Might just give up......

[kenh]

On the LS swap on my 90 C1500.

It seems the more I read the more confused I become. I've been researching this for well over a year. All I read is all the issues everybody is having. Wiring to make this or that work. Engine codes with no fix in sight. Can't make the cruise, gas gauge and other essential systems work.

My goal, like it seems to many, is to have a "modern" power plant with better gas mileage and power than the factory 5.7 with the outdated TBI. My electrical/computer skills related to automotive will not support me in doing this swap.

Ken

 

[618 Syndicate]

Stop reading and start doing. It's not a hard swap, it's been done many times. The vast majority of problems people have are from shortcuts that went wrong, or not double/triple checking things.
If you can put together an R/C plane you can do this. Scale is just bigger.

 

[Drunkcanuk]

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Watch this series of videos.
He basically goes step by step with the wiring. Like seriously, wire by wire, plug by plug! It's great to watch.
LS swaps, especially in our trucks is not rocket surgery, they have been doing them a long time, and bugs seem to all me worked out.
Like @618 Syndicate said, if you can build those RC planes, this should be no issue.
Eat the elephant one bite at a time.
Hell, even in my small 5000 person town, there are a few LS swapped OBS's running around town.

 

[Majoraslayer]

Budget goes a long way; like most things in life, the more money you can throw at it the easier it gets. If you're on a tight budget like me there's a lot more hoops to jump through to adapt everything. When I've looked into options for doing this swap, a couple of the more expensive paths I considered that would make it a lot easier:

1) Buy a complete LS vehicle with a bad body or frame for "relatively" cheap. You know it works in the other vehicle, so most of what you need should be right there. Then you can scrap or part out whatever is left over to recoup some of the cost.

2) Buy an aftermarket complete wiring harness setup, like Painless or something similar, and everything should be pretty much plug and play. Expensive, but straightforward.

I tend to do things the hard (and often stupid) way because I cut corners to reduce cost through increasing the work involved. If you get overwhelmed though, sometimes you may have to cut your losses and plan around increasing the project budget.

 

[Drunkcanuk]

Budget goes a long way; like most things in life, the more money you can throw at it the easier it gets. If you're on a tight budget like me there's a lot more hoops to jump through to adapt everything. When I've looked into options for doing this swap, a couple of the more expensive paths I considered that would make it a lot easier:

1) Buy a complete LS vehicle with a bad body or frame for "relatively" cheap. You know it works in the other vehicle, so most of what you need should be right there. Then you can scrap or part out whatever is left over to recoup some of the cost.

2) Buy an aftermarket complete wiring harness setup, like Painless or something similar, and everything should be pretty much plug and play. Expensive, but straightforward.

I tend to do things the hard (and often stupid) way because I cut corners to reduce cost through increasing the work involved. If you get overwhelmed though, sometimes you may have to cut your losses and plan around increasing the project budget.

Well said. Budget can definitely affect the ease factor of a project.

 

[Road Trip]

On the LS swap on my 90 C1500.

It seems the more I read the more confused I become. I've been researching this for well over a year. All I read is all the issues everybody is having. Wiring to make this or that work. Engine codes with no fix in sight. Can't make the cruise, gas gauge and other essential systems work.

My goal, like it seems to many, is to have a "modern" power plant with better gas mileage and power than the factory 5.7 with the outdated TBI. My electrical/computer skills related to automotive will not support me in doing this swap.

Ken

Greetings kenh,

Merging a next-generation powerplant into a GMT400 engine bay can cause a 'chicken or the egg'
troubleshooting scenario. Is the engine the perpetrator of the issue, or is it a victim of something
in the engine bay/wiring harness that I didn't marry properly?

My suggestion is that you consider a Divide and Conquer approach, by adding an intermediary step
where you verify that your engine works + you know how to get the wiring harness set up properly
to make it run on command? An engine run stand will allow you to do this.

Personally, when I am coming up to speed on a new technique, I always like to find both the minimum
acceptable procedure, followed by the max effort approach, and this way I can figure out where on the
continuum I'd like to be.

With that in mind, Here are 2 short videos to check out.

The first is the minimalist approach. Nice explanation of the bare minimum of what you need to get a
LS motor to fire up on a engine stand. (With an unspoken tip of the hat to the Evel Knievel lifestyle?)

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On the other hand, the second approach is how to minimize all risk, and maximize the moment. No
surprise, Jay Leno demonstrates how it's done when you are one of us motorhead types that is playing
the game while owning Boardwalk with a hotel on it:

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There you have it.

