LS Manual Swap Challenges

LS swaps are FUN! Right? RIGHT?!

I've been doing a swap in a way some have told me I couldn't (or shouldn't) do. But because of the way that I am, I have been doing it this way anyway, and have had several successes.. and a struggle or two.

The easiest way to think about my swap is to think of it as a 2007 Sierra 2 wheel drive manual swap. Simple. Piece of cake. E38 PCM. Pull out the slush box and the TCM, install a box of rocks. Row your way to happiness.

Almost.

I set [ECM] 439 to "Manual", it it worked great... except that I get no speedo or odo increments.

I routed the speed sensor from the trans to J1:71 & 72. HPt sees the speed signal, and it is accurate - but the dash does not update. Every other gauge works; temp, fuel, oil P, and the tach - just no speed.

I played around a bit with [ECM] 822 (Speed Output Type), [ECM] 821 (128K PPM Wheel Speed Output) and [ECM] 820 (4K PPM Vehicle Speed Output), but they brought no joy.

Reluctantly I decided to 'hot wire' in the old T42 through the OBD port, and pluged the speed sensor back into the TCM, and set [ECM] 439 back to "Automatic" - and I got speed back on the dash! So I happily wired it back in (minus the plug to the trans itself)... Buuuut now it drives like it's an automatic with manual transmission installed. The revs hang high around 2k RPM so long as I'm rolling (clutch in). As soon as I stop they drop back down where they belong. There is also some part throttle/idle bucking at low speed.

I am a far better electrician / mechanic than I am a tuner, and I'm not sure what can be done (if anything) to get the PCM to play nice - I'd really love some suggestions for that. I have tried taking some of the airflow final minimum and some of the idle spark advance away, but that had no perceptible effect to my green tuning eye.

I can't be the first guy to have ever tried this combination, and I hate the idea that I'd have to go Holley or standalone gauges. This is hotrodding - putting stuff where it doesn't belong (manual / LS swaps) and making things do things they weren't intended to do (HPt), Am I right? ;)

TIA!

Dan

The solution is simple.. Have someone who can SPS new computers set this up as something that came factory as a manual. Something compatible with your ECM PN. A vette would likely be the closest.

Quote:

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Originally Posted by Alvin

The solution is simple.. Have someone who can SPS new computers set this up as something that came factory as a manual. Something compatible with your ECM PN. A vette would likely be the closest.

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Fair enuf. I've kinda wanted to learn how to do this anyway; guess I have an excuse now. Know of any decent guides / tutorials on the process you'd recommend? I've seen a little, but know enough to know I don't have a clue yet.

There isn't anyone within 100 miles of me doing this stuff.. maybe I can be the guy who helps out.

Look into SPS reprogramming.

Just my own notes here.. I'll update as I make progress. I'm writing this down anyway, so might as well do it here just in case it helps someone else. MODS: If this doesn't belong here, please give me the opportunity to copy it out before you delete it :D

This may (very likely) contain errors. If you see me doing a dumb, call me out PLEASE. Follow my notes at your own risk. I have not yet completed this quest.

The Challenge: I am trying to run a manual swapped vehicle with in OS intended for an Automatic. In my case I can have an engine that performs like it should, or a speedo - but not both.

In at least this particular vintage of trucks, the speed information is transmitted from the TCM over the "High Speed GMLAN" CAN bus; the data is received by the PCM and BCM via that CAN network. The BCM converts the engine data to the GMLS (Low speed data) bus which feeds the cluster; the cluster does not have CAN nor a direct speedo input. Unfortunately, the instrument cluster doesn't get speed information if [ECM] 439 is set to MANUAL in the tune. VCM scanner still sees the speed, regardless of this setting, but evidently the E38 doesn't send it out to the cluster in the case it's set to manual. This OS wasn't intended to do this, so it doesn't. Side thought: There may be something in the EEPROM of the instrument cluster that affects it as well - and could cause this whole experiment to fail. Time will tell.

This would also apply to folks who have put an LS in some other vehicle that already had a manual (hypothetically let's say it was a 2005 GMC Canyon) and were of suspect enough intelligence to also swap in the instrument cluster and BCM. I assure you that if someone were to try that they'd have many other challenges to overcome too, and they really better like wiring and especially splicing wires. Don't ask me how I know, I am aware of the 5th amendment. What I can tell you is that a 2-oh-5 GMT355 has neither a High Speed GMLAN nor GMLS network (only Class II Serial) so its instrument cluster has no hope of talking to a GEN4 LS, at least not without the support of its original P12 PCM somehow (overlay harness).

