Hot Rod Forum banner
1 - 20 of 22 Posts

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #1 ·
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:

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

Jim
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
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...
 

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #5 ·
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
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
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.
 

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #7 ·
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
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
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)
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
You might have better luck at HP if you directly load your log file rather than a drop box link.
 

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #10 ·
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:


Thanks
 

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #14 ·
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.


Thanks
Jim
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
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?
 

·
Registered
1972 Chevy Nova, 650hp LT4, Heidts full frame with IFS and IRS.
Joined
·
96 Posts
Discussion Starter · #18 ·
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.
 

·
Rod...from a Chrysler?
Joined
·
5,984 Posts
Damn. I can't seem to download any tunes right now. I can open my own, but none from the website.
 
1 - 20 of 22 Posts
Top