GMT400 and L98 questions for the pros

**mr cribb** · 02-20-2022

I know how to put all the hard parts together, such as engines transmissions etc, but what I DON'T know is anything related to tuning. I have heard about burning chips and stuff like that, never done it. On my last GMT400, a 1994 model I had from 2015 to 2021, I had Ed Wright burn a chip for, but now he is retired.

The extent of my "tuning" which wasn't really tuning at all was using a handheld programmer in 2006, this was on my old 1997 GMT400.

I currently have a 1998 GMT400 truck that's currently a 4.3 v6 5 speed 4x4, I plan on swapping in a L31 350 in its place, and I have an 0411 pcm.

The 0411 I have is from a 2001 or 2002 5.3 silverado, can you reflash these to accept the L31 350 files, or do I need to find the unicorn 0411 350 pcm from the van? I understand enough that these are the files I need to successfully use the 0411 pcm on my truck.

My other project is a 1988 Iroc Camaro L98 355 TPI 5 speed, can these be redone to accept 0411 pcms, or is it worth it? Should I just stick to the tried and true chip burning?

The Camaro is still being put together, so its already apart, but I would like to drive it in the near future.

Some of this is copied from my introduction, but I have elaborated a little better to include more information. I'm not after sarcastic replies, we are all grown adults, either you can help me or you can't, if you can't scroll on.

**tayto** · 02-20-2022

LS pcm will require a crank and cam signal. eficonnection sells kits since you don't really seem like the DIY kind of person

**dave w** · 02-20-2022

My 1999 S10 was originally 4.3 / 5 speed with black box PCM. My 1999 S10 is now L31 / 5 speed with the '0411 PCM.

The process for my L31 was two fold, first I converted the 4.3 / 5 speed black box computer to the '0411 computer . . . then several months later converted to the L31 engine.

I have the ability to flash my own '0411 PCM. For the '0411 4.3 flash I modified a factory 2002 S10 4.3 / 5 speed flash. For the '0411 L31 I modified a factory 2002 Express Van L31 / Manual Transmission flash.

The 1988 IROC L98 355 TPI can be setup to use the '0411, but requires extensive harness modifications (likely a new custom harness would be le$$ work), L31 Cam Position Sensor, and L31 Crank Position Sensor.

Link to EFI Connection 4x SBC ('0411 Conversion) : https://www.eficonnection.com/home/c...ine/efi-4x-sbc

The EFI Connection system uses the L31 distributor for Cam Position Sensor.

dave w

**mr cribb** · 02-21-2022

Originally Posted by tayto

LS pcm will require a crank and cam signal. eficonnection sells kits since you don't really seem like the DIY kind of person

It's neat to see assumptions written accross the screen, for your sake you're very wrong. I don't farm anything out, the last thing I had a shop do was rebuild my old 94 k1500's rear axle. I do everything on my own if I possibly can.

Sadly you didn't even answer my question, no where close. You should already know that a 98 GMT400 has both crank and cam sensors, so I didn't include that in my post.

**mr cribb** · 02-21-2022

Originally Posted by dave w

My 1999 S10 was originally 4.3 / 5 speed with black box PCM. My 1999 S10 is now L31 / 5 speed with the '0411 PCM.

The process for my L31 was two fold, first I converted the 4.3 / 5 speed black box computer to the '0411 computer . . . then several months later converted to the L31 engine.

I have the ability to flash my own '0411 PCM. For the '0411 4.3 flash I modified a factory 2002 S10 4.3 / 5 speed flash. For the '0411 L31 I modified a factory 2002 Express Van L31 / Manual Transmission flash.

The 1988 IROC L98 355 TPI can be setup to use the '0411, but requires extensive harness modifications (likely a new custom harness would be le$$ work), L31 Cam Position Sensor, and L31 Crank Position Sensor.

Link to EFI Connection 4x SBC ('0411 Conversion) : https://www.eficonnection.com/home/c...ine/efi-4x-sbc

The EFI Connection system uses the L31 distributor for Cam Position Sensor.

dave w

So your 0411 was originally a 5.3 or something other than a 4.3 or 5.7 programming? That's been my biggest question of all with the truck.

The Camaro engine harness mods wouldn't bother me, it's 33 year old wiring, it probably needs updating.

