Lil'John

Did two searches here: "stick auto" and "manual auto". Neither gave me any real information. Most of the results were basically "yes, you can convert an auto PCM to manual PCM" but with no real details.

Here is the details and the problem:

• 2004 LQ4 from a Silverado 2500HD that came stock with 4l80e transmission
• I did a conversion using the engine but an NV4500 manual transmission(5 speed)
• I reused the stock harness with wires pulled out.
• The car will idle fine but any throttle and it acts like it is starved
• NO codes are being thrown beyond a no MIL code
• I've verified that the TB moves while running and not (Drive by wire setup)
• I have a Jet DTS tuner in my hands (yeah, I know a big dung heap with severe lack of support... hind site is 20/20 )

I've been told by numerous people that the LQ4 was available with a manual transmission and I should just use that tune. But when I ask them to put their money where their mouth is, they are unable to produce a vin for such a truck NOR a tune file

So, with all the above said, here are the questions:
1) Will a missing automatic cause the off idle throttle issue?
2) Anyone have a stock 2004 LQ4 tune that came with a stick?
3) Can anyone give me a general guide on what needs to be changed to make the PCM a manual and not an auto? Under the Transmission Parameters "tab/table", I have changed the Trans. Type to manual(2). But it made no difference.

Any and all help beyond "throw the DTS i the trash and buy <fill in tuner>" or "just ship it off" would be GREATLY appreciated.

JDMC5

iTrader: (3)

Yes, they did make a manual powered LQ4 and no, I don't have a manual tune for you. But, I can tell you......

Your idle tables will be a little different with a manual, I'm not sure its enough to make a difference though, I think your problem might not be tune related, no way to know without looking at a scan though.

Idle tables are different along with timing and VE as they relate to idle, gear ratios, deceleration tables, etc.

Besides changing the gear ratios, deleting any automatic related codes and tweaking your idle tables, it shouldn't be too bad.

Obviously you need to get a stock tune and go from there.

Lil'John

lol. That is exactly what I'm talking about. I can't find a tune for a manual powered LQ4 nor can anyone provide me with a Vin which is what GM dealer wants to flash the computer.

I've got the stock tune for the 6.0L with auto and I've got a stock tune for 4.8L with manual.

I'm leary of touching ANY fuel, spark, etc related tables because I'm not sure how those tables are effected by a manual tranny if at all. I've found some of the parameters and diag codes that make sense to change.

Lil'John

Problem somewhat solved. The issue is indeed a tune issue. Using the 4.8L manual tune that poconojoe provided, I was able to identify some parameter differences. I changed those values in my tune and flashed the PCM.

Fired up and throttle response is NICE.

So, there is something different in an auto tune that will cause the LQ4 to idle fine but not run off idle. I'm not sure which of the following groups I made changes in really helped the issue:
Fuel Parameters
System Parameters
Diagnostic Parameters
Idle Control Parameters

It should work until I can have the time and money for a professional "mpg" tune done.

With the above said, if anyone can point me to a stock LQ4 tune with a manual trany, it would be GREATLY appreciated.

Bo185

THANK ******* GOD!!!!!

I knew that was it! haha!!!!


Heres a VIN with a LQ4 NV4500 1GCHK29U24E103332
Heres the truck http://cgi.ebay.com/ebaymotors/04-CH...item27ac361f08


I am think its the system parameters. And the fuel maps are different for the 4.8l as well. It won't make full power.

Like I said before the PCM though the trans was toast so it defaulted to limp mode :idle only".

Have the dealer flash this tune with the above VIN.

JDMC5

iTrader: (3)

nice one, good to hear

Lil'John

Bo, thanks for finding that.

I'm hoping someone has a stock tune available online for free. With the intention of getting a "professional" tune, it doesn't make sense to throw out $100+ only to have it tuned to something else

I'm trying to get a stock tune to get myself a baseline for performance.

PitchblackC3

iTrader: (3)

Contact the support for your tuning software and ask them about a segment swap.

poconojoe

iTrader: (43)

John I try to get the GM dealer to load that tune for me in my bench PCM, but I don't think I'll be able to get there before next week. It pays to give them free cases of beer