84 K5 build... converting to tbi

[caliphatman8123]

Hi all... I'm currently building a 84 K5 Blazer... my donor was 88 V1500 suburban... pulled complete 350 tbi motor, 700R4 trans, and NP208 T-case... including wiring harness and ecm... was wondering if anyone could inform me on how to wire the harness into the main bulkhead(fuse block) from the factory or how to do this with out tearing up all the wiring from the truck... also swapping over the gas tank with the in tank fuel pump, and fuel lines with the powered line for the fuel pump... any advise will be greatly appreciated

[EagleMark]

Does your 84 have a CCC carb? Those can be done. Still lots of wiring... but they have an ECM to start with, wiring to CEL, Pk/N switch, VSS behind speedo etc...

If it's a carb truck then lots more wiring... may be easier to make your harness a stand alone which takes at least ten hours work but then your down to grounds, 12v power and ignition power. Or buy a stand alone harness for around $300.

Have you checked with guys at CK5? There's guys there that know these trucks inside out.

[caliphatman8123]

The 84 was ccc Carb but the motor and tbi came out of tbi truck... all the wiring came off with the motor... just have to plug it back into ecm and to a fuse panel whether factory or aftermarket... other than that plumb the fuel system and run power to the fuel pump from what I was told anyways... I have a bunch of wiring diagrams but trying to make heads or tails of it is kinda frying the brain... lol was hoping to make it look stock from the factory though... would hate to have it look like a rats nest under the hood but everything else be nice... lol

[jameslleary]

Im lurkin here to Cali!
Tis the place to be!
One bit of info...My Burb was the same CCC setup. there isna white plug behind the glove box that plugs into the original harness. That plug has the key power and constant power wires,to tap into for the ECM. I ended up using a relay for the switched key power, because you are going to be running the heavier injector power wires too.
Check your PMs.

[caliphatman8123]

I really wish I lived closer... lol if you have a reason to head down this way feel free to drop by... lol I'm good with nuts bolts and wrenches... wiring has never been my thing... the diagrams are Greek to me... if i had some training in emissions or auto electrical systems I'd feel better but I keep hearing this swap is pretty easy to do even for a efi beginner

[EagleMark]

I'm good with nuts bolts and wrenches... wiring has never been my thing... the diagrams are Greek to me... if i had some training in emissions or auto electrical systems I'd feel better...I remember saying the same thing and fighting it for years. It's not that hard to learn!

Just remember if you let the magic smoke out the part is no longer any good... :laugh:

[caliphatman8123]

OK here's where I'm at... lol

[caliphatman8123]

....

[caliphatman8123]

NP208 has been installed

[caliphatman8123]

.... hitch is going on the K5 too... lol swapping as much as I can...lol

[caliphatman8123]

....

[kunsan1987]

When i converted my 83 i went with a standalone harness.it was really a bunch less work i think.the wiring diagrams
mark has here were a big help converting my harness.

[dyeager535]

Not sure how much help this will be, but I converted my K5 from carb to EFI (TPI) so pretty much the same steps.

Suburban is the same firewall except the minor changes based on year differences. First thing you need is an '88 Suburban wiring diagram. You MIGHT be able to figure all the stuff out yourself without it, but it's not going to be fun.

When I got my TPI harness and dumped the box on the ground, I almost cried. It was so overwhelming, all these plugs and wires with no idea where they went. After staring at it for a few days, and then comparing with the wiring manual, I got a pretty good handle on what went where, and now I could probably ID everything on the wiring harness if it was back in that pile. It just takes time.

Since you have the fuse panel, remove your dash pad and steering column. Replace the fuse panel. Don't cut wires, anything that doesn't have a connector, can be de-pinned at the termination end. It's unfortunate that it looks like you have a fair number of cut wires, depending on what they are for, prepare to splice. That means solder/heat shrink, no half-a$$ garbage like butt connectors or those crimp-tap pieces of junk.

On my truck I didn't have the hole in the firewall for the ECM wiring (was a diesel truck) so I opened up the heater wiring grommet, depinned each wire from the ECM connectors, and fed it through the hole. You can probably remove the CCC wiring and re-use that grommet. Again, don't cut anything. At least until you are CERTAIN you aren't using it (AIR is a good example IMO) Cutting things = cutting corners, and simply means you will either have unexplained/near impossible to diagnose problems later, or a random failure at the worst possible time.

BTW, being CCC, you MAY be able to use the '88 ECM holder in place of the CCC holder. GM had a few setups early on (ESC/EST, CCC, then TBI) in the trucks and not all of them mounted the same way, but my '85 had the mounting tabs for the ECM holder that TBI/TPI used.

