SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

[Steve Van Gent]

My son just got his CA smog cert motor swap approved yesterday from referee on his 90 GMC Jimmy. I am writing this up as still fairly fresh in my mind and don’t want to lose knowledge. We were also told his rig is first smog legal GM 90s truck engine swap to LS in Northern California. ALL BELOW IS GOOD FOR TRUCKS, SUVs.

This was almost year long process (although could have been done in month if really serious) and surprising amount of money involved. The result is he now has 2001 5.3L Tahoe motor in his Blazer he can play with. Also, better fuel mileage (16-20MPG vs 8-10MPG) and more stock HP. Once in, lots of fun things can be done with respect to tunes and add on’s (not CA legal, but a person could do between smog visits).

Choosing donor vehicle was not arbitrary; If you choose too modern, gets harder. If you choose too old, no point. He decided to shoot for 2000-2004 series motors as they represent decent version of LS motor and straight forward for smog reasons. He landed on a 2001 49 state Tahoe with 5.3L and 4L60E trans. The motor had 862 heads, make sure to look if you choose 5.3L. In retrospect, he thinks the sweet spot swap is 2002 Tahoe.

CA RULES:

Must be newer vehicle than your current one.

Must be same CLASS of vehicle (you cannot put car motor in truck or vice versa). GVWR is considered, motor must be designed to push similar vehicle (originally they said must be LARGER MOTOR, but turned out not to be true).

Any item associated with smog control MUST be from donor vehicle (trick is know what they truly are!).

IMPORTANT POINT!
You must know what version your squarebody is before you buy donor!!! California dealers, in his year, sold BOTH CA only versions and FEDERAL emissions versions of Square body. The donor vehicle MUST MATCH!!!! If you are forced into CA version of squarebody, the CA version of Tahoe had air injection that must be moved over. My son had federal Blazer/Jimmy, so he found federal (49 state) version of Tahoe in Nevada. Vehicles we considered were Tahoe, Denali, Suburban, Yukon.

To keep your life simple, GET AS A SET FROM DONOR CAR; ENGINE, ECU, TRANS, BODY CONTROL MODULE (YOU WILL NEED), AIR INJECTION (for CA version), CROSS OVER PIPE WITH O2 SENSORS MOUNTED IN CORRECT PLACES before and after each catalytic converter x2 (you will need different cats), ALL EVAP ITEMS (charcoal canister, OEM tank that will not be used, pressure sensor, purge valve), engine and transmission wiring harness all the way back to gas tank, no exceptions. ECU serial number drives everything else requirement wise, get all parts or you will play scavenger hunt hell!
All systems dealing any form with smog must be intact. In my sons case, the Tahoe had VATS system that cuts off fuel as part of theft deterrent. THIS MUST BE INTACT!. That does not mean column must be there, but the body control module will need to exist. This should come from donor car. Be advised, it will need to be hacked to satisfy all inputs including VATS, as it will throw check engine light and you will fail! My son stuffed unit under dash and installed VATS resistor and bypassed other necessary items to prevent error code. 1-wire bus must be connected back to ECU.

NEEDED ITEMS;

TIME! See my note about passing current smog before starting swap.
RESEARCH! COMMITMENT! This is far more work than typical engine swap. Make sure you know your rig and rig you are getting parts from. Take your time!

AC DELCO EP381 FUEL PUMP
VCX NANO TECH 2 SOFTWARE KIT
DIRTY DINGO AC BRACKET (allows use of R4 90s compressor), DIRTY DINGO MOTOR MOUNT KIT
4L60E TRANS from donor truck.
SPECTRE BRAND COLD AIR INTAKE CARB APPROVED
CARB APPROVED headers (will need as stock manifolds will NOT fit between frame rails).
Adaptor to connect your 4l60E to your transfer case (he had NP241C TRNSFR CASE).
New CARB approved CATS, Small enough to fit application. Lots of options, look at your actual requirements.
Fuel line converter connectors to mount old tank lines to new fuel lines.

