best general and efi harnesses

[4x4man514]

hey guys, ive been digging around on here and found some info but most of it seemed a little old and i wasn't sure what may have changed since then.

i've got prolly 80 % percent of my bronco done now but i've been avoiding the wiring like a hangover. definitely is not my strong suit.

i need to get a full harness and a efi harness for my 393 with a lightning intake and c3w1 computer. im not really good with wiring so i need some thorough instructions to help me out with this. years ago i bought a rf kit and i think it was a little too universal. had chevy switches and everything. the instructions were a bit broad for me and prolly why ive been avoiding this for so long. so recently ive been looking at the painless 28 bronco kit and the ron francis mass air 5.0/5.8 kit. but im not too sure about how these relate to one another or if there is a better combo to go with for the wiring illiterate like myself. these seem to have pretty detailed instructions. but since ive bought neither yet i can still go any direction. which kits do yall think would be a good fit for me?

and how ell do these work with aftermarket gauges and i think its a 3g alternator i have?

and i didn't see a circuit on the efi kit for a purge cannister, would this be difficult to add in? or could i do without?

and for those of you with the painless kit, how far does the fusebox protrude out the side of the box? i relocated my glovebox over to clear the roll bar and its right next to the heater controls. prolly about a 6 inch shift. and do yall think that will affect me as far as the length of the wires?

and i also read somewhere that if you have a computer for an auto and put it in a vehicle with a manual it would burn it up. any truth to this?

thanks a bunch guys . i've had my bronco over 10 yrs now and haven't been able to enjoy it. hopefully i'm on the tail end of this journey!

 

[SevenT]

Get with EFI Guy here on the forums and he can point you in the right direction for a harness. Get R Dun.

 

[Timmy390]

I've not used them as I built my own BUT...Ron Francis seems to be what many run.

https://www.ronfrancis.com/

Tim

 

[904Bronco]

So it looks like you want to run Mustang EFI.

The Ron Francis harness or the Wild Horse's harness (same thing) is very simple to install, just a few wires to hook up. ( I think it has wires for gauges and one for AC clutch, been a while since I installed one) Auto trans vs Manual trans ECU's - back in the day of Fox body mustangs... Auto ECU's had better fuel curves because the AOD was a Dog. I ran my 92 with an auto trans ECU after I converted it to a T5. You did have to change out the Hego harness (O2sensors) as that was how they configured things for Auto vs. Man.
The two harness above have a simple plug swap, for one or the other.
My concern is you don't have a stock motor and you probably will need some tuning to get everything to play nice together?
The above harnesses don't have EGR or Can purge. I am guessing Can purge could be added by adding the appropriate wires to the harness, it is just not there.

I haven't installed a painless harness, but I know the AAW harness comes with a diagram if you are running aftermarket gauges. I and sure Painless would have something similar or their Tech could help you with that. All it really is using the aftermarket sensors, getting that wire(s) to the gauge, power in run, grnd, and dash lights power.

Remember, wiring is one wire at a time... Soon you run out of wires.

 

[WILDHORSES]

Just to add so clarification to this discussion Ron Francis is the manufacturer of the WH Bronco EFI harness. It is a different harness than the one they sell at this time. In the past it was the same. What we did was have them make ours very early Bronco specific. Dirtdonk helped with some of the specs which primarily added some length to certain leads to make it easier for the Bronco installation. The are in stock (6/13/22) ready to go for anyone interested.

https://www.wildhorses4x4.com/produ...tion-Harness-86-95-Ford/Bronco_Wiring_Harness

Jim

 

[DirtDonk]

And of course the last time or two that 904Bronco bought the harness from us, RF had shipped the wrong one and he got the standard RF harness instead of our custom length version.
Still sorry about that Doug!

However it should all be good now and all those extra lengths should be in every one we currently have.

 

[DirtDonk]

As for compatibility and ease of install, these engine harnesses come with a jumper connector designed to connect directly to the factory engine connector.
This means that the Painless chassis harness should be easily compatible as well since I believe they use the same type of three wire connector at the back of the engine.

That connector supplies switched power to the computer and feeds from the coolant temperature in oil pressure senders to run the stock gauges.
Aftermarket gauges would need to be adapted by the installer.

