The problem I see is swapping parts is going to be very expensive. The 02 sensor is $200 from eminiparts. I believe the up stream 02 sensor is the original one so maybe it's faulty? but reading online the idle would be affected which is not the case. What I can't figure out is it remains on 3 cylinders at idle and goes back to 4 after I restart the engine. the problem only happens I hold at rev's. like 1500, 2000 , 2500 etc if I blip the throttle up and down it does not happen........also I have emailed Total USA and CR so maybe they will pay?? LOL
Chris, earlier you said that the only thing you did was fill up with gas and then overnight it developed a problem. Did it rain that night? Could it be a corroded ground point or at some other point? Just guessing...
Like I said... you can eliminate the O2 by swapping upstream and downstream sensors. If problem persists, it's probably not the O2 sensor (they're interchangeable, but drive very different things to happen).
Chris to make sure you two are understanding each other. He means put the down stream O2 where the up stream is and the up stream where the down stream is. Not buy new ones. :biggrin5:
Yes I just filled up with gas and replaced the Vee belt. So I thought I'd knocked a pipe off while changing the Vee belt. Nothing was amiss. Regarding the grounds. I've had this problem before when the SES light came on because a tyre in the back move a ground, so I took off every ground I could find. cleaned them and refitted. Here's the latest from last night. Fuel pressure is around 52psi and does not change when the fault develops. Now here's the strange thing. The engine runs fine from 4000rpm and up. wideband reads a constant 14.7 to 15.3 mixture. I held the revs at 4000rpm for about 10 minutes. no miss fire. so the pressure, injectors, sparks, pump must be good. If I drop the revs the problem starts bang on 3500rpm. so from 1500 to 3500 the problem will happen. I pulled the plug off the up stream 02 sensor and ran the engine. apart from running a little richer 13.4 the same rev range applied. problem 1500 to 3500 nothing after 4000rpm. So I thinking something controls the mixture from 1000 to 35000 and then something else from 4000 upwards. The up stream is the original 02 sensor and the down stream an internet version. The wideband gauge is worth the money to take out the guess work. Tonight I'll swap the 02 sensors as suggested because I think the issue is some mixture related based on the crappy gas. How about the throttle pedal? could there be something wrong there? Also I have a spare MAP sensor some place.
I thinking maybe in the 1500 to 3500 range the pedal was faulty but maybe the 02 sensors control different rpm's? I'm hoping tonight the rain holds off and maybe moving the sensors will move the problem. I'm just hoping it is not the EMU that is faulty..$$$$$$ On another issue I forgot to mention the clutch pedal barely disengages the clutch. I have to push the pedal all the way to the bulkhead to get gear selection. I don't have carpets so with them I would not get the clutch to work. This happened Friday night too! Both the slave and master are new.
Sounds like clutch needs to be bled. The ONLY thing that has anything to do with engine performance being "different" at different RPMs is the ECU. Now, it interprets various inputs to decide what it wants to do. But there's really no such thing as something like one O2 sensor controlling part of the RPM band and the other controlling the other. It doesn't work that way. The most likely condition is that a sensor (like the MAP) is sending an inconsistent signal through a portion of its operating range. So under some conditions it's sending what the ECU would expect, but other times it isn't. This type of condition is usually what causes symptoms that vary according to RPM, load, etc. (I just used MAP as an example. I'm not saying that's your problem here, though it could be). Very difficult to diagnose if you're not getting a code that a sensor is out of range.
Well the gremlins are running amuck. Having the same problems with my 05 MCS. Engine is stumbling around 3000 RPM while pulling a load. (heavy accleration). Throwing code P0302 and P0313. I hand just installed new plugs (1 heat range colder) about 1000 miles before. I suspect a tank of bad gas and a dirty fuel filter. Put the old plugs back in and it improved somewhat but the stumble is still there.
What's interesting is searching P0313 on the net I find folks with similar issues as me but no one pin pointed the problem and like you say with no codes to guide us it is difficult to pin point the problem. It's not raining so i'll pull the 02 sensors tonight and look for the spare MAP. We can fix it!
I was searching to help out and I found out the same thing happened to me in 08 and it was bad rings in the cylinder, low compression. Here's my post from back then: I hope this is isn't the problem, but you want to do a compression check.
I didn't rain! Hey Batrugger. I read your post too after searching LOL so I did a compression check. 210psi for all cylinders. which I believe is ok. plus this was an overnight issue. The day before I drove 4 hours straight. So last night I swapped the MAP , swapped the 02 sensors around, changed the plugs back to the originals and seeing as I had a spare, I swapped the throttle pedal= same issue. Of course I didn't swap the latter all at once. I did one at a time. Now I'm starting to run out of options. I just get the P0300 error. I read that when the EMC defects a miss fire in a cylinder, the injector for that cylinder is close and the 02 sensor are put into open loop. I sure this is what is happening because the cylinders change and the spark plug goes a very light grey suggesting the cylinder does not have fuel due to the EMC shut off that cylinder. So maybe this not a fuel issue but more a sparking problem? The only thing I did not change is the wires as I don't have any. The wires are red so most likely an after market set. could bad wire be the issue?
what is the value I should be looking for? I thinking maybe the fuel I have is bad too! I might go buy some more locally.
Test Spark Plug Wires I was trying to find the resistance for the MINI, but I can't locate it and ours is out getting body work done. Basically just test for consistency. Honestly the OEM wires in MINIs are really good. if you need to replace them.
Thanks, I heard that the OEM coil pack and wires are the best. I'm going to get the wires as I'm sure the red wires are some autozone junk. When I first got the Mini the engine was on 3 cylinders (burnt valve) so I bet the previous owner tried to fix the issue with cheap wires.
Searching around I found several cars with the same issue. One was VW GTI which had carbon on the valves and Mini with a short in the wires going to the coil pack. What I remember is the engine went on 3 cylinders and ran ok for a few minutes after a re-start, then as the day progressed the misfire occurrence increases. Maybe the crappy fuel made deposits on the valves? I'll take the inlet off and check. Also I've ordered some wires from the dealer here. $60 delivered.
It stopped raining so I got some new wires from the dealer. I fitted them and the problem is still there. What's interesting is the error code came up a cylinder for the first time! P0301 and not P0300. So I did a series of start,3 cylinders, pull the plug lead to find the cylinder, stop the engine, clear the code, repeat. what was interesting is the plugs get coated in a brown residue each time I pull the plugs out. I clean them, refit and then got #4 misfiring 4 times in row. Before if was random. Is the spark/fuel loading less below 3500? I hear a popping through the exhaust just before the engine goes on 3 cylinders. Maybe at 4000 and up the fuel/RPM and spark is strong enough overcome the problem? I have a feeling the fuel in the tank is bad too! also I ran all my injectors with the crappy Gatorade fuel so maybe all of them are bad now. I did take off the intake manifold, nothing strange in there.