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Old 10-05-2019, 04:38 AM   #26
AJC
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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Originally Posted by Steve Van Gent View Post
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.
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Old 10-05-2019, 07:19 AM   #27
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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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.
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Old 10-07-2019, 01:30 PM   #28
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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 .
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Old 10-08-2019, 08:00 AM   #29
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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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.
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Old 10-08-2019, 07:40 PM   #30
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

the trans thing is crazy how the hell does that make a difference in emissions. fuel economy possibly if you kept say a th350 or 400 but emissions aren't going to change. I wonder how they deal with replacement engines on stock cars or say if this engine failed can you just swap in another 5.3? so many more things I wonder but im in ky so no point in me asking.
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Old 10-09-2019, 09:55 AM   #31
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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the trans thing is crazy how the hell does that make a difference in emissions. fuel economy possibly if you kept say a th350 or 400 but emissions aren't going to change. I wonder how they deal with replacement engines on stock cars or say if this engine failed can you just swap in another 5.3? so many more things I wonder but im in ky so no point in me asking.
The PCM expects to get feedback from sensors in the automatic transmission.
If you have an LS with the ECM TCM setup the ECM expects to get feedback from the TCM.
If the ECM or PCM doesn't get feedback from the TCM or transmission in response to its' requests it gets lost. Some ECM/PCM will drop you into limp mode and others just plain freak out.

Harvey Hardway would brute force it with a tuning package. You run the risk of missing something minor that'll freak out the ECM/PCM in some obscure manner if you try to be Harvey Hardway.

The easiest way to handle running a manual transmission or an older automatic transmission on a modern engine is to program the PCM or ECM using a manual transmission vehicle VIN and then fine tune the settings with your tuning package.

The fuel and spark tables from a 3/4 or 1-ton truck may be advantageous as well.
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1969 Dodge Polara 500 B383, A833 SOLD
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2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


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And please let us know if and how your repairs were successful.

Last edited by hatzie; 10-09-2019 at 10:56 AM.
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Old 10-10-2019, 05:17 PM   #32
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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Originally Posted by hatzie View Post
The PCM expects to get feedback from sensors in the automatic transmission.
If you have an LS with the ECM TCM setup the ECM expects to get feedback from the TCM.
If the ECM or PCM doesn't get feedback from the TCM or transmission in response to its' requests it gets lost. Some ECM/PCM will drop you into limp mode and others just plain freak out.

Harvey Hardway would brute force it with a tuning package. You run the risk of missing something minor that'll freak out the ECM/PCM in some obscure manner if you try to be Harvey Hardway.

The easiest way to handle running a manual transmission or an older automatic transmission on a modern engine is to program the PCM or ECM using a manual transmission vehicle VIN and then fine tune the settings with your tuning package.

The fuel and spark tables from a 3/4 or 1-ton truck may be advantageous as well.
I get that but it still doesn't make sense it has to be original same with the motor. so if he used a 4l80e which is totally doable he would fail or used a 700r4 which also is doable would fail. he cant retune it from the sounds either and delete or reprogram these things to work with one another. even if the engine is not creating any more emissions than it would stock. so on that token I wonder if he could use a 4l65e instead of the 4l60e. not the stock set up but nothing has to be changed in the ecm. or if ran a 10 model that has a a separate tcm unit and the ecm is same manual or auto. I think cali is overkill.
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Old 10-10-2019, 05:24 PM   #33
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

I don't live in cali will never live in cali so I don't want to clutter up his thread only curious
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Old 10-10-2019, 05:52 PM   #34
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

The peoples republic of California is run by the un-elected pencil pushers that have their little feifdoms for the benefit of the aforementioned pencil pushers.

