scotty Posted March 2 Report Posted March 2 So I was hoping someone might have some insight on this new issue. I just recently did the downstream oxygen sensor and it was spent for sure, put in the ntk as it said that is OEM. So the day after this being done she ran great. Then this morning I start the car up and heard a noise in the rear almost like something was loose then I got a light pop up which is a half lite up motor, looked it up and it said engine power reduced or something like that. Anyone ever have this or any ideas as to what it might be I would appreciate it. Note: no check engine light came on and on the return home that light went off
1975_mini Posted Thursday at 11:09 AM Report Posted Thursday at 11:09 AM On 3/2/2025 at 5:14 PM, scotty said: So I was hoping someone might have some insight on this new issue. I just recently did the downstream oxygen sensor and it was spent for sure, put in the ntk as it said that is OEM. So the day after this being done she ran great. Then this morning I start the car up and heard a noise in the rear almost like something was loose then I got a light pop up which is a half lite up motor, looked it up and it said engine power reduced or something like that. Anyone ever have this or any ideas as to what it might be I would appreciate it. Note: no check engine light came on and on the return home that light went off Unfortunately that is the default light that displays for anything feeding the ECU values outside the acceptable range. You really need to pull the codes to get a better understanding of the issue. When abouts are you located? 1975 Mini 1000, 998cc A+ w/ K&N air filter, 10" Mamba wheels
scotty Posted Thursday at 11:17 AM Author Report Posted Thursday at 11:17 AM That is what I have learned and she is currently in having it looked at. That light has gone away but now I was left with misfire codes po301 po304 so all I can do is wait now and see what they say. Thank you Corey
1975_mini Posted Thursday at 10:48 PM Report Posted Thursday at 10:48 PM Good news that is cylinder 1 and 4, so not adjacent cylinder that could be a cracked cylinder wall or head gasket. Could be a few things with that: could be it you just replaced the o2 sensor it could have been ready incorrect for a while and created a rich condition resulting in fowled plugs. A common issue on gen2's is coking on the backside of the valves, of time this buildup will effect the seating of the valves resulting in misfires. Luckily that is easily corrected with a walnut blasting of the valves. usually around $350 or so. Keep us in the loop on what they say 1975 Mini 1000, 998cc A+ w/ K&N air filter, 10" Mamba wheels
scotty Posted Friday at 12:17 AM Author Report Posted Friday at 12:17 AM I have really starting to think that myself to be honest, with 81,000 miles on the clock I am fairly certain there is a good amount of carbon buildup on those valves. Now the plugs were just replaced about 200 miles ago or so and I used NTK plugs, coil pack was done 11,000 miles ago and installed Delphi coils. I have also heard the knock sensor can cause a lot of issues also if it is indeed bad. Thank you for all your help
scotty Posted 5 hours ago Author Report Posted 5 hours ago So as of right now it is looking like the high pressure fuel pump we are getting low readings from the fuel rail on the high pressure side going to check and see if there is a leaking fuel injector but because it's a misfire in a single cylinder it is not likely. I am going to do my best to make the run on Saturday but chances are that might not be possible.