Save yourself headache, buy new aluminum radiator! Will need extra cooling anyway!

KEEP ALL CARB APPROVED PARTS RECEIPTS AND PRINT OUT CARB APPROVED DOCUMENTS FOR EACH PART! HAVE ON HAND!
SERIAL NUMBER OF DONOR CAR!
GOOD AT WELDING EXHAUST PIPES. In the end, I hacked exhaust in just enough to drive to exhaust shop, then paid tech to piece new system together.

STEPS-

STEP 1: WAIT UNTIL YOU PASS AN ANNUAL SMOG TEST! You will want the time to ferry your rig around and time to work on nuisance issues.
STEP 2: PLAN, then buy.

NOTES:

YOU CANNOT HAVE CHK ENGINE LIGHT FOR ANY REASON!!
USE CA FUEL LINE FOR ALL FUEL RELATED ITEMS. Almost failed last run due to using vacuum line instead of fuel line for pressure sensor.

IMPORTANT NOTE ON EVAP TEST!!!! It seems that GM might have had issues with evap software in ECU for that generation; it is VERY common for evap to fail on that gen vehicle. Once can run test 10X times, get only 1 pass, and nothing be wrong. In the CA smog reference guide, evap test is not required for annual test, BUT MUST PASS FOR ENGINE SWAP!!!

ECU MUST BE FLASHED BY DEALER WITH LATEST VERSION FW, CHECKSUM MUST MATCH AND VERIFIED BY REFEREE. No cheating, it must be stock with no bypass. None.

You will need to know your engine wiring harness, wire by wire. You will need to know each pin on your ECU, function of each pin and how it connects. You will need to put power and ground on dozens of pins on your ECU.

O2 SENSORS IN EXHAUST; these must be mounted in similar location to OEM, and MUST be same distance from engine as OEM. 4 total, there are 2 on each side of engine, before and after each CAT.

The OEM crossover will not fit on your squarebody, too wide. Have exhaust shop put whole system together. Cost me $200 to have all done for me (not including parts I bought), not worth my time.

Cold Air intake: Rules say that intake must be for donor vehicle. OEM air box simply will not fit! He found SPectre CARB APPROVED version cold air intake, we found would not fit on passengers side. After anguishing about it for hours, we found we could mount it up-side down and fit on drivers side. Had to weld bracket to make it work. Referee examined this quite a bit and called supervisor, ruled to be OK. You may not modify ANYTHING AT ALL FROM ORIGINAL CONFIG.

Frame rail will need to be notched slightly to fit header in; right around EGR mounting point on passenger side.

Lots more detail, will post as time permits…

If you get into this and find yourself in trouble, you can email me. steve.vangent@att.net

[Steve Van Gent]

ALSO; The transmission MUST be controlled by ECU to pass smog-I.E. must be from donor and be engine/trans as a pair.

[AJC]

Originally Posted by Steve Van Gent

ALSO; The transmission MUST be controlled by ECU to pass smog-I.E. must be from donor and be engine/trans as a pair.

What dose this mean for running a manual transmission? If the engine/trans donor has a manual trans it should be ok, or dose it have to be a computer controlled automatic? Also would that mean that only a 4.8 or 6.0 be used? As the 5.3 never came with a manual.

[kipps]

Originally Posted by AJC

What dose this mean for running a manual transmission? If the engine/trans donor has a manual trans it should be ok, or dose it have to be a computer controlled automatic? Also would that mean that only a 4.8 or 6.0 be used? As the 5.3 never came with a manual.

Presumably you're correct.

The original poster mentioned that the ECM coding had to be 100% stock in order to pass. Manual conversions require software tuning, otherwise they set the "check engine" light(another no-no) at a minimum.

[72c20customcamper]

WOW. Glad I live in NY (can't believe I just said that!) You can put anything you want in a pre 96 car. 95 and older are safety only inspections. But then again you don't see many 30 year old cars on the road except on a weekend in the summer. Buddy put a crate 454 in a 95 Camaro . Just a PCV valve with a carb .