You’ve got a lightning intake, but what about the rest of the induction system? Standard stuff?
I don’t know computer code number compatibility myself, but if it’s the same as 86 to 93 Mustang basically then the engine harness should be just fine.

As for the evap system, what are you utilizing? Standard bronco charcoal canister? Later model charcoal canister?
You can leave it connected as original, or you can add the CAN–P circuit as 904 was mentioning, but you’ll have to have the that part custom-made or use an engine harness from a factory set up.
Either way is very doable, but keeping it in standard bronco form would be the simplest path.

 

[4x4man514]

So it looks like you want to run Mustang EFI.

The Ron Francis harness or the Wild Horse's harness (same thing) is very simple to install, just a few wires to hook up. ( I think it has wires for gauges and one for AC clutch, been a while since I installed one) Auto trans vs Manual trans ECU's - back in the day of Fox body mustangs... Auto ECU's had better fuel curves because the AOD was a Dog. I ran my 92 with an auto trans ECU after I converted it to a T5. You did have to change out the Hego harness (O2sensors) as that was how they configured things for Auto vs. Man.
The two harness above have a simple plug swap, for one or the other.
My concern is you don't have a stock motor and you probably will need some tuning to get everything to play nice together?
The above harnesses don't have EGR or Can purge. I am guessing Can purge could be added by adding the appropriate wires to the harness, it is just not there.

I haven't installed a painless harness, but I know the AAW harness comes with a diagram if you are running aftermarket gauges. I and sure Painless would have something similar or their Tech could help you with that. All it really is using the aftermarket sensors, getting that wire(s) to the gauge, power in run, grnd, and dash lights power.

Remember, wiring is one wire at a time... Soon you run out of wires.

yes i guess i'm going mustang since my eec is a c3w1. are there better options for me to go with? i know you said i might have difficulty tuning since my motor wasn't stock. i was told long ago when i started this project that the mass air system would compensate for the mods. but i guess that's only up to a point? like i said i don't know this stuff but as of right now i haven't bought anything. so if i need to go a different route i'm all ears.

as far as adding the purge to the harness, is that a difficult thing to do? i may not need it but if its gonna be parked in my garage i didn't want everything smelling like fumes.

and to make sure i understand you, my eec is for an auto, i'm running a zf5 speed, so i just need to buy a manual specific hego harness? does it still utilize the favorable fuel curves you were speaking of when it is set up like this?

are there any other "sub" harnesses i will need to buy? like alternator or anything? as of right now i have zero wiring so i'm trying to make sure i have everything before i start.

thanks!

 

[4x4man514]

Just to add so clarification to this discussion Ron Francis is the manufacturer of the WH Bronco EFI harness. It is a different harness than the one they sell at this time. In the past it was the same. What we did was have them make ours very early Bronco specific. Dirtdonk helped with some of the specs which primarily added some length to certain leads to make it easier for the Bronco installation. The are in stock (6/13/22) ready to go for anyone interested.

https://www.wildhorses4x4.com/produ...tion-Harness-86-95-Ford/Bronco_Wiring_Harness

Jim

i know at the ron francis site they ask which side the throttle body is on. are the bronco specific harnesses set up one side or the other?

thanks!

 

[4x4man514]

As for compatibility and ease of install, these engine harnesses come with a jumper connector designed to connect directly to the factory engine connector.
This means that the Painless chassis harness should be easily compatible as well since I believe they use the same type of three wire connector at the back of the engine.

That connector supplies switched power to the computer and feeds from the coolant temperature in oil pressure senders to run the stock gauges.
Aftermarket gauges would need to be adapted by the installer.

You’ve got a lightning intake, but what about the rest of the induction system? Standard stuff?
I don’t know computer code number compatibility myself, but if it’s the same as 86 to 93 Mustang basically then the engine harness should be just fine.

As for the evap system, what are you utilizing? Standard bronco charcoal canister? Later model charcoal canister?
You can leave it connected as original, or you can add the CAN–P circuit as 904 was mentioning, but you’ll have to have the that part custom-made or use an engine harness from a factory set up.
Either way is very doable, but keeping it in standard bronco form would be the simplest path.

what exactly are you asking about the induction system besides the lightning upper and lower?

it looks like my eec is for a 1993 mustang auto.

we talked about my evap system on another thread some time ago. i was asking in reference to gas caps then. right now i still have all the stock can in place and was planning on tying the can p valve into that and rolling. but now hearing the harness doesn't support it i'm not sure. i do plan on keeping my eb in the garage so i don't want to stink the place up with gas but i don't really know how well the factory system works if i just run a vent off the can. is it worth the trouble of modifying this brand new harness?

thanks!