**tayto** · 02-21-2022

https://www.google.com/search?q=gmt4...obile&ie=UTF-8

https://www.google.com/search?q=tpi+...obile&ie=UTF-8

**tayto** · 02-21-2022

https://www.google.com/search?q=411+...obile&ie=UTF-8

**1project2many** · 02-21-2022

It's neat to see assumptions written accross the screen, for your sake you're very wrong. I don't farm anything out, the last thing I had a shop do was rebuild my old 94 k1500's rear axle. I do everything on my own if I possibly can.

Sadly you didn't even answer my question, no where close. You should already know that a 98 GMT400 has both crank and cam sensors, so I didn't include that in my post.

If you've been on other forums where folks tend to bash each other, this place is generally not that way. Folks here are more likely to help than to insult. It's common here to see folks who are not confident in working with electronics and tuning. Often we will see phrases such as "I know how to put everything together, but I just don't have any experience with computers or tuning." I actually thought you were in a similar situation after reading the first post in this thread.

Personally I would stay with an OBDI PCM for the Iroc. Switching to a 1227730 speed density ecm will provide you with plenty of tunable parameters in a very capable controller. It would also allow you to run the latest custom software available for the ecm which enjoys development and support from the software author and others in the hobby. Chip burners are fairly easy to find and an emulator would allow you to tune in near real-time, greatly simplifying the drive / log / read / program / drive process used by most folks for OBDII tuning. Additionally, the 7730 fits into the same space as the Iroc's current ecm and the existing wire harness will require fewer changes to be compatible. You will need to change from MAF to MAP sensor, possibly replace or reconfigure an air conditioning switch, and make some additional relatively minor changes that can be found digging through old posts here and on thirdgen.

Switching to an 0411 is entirely possible and if you are up for the challenge you could see improved driveability. Remember the new pcm's main purpose in life is to provide better emissions control and fuel economy than older controllers, so you will be working to turn off and to tune around unnecessary controls. The 0411 conversion is most straightforward if you retrofit a cam and crank sensor as previously mentioned. I would consider moving the pcm under the hood since it is capable of living in that environment. It really seems like it's tough to get a clean installation trying to install this pcm in the factory location under the dash. There are threads on thirdgen with pictures that may help you decide whether relocation is necessary. As mentioned, any path to using the 0411 will require substantial harness modification. You will be faced with a number of decisions including but not limited to how to handle the ALDL connections, how to connect to and use VSS signals, whether or not to provide A/C operation signals to the pcm, and whether or not to integrate electric fan control into the pcm.

I would use the searches provided by tayto as a starting point for mapping a path to success if you choose to use the 0411.

**dave w** · 02-21-2022

Originally Posted by mr cribb

So your 0411 was originally a 5.3 or something other than a 4.3 or 5.7 programming? That's been my biggest question of all with the truck.

The Camaro engine harness mods wouldn't bother me, it's 33 year old wiring, it probably needs updating.

The original flash that was in the '0411 computer I'm now using in my S10 was from an 8.1 Liter. The '0411 was used in several different vehicles with several different engine / transmission combinations. I'm using very expensive "Commercial" hardware / software to flash my '0411.

dave w

**tayto** · 02-21-2022

HPtuners will tune 1998 C/K truck I believe (the "bad" years are 96/97). I don't see a reason going to the '411 unless you are doing something radical to the engine or want to run a 6 speed automatic. Like wise for the TPI, it is hacked and still being updated, as well as Dynamicefi's EBL. I also wouldn't worry about the "old" wiring, GM seem to use pretty good quality wire back then. Repair what needs to be (usually connectors) and move on.

**RockLakeYachtClub** · 03-05-2022

mr cribb - Are you looking to tune, or just get a 0411 pcm loaded with the Express van OS? The OS can be flashed with PCM Hammer (freeware, find it at pcmhacking dot net), using an OBD II cable (I got one from OBDX Pro, <$100), and a laptop with Win 10. You can tune with it as well, using TunerPro to modify the bin, and then PCM Hammer to flash it back to the PCM. Other freeware being developed at pcmhacking like Universal Patcher (allows segment swapping, as long as the OSes match). As for your Camaro, I agree with using a 0411 for that. I have an '87 350 TPI, and I plan to make it into a TPI/Vortec. See Thirdgen dot org and check out "TPI OBDII - Thoughts/Opinions".