PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

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Old Jan 27, 2007 | 11:40 AM
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Default Iat

MY IAT is always high (in the RED with HP scan)

How does this affect the tune? Does it lean it out?
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Old Jan 27, 2007 | 11:49 AM
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It adds fuel and pulls timing if its reading hotter. At around IAT = 45 degrees celcius it will pull 1-2 degrees at over 75KpA MAP and will add fuel at around 40 degrees celcius IAT.

This is all from my stock tune, the actual amounts may differ in your tune.

Last edited by brad8266; Jan 27, 2007 at 11:56 AM.
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Old Jan 31, 2007 | 12:54 PM
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Pull timing and add fuel, Hmm not so bad for my juice then
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Old Jan 31, 2007 | 01:58 PM
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Originally Posted by brad8266
It adds fuel and pulls timing if its reading hotter. At around IAT = 45 degrees celcius it will pull 1-2 degrees at over 75KpA MAP and will add fuel at around 40 degrees celcius IAT.

This is all from my stock tune, the actual amounts may differ in your tune.
The PE adder vs. IAT is only present in either 2k and up or 2k1 and up, but by default I have ALWAYS seen this table empty. I think this is why it is not available in LS1edit... I have looked at a LOT of this very very recently; I am working on making a nice neat IAT box with weatherpack connectors to use in conjunction with tuning for n2o...
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Old Jan 31, 2007 | 02:00 PM
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Originally Posted by brad8266
It adds fuel and pulls timing if its reading hotter. At around IAT = 45 degrees celcius it will pull 1-2 degrees at over 75KpA MAP and will add fuel at around 40 degrees celcius IAT.

This is all from my stock tune, the actual amounts may differ in your tune.
Which table are you looking at to see how it reacts?

Predator, you're getting an IAT of 45 Celcius (113 fahrenheit) right now? Is that when the car is at idle and not cruising around? Cause that's friggin hot!
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Old Jan 31, 2007 | 02:15 PM
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The "red" zone on gauges I think is entirely arbitrary,
and you can change it (somehow) I bet. Focus on the
value and not the display. Look at it relative to ambient
temps for an idea of whether you want to modify the
plumbing. My car holds 5 degrees above outside temp
with an SS hood and a hacked bottom side CAI.
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Old Jan 31, 2007 | 04:39 PM
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Originally Posted by Frost
The PE adder vs. IAT is only present in either 2k and up or 2k1 and up, but by default I have ALWAYS seen this table empty. I think this is why it is not available in LS1edit... I have looked at a LOT of this very very recently; I am working on making a nice neat IAT box with weatherpack connectors to use in conjunction with tuning for n2o...
My LS1 Edit has it and it has values in it. Version 1.53
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Old Feb 1, 2007 | 08:42 AM
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I don't have edit, but have been on the phone with a pro tuner and had him doing some digging to see what the PCM files looked like across platforms. FWIW all of his IAT vs. PE tables were full of zeros as well (his HPT tunes). I have about 2 dozen files from 01-02s on hand and they are all zeros. 6 of them are OEM images. I don't know what to tell you. When I download the 'stock' files off of Horist's old repository they have zero'd tables like the the OEM tunes I pulled from my buddies' cars... Is it possible someone filled yours out for the purpose of IAT tricking for N20?

Can anyone else with an 01/02 F-body tune look at the PE vs. IAT table and let me know if it is populated with anything other than zeros? Thanks.
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Old Feb 1, 2007 | 09:53 AM
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Originally Posted by Frost
I don't have edit, but have been on the phone with a pro tuner and had him doing some digging to see what the PCM files looked like across platforms. FWIW all of his IAT vs. PE tables were full of zeros as well (his HPT tunes). I have about 2 dozen files from 01-02s on hand and they are all zeros. 6 of them are OEM images. I don't know what to tell you. When I download the 'stock' files off of Horist's old repository they have zero'd tables like the the OEM tunes I pulled from my buddies' cars... Is it possible someone filled yours out for the purpose of IAT tricking for N20?

Can anyone else with an 01/02 F-body tune look at the PE vs. IAT table and let me know if it is populated with anything other than zeros? Thanks.
Not possible. I am the first person to tap the pcm and do any tuning to it. All my IAT tables are like they came from the factory. Dont know what to tell ya.
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Old Feb 1, 2007 | 12:11 PM
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Originally Posted by Xtnct00WS6
Which table are you looking at to see how it reacts?

