[jvgrago]

I am working with a tuner to get my LT4 Nova dialed in and we've run across something that we cannot explain nor do we know how to troubleshoot. For those of you who have HP Tuners, please load up this quick data log (see dropbox link) and have a look at the Map sensor readings. I swapped out the map sensor (outlet side) before taking this data log as the original one I had installed did the exact same thing. So I know it's not a map sensor issue.

Link to HP Tuners data log:

22-02-03 19-06-10.hpl

Shared with Dropbox

www.dropbox.com

This makes tuning difficult as the pressures are not staying constant.

Jim

 

[95 Truck]

Have checked out Gearhead EFI? them guys do a lot of tuning type questions.

 

[jvgrago]

Have checked out Gearhead EFI? them guys do a lot of tuning type questions.

I haven't but will check them out.

Thanks

 

[123pugsy]

More than the MAP issue. You have negative torque and HP.
In 1st gear selected, zero MPH. At the end you finally show 158 MPH at zero RPM's.

Do you have a VSS hooked up?

If you're working with a tuner, does he have all the parameters messed up?
I haven't used my program for a year and a half, so I'm rusty, but take another look at everything. Torque, MPH, HP, etc...

 

[jvgrago]

I wasn’t moving during this data log as it was just idle. Not sure why it would show the mph incorrectly but we’ll get to the bottom of this and I’ll post what we find.
Jim

 

[123pugsy]

If in idle, speedo was correct. However, I saw it showing it was in 1st gear, that's why I asked. Why it showed 158 MPH at the end is a mystery. Well, a lot of the parameters are a mystery.

Did you join HP Tuners forum? That's where I posted all my questions.

 

[jvgrago]

If in idle, speedo was correct. However, I saw it showing it was in 1st gear, that's why I asked. Why it showed 158 MPH at the end is a mystery. Well, a lot of the parameters are a mystery.

Did you join HP Tuners forum? That's where I posted all my questions.

Yeah this tune is completely screwed up. I am a member of HP Tuners and posted a message there several days ago but never got a response. I was considering downloading the stock tune from a 2017 Corvette and starting with that (the VIN shows 2017 Corvette). Not sure if there is a way to start fresh on this as many hands have been on it.

Jim

 

[123pugsy]

Once you load the new tune, it just writes over the old on. Save every tune before making changes. Name them all different names or date each one for the name. I got a million different files in my laptop now. If you can't install the whole tune at one go, you can install parts at a time by opening your tune, opening the new tune using "compare" and then you can change pieces of it slowly until it's all done. ( I think)

 

[123pugsy]

You might have better luck at HP if you directly load your log file rather than a drop box link.

 

[jvgrago]

and have a look at the Map sensor readings. I swapped out the map sensor (o

You might have better luck at HP if you directly load your log file rather than a drop box link.

Each change to the tune we save it as a new file name so we know what we've done.

I only put the tune on dropbox here because it would allow me to upload it as it said it was an invalid file extension. I loaded the tune and data log at HP Tuners:

LT4 Map sensor pressures erratic

I have a 1972 Chevy Nova and I put a GM performance connect and cruise LT4 and 8L90E tranny in it. I have never been able to get the tune or shifts right and even after bringing it to a local performance garage, it's still off. A friend is helping me with the tune as I am not very good with this...

forum.hptuners.com

Thanks

 

[123pugsy]

Give your thread there a bump.

 

[jvgrago]

Have checked out Gearhead EFI? them guys do a lot of tuning type questions.

I registered days ago and my account is still not active. Not sure what's going on there...

 

[123pugsy]

Can you post your tune and the Vette tune?
I'd like to compare them.

 

[jvgrago]

Can you post your tune and the Vette tune?
I'd like to compare them.

I just found out that the tune for the corvette is for the non supercharged engine, so that will not help me (back to square 1). If you want to look at my current tune I have saved it to my dropbox as the file type was not allowed here.

Jims 72 Nova -2.hpt

Shared with Dropbox

www.dropbox.com

Thanks
Jim

 

[123pugsy]

It got corrupted or something.
What car. year, liters?

 

[jvgrago]

It got corrupted or something.
What car. year, liters?

It's a GM Connect and Cruise LT4. 6.2L supercharged engine with 8L90E trans. The PCM Vin shows a 2017 Chevy Corvette Z06.

 

[123pugsy]

So, you got the engine, tranny and PCM as a package? What happened to the stock tune it came with? Did someone adjust it without saving the original?

 

[jvgrago]

So, you got the engine, tranny and PCM as a package? What happened to the stock tune it came with? Did someone adjust it without saving the original?

Yep, I can probably reach out to the engine reseller and see if they have a copy of the original connect and cruise tune.

 

[123pugsy]

Damn. I can't seem to download any tunes right now. I can open my own, but none from the website.

 

[jvgrago]

Try a different browser.