PCM
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Define "tuning."
"Why Do I Need Tuning?" (from linked source below)97cargocrawler said:
Many people do not understand what tuning a car computer is about, or why or when it needs done. Here are some reasons:
* You want to improve full-throttle horsepower and torque, and throttle response, even on your stock engine
* You want better MPG (miles-per-gallon) for your daily or weekend driver
* You modified your engine, like with a new cam, heads, different displacement, fuel injectors, or static compression ratio, and the car is now sluggish
* You swapped an engine into a different vehicle and it won't start/stay running (VATS/anti-theft)
* You switched from automatic to manual transmission, or vice-versa
* You want a cooler engine to prevent knock retard and sluggishness, via the fans coming on sooner
* You changed your tire size and/or rear gears and need your speedometer and/or automatic shifting corrected
* You disabled some systems like emissions (EGR/AIR), A/C, etc., and want them and their error codes disabled. Did you know that removing the EGR system without reprogramming for it can cause spark timing issues?
* You want your shift points changed, harder shifts, or your TCC lockup points modified
Those are just some of the reasons why you would want your PCM tuned! There are others!
Source-
http://www.lt1pcmtuning.com/why/
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1,359 Posts
I was told that if I want my existing computer to run the 5.7 it would have to be reprogrammed? I have the computer and wiring harness out of the donor vehicle also. Some say to use that, seems like a lot of work to remove the existing harness and install a new one not to mention it wont have anything for the transfer case. So that is why I asked. I am putting a custom ground cam in the motor but a mild one and it should not create problems with the emissions stuff?
I would like to get more HP out of it
Better fuel mileage
towing capabilities ( not all that important) but would be nice.
Would also be nice to correct the seedometer
I would like to get more HP out of it
Better fuel mileage
towing capabilities ( not all that important) but would be nice.
Would also be nice to correct the seedometer
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5,082 Posts
Mmusicman should be able to upload a tune for you.
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87 Posts
Your PCM does not have to be reprogrammed for it to run. It will run but once it has been installed into another vehicle it will most likely show the check engine light. If the express van had a security system it may or may not run. As far as reprogramming your PCM it can be sent to many people to be done. If you can get it running you can take it to a local shop that can do programming. You can use the harness from the other vehicle and cut and modify all day long until it is what you want but you should be fairly proficient at electrical before you consider doing that.
I just put an LS into my van and I am not a great electrician by any means. I went with a new harness from Painless Wiring (part #60508). It is a stand alone harness to make it run in any vehicle you want. It is almost completely plug and play and uses all GM connectors and wire coloring. You will have to modify your van for some minor stuff like the gear selector switch but it is not hard. It can be installed in an afternoon. They will also reprogram your PCM for free if you mail it to them, they will retrn it to you in a short time. They will program it to any specs you want including tire size and gear ratio. It is not cheap but will save you a lot of time and aggravation. If you subtract the $200 or so that a tuner will charge for the PCM its a decent deal.
BTW their harness does require an LS intake to work properly and it is my understanding that the van/truck intakes will not clear our vans if it is the Vortec style.
I just put an LS into my van and I am not a great electrician by any means. I went with a new harness from Painless Wiring (part #60508). It is a stand alone harness to make it run in any vehicle you want. It is almost completely plug and play and uses all GM connectors and wire coloring. You will have to modify your van for some minor stuff like the gear selector switch but it is not hard. It can be installed in an afternoon. They will also reprogram your PCM for free if you mail it to them, they will retrn it to you in a short time. They will program it to any specs you want including tire size and gear ratio. It is not cheap but will save you a lot of time and aggravation. If you subtract the $200 or so that a tuner will charge for the PCM its a decent deal.
BTW their harness does require an LS intake to work properly and it is my understanding that the van/truck intakes will not clear our vans if it is the Vortec style.
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The original Astro PCM can not be programmed to run the new engine. You will have to run 2 PCM's, 1 for the engine and one for the chassis.
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What happened to that PCM's are the same you just need to swap PROMs stuff?
I'm SO thankful that all I had to do was throw a carb on a basic V8.. and I was done! No mystery, no programming, no computer compatibility issues, no searching for complicated answers, nothing. I just turn the key, give it 12v, and it runs! All the accys from the front of the V6 fit the V8... it couldn't be any easier.
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My 5.7L is an L31 (LS1?). I have to run 2 wires for the 2 extra injectors, Pick up the power from the pink wire in the present injector harness, lengthen the wire for the knock sensor. I do believe that is the extent of the wiring, I just have to figure out the pin port numbers relative to the 7 and 8 injector. The only other hurdle is the modified cam, if the truck runs I can bring it to be dialed in to an experienced tuner, if not I will have to send the computer out to be tuned to the data I provide, there are a couple of them close by. If I do send it out I can have them turn on the efan and that saves some $ and wiring?codydaniels said:
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