Predator, you're getting an IAT of 45 Celcius (113 fahrenheit) right now? Is that when the car is at idle and not cruising around? Cause that's friggin hot!
Yeap at idle that is about right. I have a FIPK (K&N) and it reduces on highway or during juice burns, but while in the lanes this thing is hot. Outside temp in the 30*C
My IAT vs PE tables are zeroed as well.

I'm thinking of going with a SLP Ultra hood to get some fresh air on that sucker. I dunno if it affects my runs at all.
That is why I'm posting, to understand what is the effect on the performance.
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Old Feb 1, 2007 | 12:20 PM
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Care posting a screenshot brad?

Also frost keeps mentioning 01-02 fbodies, but in brads sig it lists an 00 fbody.
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Old Feb 1, 2007 | 12:22 PM
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yeah i have a 2000, Ill get some shots when i get home later.
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Old Feb 1, 2007 | 12:30 PM
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Thanks, im not arguing but a Screenshot should help clear up any questions.
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Old Feb 1, 2007 | 12:32 PM
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Originally Posted by brad8266
Not possible. I am the first person to tap the pcm and do any tuning to it. All my IAT tables are like they came from the factory. Dont know what to tell ya.
I'm not being argumentative, but I have been told that by at LEAST 5 or six people who have had PCMs that varied in quite a few areas from "stock". 3 or 4 of them even knew the party that owned it prior to them and said that they would not have done anything with it either, yet in at lease 2 of these last situations I found jacked aound timing and upward sloping PE tables....

Like I said, I have been digging in this area as it is related to a device that I am building 50 of in the first batch. TBH, in ALL of the tunes that I have looked at it was zero'd. 01-02... were the focal years for this though. The table MAY appear because of [the tuning] software in earlier years but everyone spoken to who was a authority and my logging in a 99 that oddly showed up in edit (forgot about that one) show that the table did nothing. I would like to confirm this in an 00 as well....


Originally Posted by PREDATOR-Z
........
My IAT vs PE tables are zeroed as well.
......
Thanks for checking, and sorry to jack your thread around.
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Old Feb 1, 2007 | 12:40 PM
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Originally Posted by Frost
I'm not being argumentative, but I have been told that by at LEAST 5 or six people who have had PCMs that varied in quite a few areas from "stock". 3 or 4 of them even knew the party that owned it prior to them and said that they would not have done anything with it either, yet in at lease 2 of these last situations I found jacked aound timing and upward sloping PE tables....

Like I said, I have been digging in this area as it is related to a device that I am building 50 of in the first batch. TBH, in ALL of the tunes that I have looked at it was zero'd. 01-02... were the focal years for this though. The table MAY appear because of [the tuning] software in earlier years but everyone spoken to who was a authority and my logging in a 99 that oddly showed up in edit (forgot about that one) show that the table did nothing. I would like to confirm this in an 00 as well....




Thanks for checking, and sorry to jack your thread around.
I know youre not being argumentive, the pcm was completely stock untouched before i tuned it. I have no idea why there are values in the tables. Maybe the 2000 PCM is different or something.
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Old Feb 1, 2007 | 12:42 PM
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I assume its just a table thats marked differently then either hptuners or efilive. Probably that simple which is why a screenshot should shed some light as hopefully we can then match it up to the table in hpt or efilive as to what exactly it is/does.
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Old Feb 1, 2007 | 12:47 PM
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Originally Posted by foff667
I assume its just a table thats marked differently then either hptuners or efilive. Probably that simple which is why a screenshot should shed some light as hopefully we can then match it up to the table in hpt or efilive as to what exactly it is/does.
if you could quick post a hpt table I can tell you if its the same by looking.
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Old Feb 1, 2007 | 12:55 PM
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00's don't have an afr iat adder/multiplyer table in hpt or efilive.
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Old Feb 1, 2007 | 12:58 PM
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Originally Posted by foff667
00's don't have an afr iat adder/multiplyer table in hpt or efilive.
Oh i see

It looks just like the PE RPM adder table except its IAT instead of RPM's
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Old Feb 1, 2007 | 01:04 PM
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If you are talking about this table, that is a coolant temp adder. This is version LS1edit 1.5.
Attached Thumbnails Iat-edittemp.jpg  
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