how deactivates the misfire detection but what is strange is, if I connect another T-map to the plug leaving the other T-map in the intake the engine runs really bad but does not go to 3 cylinders. Which makes me think intake pressure/load influences the misfire detection. Seeing as I have moved forward to having just 1 cylinder now deactivating and the misfire range has gone from 1500-3500 to 3000 to 3600. I'm going to run the engine with the V belt off again and maybe even take off the harmonic balancer. We are close!
Chris you are the most persistent person I know. Keep at it you will get there. Rally is a drug & that is what keeps you going! Best of luck friend. :fingerscrossed:
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.
Chris, If the misfire is between 3000-3600 don't ever let the engine go below 3650 RPM. Duh! Problem solved! Your welcome I am glad I could help. :biggrin5:
Last night was very interesting, I did 2 tests: test 1: Run the engine with the T-Map in the intake and plug another T-map in. The engine runs like crap , runs rich but never runs on 3 cylinders. I got more error codes, some related to the coil pack which is a first. I think the ECU was very confused trying to make the engine run correctly. LOL Test 2: I took off the V belt and ran the engine for a short while due to over heating. The fault happened just once , then didn't happen again. Now I'm well confused! either the water pump or tension wheel are causing vibration or the alternator is causing some voltage issue. Also the T-map could be sensing the wrong intake pressure when running in the intake. I was thinking to run the tests again tonight and try to figure out what exactly is the culprit. These are the error codes from running the second T-map out the intake.
Man, you are persistent. Funny enough, my R53 (w/ 120K miles) is now throwing P0300. Seems to happen around 2500 RPMS. The car also seems to be in sort of a limp mode (stuttering acceleration and reduced power - cant get above 2500 or so in 6th), and when in gear, it idles kind of weirdly. The coil, ignition wires, and spark plugs were replaced (about 3K miles ago.) It's sitting at the mechanic now, but if they have to run the of gamut of tests like you have, I may have to just cut my losses and let it go.
I know anything is possible but you just switched out the alternator and you have a new battery so the tensioner appears to the only item that hasn't been touched of that group. Is there a sensor that is reading this vibration and if so can you dummy in an acceptable reading ??
ah ha...the fault is spreading to other Mini's....don't read this thread unless you want the curse of the misfire! I don't know what is more frustrating? not knowing the issue or knowing what the issue is but don't know how to fix it! Last I ran the same tests again. The V belt off is limited due to the engine will overheat. So while the engine was cold I ran without the V belt. So the only rotating part was the new pulley. Guess what? the fault range narrowed again. Now the fault happened just at 3500 and took about 2 minutes or more to go to 3 cylinders. Then I fitted(don't laugh) several elastic bands from the pulley to the water pump and ran some more. The same thing happened. 3500rpm. So the water pump and tension wheel are excluded as potential suspects. I then put the V belt on then did the T-map test but this time I hooked up a shop vac to the T-map to simulate some suction. The engine ran a little better but was running way to rich and very rough. Switching the vac on and off didn't make much difference, like before the engine did not go to 3 cylinders. Based on those 2 tests I would doubt that the sensor is so sensitive that rotating parts would cause a misfire, if that is the case I bet 50% of Mini's would be misfiring! I think the pulley helped with the misfire because after changing it the only cylinder to deactivate is now #4. Guess where the crank sensor is??? at #4. With the T-map it seems the pressure in the intake gets to a certain pressure that is working with the crank sensor/ECU to cause the misfire. The crank sensor is new but looking at the above the crank sensor is in the middle of both tests. Another interesting thing is the cheap scan reader shows voltage to the ignition and main relay. The ignition is a constant 13.6V but the main relay read 13.6, 12.8, 0.0, 13.6 etc repeating like that, 0.0V for a split second can't be good. There are 4 main replays that control all the sensors,injectors and ignition. I suppose it is possible one or all have carbon build up? My next check is the crank sensor and relays.
A shop vac, several elastic bands? This is getting crazy! If some guys show up with a white shirt with no holes for your hands.............RUN! I am sure they are around the corner
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.