E67 from crate engine, what is different

[Tapi]

This may have been discussed many times before but my search wasn't resulting a clear answer:

Is GMPP crate engine E67 ecm different from cars from production line?

I have been struggling with 2 separate E67 controls and both seem to have some weird things especially in idle air control. It seems no matter what I put into airflow final minimum or idle speed, it idles the same. Today I studied one LS3 in C2 Corvette in which the cam has been replaced lately and it was idling with almost zero ignition advance to keep it at desired idle while the t/b was 20% open. I was aiming to get the t/b opening smaller and ignition advance up but no matter what I did, the blade was 20% and the ignition advance so low that when you start driving, the advance jumps ~30 degrees up and causes jerky movements. I put very small advance in main table on idle area and a bit on top of that to get the car moving more softly but I think this is the wrong way to tackle the problem.

[kevin87turbot]

The 480 hp version and the 520 hp version idle tables can't be accessed by HP Tuners in their stock GMPP format.
The 430 hp version can be modified with no issues.

[Tapi]

Thanks for the prompt reply!

When using HPtuners, would the correct way to continue be like write entire with a tune that is from a car that is originally equipped with E67? And start from scratch?

[kevin87turbot]

Thanks for the prompt reply!

When using HPtuners, would the correct way to continue be like write entire with a tune that is from a car that is originally equipped with E67? And start from scratch?

You can just go to the tune repository and download a GMPP 430hp calibration file. Do a "Write Entire" and you'll be able to control the idle as needed.

[B52bombardier1]

Make a copy of your original tune first and save it!!! This will be your insurance policy against something bad happening later.

Rick

[TheMechanic]

I have had some issues trying to "fix" a couple Connect and Cruise crate motors. Seems as though they are kind of tuner locked. You can try and mess with them but is seems like nothing changes on many parameters.

[blindsquirrel]

You can just go to the tune repository and download a GMPP 430hp calibration file. Do a "Write Entire" and you'll be able to control the idle as needed.

Does that really work? I haven't done it myself but previous threads here people have tried switching to production OSes and the locked areas of the tune still didn't respond. Based on that I was assuming it had to be board-level hardware limitations in the 'special' GMPP ECM.

[kevin87turbot]

Does that really work? I haven't done it myself but previous threads here people have tried switching to production OSes and the locked areas of the tune still didn't respond. Based on that I was assuming it had to be board-level hardware limitations in the 'special' GMPP ECM.

Yep. There are a few threads about it. I had a tuning buddy tell me a few years ago.

https://forum.hptuners.com/showthrea...-ls3-high-idle

[Tapi]

I can't find the mentioned GMPP 430 file from repository. There are 6 files with GMPP search term and none of those state that 430.

[Tapi]

Still haven't found the GMPP 430 file with which I could get the idle sorted. Could someone be so kind to share it?

[blindsquirrel]

There is one in there for a 430hp E-Rod. It's E67 but I dunno if it's the right one or not. Search for 'RX-7'.

[pannetron]

My crate E67 was for a 430 HP version. Here's the original OS that came with it: OriginalVCM.hpt