Soup to nuts.

A-Z.

Figure out where you want to be on the engine test stand continuum, buy it, use it...and when you are
done it, sell it to the next GMT400/LS swapper guy in line. Bonus points for locating a used engine test
stand for the right price, using that, and then selling it for what you paid for it?

And for what it's worth, I'm plenty comfortable with making engines work, and troubleshooting my way out of
a no-joy situation. But I wouldn't buy a treasure yard LS motor and stuff it directly into a GMT400 engine bay.
I know it's done all the time. Some of the time it works right off the bat, but other times there's significant
chase your own tail sorting out after the fact.

But I would have no trouble if the engine bay was in good shape *before* the project was started. And then
the donor engine is made to run on a stand. Then the 'marriage' of good engine bay + tested-good LS engine
is just a matter of careful bolting & connecting, with very little pondering why did I choose this $^#%*& hobby? :0)

And if you document your build in here with sharp photos and the occasional question for us to kick around, we
might end up with a nice, self-documenting How To LS-swap build thread that others could learn a lot from.

Sounds like fun to me.

Cheers --

 

[Schurkey]

Perhaps a moderator will move this thread to the LSX + Carb Swaps sub-forum.

 

[KansasOBS]

I've been researching this for well over a year. All I read is all the issues everybody is having. Wiring to make this or that work. Engine codes with no fix in sight. Can't make the cruise, gas gauge and other essential systems work.

Pretty much everything you posted as a worry, is far from being any type of issue. Even if a person isn't really mechanically inclined.

Engine codes are going to be just that, engine codes. Any type of regular problem a person might have with a newer vehicle. I don't know of anything with "no fix in sight"

If you're going to run drive by wire, the TAC module bolts right in place where the factory cruise module does. The TAC supplies the cruise in that case. You would have to connect up the control wires from the switch, etc. For a gas pedal you get an electric pedal for a diesel version GMT400. Bolts right in, swap a couple wires.

If you keep drive by cable, its just a matter of hooking the cruise cable to the throttle body. Simple. The cruise control is a separate system of its own. I went with cable on mine, cause old school.

The fuel gauge is also a system on its own. It has nothing to do with the computer. Fuel sender....gauge. The rest of the gauges are easy also.

You can even get the whole mechanical side of thins done, and then deal with the electrical. No problems painting yourself into a corner.

618 Syndicate is right about stop reading, and start doing. Its the whole "How do you eat an elephant....One bite at a time" Once you start doing, you'll find a lot of things work themselves out, or you can find the answer and retain the information, without being overloaded. For anything else, I'm pretty sure those of us on here that have done the swap can also answer any questions you may run into, though sometimes I am an idiot.

 

[Leeztruk]

Gonna say something right from the start. No offense to you, but your attitude is what's gonna defeat you . Either do it or don't. I'm 76 (gonna be 77 this year) and I just did this swap last summer, by myself!! Hardest part was handling the hood. I'm not as strong as I yousta be, and I got help from a friend for that. Everyone goes into panic mode when it comes to wiring, but you're only gonna need a couple from the truck's engine harness (oil press. and temp.). the only wires needed on the pass. side firewall connector are A/C wires and red power wires from the buss bar, and maybe the ground wires. The biggest electrical hurdle for me was the gauge cluster. Because my truck ('89) and yours has/had the Moonies, the speedo has an internal DRAC. I swapped in a cluster from a '93 truck (requires a connector change), so the PCM drives the speedometer. Wirings done! Do your swap in stages,ie. get engine in, do the fuel system, exhaust, cooling system, etc. Don't try to do EVERYTHING at once.

Concerning the fuel system, either lift the bed off or tilt it using a high lift jack (8 screws holds the bed to the frame). take out the left side screws, loosen the right side, and lift the left side up high enough to get in and make your changes. you can even use some of the original hard lines

Concerning the harness, probably easiest to just buy a quality pre-made harness. It's plug-and-play. Forget the cheapie fleabay or chinazon stuff. They can be a bigger hinderance than they're worth.

This isn't gonna happen overnight. Took me a couple of weeks. Just devote time to a system, and before you know it, you're done. Check out my posting here ('89 DD ls swap) for some pictures and thoughts. PM me if you have questions, and maybe I can help. And remember, if you go into this with a less than positive attitude, you'll never get it done

 

[0xDEADBEEF]

It's really not that hard, but there are shops out there that will do it.