1979 GMC Dually TBI swap

**Randy 79** · 02-03-2014

Time for a long overdue update. Finally got the engine back in mid-December, a few months later than expected. It is now in the truck at last.

I have the sending units for the tanks (Left side plain, right is TBI sender) and have the pump coming for the TBI. Left tank will be an aux tank and feed into the right tank. I rebuilt the Throttle body with new gaskets and o-rings, it needed it. Also pickup up a replacement distributor as the old one was worn out. Still have a few more pieces to get. I might get lucky on the tuning, the previous owner thinks he has the stock Bin for the truck, he is checking to see. That could help out. Wiring harness is just about done, just need to get the inside connections squared away.

On a side note, sort of an FYI, the 12si 140 amp alternator that was on the truck will bolt in the same place as the 92 CSI 105 amp alternator, with just a little grinding on the bracket in two spots. It at least gives me options.

Some questions I have about it.
1. Fuel lines to the TBI, are the 6AN adapters a good way to go? I will be hooking it to the stock 3/8" fuel line and running a new 5/16" return (it only has a 1/4" return line now). Plan to use adapters to join to the steel line, probably with just a short length of EFI hose.

2. Hot fuel handling module: I don't have the module, just the plug. It looks like there is a power line, ground and line to the pump. Will it work unplugged or do I need to connect any of the three wires together. Hard to tell from the wiring diagram.

3. A/C connection: I have the a/c compressor connector in the EFI harness, can I hook the trucks original wire to that harness, this would be the green wire? Will the computer know then if the a/c is on?

I will probably have more questions as I put it all in. Thanks for the help, Randy

**Randy 79** · 04-08-2014

Another update. I am just about to the point of getting it running. I got my stuff from Moates (Burn2 and G1 adapter with ZIF socket, HDR1) and was able to download the stock BANF bin. Everything looks good in TunerPro, best I can tell. If anyone could take a look to make sure, since this is my first time.

I also downloaded the BANF-5 bin from the 7060 thread, http://www.gearhead-efi.com/Fuel-Inj...ed-to-D8/page2
It sounds like a good tune for what I want to do. Biggest thing I'm not sure about is tweaking/turning off the 4L80E stuff in the bin. I can see it in TunerPro, just need a bit of guidance to get it right. Thanks for all your help.

Edit: I also have a Comp Cams 11-302-4 cam (one of their TBI cams), headers and Edelbrock TBI intake. TBI has an adjustable regulator, was set to 25 psi, I will verify once I get it powered up and can change it if needed. Just in case any of this info is needed for the tune.

**1BadAction** · 04-08-2014

Originally Posted by Randy 79

Another update. I am just about to the point of getting it running. I got my stuff from Moates (Burn2 and G1 adapter with ZIF socket, HDR1) and was able to download the stock BANF bin. Everything looks good in TunerPro, best I can tell. If anyone could take a look to make sure, since this is my first time.

I also downloaded the BANF-5 bin from the 7060 thread, http://www.gearhead-efi.com/Fuel-Inj...ed-to-D8/page2
It sounds like a good tune for what I want to do. Biggest thing I'm not sure about is tweaking/turning off the 4L80E stuff in the bin. I can see it in TunerPro, just need a bit of guidance to get it right. Thanks for all your help.

Edit: I also have a Comp Cams 11-302-4 cam (one of their TBI cams), headers and Edelbrock TBI intake. TBI has an adjustable regulator, was set to 25 psi, I will verify once I get it powered up and can change it if needed. Just in case any of this info is needed for the tune.

This should help your 4L80E Tuning. Plug your current numbers in and go from there. the bigger the spread between the gears, the more throttle it takes for a downshift. From my experience with an HD truck and towing, keep them spaced on the wider side or it'll want to downshift too quick.

I will caution you, something is up with the Torque converter lock tuning in the 7060. In my tune it is not commanded to lock in 3rd at any time, yet when I pull the gear selector into third, it's very clear the TCC is locking up. There is also a MPH range that it is going through a lock/unlock hysteresis, which I have not figured out either.

**Randy 79** · 04-08-2014

Thanks for the info, 1badaction. I actually have a manual trans in my truck (SM465) so I was needing to turn off the 4L80E stuff. I wasn't clear enough in my post, sorry. That's what I get for posting late at night, right before bedtime.

Another question, I have a wire that went to the stoplight switch, originally part of the TCC circuit, any benefit to hooking it up? Otherwise I will just tape it up.
Thanks.