What they do doesn't have to make sense. If you ask... it's because they say so.
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1969 Dodge Polara 500 B383, A833 SOLD
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1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
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Old 02-25-2020, 10:37 PM   #35
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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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.
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Old 02-26-2020, 09:47 AM   #36
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

You can use the 87-91 saddle tanks with the baffles and senders with fuel pumps as high volume low pressure lift pumps and a fuel pump on the frame rail to push the pressure up to LS specs. You'll need to upgrade the NL2 dual tank valve to the motorized Pollack valve. The NL2 wiring and switch will need to be updated to the 1987-91 TBI setup using the fuel system power wire from the LS ECM in place of the same from the TBI ECM. This allows you to keep your 40 gallon capacity with two tanks.
The LS ECM should cut fuel pump power as soon as the engine stops so... as long as you're switching the fuel pump power with the ECM you don't need the oil pressure switch as a safety system.

The 1987-91 Emissions and Driveability books in my manuals thread have detailed information on how the power feed from the ECM feeds the fuel pump relay and the NL2 valve power. Look up the Dual tanks theory of operation thread for more information as well.

Several European and US automobiles use the in-tank HVLP lift pump to HP fuel pump scheme for fuel supply.

The TBI pumps will push significantly more volume GPH or GPM at lower restriction/pressure.

When tanks without baffles are your only option you can put a submersible LS fuel pressure pump in a slosh can with feed and return to-from the tanks and to-from the fuel rails. It's not needed with the 87-91 TBI fuel tanks.
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1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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Old 02-29-2020, 03:33 PM   #37
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

Quote:
Originally Posted by hatzie View Post
You can use the 87-91 saddle tanks with the baffles and senders with fuel pumps as high volume low pressure lift pumps and a fuel pump on the frame rail to push the pressure up to LS specs. You'll need to upgrade the NL2 dual tank valve to the motorized Pollack valve. The NL2 wiring and switch will need to be updated to the 1987-91 TBI setup using the fuel system power wire from the LS ECM in place of the same from the TBI ECM. This allows you to keep your 40 gallon capacity with two tanks.
The LS ECM should cut fuel pump power as soon as the engine stops so... as long as you're switching the fuel pump power with the ECM you don't need the oil pressure switch as a safety system.

The 1987-91 Emissions and Driveability books in my manuals thread have detailed information on how the power feed from the ECM feeds the fuel pump relay and the NL2 valve power. Look up the Dual tanks theory of operation thread for more information as well.

Several European and US automobiles use the in-tank HVLP lift pump to HP fuel pump scheme for fuel supply.

The TBI pumps will push significantly more volume GPH or GPM at lower restriction/pressure.

When tanks without baffles are your only option you can put a submersible LS fuel pressure pump in a slosh can with feed and return to-from the tanks and to-from the fuel rails. It's not needed with the 87-91 TBI fuel tanks.
Thanks,great Info here. If I stick with the saddle tanks I will change them to the 1987 TBI tanks but I am also considering a blazer tank conversion. My main issue is making everything smog legal. I know they need a vapor pressure sensor or something like that. Figured swapping to a single tank would make things easier. The swb saddles are only 16 gallons each so I wouldn't be losing too much and rarely filled both tanks in previous trucks.
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Old 02-29-2020, 05:03 PM   #38
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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Thanks,great Info here. If I stick with the saddle tanks I will change them to the 1987 TBI tanks but I am also considering a blazer tank conversion. My main issue is making everything smog legal. I know they need a vapor pressure sensor or something like that. Figured swapping to a single tank would make things easier. The swb saddles are only 16 gallons each so I wouldn't be losing too much and rarely filled both tanks in previous trucks.
The fuel tank pressure sensor is just like an old fashioned MAF sensor. You need a bung that it'll fit through tightly.

The rest of the LS version of the EVAP system is fairly simple. If you weren't in the Peoples Republic of California you could bypass the EVAP readiness test and plumb the less expensive components from the 1970's evap canister setup to the purge valve. It would work just as well as the LS system but your overlords have no doubt decreed you shall use the LS motor evap system or else... off with your head...
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1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8


RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.
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Old 02-29-2020, 05:19 PM   #39
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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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.
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Old 02-29-2020, 05:43 PM   #40
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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
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Old 03-02-2020, 08:41 PM   #41
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Re: SMOG LEGAL ENGINE SWAP TO LS yesterday passed!

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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.
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