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LS LQ 9 ( from a 2002 Escalade)-- what we need from the donor truck to install into our 1988 K5

folkenheath said:
Yes, that is correct, if you have the time. I just don't have time to tune with the stock ECU when the aftermarket ECU can be tuned live while the engine is running and see the results immediately, and these days does it by itself most of the time, and it is definitely more versatile than the stock ECU. Also, the harness comes plug and play for some applications vs hours of depinning, cutting, removing, etc. I use the factory ECU in the factory vehicle, because it's also integrated into other aspects of the vehicle most of the time. Once you remove the engine from the vehicle, I'll take the aftermarket ECU pretty much every time because of the amount of time it saves.

BTW, are you saying you can buy an ECU at the parts store in a pinch? I'll be honest I've never looked. The Holley Terminator system uses all the stock sensors except the 02 sensor, which is from an Audi or something like that. All of the sensors can still be purchased at the parts store if you know what vehicle to look for. In the truck I keep a list of the sensors in the glove box along with what vehicle they came out of.

But with the LS engine it's easier because you just need to know what vehicle you took the engine out of. But with a tuned factory ECU you would still need your laptop and then a new code from HP tuners for the new ECU, then pay more money for a license for the new ECU, it still wouldn't be an easy fix if you lose the ECU. Luckily that's rare.

I guess what I am saying is the ECU and wiring harness are the only thing aftermarket really. Neither of which are easy to change with a tuned stock ECU or an aftermarket one.

Thank you for standing up for of the stock ECU, I always respect your opinion Luke.
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Yes, that's very true for a paying customer, the labor time can quickly overshadow the upfront parts cost. I think the numbers change a lot with volume, as there are batch licenses with HPTuners and EFI Live for all cars of a type, instead of $100 in credits per vehicle. I've always been on DIY side of just doing one vehicle at a time, for myself, at my own leisure. If I'm going to be tinkering around the shop doing something, it might as well be re-pinning a factory harness, save the $500 and pay somebody $50 to cut the grass instead.

I think I was partly jaded about the aftermarket EFI because of all the horror stories getting things running right after spending $3k on the setup with the promise of "self learning". Meanwhile you could get the factory ECU on for $500, pay a tuner $500 and be done. Anecdotally, the aftermarket setups have finally come into their own where they work more as advertised. I think part of the confusion is always user error because you still have to understand how an EFI system works whether using factory or aftermarket. You can't self-learn around a giant vacuum leak, mis-wired sensor or a host of other physical problems that can easily arise after an engine swap.

BTW, HP Tuners does have real-time tuning that adjusts tables based on O2 while driving. I haven't tried it. I believe EFI Live has the equivalent. You do have to flash the adjusted tables in when it's done.
 
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It's good to hear the tuning software is offering stuff like that and upping their game.

And I agree with you, too many times EFI gets blamed for mechanical issues because it's easy to blame what you don't understand rather than going back to basics and reading plugs and checking compression, oil condition, vacuum leaks, fuel pressure, etc.

I've even seen EFI get blamed for busted rocker arms, they wasted a bunch of time checking injectors and electronics when the whole time it was a busted rocker arm.

Or people think, hey, a ground is a ground, and don't understand ground loop issues, and then wonder why it won't run consistently. I've seen ECUs grounded to the inner fender. Fixed that, and it magically ran correctly.

For me, I am a total do it yourselfer as well, and I feel like having to pay someone else to use the software for a different engine or ECU still isn't myself. I would rather buy the system, and be self sufficient there after. With aftermarket, the software is free, anyone can download it and use it or play with it before they even buy the system. And you can use the same software whether you have 1 or 10 ECUs. It just feels less trapped to me.

But there are definitely times when the factory ECU makes sense.
 
hi all! ok it is a year later and we are gearing up for the swap. due to the poor condition of the Blazer we had to sell the LQ9. we now have a full setup from a 2004 chevy 2500. so it is a LQ4, transmission (4L80 i assume) and all the electronics from the Mass air flow senor, the wiring for the gas pedal, the computers and all the trans wiring. i want to get the harness all set and the computers all set up and plan to start the install in the fall. i also have all the accessory drive stuff from the 6.0.

so what do i need to do to use the factory harness and computers. i hear the computers need to be unlocked so we can use them on this truck.

are there better options that the factory harness and computer?

what do i do concerning the accessory stuff like power steering, alternator and A/C?

also i have to get the broken exhaust manifold bolts out and i want to bench start this engine before it goes into the truck. any ideas on how to make a set up to bench start the motor?

any helps is greatly appreciated!

john
 
Reusing the factory LS harness is fine if you have the time to repin it yourself. Though, in my case the time to go through the harness was non-existant and getting a stand-alone harness was more within my time budget. Plus having worked on the trucks these LS engines came from I was well aware of what butchery can happen to them plus the general wear and tear of use over 20 years now is never kind to them.

I got my stand-alone harness from Howell and got the ECM tune from them too. I gave them all the specs what my setup was with cable throttle and provisions to pt evap on the truck later, they built the harness to my spec and tuned it for all my options.
 
If you plan to leave the engine bone stock then the factory computer may be cheaper. If you plan to change the cam or anything I would definitely use an aftermarket ECU for the time and/or money it will save on wiring and tuning.
 
hi all!

we are keeping the engine stock. just want to drop in the trans and the motor. so i would send the harness and the computers to one of the above mentioned companies and then they set it up?

also i saw that companies like Holley have an accessory drive set ups. how does the power steering, AC and such mount up to the 6.0 from the 350?

john
 
I would keep the 6.0 power steering and alternator bracket.
I wouldn't run the R4 A/C compressor, I would find a bracket to run a Sanden, even though it means custom lines. The durability of the R4 is very poor, IME
 
If the engine, transmission and PCM all came from the same donor, there's no tuning required. I'm assuming you're using the same FPR, MAF and MAP* from that vehicle. So all you need is for somebody to turn off anything in the PCM that's not part of this vehicle and make some wiring changes. Surely the exhaust backpressure will be a little different, but it's not going to make a big difference. Like any other stock vehicle it would benefit from tuning, but it's optional. In general, people usually have the Performance Enrichment turned on and reduce/remove torque management (engine and tranny), but these are all well-known things any tuner can do for you without having to see datalogs.

*(actually MAP tuning is usually pretty rough on these vehicles and is really just used as a backup limp mode in case the MAF fails. If you will be looking for maximum performance, it's best to have someone tune this in the vehicle and have the whole VE table dialed in, but in general you don't have to worry about it.)
 
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