**1BadAction** · 04-08-2014

Ahh I see. Not sure about the TCC stop circuit. Just out of principal I'd like to know the ECM is getting the "brakes applied" signal, but it may get it from somewhere else, not necessarily that circuit. It would probably run just fine without it, too. With a manual trans you will need to change some of the IAC tables to prevent stalling when coming to a stop for one (Throttle follower, IIRC). Mark has done it in a truck and probably can fill you in better on that subject. The latest XDF I've been working on does have those tables defined, the older one listed here didn't. I still need to get off my ass and finish organizing it, but it does have what you will need.

**Randy 79** · 04-21-2014

Well, I am quickly figuring out that I have a pretty steep learning curve with this EFI stuff and need some help. I am getting around in TunerPro RT pretty good and would be able to burn a chip for my truck, if I can ever figure out what I am doing with the bin.

I am pretty confused on what I need to do to turn off the 4L80E trans stuff in the bin (I have a manual trans in truck). The .xdf that 1badaction put up has helped a bit (thanks very much for it), but I am not sure what needs to be done. Since there isn't an obvious "off" for the trans stuff, I presume that it involves tweaking the settings. Do they all get tweaked or does just changing a few of them do the trick? Also I'm not sure what IAC tuning is needed as well.

Bad thing is I am in a time crunch and really need to have this beast moving this weekend to get the engine and clutch broken in. I have an event in 3 weeks in which I need it to tow my trailer so I would like a little time to make sure everything is working. If anyone is willing to help out, you can email or pm me on what you need from me. I would greatly appreciate it.

**Randy 79** · 04-28-2014

Still trying to figure this out auto to manual trans stuff with the 7060. I was shooting ideas back and forth with a friend and he suggested to try deleting the tables for the Auto trans stuff. Sounds like it may be a possibility, as I can redo the chip pretty easily if it doesn't work. But I figured I would run it by the more experienced minds here, so I don't royally mess it up.

Alternatively, could you just blank the tables for the auto stuff? Maybe changing the settings to something that would defeat the auto stuff (for lack of a better term)? I really would like to figure this out, kinda has become a challenge for me to see it work. I am going to download the manual and auto BINs for a 6395, so I can compare the two and see if the differences make any sense to me.

As a fallback plan, I am considering switching to the 6395 pcm, as suggested by Moates. I see there are already manual BINs for it, so that may be a better way. It would take a bit more time with getting the computer, memcal and repinning. But in the long run it may be better. I realize the fuel tables would have to be changed since i have the low-pressure 80 lb injectors. Eventually I will get the hang of this stuff, just may take me a while.

Thanks for all your help and patience.

**EagleMark** · 05-07-2014

Good idea for the tanks. Running dual EFI tanks requires lots of plumbing. When switch changes tanks supply it must also change return. If you've ever looked at one that came from factory with duel tanks your jaw would drop from all the plumbing/switches/valves... let alone expense!

You already have the 7060 and equiptment to burn chips so go with it. The 7060 never had a manual but I'm sure it could be made to run fine on manual trans. Going to 8747 is a step backwards in ECM/PCM, it's not that great.

**Randy 79** · 05-20-2014

Originally Posted by 1BadAction

Ahh I see. Not sure about the TCC stop circuit. Just out of principal I'd like to know the ECM is getting the "brakes applied" signal, but it may get it from somewhere else, not necessarily that circuit. It would probably run just fine without it, too. With a manual trans you will need to change some of the IAC tables to prevent stalling when coming to a stop for one (Throttle follower, IIRC). Mark has done it in a truck and probably can fill you in better on that subject. The latest XDF I've been working on does have those tables defined, the older one listed here didn't. I still need to get off my ass and finish organizing it, but it does have what you will need.

Its been a busy time the past week, so not much done with this. Finally able to get back on it and hopefully get somewhere.

On the IAC adjustments, there are two tables: IAC follower Delay Low VSS and IAC follower Delay High VSS, are these the throttle follower tables? If so the low is set at 400 msec and high is 1000 msec. To prevent stalling when stopping, do you want the delay longer or shorter? My guess is longer on the low VSS table.

With quite a few constants and tables for the transmission, do all of them need to be addressed? The constants seem fairly straight forward, either set them low/high, or out of range so the computer doesn't look for them. May just have to try some settings and see how it goes.

On a side note, I had an autocross event to go to this weekend, so I borrowed my co-drivers truck to pull the trailer. That may have been a "bad" move. It's an 02 Silverado 2500HD with the 8100 and Allison transmission. Pretty amazing combo, especially the transmission. It pulled my trailer with ease, much better than my truck did. I sure hope this 454 pulls the trailer decently, it should at least pull better than the 350 did.

