Hey everyone,
Having an ongoing issue where the engine will cut out for a brief second and RPM drops. It seems to happen more in hot weather, but not always. Fuel pressure is good, new filter and both pumps. Dist cap should also be fine since it's pretty new
Having 2 codes, speedo and 322 burn off from MAF

I recently did the capacitor repair for the Yazaki speedo, and it works inconsistently. I did notice that the issue occurs more when the speedo needle is going nuts. Does the speedo send a signal to the computer that could affect ignition/airflow?

I have a new MAF, as of last August. Connection seems fine. Could that 322 code cause my issue? I can't figure out what the code actually means... if anyone has insight on that.

Thanks in advance

 

I don't think your speedometer has anything to do with the engine cutting out. The speedometer does send a signal to the ECU but if it were missing you would be getting a 3-1-1 code.

Intermittent engine cut-outs can be caused by an intermittently failing crank position sensor. Check the sensor. If the coax wire from it has cracked and flaking insulation then it should be replaced.

 

I do have the 311 code

crank position sensor is new, less than a year old.

 

I had the 3-1-1 code on my 240 and the only noticeable drivability issues were the tendency for the engine to stumble and sometimes die when coming to a stop. Otherwise the car would idle and drive just fine.

Since the 240 has a different speedometer than the 740 I'm not much help in diagnosing the faulty speedometer signal to the ECU. You'll have to get a wiring diagram and trace the signals. Maybe need a rebuilt speedometer?

 

I'll try to find some info about the speedo to ECU wiring; stumbling and dying seems similar to what I'm experiencing.

Do you happen to have any knowledge of the 322 MAF code?

Thank you for your help

 

I don't know what MAF you have installed on your car nor do I know what version of fuel injection system you have. I have read online that you can use an LH 3.1 MAF on a LH 2.4 fuel injection system but you will always have the 3-2-2 code since the LH 3.3 MAF doesn't use the "hot wire". My understanding of the 3-2-2 code is that there is a test where the ECU runs a current through the wires that act as the air flow sensor. The purpose of this is to burn off any contaminants from the wire. Since the LH 3.3 MAF uses a thin film instead of a wire to sense air flow, the burn off test that an LH 2.4 system runs will fail when running the LH 3.1 MAF..

 

Thanks! I will check out which one I have.

I appreciate the help

 

It's probably MAFS related. A MAFS is a tricky customer, hard to diagnose and it presents various odd symptoms. Whenever I've encountered what you describe it's been the MAFS. I keep spares, swap in a good known one to make sure.