[EagleMark]

Just take your time, do not rush or plan to do it fast. It all looks overwhelming. Take one wire at a time! It will all come together.

[caliphatman8123]

Is there any difference in knock sensor? It showed 2 different ones for year of motor but only one for the year of Burban... and all 3 were different... help please... lol

[EagleMark]

Knock sensor has to match ESC/Knock module that has to match cubic inch. There is only one for a 1988 5.7L Auto any truck.

From Rock Auto
ACDELCO Part # 213324 {#10456288}

There are three for that year. One for 4.3L, one for 5.0L and one for your 5.7L

[caliphatman8123]

hi all I'm currently working over the fuel lines for this swap... does anyone have diagrams to compare the 84 to the tbi fuel line set up?

[dyeager535]

Sorry no images. Lots of ways to make it work, but the hard part is from the TBI to the frame. If you pulled at least those lines from the '88, you can make something ork pretty easy. Hose is acceptable for short sections, especially at the low TBI pressure. But you need fuel injection hose.

[caliphatman8123]

Sorry no images. Lots of ways to make it work, but the hard part is from the TBI to the frame. If you pulled at least those lines from the '88, you can make something ork pretty easy. Hose is acceptable for short sections, especially at the low TBI pressure. But you need fuel injection hose.
I've robbed the two fuel lines I need from my donor burb... way to long so I have to shorten them... my issue is I don'y know which line goes where to the sending unit or to the tbi... this is where I need help

[EagleMark]

IIRC the bigger one to feed and the smaller one to return.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1&d=1320981957

[caliphatman8123]

IIRC the bigger one to feed and the smaller one to return.

http://www.gearhead-efi.com/Fuel-Injection/attachment.php?attachmentid=1&d=1320981957
Tnak you now all I need is the other end at the tank... then I can shorten my lines and install them on the frame

[dave w]

I'm going to make a HUGE ASSUMPTION, that your not color blind (more than 10% of the male population have color blindness). I'm going to make another HUGE ASSUMPTION, you OWN and have the SKILLS to use a multimeter. If you DON'T OWN and DON'T have the SKILLS to use a multimeter, then STOP READING NOW!!!! For some unknown reason, vehicle owners who DON'T own a multimeter and DON'T have the SKILLS to use a multimeter are extremely PRONE to starting electrical fires, go figure!

Somewhere on the 88 wiring harness will be several wires that are pink with a black stripe (pnk / blk). The pnk / blk wire is powered from the ignition switch when the ignition switch is in the "ON" and "START" position. The 84 K5 Blazer has a PINK wire that goes to the HEI Distributor that is powered from the ignition switch when the ignition switch is in the "ON" and "START" position. The PINK wire from the 84 K5 will need to supply power to the TBI ignition coil PINK wire and supply power to the pnk / blk wires.

Somewhere on the 88 wiring harness will be several wires that are black with a white stripe ( blk / wht) which are Battery ( - ) Negative / Ground. If the 88 wiring harness is in excellent condition, there will be a couple large ring terminals (large enough for a 3/8" bolt to go through) that have blk / wht wires crimped to them. GM will often use a TAN wire for ground also, and usually the TAN wire will be crimped with a blk / wht wire on at the large ring terminal.

Orange (ORG) is used for Battery ( + ) Positive. Somewhere on the 88 wiring harness will be an ORG wire with a fusible link that was connected to Battery ( + ) Positive.

Somewhere on the 88 harness is a PURPLE wire with a WHITE stripe (PPL / WHT) that was connected to the starter solenoid "S" terminal.

That's it, four wire connections. Battery ( + ) Positive, Battery ( - ) Negative / Ground, Ignition Switch Power in both "ON" and "START" positions, and the Starter Solenoid "S" terminal.

dave w

[EagleMark]

Tnak you now all I need is the other end at the tank... then I can shorten my lines and install them on the frameThey should only go on tank sending unit one way. One is smaller 5/16th line the fuel return and one is larger 3/8th line. 3/8th line is the fuel feed. Take unit out of tank and it's easy to see return and feed from pump.

[EagleMark]

To add some color info to Dave w. post.

Orange is the same as red, 12 volt power always, key on or off.

Pink is 12 volt power key on.

Grounds can be black, black white stripe, Grey, Tan.

[dave w]

To add some color info to Dave w. post.

Orange is the same as red, 12 volt power always, key on or off.

Pink is 12 volt power key on.