Proposed Solution: Upgrade to an OS that was intended for a manual trans.

Current OS: 12614088, VIN 3GNEC12037G134210, 2007 Chev 1500

2006 / 2007 E38 OS compatibility:
12602922, 12605732, 12605898, 12607218, 12608677, 12609099, 12611833, 12612281, 12612291, 12612381, 12612739, 12613889, 12614088, 12614676, 12614682, 12616478, 12617569, 12628981, 12628988

Other model years with the E38 PCM exist, but it's likely that the hardware changes with time, so stick with the same model years.

TASK: Find a vehicle with the feature set you want in the repository, and confirm it has an OS within that list.

07 Vette 6.0 Manual: 12613889 (From repository)

OS Upgrade:

The full OS swap can't be done in HPt; you have to use GM's SPS application through the AC Delco Tools site.

Accessing SPS requires registering with AC Delco Tools, which is free.

SPS access is paid based on the # of vehicles you want to do. Once you buy a subscription, it's good for 2 years. If this takes longer than 2 years I may be in trouble. From the subscription page:

There are two limitations on the per-vehicle programming. The subscription expires based on whichever of the following occurs first:
1. 24 Months.
2. The number of programming equals the number of programmable modules in the vehicle.

Question: Does that mean you can program the OS only 1 time?

J2534 interface is required - seems to be many available - pick based on your preferred price point and trust level.

Warning on AC Delco site:

WARNING- USE OF COUNTERFEIT "CLONE" GM MDI DEVICES will result in your account being locked. Aftermarket J2534 devices are not impacted.

So don't do that. I'm betting that J2534 isn't impacted because it isn't a GM specific protocol.

What is J2534?
J2534 is an interface standard designed by SAE and mandated by the US EPA for vehicle ECU reprogramming. Its purpose is to create an API which would be adopted by all vehicle manufacturers, allowing the Independent Aftermarket (IAM) the ability to reprogram ECU?s without the need for a special dealer-only tool.

How thoughtful of them.

When you get into SPS, it appears you will select your OS based on the VEHICLE VIN, so grabbing that from the calibration downloaded from the repository is critical.

VIN: 1G1YY26U975113744

I think SPS will give you the most recent OS for the VIN you feed it, which I expect won't match the OS you found in the repository. That's fine, so long as you didn't mess up the VIN and you end up with an OS for a Lada Niva. Double / triple check.

Important When you reprogram an ECU with SPS, it's going to update the VIN and OS (maybe the serial number?) to the new one; this means you will lose your HPt license for that hardware, requiring you to buy more credits to continue tuning that PCM.

Feedback from HPt Support:

Licenses consist of three pieces of information. They tie in VIN, Serial Number and OS. If you change any of this information you will break the license and have to license the new combination of information you created. You will need to hold a license for the file you are writing as well as the vehicle you are writing to.

I think the the best approach is to locate another E38 to license after the OS swap - then I'll still have a spare, licensed E38 for an Auto application. I suspect it may be possible to program the original PCM back to the Silverado VIN, but unless the VIN, Serial and OS match, HPt will want a fresh pair of credits for it. You might not care about having to relicense, or you may have unlimited access to that platform; but I'm cheaper than a $3 haircut.

More to come...

Just a quick "In other news" update, here. I'm struggling with the tune, but have made other decent progress.

I have the speedo working again without having to change to a manual OS - I added the RepTOS input to J1:71 from the TCM and set the E38 to manual trans, et voila! Weird that it didn't work with the VSS sensor wired directly to J1:71 & 72; it must be a different signal type. If I get some time I might put the scope on it to see what gives.

This is what works / doesn't work as far as speed to the instrument cluster:

Trans set to manual, VSS input to J1: 71 & 72: Scanner sees the speed, but no speed on the instrument cluster
Trans set to Auto w/ TCM receiving VSS, no RepTOS output connected: Scanner sees speed, cluster shows speed, drives like garbage.
Trans set to Manual w/ TCM receiving VSS, no RepTOS output connected: Scanner doesn't see speed, cluster doesn't show speed
Trans set to Manual w/ TCM receiving VSS and RepTOS connected to J1:71: Scanner sees speed, cluster shows speed.

I am still keeping an eye open for another E38 to program with a Manual Vette OS - it would be cool if I can delete the TCM.

Cheers!