Recommend an ECM to replace my 8747?

[EagleMark]

Since this thread is sorta about the 8747 and you're a moderator, why is the 8747 thread at the top of the page a sticky? Just curious...

Me too? Who made that a sticky? I just don't see a reason for it?

[dave w]

Me too? Who made that a sticky? I just don't see a reason for it?

I don't think I made the post a sticky, maybe I unintentionally did. I don't think the sticky is an option in the Moderation Tools? Is there a short cut key / hot key that would make a post a sticky?

dave w

[JeepsAndGuns]

Just to confirm what has already been confirmed. I am currently (trying to) part out a 93 C3500 with a 454 and 5 speed. It too has the 8747 ecm with the bcc ARPY. It appears to have nmever been removed and I would believe its factory.

If you were to swap to a different pcm, say for instance a 7427, the hardest part is going to be finding a 454 memcal. Right now your ecm uses the knock filter seperate from the ecm.

[dpilot83]

Just to confirm what has already been confirmed. I am currently (trying to) part out a 93 C3500 with a 454 and 5 speed. It too has the 8747 ecm with the bcc ARPY. It appears to have nmever been removed and I would believe its factory.

If you were to swap to a different pcm, say for instance a 7427, the hardest part is going to be finding a 454 memcal. Right now your ecm uses the knock filter seperate from the ecm.

I wish you were closer, especially if your pickup was a crew cab with a tan interior. I need a rear seat (employee spilled gear oil all over it) the glove box hinge piece, and I'm sure about a zillion misc pieces that I am not thinking of right now.

I haven't heard of the knock sensor being separate from the ECM. Can you elaborate on that more? Thanks.

[JeepsAndGuns]

I wish you were closer, especially if your pickup was a crew cab with a tan interior. I need a rear seat (employee spilled gear oil all over it) the glove box hinge piece, and I'm sure about a zillion misc pieces that I am not thinking of right now.

I haven't heard of the knock sensor being separate from the ECM. Can you elaborate on that more? Thanks.

The knock sensor is always seperate from the ecm, its threaded into the block somewhere. Its the knock filter I was talking about. Its what recieves the signal from the knock sensor when there is knock, and then sends a signal to the ecm to retard timing. The knock sensor and knock filter are engine specific. On yours, its the squareish shaped flat box with about 4 wires going into it, should be mounted beside or under the map sensor on the right of the intake. (it was on the truck I am parting out anyways)
On the later pcm's (such as the 16197427) the knock filter is part of what is called a memcal. It has the main prom chip, the limp home chip, and the knock filter all in one removable unit in the pcm. The V6 and 5.7 memcals are easy to find, but a 7.4 memcal is not as easy. You could use a 5.7 memcal, and re tune the chip to work with the 7.4, but the knock filter will be incorrect and the knock retard will not function correctly. It could either pick up false knock and retard your timing, hurting performance, or not pick up knock that is there, and then your engine could get damaged.

[dpilot83]

The knock sensor is always seperate from the ecm, its threaded into the block somewhere. Its the knock filter I was talking about. Its what recieves the signal from the knock sensor when there is knock, and then sends a signal to the ecm to retard timing. The knock sensor and knock filter are engine specific. On yours, its the squareish shaped flat box with about 4 wires going into it, should be mounted beside or under the map sensor on the right of the intake. (it was on the truck I am parting out anyways)
On the later pcm's (such as the 16197427) the knock filter is part of what is called a memcal. It has the main prom chip, the limp home chip, and the knock filter all in one removable unit in the pcm. The V6 and 5.7 memcals are easy to find, but a 7.4 memcal is not as easy. You could use a 5.7 memcal, and re tune the chip to work with the 7.4, but the knock filter will be incorrect and the knock retard will not function correctly. It could either pick up false knock and retard your timing, hurting performance, or not pick up knock that is there, and then your engine could get damaged.

I see. Thanks for the explanation. I understood that the knock sensor was separate from the ECM (I meant to say knock filter in my previous post, sorry about that). I had just never heard of the knock filter before.