CA legal LS swap

[swilson143]

There is SO MUCH misinformation out there on doing a CA legal swap! I've now done two. My first was a 3RZ swap in a Toyota. The second was a LQ4 swap into my V2500 Suburban. I thought I'd post some details of the swap while it is still fresh in my mind. This is by no means a replacement for the engine swap guidelines from the Bureau of Automotive Repair, but as you'll see when you look at them, they're clear as mud to the layperson. I hope this article will shed a little light on what is needed to do a CA legal engine swap.

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PART I: MY SWAP STORY

I purchased a 1991 V2500 Suburban. It came with a TBI 350, which back in 1991 had a whopping 185 HP. Transmission was a 4L80E. I was loving the old Squarebody, but the poor old truck couldn't get out of it's own way! The first week of owning it I was already dreaming about engine swaps.

I knew enough details about the CA engine swap requirements to know I needed to pick a donor vehicle that was somewhat similar to my vehicle. Knowing the LQ4 was found in 3/4 ton vehicles, I guessed it was going to be ok in my 3/4 ton Suburban. With what I know now about Emissions Category Certifications, I got lucky. I should have done some deeper digging on the requirements. I'll elaborate later in this article.

I decided the 6.0L LQ4 was what I wanted and when I found a fair price on one at a local wrecking yard, I took the plunge. I knew the owner of the yard, so I was able to take the donor truck home for a month and pull the engine myself. It was really handy having the donor just outside the garage. Anytime I needed a bolt, bracket, clip, etc., I could source one off the donor truck. The donor was a 2002 Chevy 2500HD 2wd. Tranny was a 4L80E, but the yard had already sold the tranny.

Just as I decided to pull the trigger on this engine swap, I got the weekly email that comes from this GM Squarebody forum. In the email was "1991 5.3L 2500 Burb" listed in the engine swap forum by Kelvin. I couldn't believe my eyes! Talk about good timing! You can find the thread here https://www.gmsquarebody.com/threads/1991-5-3l-2500-burb.31558/

I read through the thread and found that he was nearly finishing his swap. I ended up contacting Kelvin and next thing I knew he was texting me his entire parts list, which he's since added to his engine swap thread. Please check it out, so much good info there. Saved me hours of research and tracking down part numbers.

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Using the same motor mount adapter plates as Kelvin, the engine bolted right in, requiring no changes to my transmission crossmember. Technically it required no frame mods at all... however it was really tight at the passenger side manifold, where it bulges out for the EGR pipe. I ground a little steel off the upper edge of the frame to be sure it wouldn't hit the frame when the motor torques over on it's mounts. The other spot the engine is really tight is behind the driver's side head. It did fit without firewall modifications or massaging.

Not knowing how many miles were on my existing 4L80E, I opted to have a local shop with a great reputation (Bob's Almaden Transmission, San Jose) build me a 4L80E. I'm really glad I did. My 91 tranny was one of the first years of the 4L80E and many improvements were made over the years. I also learned one (maybe more than one) of the shift solenoids must be changed out to work with the newer PCM, so I didn't have to deal with that, since I had him build me the correct 4L80E for my 2002 motor.

And now... lets get to the specific CA stuff. CA requires that the motor be 100% functioning as it was from the factory, all the way down to secondary O2 sensors, EGR, EVAP, etc... this was the main reason I wanted the donor vehicle nearby while completing the swap. I wanted to know every little piece was available to me.

The EVAP system requires that the PCM know the pressure in the fuel tank. My 91 tank had no provision for that pressure sender. I ended up filling the tank with shielding gas and then welding a bung to the tank, to get the thickness required to hold the sender. Then I drilled through the bung and slid my sender into place. I read some guys have just put a T in their gas tank vent line and installed the sender there, since it'll be measuring the same pressure. I just kept envisioning getting a stickler of a referee, so I opted to put mine directly in the tank, as it was designed.

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[swilson143]

Beyond that, you'll need to install the rest of the EVAP system with your donor engine. This includes the purge valve (located on top of the intake manifold), vapor canister (large black plastic box located beside the gas tank) and vapor vent valve (located beside the vapor canister).

