PCM swap help!

[BraedyShaw]

Sorry I don’t know if is the right area for this or if this has been addressed before, didn’t see anything.

So I received my new unlocked PCM/I3 tuner from Hemifever this morning. I drove the truck this morning (so I know is fine). I get home, disconnect the battery, swap the pcm, reconnect the battery, go to start and nothing. The light and radio are on, but nothing from the engine, doesn’t show any info for engine temps, etc, no turn over, can’t hear the fuel pump. So I figure maybe it’s just this new pcm, swap the stock one back in and exact same thing. The connections are pressed in all the way and locked in. I don’t see any broken wires, all three bolts holding pcm in are tight(if that matters).

Has anyone had this problem? I’m going to pull out the intake box so I can more room in there and really make sure every wire is fine, but it’s 109° out so I came in to take a break. Thanks for any help,
Once again not sure where exactly to post this.

 

[Tach_tech]

Triple check the connectors, make sure they’re down all the way and both slide tabs for each connector are seated as well. Maybe take a picture if you can.

 

[Ramm5.7]

If both new AND old are doing same same its gotta be the connections?

 

[MADDOG]

Yup....gotta be the connections.

Did you disconnect the battery before you pulled the stock PCM?

 

[BraedyShaw]

Yea I disconnected the battery. I’ll go check the connections again

 

[BraedyShaw]

Okay good ish news, messed with the connections and got it started up(with the stock pcm). Going to try and get the unlocked one now

 

[BraedyShaw]

Update:
Install the new pcm and she starts up, throttle is calibarated. Only thing is she don’t sound the same, and I’m going a weird idle, almost bouncy. Any ideas?

Also it seems to be backfiring or something, I’ll try and post a vid.
I have muffler delete so it’s always a little raspy but this is different.

 

[Tach_tech]

With a new pcm it needs to relearn fuel trims,idle,fuel shut off etc. It’ll take a few days before it learns all that.

 

[BraedyShaw]

Okay that makes sense, because this thing sounds crazy right now. Also it’s telling me my battery voltage is low? Any idea? The battery should be fine, cranks it fine, driving for a few min now and it’s showing normal 13-14v

 

[Tach_tech]

Does it still have the battery message after driving around? Turning the key on with the PCM off will set a crap load of codes. Might not hurt to do a battery disconnect and capacitive discharge to clear them.

 

[BraedyShaw]

Here’s as clip of me excelerating, around 80% throttle.
I’ll try and do a discharge to see if that helps anything. Thanks

 

[FXCLM5]

holy crap I wouldnt be using 80% throttle if my truck sounded like that.

wow

 

[Tach_tech]

That doesn’t sound right at all. I’m assuming it didn’t sound like that before? Sounds like rod knock.

How’s it drive with the old PCM? I wonder if there is still aconnector issue. Can you post a picture of the connectors installed?

 

[BraedyShaw]

No before the swap it sounded perfectly healthy. I’ll post a pic of the connectors as soon as I get a chance, at work right now.
Previously with the old pcm it drove normal, no issues or anything at all. No weird sounds, no weird idle, no thing. I’m going to put it back on and see if it goes back to how it was

 

[U1arunit]

No before the swap it sounded perfectly healthy. I’ll post a pic of the connectors as soon as I get a chance, at work right now.
Previously with the old pcm it drove normal, no issues or anything at all. No weird sounds, no weird idle, no thing. I’m going to put it back on and see if it goes back to how it was

Good luck, keep us posted!

 

[RedSRT4Me]

Oh the sound!

 

[WadXpress]

Did you contact hemifever? Data log and send it to Him see if he can see something that needs to be corrected

 

[BraedyShaw]

Alright, here’s the update.

(With unlocked pcm)
Disconnected battery, discharged then started up. All the same problems.

Install one of the stock diablo tunes, still the exact same thing.

Checked the codes, it showed ignition coil codes, misfire codes, intake and manifold codes. Which kinda makes sense due compared to the sound and vibrations. Installed the stock pcm and everything seems to be normal, thank god. Went for a drive and it’s All good.
Thank god, was getting worried haha.

And I did contact Hemifever, they just said it was normal for a new pcm to be different as it learns but he hadnt heard the sound clip yet so I don’t think he understood how bad it was.

 

[wink]

That's definitely not an adaptives learning issue. My bet is a bad PCM. It happens. I had to have the first PCM I got from Diablosport replaced. However I had to go to their parent company PowerTeq to get it. DS was useless as far as support. I would've suggested reloading a tune. You did that, and the problem didn't go away. And the OEM PCM is fine. That would suggest a bad PCM. Sure wouldn't run the engine like that.

Good luck!

wink

 

[Riccochet]

sounds like a 4 stroke dirt bike.

Nope. Would not drive.