MAF Sensor/ECM problem '93 Explorer

[sodacan7]

So I have a 1993 Ford Explorer that was running fine until a couple weeks ago. I started getting a really rough idle and very little power when driving my vehicle. Unplugged MAF Sensor and it ran fine. Changed out the MAF Sensor and it drove fine again for 2 days. On the third day the exact same rough idle and lack of power problem kicked in. Had a mechanic friend look at it and the wires to the MAF Sensor are being overcharged. He theorized it could be an issue with the ECM? Has anyone experienced a similar problem or situation? If so, how did you fix it? How much should I expect to pay to get my ecm replaced at an auto shop? The ecm prices online that I found (used and new) have a fairly wide range. Thanks!

 

[Anime]

Problems that have no other apparent cause can sometimes be traced to a bad ECM/PCM that has the capacitors leaking onto the circuit board. Ford used poor quality capacitors in the first gen Explorer and so they eventually go bad and leak electrolyte all over the circuit board and the effect is that of an ECM that sometimes works depending on termperature and other factors.

Easiest way to check is to disconnect the battery and pull the ECM out, open up the case and check out the capacitors and the circuit board under them. If you see brown/yellow blotches and fried copper traces, the caps have leaked and the ECM needs to be repaired or replaced.

New ECMs are usually priced insanely high. A refurb is fine as long as it's the same exact ECM code, both the part number and the 4-digit letter/number code. A used, non-refurb is only worth it if it's in good shape and you either need a spare to use or will have it refurbed, in the rare cases that off-the-shelf refurbs of that particular ECM are not in stock or easily available.

You will probably pay hundreds of dollars at an auto repair shop to have it replaced just because they will make it seem like a high-tech complicated issue to repair. You would be much better off paying the $100-150 online for one (Rockauto.com is a good source, as is Advance Auto Parts with their online coupons) and installing it yourself, or even having an auto-knowledgeable friend show you how. It's very simple, just disconnecting the battery, pulling the kick panel, loosening a few bolts, unplugging the ECM without damaging anything, plugging the new one in, and bolting everything back up. Done.

 

[arco777]

Personally I would look at the MAF itself first. Junkyard part swap might be worthwhile.

 

[sodacan7]

Thanks for your help Anime! I am going to pull out the ecm tonight, check the number, and hopefully get a replacement ordered asap.

And thanks Arco, we did try that initially hoping it would be a simple fix. The new MAF sensor worked for 2 days then the same problems came right back.