98 GMC Twin Turbo with 12200411 PCM--- It's Alive

Performance modifications, tips & tricks

Moderators: flyingpolarbear, Dev, James B.

Aloicious
Posts: 2240
Joined: Sat Apr 14, 2007 6:00 am
Location: 96, C1500, LS31, T56, 24x CNP/LS2 coils, Whipple, 411, EFILive, MPFI, ZZ4, Trutrac, 4.88...etc

Post by Aloicious »

hah :lol:

L31Sleeper
Posts: 921
Joined: Mon Sep 03, 2007 7:19 pm
Location: Modesto, CA

Post by L31Sleeper »

Hey !!!! Justins ROCK !!!! Left handed Justins are even better !!!

kag96
Posts: 238
Joined: Fri Aug 24, 2007 8:36 am
Location: Northern Virginia

All hail the Leftorium

Post by kag96 »

Yes! Yes we rock.

ThunderTT
Posts: 2842
Joined: Sun Apr 03, 2005 10:27 pm
Location: 97 ECSB 2WD 98 CCLB 2WD 00 Escalade 4x4

Post by ThunderTT »

i am so NOT a Justin.....i do not rock.

Smoove
Posts: 7
Joined: Tue Apr 26, 2011 6:39 pm
Location: AZ

Post by Smoove »

Thank you to Lextech and everyone who helped in making this conversion possible for the rest of us to do. The swap took me about 8hrs if you include lunch and smoke breaks. My truck idles really rough right now, but it will get tuned on a Dyno in the morning. I also got the crank relearn error which again will get cleared.

redfury111
Posts: 64
Joined: Mon Feb 14, 2011 9:16 pm
Location: isanti, mn

Post by redfury111 »

Smoove wrote:Thank you to Lextech and everyone who helped in making this conversion possible for the rest of us to do. The swap took me about 8hrs if you include lunch and smoke breaks. My truck idles really rough right now, but it will get tuned on a Dyno in the morning. I also got the crank relearn error which again will get cleared.
I can't stress enough that you need to aquaint yourself with the spreadsheets and understand the basics...if you look at the way the old PCM is wired, certain functions/sensors are bundled into one block and you can get a big tangle of wires if you aren't paying attention to where they are all going. Mine could have been much cleaner if I had taken the time to route each wire not only into the new connector, but out of the OEM loom.

It's really quite simply "take this from here, put it there". The hardest part is getting the old wires out if you don't have the GM tool, but it's not difficult if you understand how they clip into the weatherpack harness. It's quite a nice bit of GM engineering..something I don't say all that often when working on this Astro of mine :P

The biggest snag I ran across was the wrong O2 sensors. Replace your O2 sensors with Express van sensors! They are not all alike, and you can just as easily swap the newer flat connector to the square connector from your old sensors. It made my van run rough, and I couldn't see any activity on my scanner. If your new PCM swap leaves you with ghost O2 sensors, it's VERY likely they need to be swapped out with the express van sensors. They are actually relatively cheap, so it's completely worth it.

mr_custom
Posts: 6
Joined: Wed May 11, 2011 2:17 pm
Location: California

questions about swap for anyone who can help

Post by mr_custom »

ok fist of all lextech fantastic spreadsheet everything was pefect and this swap is so easy
now i had the funky ground jumper that went from pins C3-18,C2-26,C4-12 so i had no ground for C2-1 on the new connector instead i used this jumper to gound my Ac and C2-1 to the chassis of the truck is this acceptable also whats involved with a crank relearn i dont have the ability to do this is that ok and the computer will not communicate with a snap solus scan tool any one know why and it not setting my egr,o2s,or cats in the computer any help would be greatly appreciated

Lextech
Posts: 964
Joined: Tue Mar 07, 2006 7:27 pm
Location: Oak Forest Illinois,U.S.A.

Post by Lextech »

I think that jumper deal was a bulletin that was performed at the dealer. I have never used a Snap On scanner. I use EFILive or the Tech2 for the CKP relearn. I don't know the answer to your last question.

Jeff

mr_custom
Posts: 6
Joined: Wed May 11, 2011 2:17 pm
Location: California

Post by mr_custom »

i have a handheld scanner from autozone and it reads emissions status and it is showing those as not set
is the crank relearn a must for the swap to be correct
is there any way that i can get ahould of a previous member stealth97 i saw that he was from california so he might be able to help me get through what needs to be done with cali emission testing from first hand experience
the snap on would not link and read any live data off of the pcm for some reason any ideas
i also had two unlisted black wires left over?

mr_custom
Posts: 6
Joined: Wed May 11, 2011 2:17 pm
Location: California

Post by mr_custom »

also got a p0101 code

Speeder
Posts: 10763
Joined: Fri Apr 30, 1999 9:12 pm
Location: 2021 Dodge Durango R/T 2WD, 2008 Colorado work beater, 2003 Dodge Dakota pro-touring project

Post by Speeder »

mr_custom wrote:also got a p0101 code
http://www.obd-codes.com/p0101

So far as Stealth97, he went on one too many rants and has the dubious honor of being the only member ever kicked out of here. I swear you say something about what crap Supras are and he was off and running. You would have had to speak to his mechanic on what is needed to pass anyway. There are others here from Cali that would be able to help you out, I'd suggest starting a new thread asking for help with passing emissions in CA.