Grounds can be black, black white stripe, Grey, Tan.

Good point, I've been thinking grey was a reference ground from the ECM. I haven't had need to ground the grey wires, because they have grounds from the ECM?

Anyway here is a video of me bench testing a harness, this one is a TPI. The Noid light shows the injectors are getting power (first on bank 2 then I transfer the Noid light to Bank 1) , the other light in the video is for Fuel Pump Power. The drill is used to spin the distributor to generate a reference pulse so the computer will "WORK".

dave w

http://i239.photobucket.com/albums/ff290/buildabot2002/TPI System/th_DSCN3633.jpg (http://s239.photobucket.com/albums/ff290/buildabot2002/TPI System/?action=view&current=DSCN3633.mp4)

[EagleMark]

For some reason there are differant colors in differant years. If you strip down a harness for stand alone wiring you can see junctions with all these ground colors.

I had one that fuel pump reference signal was grey?

[dave w]

For some reason there are differant colors in differant years. If you strip down a harness for stand alone wiring you can see junctions with all these ground colors.

I had one that fuel pump reference signal was grey?

I've also seen different colors for different years. I'm thinking its ALWAYS best to have the wiring diagram from the TBI donor vehicle, just to make sure the wire colors match the harness. I'm thinking its an excellent idea to bench test the harness just like, or similar to the method I showed in the video. I'm thinking its WAAAAAAAAAAY easier to fix, or figure out a wire harness problem on the bench rather that in a vehicle!:thumbsup:

dave w

[EagleMark]

Pin to Pin is always perfect when colors don't match! Digatal Volt Ohm Meter is your freind.

I agree on building the harness on bench. Since I've been doing this I've never had an issue when installed or started. But since he is doing a retrofit I'm not sure this would work? He's using part of trucks CCC system to start and combining with EFI TBI system.

[caliphatman8123]

I still have the donor truck if it would be easier to rob the fuse block out of it and wire it in... would really like it to look like it came from the factory that way... lol

[EagleMark]

That would be my first choice. Just don't know the complications. Would be cleaner in the end even with more work!

[caliphatman8123]

That's what I was thinking... lol I may drop my gauge cluster and remove the dash pad and see how bad it would be sometime in the next week or so....

[dave w]

I've built standalone TBI harness that looks factory? Below are a few pics. The service items, fuses and fuel pump relay were located on the knock sensor bracket. The pink wire from the standalone harness is connected to the old HEI BAT pink wire. The battery + wire from the standalone harness is connected to the large post on the starter solenoid. The Battery - from the standalone harness is connected to the knock sensor mounting bracket bolt. The start wire from the standalone harness is connected to the "S" terminal of the starter solenoid. The standalone harness included a three wire heated O2 sensor upgrade, and 2 Pin Weatherpack connector was wired for the fuel pump. The EGR has been blocked off, and the EGR solenoid removed from the knock sensor bracket to allow room for the fuel pump relay and fuses.

dave w

[EagleMark]

It's not that hard to pull dash, cluster, glovebox, I would, just to do the TBI swap. ECM, VSS, DRAC, Park/Neutral, power are all under there. What transmission? Brake switch wires for TCC. Although all this stuff is probably already over to CCC ECM.

Does anyone have CCC wiring diagrams?

[EagleMark]

I like that bracket and wiring Dave! :thumbsup:

[dyeager535]

Sorry not ignoring, just no time.

The TBI side of the fuel lines is the one with the braided section crimped to the hard lines. Tank ends should be removable braided sections. I don't believe the K5's or 'burbs used rubber hose with clamps on TBI due to the passenger compartment extending over the tank.

Use the factory fuse panel. There are ways around it, but running the ECM wiring, injectors, etc is not as clean as running factory. If you install the '88 wiring in the truck, you buy an '88 wiring diagram and the troubleshooting works the same as it did on the '88. Believe me, I've been there, if you have codes that require flow charts, it's easier to follow factory wiring than what you've done. Not impossible to cobble things together, but it's a bit more complex.

[caliphatman8123]

That's a way clean set up... I do have to keep the egr and wiring for that... but what do I do about the huge plug that goes where the cluster of wires went that I'm reducing down to that goes? I'm sure I'll need it for the accessories(a/c, alternator... and the other stuff)? And I need to swap over the ALDL wiring inside... I still have a lot to wire up... lol

[EagleMark]

Looking at the big picture is good but in the end it's one wire at a time.

[caliphatman8123]

So I should be able to transfer all the wiring under the dash to the blazer from the burb?