 

[DirtDonk]

I think the newer systems with the computer controlled solenoid were probably more efficient, but there was never anything wrong with the early ones either.
They still did the same job of keeping the fumes inside the system and not out in the garage. They just use the gentle suction of the air filter rather than the hard vacuum of the intake manifold.
So yes, even the old system without the Can-P valve work very well.

 

[4x4man514]

I think the newer systems with the computer controlled solenoid were probably more efficient, but there was never anything wrong with the early ones either.
They still did the same job of keeping the fumes inside the system and not out in the garage. They just use the gentle section of the air filter rather than the hard vacuum of the intake manifold.
So yes, even the old system without the Can-P valve work very well.

So I how would I vent the cannister in that case? One to atmosphere and one to coolair box?

 

[DirtDonk]

Exactly right.
Small one collecting vapors from the condensing tank in the cab.
One large one vented to atmosphere inside the engine compartment. Higher up keeps debris and water away.
Second large port into the air cleaner housing.

Where it becomes less effective is if you have an open air cleaner element. It still works to a certain extent in that case, but probably can never be 100% effective.

Do you still have the plastic tank under the panel cover beside the drivers shoulder?

 

[DirtDonk]

i know you said i might have difficulty tuning since my motor wasn't stock. i was told long ago when i started this project that the mass air system would compensate for the mods. but i guess that's only up to a point?

Correct. Only to a point…
I don’t know anything about your specific computer, so there may be more details, but in general if everything on the engine is stock but you change something like add headers, or a mild cam you can probably count on the computer to compensate.
But once you change cubic inches, injector sizes, mass air meter and throttle body sizes, and also add a cam and bigger exhaust, all bets are off. You may have to have a custom tune to get the most out of it.
Doesn’t mean it’s difficult, just means it’s another step to make it right.

and to make sure i understand you, my eec is for an auto, i'm running a zf5 speed, so i just need to buy a manual specific hego harness? does it still utilize the favorable fuel curves you were speaking of when it is set up like this?

Wait for a definitive answer, but don’t think it’s the HEGO aspect. Or at least not by itself.
The computer is expecting different inputs from things like a VSS and a different ground location in the main ECM harness pinout. (Wire location)

But the nice thing about the EFI harness we’re talking about is that all you have to do is plug it into the computer and make sure the gray and black jumper wires are switched to the automatic location.
That’s all you need to do to change between manual or automatic computers. Doesn’t matter what transmission is being used as long as the wire harness is oriented to the ECM.

are there any other "sub" harnesses i will need to buy? like alternator or anything?

Alternator certainly. Depends on which way you are going. Did you say you’re doing a 3G? Or Explorer front set up perhaps?

 

[DirtDonk]

i know at the ron francis site they ask which side the throttle body is on. are the bronco specific harnesses set up one side or the other?

I can’t say from personal experience that it wouldn’t work with a driver side oriented induction, but by far the most common orientation is with the throttle body facing the passenger side.
It isn’t just to suit the harness though, as there’s just more junk on the driver side to work around. Power brake boosters, pumps, steering systems and such.

 

[DirtDonk]

what exactly are you asking about the induction system besides the lightning upper and lower?

Whether or not there were any aftermarket add-ons, such as a larger platinum to take the place of the stock lightning upper. And any changes to the throttlebody location or intake tract shape and length. Just general stuff mostly.

we talked about my evap system on another thread some time ago. right now i still have all the stock can in place and was planning on tying the can p valve into that and rolling. but now hearing the harness doesn't support it i'm not sure.

i do plan on keeping my eb in the garage so i don't want to stink the place up with gas but i don't really know how well the factory system works if i just run a vent off the can. is it worth the trouble of modifying this brand new harness?

Whether it’s worth the trouble is entirely up to you. If I had a preference, I’d rather have the system controlled by the computer. But if I had to add it to an existing harness, I totally pass on it. I just hook it up like the factory had it from 1970 until the computers took over in the 80s.
It sounds like you’re going to make an airbox for the filter. That shouldn’t hands the function of the charcoal canister system.