Aloicious
Posts: 2240
Joined: Sat Apr 14, 2007 6:00 am
Location: 96, C1500, LS31, T56, 24x CNP/LS2 coils, Whipple, 411, EFILive, MPFI, ZZ4, Trutrac, 4.88...etc

Post by Aloicious »

mr_custom wrote:i have a handheld scanner from autozone and it reads emissions status and it is showing those as not set
is the crank relearn a must for the swap to be correct
you should get a crank relearn, a shop or someone with a TechII or EFILive can do it really easily. takes just a couple minutes

the emissions readiness tests require a few drive cycles before they will read that they are ready and pass. drive it around for a week or so and see if the emissions tests set themselves.

mr_custom
Posts: 6
Joined: Wed May 11, 2011 2:17 pm
Location: California

Post by mr_custom »

ok thank you i will give it a shot and come back with updates and maybe pics if i can figure that out?

redfury111
Posts: 64
Joined: Mon Feb 14, 2011 9:16 pm
Location: isanti, mn

Post by redfury111 »

I'd like to point out for anyone that is doing the swap in an Astro that doesn't already have the 411PCM ( 2002's have it, I'm sure the 2001's do to )...if you order a new battery box for a 2001-2 Astro, you'll be able to clip the new PCM in like it was factory, because they had them in them! I got lucky and had one show up at the local JY and I snagged it for pennies. A replacement GM box is going to run you 30-50 bucks new. I had the original 98 battery box and because the PCM is held upright, I had to hold it in place with a rubber strap, but the heat of the engine bay quickly wore that down, so getting the correct Battery box saves me a ton of potential headache.

I wonder if one could use the ASTRO base tune and change the parameters to the 5.7L Vortec and have a better base tune than that of an Express van. I currently scan my 98 Astro as a 2001 Express van with a 5.7L when I use the OTC Genesys scanner at our shop, otherwise stuff doesn't like to show up on all the tests.

96SWB
Posts: 2
Joined: Tue Jan 10, 2012 10:44 pm
Location: San Diego, CA

Hi all, new to the site!

Post by 96SWB »

First, I would like to introduce myself. Name here is Kevin and I have a mint condition 1996 short-wide C1500. Fully loaded including leather, cd, and 350. 30,000 original miles on the clock.

After taking about 4 hours of reading this thread, I am extremely interested in doing the 411 swap. I have always been interested in doing a cam, headers, and possibly marine intake or aftermarket intake. I never knew there was a way to get around our PCM until I stumbled across this thread somehow.

Does anybody know if the diagrams, pcm's, or connectors are still available anywhere? If so, does anybody still have ability to load a van basefile? I know that forum member Stealth was handling those requests but I see he hasn't been around for a couple years. I sincerely apprieciate the ingenuity of the people that pioneered this swap and I wish I could have seen this long ago. My truck is mint, and completely unmolested after 15 years with only 30k miles! I think it deserves some 411 love.

Kevin V

stroker97k1500
Posts: 2702
Joined: Thu Apr 12, 2007 6:13 pm
Location: Macon Ga., 94Toyota truck with LSX stuff

Post by stroker97k1500 »

I do believe "Lextech" the pioneer and original poster of this thread is the man who can hook you up with the ECM , tuning(as in loading an ECM with a baseline van tune), wiring diagram and possibly connectors too.
PM him and see where that takes you.

redfury111
Posts: 64
Joined: Mon Feb 14, 2011 9:16 pm
Location: isanti, mn

Post by redfury111 »

Yup, Lextech is the man. He helped me out tremendously with my van, as did others when I did the swap. He's a great guy to deal with. All I ask from anyone that plans to do this is to not screw Lextech over in any way, shape, or form. I'd hate to see the community at large lose such a large asset...he's done this plenty of times and knows exactly what he's dealing with in regards to these swaps. I can't speak highly enough of him. He is THE MAN to get you started on your 411 swap.

Steve 68
Posts: 1
Joined: Sun Jan 29, 2012 7:37 pm
Location: Boise,Id

Post by Steve 68 »

I did my 0411 swap and I have two wires I dont know what to do with on my 98 454. The connector C3 13 and C1 18 go to the same C2 54 on the 0411. C3 19 and C4 12 go to the same C2 57.
I do not have dual tanks can I tie the grounds together and the tank sensors together?

redfury111
Posts: 64
Joined: Mon Feb 14, 2011 9:16 pm
Location: isanti, mn

Post by redfury111 »

Any wires that you don't end up needing can be taped off back into the harness. Putting legitimate ground wires into the PCM never hurts though.

Lextech
Posts: 964
Joined: Tue Mar 07, 2006 7:27 pm
Location: Oak Forest Illinois,U.S.A.

Post by Lextech »

Steve 68 wrote:I did my 0411 swap and I have two wires I dont know what to do with on my 98 454. The connector C3 13 and C1 18 go to the same C2 54 on the 0411. C3 19 and C4 12 go to the same C2 57.
I do not have dual tanks can I tie the grounds together and the tank sensors together?
Don't use C1-18--Just tape it back into the harness. Tie C3-19 and C4-12 together and pin them to 0411 C2-57. Some of the big block trucks have the extra wire in C1-18.

Jeff

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