[EagleMark]

Not to add EFI.

Changing all would scare me!

[caliphatman8123]

It kinda scares me too... lol but I'm thinking it may be the only way to get the look and functionality I want... like you all said one wire at a time... lol it's not impossible and could be the best way

[dave w]

There are several options on how to wire in the TBI. There is the cost vs. time factor; which usually means the less time spent working on the wiring harness usually has the highest cost...or does it? http://www.larryselectricsite.com/storefront/viewitem.php?productid=3&groupid=0 I'm thinking the EGR wiring for a Larry's Electric TBI harness is extra $$.

dave w

[dyeager535]

The wiring will most likely all transfer over, the radio plug MIGHT have changed. Power windows, door locks etc all unplug from the harness.

If you want to convert over to the '88+ front end, this would make that easier too.

[caliphatman8123]

It's not that hard to pull dash, cluster, glovebox, I would, just to do the TBI swap. ECM, VSS, DRAC, Park/Neutral, power are all under there. What transmission? Brake switch wires for TCC. Although all this stuff is probably already over to CCC ECM.

Does anyone have CCC wiring diagrams?

I'm running the 700R4 that was in it... the burbs wiring look a lot scarier than I thought... lol the ALDL is already in the blazer... the more I look at it the better the stand alone for the efi sounds better... just have to. Figure out how to keep the egr and all my accessories

[caliphatman8123]

:rolleye:I also pulled the harness out from the blazer it was a tangled mess and need to lay it out straight so I could figure out how to start piecing this thing together...

[dyeager535]

Unless you thoroughly understand the harness and connectors (IE what each wire and connector does and goes to), my opinion is that making a standalone harness doesn't get you anywhere. There isn't anything extraneous on the factory harnesses except maybe AIR, AC, and EGR that you could/would want to get rid of. Not a lot of extra wiring.

I don't know about the '84 specifically, but if it's got the "old style" fuse panel (the one that doesn't have all the accessory terminals along the top, instead scattered about the panel) it's a good idea to replace it anyways. The later ones offer FAR more flexibility in expansion circuits that are controlled by the ignition switch.

[caliphatman8123]

Just a question... does anyone have a wiring diagram for a stand alone tbi for the 5.7L... just not sure where to start and I'm very limited on funds so I'm thinking I might try to make the harness myself... besides then I can take credit or blame for it working or not working... lol

[dave w]

What year / vehicle / engine TBI wiring harness are you going to use to build a stand alone harness? Knowing which wires are, battery +, Battery -, ignition switch on / start, and crank input for the computer is a good place to start. Knowing what year / vehicle / engine the donor TBI harness really helps!

There are several ways to build a standalone harness, converting a used harness is usually the lowest cost way to go about building a standalone harness. Soldering wires and connectors will save money. Butt splices, will cause problems in the long run! I've done precise electrical measurements on soldered wires vs. butt spliced wires. One butt splice in the middle of 5 feet of 16 AWG wire is equal to about in 4 soldered wires to make 5 feet of 16 AWG wire length!!! There are several wire colors that are used for more than one function. There are several wires in the harness that have nothing to do with the TBI! There are likely some wires that will need to be added to the harness, ALDL connector and Service Engine Soon light are a couple I can think of. Quite often wire lengths will have be changed, longer or shorter.

dave w

[PJG1173]

I used the wire diagrams in the ecu info threads to build my harness. Ditto on using solder and heat shrink vs butt connectors. It took me about a week to build my harness working on it about 2 hours a night. Having a label maker will also be a huge help keeping the same colored wires mentioned above organized.

[caliphatman8123]

Well I have both the wiring harness from the 84 K5 off and the wiring harness from my donor 87 5.7 tbi engine off and gonna see where that takes me... lol

[dave w]

Well I have both the wiring harness from the 84 K5 off and the wiring harness from my donor 87 5.7 tbi engine off and gonna see where that takes me... lol

I use a full size sheet of plywood held up by saw horses to make a temporary table to organize the wiring. Label everything! I put a complete TBI intake / EFI system on the table and start hooking things up.

dave w

http://i239.photobucket.com/albums/ff290/buildabot2002/TBI%20TEST%20BENCH/DSCN2730.jpg

[caliphatman8123]

This wiring is driving me nuts... from what I can tell I need to splice in the altenater, a/c and started wiring... that will be the easy part... its making the efi and making sure the gauges work properly and the ALDL works

[dyeager535]

Assuming this wiring is for the CS series alternator, I would advise dumping the older SI series and going with the CS. Normally it's output is much higher than the SI, and in my case, is much better at keeping up with electrical load at idle.