For my engine wiring harness, I was using a Painless wiring harness #60217. That harness doesn't include provisions for secondary O2 sensors or fuel tank pressure sender. You must also add Painless emissions control harness #60322, which adds in the wires and connectors for secondary O2s and fuel tank pressure sender.

If you're going to use an aftermarket harness, I highly recommend you have a stock harness available to you that you can cannibalize. I ended up adding several more wires, which requires the correct pin at the end of the wire, so that you can clip them into the large electrical connectors at the PCM. Having a factory harness I could cut-up let me have those pieces on hand, and even let me keep wiring correctly color coded to aid in trouble shooting.

The LT1Swap web site was a great resource for me. Especially this page that has the complete pin outs for both PCM connectors for GenIII LS truck motors. https://lt1swap.com/99-02_vortec_pcm.htm

The Painless harness will have 95% or more of the wiring done for you, but you may have to add to it. The most notable circuit I added was the fuel level sender. Painless should have made this part of the emissions control harness, but it's not. GM designed the PCM such that it will not run the EVAP or O2 sensors tests if the fuel tank level is over 85% or under 15%. You must wire your fuel level sender to the PCM so that it has this data and can run the tests. Without this your EVAP and O2 monitors will never set.

The 1991 GM fuel sender in my tank was a 0-90 ohm unit. The PCM was designed to work with a 40-250 ohm sender. One option is to wire in a 100 ohm resistor when you wire the old style sender to the PCM. That will make it a 100-190 ohm sender, which is within the 40-250 ohm range the PCM is looking for. The problem I ran into with this setup is that your fuel gauge will no longer work. The PCM is a 5V system and your gauge is a 12V system. Not even the good ol' diode trick will allow you to use one sender to satisfy both the PCM and fuel gauge.

My solution was to modify a 40-250 ohm sender and put it in the tank beside my existing sender. It's not the prettiest looking solution, but it's hidden inside my fuel tank, so I never have to look at it. It did require drilling a hole through the top of the assembly so the extra wire could exit the fuel tank. Of course, you'll have to seal the hole very well, since the EVAP system measures tank pressure. With two separate fuel level senders, both my fuel gauge and PCM are happy, and with no resistors.

A quick note on monitors... ALL monitors must be set to pass your referee inspection. I read several places that you an pass with one monitor not set. That is either outdated or just plain bad information.

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[swilson143]

PART II: CA BUREAU OF AUTOMOTIVE REPAIR GUIDELINES, REFEREES, AND THE PROCESS

My first swap went to the referee in about 2018. It was a 3 hour in person inspection. It was not a smooth experience and at the end of it I swore I'd never swap another vehicle that needed to go through the referee. I guess time heals all wounds, because I did it again. This time was after COVID-19. They made some significant changes to the process, which I think are fantastic!

Currently when you call to make your engine change-over inspection appointment they first schedule you for a phone appointment with the referee. Then once you pass that, you're approved to make the in-person inspection appointment. The phone appointment was great. I learned so much in that 20-30 minute appointment.

My prior experience at the referee's office was that you only get a couple precious minutes to talk with the referee and if he's not a personable guy, good luck getting useful information from him. The phone appointment was great because you actually get to have a discussion with the referee. I'm sure it didn't hurt that my referee was a pleasant guy to speak to and understood that part of his job was educating people about the process. I felt he was generous with his time and was very willing to help me understand the process.

After getting the details of my vehicle and the engine I had swapped into it (including VIN), he asked if I had already checked "On road engine certifications" to be sure my swap, on its face value, was even possible to get approved under the current engine changeover guidelines. My answer was that I took an engine from a 3/4 ton GM pickup and swapped it into a 3/4 ton GM Suburban.

He said that's not enough information to know if the swap is ok on its face value. He asked me the GVWR for the donor and swapped vehicles. My donor was 9200 lbs and my Suburban was 8600 lbs. He was alarmed at this. His initial guess was that my swap probably was not going to meet requirements since the GVWRs were considerably different.

He explained that "Emissions category certifications must match" between the donor and swapped vehicles. Examples of the categories he mentioned were, "LDT1, LDT2, LHD1, LHD2." What I understood was, this prevents you swapping engines from different categories of vehicles. For example, you can't take a 8.1L from a 1-ton pickup and put it into a 1/2 ton pickup. Same would go for a Corvette motor into a light or heavy duty truck.

