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I tried to search but only found one thread with one reply.

All the CP4 failure stories online has me scared. Any of you done CP3 to CP4 conversion? Can I do it with Cab on? Also does the LML conversion kit work on LGH? I'm not seeing any kits bing sold specifically labeled for LGH

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I tried to search but only found one thread with one reply.

All the CP4 failure stories online has me scared. Any of you done CP3 to CP4 conversion? Can I do it with Cab on? Also does the LML conversion kit work on LGH? I'm not seeing any kits bing sold specifically labeled for LGH

Thanks
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I did a LGH CP3 conversion on my 2016 ambulance. This is a long-term body off frame project, with a 24" high top, additional 30 gallon fuel tank aft rear axle, non-4WD.
I installed this SS Diesel CP3-CARB $2,500 pump and I am keeping all emissions intact. I do not believe in deleting emissions. One benefit is it has a factory emergency vehicle tune, and does not limit speed due to DEF failures. It still shows the 55mph and 4mph warning messages on DIC, but does not actually limit speed.

https://proformance-diesel.com/product/ss-diesel-carb-2011-2016-lml-cp3-conversion-kit-with-sportsman-pump/

It took me a while to come to terms with myself to spend this amount of money on a single upgrade. Even though I understand the actual failure rate is about 1%, ultimately I decided I wanted to get rid of the anxiety of the CP4 failure being fully loaded with trailer in the middle of nowhere, as I then would have been facing a $1,000+ towing bill and a $7k GM dealer bill and forced to stay in a hotel for a week while they are fixing it.
As in the comfort of my own shop at home, I installed the pump in half a day or so, because the body was already off frame already for other work and I had full engine access. Very straightforward install then. If I had to do it in a van, it'd have taken 2 days. I'd rather lift the body first. Exhaust manifolds or Turbocharger do not need to come off, just the EGR cooler, and Y-bridge. When you order, you need to let them know it goes into a van, and they change out a couple of small p.arts from the kit.

I have not run the engine with this pump yet, so cannot comment on performance.
 

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Has there been a comparison between failure LML vs LGH? I'm wondering about the van having a lift pump would affect failure rate?
 

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Failure rate is the same as they are the same components. You just do not hear as often as there are 100+ times more diesel pickups out there than diesel vans. Vans do not have a lift pump. Vans have a "prime" pump that runs only with Key On, Engine Off and the only reason for it being there is there was no room under the hood for a traditional prime pump. As long as your fuel supply is not losing prime, you can as well disconnect that pump.
 

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There are people with lift pumps and different filters that still had CP4 failures. When it decides to go it goes and mileage varies.
 
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One benefit is it has a factory emergency vehicle tune, and does not limit speed due to DEF failures. It still shows the 55mph and 4mph warning messages on DIC, but does not actually limit speed.
Can that tune be programmed into any of the vans?
 

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Can that tune be programmed into any of the vans?
Yes using EFI Live. These tune files are not in free circulation. I had to buy my file from some tuner online for $50 so only have the 2016, other years will need to be bought separately. And you also will need to buy the EFI Live controller license which is $125 to allow to flash your ECM.
 

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Yes using EFI Live. These tune files are not in free circulation. I had to buy my file from some tuner online for $50 so only have the 2016, other years will need to be bought separately. And you also will need to buy the EFI Live controller license which is $125 to allow to flash your ECM.
I should have added, can this be done at the dealer with their equipment?
Would it be the same deal, need the vin off a same year van?
 

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Yes, from the technical standpoint there are no issues. If you can persuade them to write a different VIN tune into your vehicle.
You can actually purchase your own MDI for ~$200 off eBay and then a GM subscription which is $40 per VIN from acdelcotds.com, and DIY from your laptop. Reflash any module on any GM vehicle 2000-current. That's what I do.
 
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