 

[904Bronco]

Damn Paul, I just can't keep up with you...

A few short answers...
An ECU has some set parameters that it operates in. When you have larger injectors, bigger TB or MAF, different cam, intake, etc. it may not be able to compensate for all that . A tune, piggyback chip, may need to burned to compensate and give you all that you are hoping to gain. The MAF should be calibrated to the size of injectors you are running.

If you buy the WH's/RF EFI harness it has a single weatherpack plug that plugs into one or the other connectors to determine Auto or Man ECU selection. The O2 sensor harness, which was separate in the mustang is incorporated to the engine harness as a single harness. Very easy to use!

Canister purge operates at engine cruise speed, say 2000 rpm or so. It allows engine vacuum past the purge valve to draw vapors out of the CC. Some Bronco have a gas smell, others do not. Don't ask me why... If you add it, it should be as simple as adding two pins to the ECU plug/harness. Simplified, the valve has power to it when the engine is running, at the correct rpm, the ECU sends a Grnd signal the valve causing it to open. It would be a matter of adding these two things to the EFI harness. Since it is a Ron Francis product (Based on Ryan's design), I would think they (Tech) could help getting that in place. There are also a few Folks here that could that answer that for you as well.

I would suggest using a 87-93 fox body mustang charcoal canister, (The canister was used on many ford products of that era and beyond) mounting it high like the 76-77 bronco, run a vent line back to your tank(s) and then do as Paul suggests, sort of the passive system with air being drawn into the TB at the air cleaner to create the vacuum to purge the tank or go with the Canister purge valve option. Number of threads on here about that...

 

[4x4man514]

thanks a whole bunch guys! i don't know what id do without yall! im starting to get it.

so i guess first question since apparently my motor does fall into that other category. as said b4 i am at 393 cubes. lightning intake with 70mm MA and TB(i think). dark blue or purple injectors which i think are 36#. aluminum heads and a pretty healthy cam(not huge). so do i still use my c3w1 computer? are yall saying it can be changed? or am i better off going with something else to begin with?

i still have my in cab vent tank and it is plumbed up correctly. it seems if i used the stock system and plumbed it into air box it would still be just venting to the atmoshere since that would be b4 the filter so i need to somehow plumb it into hose? or just get this can p thing figured out and go that route. so i guess by what yall are saying you can add or remove wires on the main plug on the computer ?

so am i understanding yall right when you say all the o2 sensor wires i need are already included in the harness?

right now my tb is pointing toward the passenger side, im just trying to verify the harness is or is not set up for that.

i think my alternator is a 3g but i dont see it written anywhere. how can i confirm that? and as for brackets i have 1990 f250 brackets on it now. i havent dropped it in yeat so i dont know if ill have issues there or not. but it is on the passenger side. are explorer alternators on the passenger side too? i just thoought i needed to make sure the harness will reach everything ok

and the last thing is nobody answered me about the glovebox. i shifted my glove box location over about 6 inches. its pretty tight against the heater controls. how far does the fb protrude outside the glove box? and do yall think that will cause some length issues with my harness? and also where is the hole for the harness to go through the firewall at?

thank you so much again guys!

 

[bronco italiano]

For sure contact EFI guy and send him your ECU and motor specs and have a chip made along with any diode replacements the ecu may need (he told me every 5 years to service the diodes).
I used Painless and am still very pleased. I used the AAW for my sons Firebird and you need to buy 100 worth of crimpers too terminate many wire ends.
-There should be a ton of EFI Ford guys in your area, it may be safest to have one of them do the wiring.

 

[stretch]

I'll jump in here, since the RF harness is what I run on an Explore motor. The loomed harness is generally set up to run the TB on the passenger side, although you could purchase the harness that is not loomed and customize to your liking.
The tank vent solenoid is difficult to wire at the computer, but several have just bypassed the solenoid and vented the charcoal canister to an inlet at filter. You would need a vented gas cap, as I believe it would pull a little vacuum through the canister constantly. I attached a link below from Duff. I PM'd him several months ago to ask if he had any problems with this venting setup and he hadn't. Just something else to consider.

https://classicbroncos.com/forums/attachments/20170121_053637000_ios-jpg.411603/