You'll be able to find this information by doing an internet search for the EO (Executive Order) document for the engine family of your donor motor. My GM Emissions Label was missing from my donor vehicle, but thankfully I had already gone to a GM dealer and paid about $40 for a replacement label. From that label, I knew my donor engine family was 2GMXE0111917. An internet search for this number quickly turned up a document titled "Air Resources Board, Executive Order A-6-1053"

I asked for some assistance understanding the EO document for my donor motor. The referee was kind enough to open it on his computer and take a look through while I also viewed a copy on my computer. Inside that document was a list of all of the vehicles for which the engine had been certified for. It included vehicles from 2wd 1/2 ton pickups all the way to 4wd 1 ton pickups. It also included SUVs like the 3/4 ton Yukon XL. After seeing the wide range of vehicles the engine had been certified for, he was immediately sure that my swap was going to be acceptable.

He gave me his email address and a list of things I needed to send to him. They included a photo of my registration, photos of the installed engine, photos of the entire exhaust system including manifolds, catalytic converters, and O2 sensors, photo of OBDII readout showing all monitors have set, and an invoice from a GM dealer showing they had inspected my PCM, that it was the correct PCM for the engine, and what the Calibration ID number and Calibration Verification numbers were.

Once I provided all the above items, 1-2 days later I received a reply that I was approved to schedule my in-person inspection. Today was my in-person inspection. If it weren't for the technician's computer giving him fits, the appointment would have been finished in about an hour. With the technical problems and him having to put my vehicle through a 2nd smog check, it took about 2 hours. My patience was rewarded a sticker on my firewall from the CA Bureau of Automotive Repair which shows that a 2002 Chevy 6.0L is now the correct engine for my Suburban. Hallelujah!

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[swilson143]

PART III: CAN YOU CHANGE YOUR PCM?

In my research for my swap the most misinformation I read was about PCM changes. The most recent info I found on CA legal swaps was from someone who had gotten their LS swap approved within the last 2 years. They said that absolutely no changes could be made to the PCM and that to pass the referee they even had to wire the donor BCM (body control module) into their vehicle and figure out the resistance of the security key to get passed the VATS (Vehicle Anti Theft System) which is built into the PCM. I'm here to tell you, that's not accurate.

During my phone appointment with my referee he said things like "unmodified PCM" and "stock PCM" and "no changes to the PCM." Then at the end of my phone appointment said, well it sounds like you're about ready for your inspection... Email me the items I needs and if they check out, you'll be approved for your inspection appointment.

I was extremely honest with him and told him I had paid a shop to disable VATs in my PCM and also activate the electric fan controls, so it's no longer stock. I told him I'll first need to return it to stock, then locate a BCM and wire it in and yada yada yada. To my surprise, he suggested that I just go to the GM dealer visit first. I took his advice and did just that. The dealer found that my PCM was the correct one for the engine, found that it had the correct engine management programming and provided the codes needed by the referee.

However, before I could get to the referee for my in person inspection, warm weather hit. I found that the settings for my electric radiator fans were not ideal and the fans ran almost constantly. I had no real choice except to have that shop I previously had program the PCM, change it again with different cut off temps for the fans. While there I also had them enable tranny performance mode, which is what you get when you hit that TOW/HAUL button in the donor vehicle.

Fearing that these changes would somehow affect the engine programming and/or calibration and verification codes provided by the GM dealer on their invoice, I returned to the dealer and had them verify everything again. They found that nothing had changed. I was still running the correct engine management programming and the codes requested by the referee were the same as at their previous inspection.

I can only interpret the referee's statements about have an "unmodified or stock" PCM, to really mean no changes to the ECM (Engine Control Module, which is part of a PCM). Essentially, don't modify any of the engine management software.

In my experience, disabling VATS, enabling the electric radiator fan controller, and enabling tranny performance mode all had no effect on engine management. This makes sense, none of those things should be affecting emissions or engine management! The GM dealer found that I was running the correct programming and that was what the referee needed to see in my documentation.