Not sure what starter wiring would need spliced, GM used the same starter setups throughout AFAIK.

[caliphatman8123]

ok if the efi harness off the donor connects to all the sensors and all that already works... then all I should have to do is figure out how to wire in that harness to the fuse block that plugs into the outside part of the firewall of truck... right??? basically connecting all power wires and grounds... I really wish I had a blown up view of the wiring that went to each of those plugs to compare... although the more I read and the more I stare at these harnesses the less scared I'm becoming... once the fear is gone I guess it will be an F' it moment and jump in... worst case senerio i screw it up and have to start over

[dave w]

The old EFI harness will need it's power (ignition on/start power, battery "+" power, and grounds like you describe. The old EFI harness will also need a wire connected to the "S" terminal of the starter motor.

Usually the ORANGE wire on the old EFI harness is Battery "+".
Usually the Pink wire with a Black Stripe is the Ignition Switch On/Start Power.
Usually the Black wire with a White Stripe is the Ground / Battery "-".

dave w

[dyeager535]

The '84 truck fuse panel, does it have all the "auxillary" terminals along the top, or are they still kind of randomly scattered around the panel? These are the single connector terminals, that have things like your rear power window hooked up to them, these are not the empty fuse slots.

Either way, you really only need to use two of those to power the EFI stuff (edit: not true, you only need ignition switched. If you add fuse panel underhood, run wire directly from battery to it)...ignition 12V, and battery 12V. This is what I initially used to "get around" the limitations of the older fuse panel, without having to hack it up: http://www.ebay.com/itm/ATC-ATO-6-way-Raised-Fuse-Block-/330849106383?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d0824b9cf&vxp=mtr Each of the auxillary terminals on the fuse panel is protected by a 30A breaker, but obviously you use the ebay-linked fuse block to properly fuse each EFI lead (ECM, injectors, etc). You really aren't going to want to try and use the engine side of the firewall connector to run this stuff, there are empty terminals, but it's just easier to run it under the dash over to the passenger side, and out through the heater or ESC grommet if you need to.

If you want something a bit more adaptable, on the ~early 90's Cadillacs they have a mini fuse terminal (actually the cars had three of them, one with just fuses, one with about 10 fuses and 2 relays, and another one I didn't look closely at) which could be used under-hood to do the same thing. The trucks have huge wasted areas on the firewall in the engine bay, normally with lots of bolts and holes, which makes mounting easy for something like this. Initially I wired the above linked fuse block in the cab, as it was close to the fuse panel, but have since changed over to the Cadillac one. The advantage to using the Cadillac fuse panel is that you can power multiple fuses off of ignition 12V, or battery, or however, instead of needing a separate 12V feed for EVERY fuse, which kind of makes the ebay linked one a mess when you start dealing with 6 fuses/12 wires.

If you start getting into other components like extra lights, headlight relay mod, electric fans (a waste on a truck unless you absolutely need them IMO) then you will start to see the advantage of going with a later fuse/relay center underhood...they are more compact than mounting the fuel pump relay in one place, the fan relay somewhere else, and the additional relay(s) to power the igntion 12V fuses themselves. This greatly cleans up wiring.

If you are locating the ECM behind the glove box, it also makes for shorter runs of wire to the ECM.

I hope this makes sense.

[caliphatman8123]

Another day stuck at work... its been to long to not be working on the K5... between work and making time for my family this project is taking way to long... I'm just itching to drive my truck... OK done with my rant... venting done back to work at work instead of on my K5... this sucks

[jameslleary]

I really wish i could get down there and help. 3.5 hours is a stretch.

[caliphatman8123]

Well update time... Wiring harness almost completed... Ty Jim for all the hard Dork you've put into this... I really appreciate it all

[EagleMark]

I hope that's a spell check issue and your not commenting on Jims hard dork?

:laugh:

[caliphatman8123]

Yes that's a spell check issue... Lol not commenting on his Dork... Lol his work he put in on my harness is amazing it looks great and he made it the way I wanted to so it all along...

[caliphatman8123]

Wiring harness is partially installed... Everything is connected to the motor... I need to install the starter and connect that wiring... There are a few connections to make on the firewall but nothing to major there... Then I need to finish up under the dash... I am hoping to be able to start it soon and hear the motor roar back to life... Still need to finish the fuel lines as well but already have the filter,just need a bit of fuel injection line to connect the two ends of the lines and then bolt them back to the frame rail... Another update coming soon