Is it worth it for me to learn to do this stuff myself? (TBI 4.3L to 5.7L swap)

[PPPPPP42]

All this tuning fascinates the hell outa me, not for scraping up every last horsepower but to be able to take random combinations of vehicle and engine and GM TBI (the best fuel system ever made as far as I am concerned) and actually make them run correctly together.
I'm not afraid of EFI wiring and sensors, I managed to check continuity to the pins in the ECM connector on a '98 Cherokee when it had a MAP low input code that wouldn't go away and found that the harness had worn through and was grounding the sensor wire for the MAP (though the 5v signal and ground were fine)

At this point all I really need to do is take my 1992 K1500 4.3L 5spd and make it a 5.7L. I plan to get a stock 5.7L of the same year just to cut down on parts lookup complications down the road.

I'm under the impression that my manual transmission adds a complication and someone made it sound to me like it would be easier to have my prom in my current computer reprogrammed to 5.7L specifications (rather than replace it entirely). I also would like several emissions pieces removed at the same time and the programming adjusted accordingly.

I don't know how often in the future I would be doing this stuff though I do have a laptop lying around if its as simple as buying a connector and software and learning to use it.

I'd rather like to learn to do this stuff myself, but I may be trying to take on too much at once and possibly would be better off just having someone reprogram this chip for me. If I do learn this stuff I would probably be doing a lot more of it in the future.

Not to muddy the waters with another questions too, but I keep reading that the 4.3L and 5.7L throttle bodies are identical but have different injectors. That doesn't make any sense to me as a 4.3L needs less air than a 5.7L so I would expect the bore to be different. It would certainly save cash to be able to reuse everything but the intake if that were true though.

[1project2many]

Replacing your engine with another that was available in your truck is a fairly straightforward process. Using the V6 calibration will cause issues but since the truck was available with a 5.7 the correct calibration is easy to find.

The 4.3 does use the same diameter throttle body as the 5.7. The injectors are usually smaller so total fuel delivered is reduced. You'll need to check the injector size and likely move up to 5.7 parts. It might be easier and less costly to buy a complete used engine for parts.

[RobertISaar]

if plan on swapping engines/transmissions/ECMs a lot...... you would be best to learn how to DIY, from both an investment and capability standpoint.

[EagleMark]

There's also time to think about. All this cables, laptops, software chip burn equiptment, not to mention time and learning curve! Do you have time, money and desire?
*Warning! The 12 step EFI addiction class was closed do to everyone thinking AA was to disable checksum. *

I've got a 4.3L TBI here... well it has 4.3L injectors and it is smaller bore then 5.0L and 5.7L which are the same... so are you guys sure?

1992 4.3L or 5.7L manual probably has a 1227747 or equivlent (288?) and not the newer Memcal ECM which came in auto trucks. Pretty sure a 7747 plugs in so tuning would be a great ECM to start and learn on.

[1project2many]

I've got a 4.3L TBI here... well it has 4.3L injectors and it is smaller bore then 5.0L and 5.7L which are the same... so are you guys sure?

How much smaller? I've only seen three sizes on TB bore. 2.8, 4.3/5.0/5.7, 7.4. If the bore is a lot smaller it's probably a 2.8 TB.

[EagleMark]

So are 5.0 and 5.7L same? This one here is smaller then 5.7L TBI but does have 4.3L injectors and does not look to be ever taken apart...

[gregs78cam]

http://www.dynamicefi.com/TBI_Fueling.php

I don't think Rbob would put up false info. I have a few here I could measure if I can find them.

[EagleMark]

Well this must have had injector pod changed long ago. Been here so long I can't remember where I got it.

[gregs78cam]

Ya know I just remembered that when I put the dual TBIs on the camaro, they had the same bore and what I thought was the same numbers on the injectors, later I found out that one of them had 4.3 injectors in it. Pretty sure they weren't changed before I got them.

[PPPPPP42]

Its stupid of them to use the same choked off throttle body on the bigger V8's, even on the V6 I discovered the engine is desperate for more air since when I left the main PCV hose unplugged by accident (it splits evenly to both bores) I suddenly had way more power (and a high idle). Definitely going to get a better air cleaner on the 350 since that was likely a large part of it.

Wish I had decided to do this earlier, about a year ago I replaced both injectors and the radiator. Probably can just sell those.
So it looks like my complete parts list is down to the '92 long block 350 with intake, 2 correct fuel injectors a clutch and flywheel, water pump, radiator with fan shroud, hoses, exhaust and a new chip in the ECM (assuming the computer itself is correct which I have no clue how to determine). I suppose I will also need to extend the harness in places but considering its damn near the same setup I see no reason to change it over unless it happens to come with the engine.
Though it about doubles the cost of this adventure I am seriously looking at this: http://www.moates.net/apu1-autoprom-...b-version.html
And since I only have the most general idea of what this means: "Keep in mind you'll still need a chip adapter and probably a ZIF" I have ALOT of homework to do. Fortunately that site has a lot of stuff to read and I can harass you people when I am too stupid to get around something.
This is going to be VERY entertaining. I can already hear my dumbass Chevy friends "so I hear you have a tuner..." maybe I'll make some money back off this. Eventually it would be fun to put a 4.3L TBI setup on a Jeep inline 6 since they make the various adapters to accomplish that.

[EagleMark]

Choking an engine from lack of air does reduce HP. But it also increaes tourqe and drivability for which the engine was designed. Put a BB TBI and dual exhaust on a stock 5.7L TBI engine and it drives like crap...

Get the numbers and four letter BCC code from the ECM and we can figure it out.

I've had an AutoProm for a few years. Best dollars I've ever spent.

[PPPPPP42]

Pulled the 4 screws for the glove box liner out, easy access to ecm though it looks like it would take more work to actually remove it.
On a side white tag it had:
1GN0051971 AZUS

And on the top tag it had:
SERV. NO. 16144288 AZUS
86AZUS K312970514

Now I just need to figure out what it takes to set it up for a 5.7 or what I need to replace it with.

[EagleMark]

Here's BCC find to look up the four letter BCC code. Your's comes back to a newer ECM number but same thing.
http://www.gearhead-efi.com/BCCFind/

Here's that ECM:
http://www.gearhead-efi.com/Fuel-Inj...Information-AO

But it has a permanent limp home chip.

I never finished testing but I had burned a $42 7747 bin to that ECM and ran... but the vehicle had so many mechanical issues I could not complete testing and used a 1227747 ECM.

A 1227747 will plug right in. The definitions and hack is much more developed:
http://www.gearhead-efi.com/Fuel-Inj...Information-42

[PPPPPP42]

Looks like with a 1227747 I want to use ARHT-$42-5.7L-Manual.bin‎ with my transmission since everything matches my current code but the engine. If that ECM plugs right in I'll be set, hopefully the rest of the harness is as cooperative. If I pick one up used I assume it doesn't matter if its a manual or auto truck so long as its a 1227747 since I will be changing the programming right?

Looks like this is mostly a 1991 ECM, so the manual transmission trucks got an older ECM or so I thought someone mentioned?

[EagleMark]

This is the older ECM everyone mentions, 1614428 and 1227747 are same ECM with slight differences. Newer ones are 8192 baud and have a memcal.

You should always try to start with manual for manual. ARHT would be a good start.