CA swaps definitely have some extra hurdles to get through and require more effort to make sure the engine and components you choose will be acceptable. In the end, it was worth the effort and I'd probably even be willing to put myself through it again. Now I get to go enjoy my Squarebody Suburban with modern power, in the state with the most stringent automobile emissions.

 

[Dmack]

Nice write up. Makes for one more reason I'm glad I don't live there .

 

[TPISly-C10]

nice built! i love mine too!

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[ghopp24]

Planet California...what a PITA. Surprised they dont make you put a mask on the engine. Sorry you have to deal with all that BS just to put an engine in a truck. We do what we want out here...Good luck.

 

[Joe Brown]

Thanks for taking the time and care to write this up!

 

[Camar068]

PART III: CAN YOU CHANGE YOUR PCM?

While there I also had them enable tranny performance mode, which is what you get when you hit that TOW/HAUL button in the donor vehicle.

Did you use the BCM or did you just put a momentary switch on pin 71 to ground?

Also, was this install with/without the trans position sensor on the side of the transmission?

Thanks for the write up

 

[82sbshortbed]

I don't live in California because I like liberty and freedom.

 

[swilson143]

Good for you. I like that stuff too. Now do me a favor and don't post here unless you have something constructive to say that's related to this thread.

 

[swilson143]

Did you use the BCM or did you just put a momentary switch on pin 71 to ground?

Also, was this install with/without the trans position sensor on the side of the transmission?

Thanks for the write up

Just used a momentary switch.

For those looking to do this, Tow/haul needs to be turned on using HP tuners. If my memory serves me, it's actually called tranny performance mode in HP tuners.

Then you'll need to run a wire inside the cab from your PCM (pin Blue-71) to a momentary switch. The other side of the momentary switch just gets grounded.

After you've started the engine just press the momentary switch once to activate tow/haul. Press it again to deactivate it.

You'll get no visual feedback that tow/haul mode is activated. And each time you turn the ignition off Tow/haul will go back to the default, which is off.

You'll be able to feel it when you drive though. It causes the truck to hold gears till a higher RPM before shifting. Also helps it not to shift to a lower gear when you're climbing hills.

 

[Camar068]

Just used a momentary switch.

For those looking to do this, Tow/haul needs to be turned on using HP tuners. If my memory serves me, it's actually called tranny performance mode in HP tuners.

Then you'll need to run a wire inside the cab from your PCM (pin Blue-71) to a momentary switch. The other side of the momentary switch just gets grounded.

After you've started the engine just press the momentary switch once to activate tow/haul. Press it again to deactivate it.

You'll get no visual feedback that tow/haul mode is activated. And each time you turn the ignition off Tow/haul will go back to the default, which is off.

You'll be able to feel it when you drive though. It causes the truck to hold gears till a higher RPM before shifting. Also helps it not to shift to a lower gear when you're climbing hills.

Thanks, did you use the AT manual shift shaft position sensor? Reason I asked is I bypassed mine. Not sure if it makes a difference.

Thanks for your reply.

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[Craig 85]

@swilson143 just an idea I had after your post above. GM does make Tow/Haul switches for a few trucks in case someone wants a factory looking switch. I looked at a few of the pictures and they appear to be a 2-pin connector, but I don't know if it is a momentary type switch or on/off.

The last picture is a lighted Tow/haul button from Billet Automotive Buttons. It comes in back lit, Halo or Stainless halo. There are multiple colors and comes as a latching or momentary switch.

https://billetautomotivebuttons.com...billet-push-button-switch-towing#&gid=1&pid=1

GM 15029440 - Tow Haul Switch '99-'01 Chevy Blazer / GMC Jimmy

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GM 25732940 '03-'07 Express/Savana Van or
GM 15860532 '08-20 Express/Savana Van

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Billet Automotive Buttons - 22BBL

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[Camar068]

@swilson143 just an idea I had after your post above. GM does make Tow/Haul switches for a few trucks in case someone wants a factory looking switch. I looked at a few of the pictures and they appear to be a 2-pin connector, but I don't know if it is a momentary type switch or on/off

Good idea. They may have a self holding relay/connection in the switch that gives you an on/off display as well as a separate momentary switch all built into one. With out looking, probably 3-4 connections.