schekan
New Member
- Joined
- Apr 27, 2009
- Messages
- 7
- Reaction score
- 1
- Points
- 3
- Location
- Archbald PA
- Vehicle Year
- 94
- Make / Model
- ford
- Engine Size
- 4.0
- Transmission
- Manual
First, Admin feel free to move to proper area, I wasn't sure where to post this. But wanted to give back to the forum I have used so often. My story may help others. I have attached photos as well.
My story is , 4.0 94 Ranger XLT. Most reliable truck I have ever had all of a sudden stalled, then had a hard time starting. Acted like it starving for gas.
So i did the obvious and replaced the fuel filter and pump. No change.
I ran the diagnostics with my code reader. And it had MAF codes 157 and 158.
I hit the junk yard, found a MAF sensor. Did nothing to change the stalling issue, truck was not drivable. It would stall seconds after starting. So for the hell of it I unplugged the MAF and it ran. Not the best but it ran. And from the forums I found out that is because it runs in a closed loop when there is a complete failure of a major sensor.
So I bought a new MAF and still no change. It was really pointing to the PCM, I removed the PCM and did a visual. I am an IT professional and have been working on PC's for 20 years, I can spot a bad MB by looking at the Capacitors pretty quickly. Well I saw no swollen tops, or leaking tops. So I put it back in and checked every ground and even ran wires directly to the MAF sensor. And still nothing.
So I decided to have a closer look at the PCM. I pulled both covers, got a really bright LED work light and a magnifier. And was amazed at what I saw. There was one Cap that blew out the bottom, and a diode that was crusty green. Not good. So I ordered a reman on Rockauto and it solved all issues. It runs like a bear again.
I wanted to share photos of what a bad PCM can look like with a visual inspection. Hope this helps someone, even if it's not the same symptoms if you suspect the PCM and see something like this then it is definitely bad.
My story is , 4.0 94 Ranger XLT. Most reliable truck I have ever had all of a sudden stalled, then had a hard time starting. Acted like it starving for gas.
So i did the obvious and replaced the fuel filter and pump. No change.
I ran the diagnostics with my code reader. And it had MAF codes 157 and 158.
I hit the junk yard, found a MAF sensor. Did nothing to change the stalling issue, truck was not drivable. It would stall seconds after starting. So for the hell of it I unplugged the MAF and it ran. Not the best but it ran. And from the forums I found out that is because it runs in a closed loop when there is a complete failure of a major sensor.
So I bought a new MAF and still no change. It was really pointing to the PCM, I removed the PCM and did a visual. I am an IT professional and have been working on PC's for 20 years, I can spot a bad MB by looking at the Capacitors pretty quickly. Well I saw no swollen tops, or leaking tops. So I put it back in and checked every ground and even ran wires directly to the MAF sensor. And still nothing.
So I decided to have a closer look at the PCM. I pulled both covers, got a really bright LED work light and a magnifier. And was amazed at what I saw. There was one Cap that blew out the bottom, and a diode that was crusty green. Not good. So I ordered a reman on Rockauto and it solved all issues. It runs like a bear again.
I wanted to share photos of what a bad PCM can look like with a visual inspection. Hope this helps someone, even if it's not the same symptoms if you suspect the PCM and see something like this then it is definitely bad.
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