[hatzie]

Originally Posted by kipps

Presumably you're correct.

The original poster mentioned that the ECM coding had to be 100% stock in order to pass. Manual conversions require software tuning, otherwise they set the "check engine" light(another no-no) at a minimum.

Look up a VIN in the donor engines' model year with a manual transmission. They were available on the GMT800 chassis trucks.
Then re-code the PCM with a J2534 passthrough ( I use a WiFi MDI clone ). You use that VIN with a single VIN license in the web applet at the AC Delco TDS web page. Program as a replacement PCM and it'll dutifully program your PCM with manual transmission parameters etc for that VIN.

[Bloodhound]

That is an impressive write up. I don't know how this hobby still exists in your state.

[Loco83]

Nice! do the E-rod crate engines fall under the same class of car or truck engines as a donor.

https://ww3.arb.ca.gov/msprog/afterm...o/d-126-30.pdf

[mgchevyparts]

Originally Posted by Bloodhound

That is an impressive write up. I don't know how this hobby still exists in your state.

We generally do not mess with 1976 and newer vehicles due to smog laws.

[kwmech]

This is why I will not put an Ls in my '91 suburban. I'll go 383 or 400. They have no idea what's under the valve covers. As long as it passes visual and emissions I'm golden

[Ryan Hubbard]

Originally Posted by kwmech

This is why I will not put an Ls in my '91 suburban. I'll go 383 or 400. They have no idea what's under the valve covers. As long as it passes visual and emissions I'm golden

I was going to put the Erod in my 90 3/4T Suburban but found out there is a weight limit for the vehicle and my suburban is 1000 lbs over the weight limit for the Erod LS3.

[EricU]

Originally Posted by Ryan Hubbard

I was going to put the Erod in my 90 3/4T Suburban but found out there is a weight limit for the vehicle and my suburban is 1000 lbs over the weight limit for the Erod LS3.

I ran into the same thing as I had talked myself into just paying the extra monies for an E-rod. I had justified the LSA/8-speed version as it would outlast me for a weekender hot rod in my 2wd 89 C30 (R30). Then I missed a call back from my local (North SF Bay) smog ref who did mention on the voice mail;
1) no car engines (good bye plentiful Camaro 6.2/6L80e)
2) no "E-rod" conversions.

Then I found out about the class 1 (<6.5k GVWR), 2a (6k-8.5k) & 2b (8.5k - 10k)

My truck happens to be a non-CA R30 (1-ton dually C30 for 89) So, now I'm trying to figure out what more modern (but as said above "not too modern") trucks came with either a 6.0 or 6.2 along with a six speed automatic that will meet the GVWR criteria for the class 2b (8.5k-10k lbs GVWR).

I have another call into my local smog ref and hope to pin down some more info.

Though it doesn't help to whine about it, I am still amazed that I can't swap a much cleaner burning more modern engine/tranny and pull out the TBI 454, but "oh well". Funny thing is that it is the GVWR that is going to cost me a bunch of money and time and the only thing that I will tow is my woman and a couple of German Shepherds!!

[Steve Van Gent]

Yes, E-rod is an option, not cheap ($10K -ish) and almost sample level complexity;

[demian5]

Originally Posted by Steve Van Gent

Yes, E-rod is an option, not cheap ($10K -ish) and almost sample level complexity;

How much did this cost you to get to this level?

What fuel tank is in the truck?

[Steve Van Gent]

Originally Posted by demian5

How much did this cost you to get to this level?

What fuel tank is in the truck?

Motor / power plant from donor Tahoe with all parts was $1500; All in was about $6000 including trans rebuild and all exhaust work, drive shaft, motor mounts, etc;

OEM fuel tank in truck. No change.

[68c10owner]

Originally Posted by Steve Van Gent

Motor / power plant from donor Tahoe with all parts was $1500; All in was about $6000 including trans rebuild and all exhaust work, drive shaft, motor mounts, etc;

OEM fuel tank in truck. No change.