**Roadknee** · 05-20-2014

Originally Posted by Randy 79

On a side note, I had an autocross event to go to this weekend, so I borrowed my co-drivers truck to pull the trailer. That may have been a "bad" move. It's an 02 Silverado 2500HD with the 8100 and Allison transmission. Pretty amazing combo, especially the transmission. It pulled my trailer with ease, much better than my truck did. I sure hope this 454 pulls the trailer decently, it should at least pull better than the 350 did.

I find it wise not to drive that newer nice stuff. I recently borrowed a buddies new Dodge 3500 Quad Cab Long Box Diesel to go pick up a '95 k1500 parts truck I bought. Super quiet, set the cruise control and go. Kinda made me wonder why I'm wrenching on my '95. Oh yeah, it's the $50K or so he paid...

**Randy 79** · 06-17-2014

Update time. Last night I almost got to the point of trying to start the truck. I hooked up the battery to check everything out and no magic smoke was lost from the harness anywhere, thankfully. Can you tell I also own a British car (75 MGB)?

Fuel system did have two bugs though. One, the fuel pump runs as long as the key is on, it doesn't stop after a few seconds. I don't have a hot start module so that wasn't causing the issue. I have another relay I can try to see if that changes anything. Only other thing I can think of is the oil pressure sender is acting up. Second issue was the fuel pressure, it went right past the 30 psi mark on the gauge around to the stop pin at 0. Unhooked the return line (with the key off of course) and it was dry, no signs of fuel. So off came the TBI to check it for obstructions and to check the regulator (adjustable type). Turns out the previous owner had the regulator turned up most of the way (said it was set at 25 psi), which was blocking off the return. Backed it off quite a bit and put it all back together. Now it holds a nice 20 psi. Glad that was an easy fix, just wish it was adjustable on the vehicle. Something to look into later.

So hopefully tonight I can see if she runs, but I will check everything out again before I try, just to be safe. I also need to get one of the ALDL cables so I can do some datalogging, kinda forgot about that. I am curious to see what transmission codes I get once it is running, cause I am pretty sure I don't have all the trans stuff tuned out yet.

**Randy 79** · 07-23-2014

It's been a while, ran into an issue while trying to start the truck. It wouldn't fire at all, no fuel out of the injectors either. Luckily it didn't start as I had a bunch of oil coming out of the bellhousing area, around the rear main seal area. So after taking the transmission, clutch and flywheel out, turned out it was an issue with two of the galley plugs at the back of the cam. That took quite a bit of work to get back together, but it is together now.

I did figure out what was wrong with why it wouldn't fire and why the fuel pump just ran. Turned out I had the chip backwards in the ZIF socket in the G1 adapter. I had the chip notch towards the lever, as it is when using the Burn2. Supposed to go the other way, glad I figured it out before I tore back into the wiring harness. I was able to fire the truck up tonight. It started right up and runs pretty darn good and was able to break in the cam. No "check engine" lights yet, will see if any codes show up later. Looking forward to driving this truck, instead of working on it. Thanks everyone for the help.

**Randy 79** · 08-04-2014

Since I have driven the truck a few times now, a update on how it is doing. Truck runs great, no problems so far with the EFI or the tune (knocking on wood, just in case). The BANF-5 tune that EagleMark did in the 7060 thread really runs good. The engine runs strong and pulls great, runs better than most 454 TBIs I have been around (which isn't too many). It runs fine with the fuel pressure at 20 psi, with the headers and bigger cam it probably needed more psi. I need to get the datalogging going so I can see how it is doing now.

It seems that the 7060 ECU isn't upset about there not being a 4L80E hooked up, no codes or check engine light so far. This is a bit of a surprise as I haven't really turned off much in the bin. I'm happy about that.

The only thing I can see that may need some tweaking is decel, but I expected that. Doesn't do anything funky now, but it probably can use some fine tuning. It doesn't stall when you push the clutch in when shifting or slowing down. A couple times when slowing down in lower gears it started to buck a little, when it got below 1500 rpms. I think it might be coming into a point where the IAC is having an effect. Datalogging may show what is going on here too.

That is all for the moment, I will update as I figure out more on this.

**Roadknee** · 08-07-2014

A lot of times low rpm part throttle bucking can be fixed with more ignition timing. Some applications can use as much as 50 degrees.

**Randy 79** · 08-08-2014

Timing may have an effect. Right now the bucking occurs with my foot off the throttle when slowing down. Add a little throttle and it stops. Last night when I drove it, it wasn't bucking at all. Maybe it just needs to be run more.