Thank you again Steve83 for your advice and patience with someone just learning about my truck. Because I have not done this before, and I do not want to add to my trouble, I am asking for a bit more advice. Hopefully this will help others who come along after me.

When I looked at it last weekend, I thought that the two retaining screws (top one circled in yellow in the picture) above and below the PCM were part of the PCM, and so, the module would not come out through the firewall. Upon closer inspection, I see that the screws are part of the retainer behind the firewall that is separate from the PCM and holds it in place. I also see two small clips that are part of the retainer (circled in blue in the picture).


One more question. I am pulling on the PCM, but it is difficult to get it to come. I assume a rubber seal on that retainer that is making it difficult to extract? Keep wiggling and it will come? I can see that once I get it out, I can just drop it through the fender liner.

Thanks.

 

No, it's just stuck from being old & rusty. Grab the gray plastic connector lip (by HAND) and yank/wiggle/pull it out. If it really won't move, it's rust-seized, and you may have to push it from inside. But it MUST go out forward only.

This is a truck I'm stripping right now - I took this pic yesterday.

 

Thanks again Steve83. ECM is out, it only gave me a bit of resistance after my last post, and just popped on out. I opened it up and had a neighbor, who is an electrical engineer, look at it with me. Looks like a diode and capacitor are damaged. It also looks like water got inside the unit. It was very rusted and corroded on one side, and two of the screws just disintegrated as I opened it up. In the end, a replacement is on the way from Flagship One.

Thanks for the advice.

 

Water & rust don't hurt the EEC. If the engineer can solder, he should have no trouble replacing the diode & capacitor(s), and that EEC will probably work a few more decades.

 

Because of this post about the PCM/ECM/EEC (whatever the preferred acronym), I read through Steve83’s website links. I’m not sure I have absorbed all the information about emission control systems yet, but I just wanted to thank Steve for his time and effort in sharing his knowledge. I ordered a Bosch OBD I/OBD II scanner tool to help me in improving my old truck! Thanks, Steve!

 

Yes, I agree with you, Steve has been integral in assisting me in my process as well. Thanks for your patience.

One thing that may help. I also bought an OBDI/II reader, not the Bosch, but another. It has been very helpful, BUT, when I took my truck to the trans shop, the mechanic their showed me how to get the codes through the dash. We picked up codes that way that we weren't getting through my OBD reader.

 

You should return it for refund as soon as it arrives. It can only cause problems.

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You should try to return that one, too.

 

Wanted to circle back around and close the loop on my experience.

I bought the truck over Labor Day weekend, with known transmission problems. My son and I pulled the trans, replaced the front pump bushings and seals, which addressed the leaky transmission issue. After that, we were still getting codes, and I took it to a trusted transmission shop, shout out to Jim at Leon's Transmission in La Mirada, California. Jim led me to replace the ECM, which solved the code issues.

When I pulled the trans, I also installed an aftermarket transmission temperature gauge. Unfortunately, the gauge was reading 30-45 degrees higher than actual fluid temp, which screwed with my brain for a while. The folks at Leon's kept the truck for a while, put it through its paces, did a couple of slow scans, and a bunch of accurate temperature readings. Today, I learned that I need to throw the after market gauge in the trash, and my truck has a clean bill of health.

Now it's on to tracking down an AC leak!

Thanks again for all the help from this forum!