Just wanted to clarify because Im planning a swap in my 79 C10, are you using the OEM blazer tank or the OEM tank from your donor? My 79 has saddle tanks that Id like to reuse but I`ve also been thinking of swapping to a 87-91 Blazer tank to keep it simple with 1 tank.

[layinrocker65]

This is why I’m so happy I have a 74

[mikentosh]

@stevevangent Which ref did you go to? I’m assuming one near Redding.

We are just starting a 5.3 swap from a clean 2003 Yukon into an ‘86 shortbox with California emissions. Trying to piece back together the 80s computer controlled carb setup looks to be a nightmare so swapping it is. On the ‘03+ trucks and SUVs it is DBW and California emissions models no longer have air injection.

Interesting to know about the VATS setup. We were unsure whether the ref would allow VATS to be disabled in the ECU, so was going to hack together something to keep it all intact anyway.

[Steve Van Gent]

Originally Posted by mikentosh

@stevevangent Which ref did you go to? I’m assuming one near Redding.

We are just starting a 5.3 swap from a clean 2003 Yukon into an ‘86 shortbox with California emissions. Trying to piece back together the 80s computer controlled carb setup looks to be a nightmare so swapping it is. On the ‘03+ trucks and SUVs it is DBW and California emissions models no longer have air injection.

Interesting to know about the VATS setup. We were unsure whether the ref would allow VATS to be disabled in the ECU, so was going to hack together something to keep it all intact anyway.

SOrry, been tied up at work- Butte Jr college is nearest ref;

[Steve Van Gent]

Originally Posted by mikentosh

@stevevangent Which ref did you go to? I’m assuming one near Redding.

We are just starting a 5.3 swap from a clean 2003 Yukon into an ‘86 shortbox with California emissions. Trying to piece back together the 80s computer controlled carb setup looks to be a nightmare so swapping it is. On the ‘03+ trucks and SUVs it is DBW and California emissions models no longer have air injection.

Interesting to know about the VATS setup. We were unsure whether the ref would allow VATS to be disabled in the ECU, so was going to hack together something to keep it all intact anyway.

The firmware and tuning in ECU MUST be exactly as OEM rig- you may NOT turn off VATS with tuner! They will check! This adds complications; for example, the resistance value of the fuel level sender is easy to change in ECM with tuner, but NOT ALLOWED! the ECM checksum must be from written document from OEM. Any tuning changes will change checksum.

ALso, the VATS system resistor value in ignition key is read VIA the body control module and sent to the ECM over GMs proprietary com bus.

Never fear however, if the body control module came from donor car, actually just becomes wiring exercise. Once you find the ignition key resistor value, just hard-wire a fixed value resistor to body control module.

[Tom]

Excellent info for anyone choosing to be suppressed so heavily by a state.

[Crcrft78]

Do you think what you spent on doing the swap your way versus purchasing an E-Rod engine kit is a better route money wise?

[Steve Van Gent]

Originally Posted by Crcrft78

Do you think what you spent on doing the swap your way versus purchasing an E-Rod engine kit is a better route money wise?

Probably with trans rebuild, all exhaust work, HP tuner (needed to diag issues), all-in probably about $3500 plus many hours. Some of this was due to mounting issues like width of OEM engine vs original space, engine mounts, A/C mounting issues, purchase of 12 different serpentine belts, etc.

However, I am sure the kit is not completely pain free or labor free;

[SunSoaked]

Originally Posted by Tom

Excellent info for anyone choosing to be suppressed so heavily by a state.

The Almighty one strikes again!

[NorCalAnthony]

Thanks for posting all that info, I'm sure it'll help someone thinking about doing the same thing in the future. How did you guys handle the fuel tank pressure sensor? I had an '89 Blazer and a wrecked '01 Yukon that I was planning on swapping drivetrains but that was one of the hang ups with the emissions part of the swap that turned me off that idea. I wound up selling the '89 Blazer and bought a '84 diesel Blazer (smog exempt) just to avoid all of those headaches lol.