I am having problems with my ECM communicating with the O2 sensors and causing it to run very poorly. I need to get a good ECM or help with how to fix it if possible. Thanks in advance.

 

jefflongino,

That sounds quite an unusual situation. What makes you think it's the ecu, rather than the O2 sensors, or the wiring, or ecu plug etc? Those are the much more likely problems.

Cheers

Paul

 

What is the basis for your diagnosis?
Do you have the part no for the ECM?
I have a known good one from my 94, 4.0 donor car.

 

The shop tested the O2 sensors and looking at the ECM discovered that the they could move the ECM around and it would disrupt the running engine. They looked for a short, opened the ECM and didn't find anywhere they could see a problem.

 

I am looking for one (LHE1410AE/601).

 

I’d recommend eBay, if that’s the diagnosis you’re sticking with. If the car changes behavior when the ECU is moved, the problem is likely the wiring harness or the connectors at the ECU. If the shop saw no corrosion where the ECU and the harness are plugged into each other, then, to me, the ECU isn’t the primary suspect….the wire harness is.

You could run new wires from the ECU pins to the oxygen sensors and see if that does the trick.

How old are the sensors? They are not a lifetime part, and could require replacement as early as 60k miles.

 

I'm at 90k on the thing. The shop said they checked the O2 sensors and they were good. I don't know how you check them and like you a connection seems like the most logical thing, but they insist it is the ECU. I live right near the bay / ocean so salt water is always a concern here. The Jag has been kept in a garage so that helps, but everything is suspect. May try your jumper trick. Not sure which pins run to the O2 sensors. Will look to see if there is a wire color that I can trace. Thanks

 

Jeff,

What was the basis on which you started being concerned that it is the communication of the ECU to the O2 sensors that is causing the poor running? The ECU has inputs and outputs relating to the fuel pump, fuel injectors, crank sensor, ignition etc etc. If moving the ECU about causes "poor running" (does that mean stumbling, misfiring, hesitation or something else?) then I would start by looking at the ECU wiring plug and the integrity of all the ECU pins and the wiring plug pins. I'm not sure that I would start by thinking it's the O2 sensors rather than one of the other ECU-controlled elements.

Good luck

Paul

 

The car starts and idles great. Then you start driving it and it runs for a time and suddenly wont get rpms to accelerate. It doesn't have any power. The shop said that one of the banks is not adjusting the fuel mixture thinking it needs fuel and floods 3 of the cylinders. They checked the O2 sensors and then inspected the ECU. They also inspected the wiring looking for a short. They said that they could move the ECU around and it would straighten up and then get bad again.