512M 3000 RPM MISS

i am starting a new thread. the other one is getting too long and also digressive.

1. engine diagnotic codes for 1/6 are 4114 and 1111 and then they repeat and repeat. 4114 is Top Dead Center control. 1111 is hot wire airflow.

2. codes for 7/12 are 1211 and 1121 and then they also repeat. 1211 is lamda regulation. 1121 is rpm sensor.

3. i will look at the air flow meters first since they are easy access

4. i will also order a set of NGK DCPR9EIX, if the Rifle driver approves. The Champion A-GC6s were installed at engine out service 1500 miles past (in 2008). I have not had good luck with Champion in the past and these plugs are out of date anyway. i usually try to put a bosch plug in if it is a bosch ignition which the M is.

 

1. the check engine light for the bank tested flashes out a code when you push the test button on the ecu for 2 to 5 seconds.

2. see fuel injection section, tab c in the service manual.

3. i will remove, check, clean the 1/6 airflow meter tonight and see what happens.

4. i do not like the Champion plugs and rationalize that plug technology today has surpassed 1995.

5. i am hoping for a response from rifledriver on the NGK DCPREIX iridium

 

1. i drove the car on two 20 minute trips yesterday. the 3000 rpm miss problem seems to have been solved, although the idle seemed to be a bit rough.

here is what i did the previous night:

2.removed the 1/6 air cleaner and box. removed the air flow meter.

3. the air flow meter cable connectors had clean grease in them but it appeared to be dried out. i cleaned both with aersol contact cleaner. i cleaned the road grime from the meter, looked at the hot wire and temp sensor, and reassembled all.

4. the rpm sensors for 1/6 and 7/12 are both located on the lower right cam very near the air flow meter so i decided to check and clean those connections. this was a deviation from my plan of one repair task and then test drive.

5. after cleaning the area with solvent (it was very dirty), i noted a vacuum hose physically in contact with both sensor cables and pushing on the connectors. i rerouted the hose away from the cables. the conections looked good but i cleaned them anyway with the contact cleaner then reassembled everything.

6. last night after the 2 successful test drives, i checked the error codes on the motronic 2.7 ecu(s). the same codes appeared as in my first reading before the fix. this was unexpected because i had erased the memory and the reset so only new codes would be stored.

 

1. yesterday after numerous drives and higher rpm blasts up the freeway on ramp, i am pleased to report the 512M is running great again. no missing and apparent full power.

2. summarizing my previous report, the electrical connections on the air flow and rpm sensor were the problem. contact cleaner and the dissassembly/reassembly process solved the problem.

3. this experience reconfirms my general feeling about older cars, the electronics are usually good. it is the corroded and resulting high resistance cable connections that cause the problems. most common example is the battery.

4. i do yet not understand why the diagnostic codes are still present......maybe i did not perform the reset properly. will perform the battery disconnect reset and see what happens.

thanks for all the responses..............
js