Yes, it is true. Each sensor is calibrated with a resistor so it's plug n play as there is no way to calibrate it thru the software.

 

Get the NTK O2 for sure, I learned that lesson.

 

Hopefully the one in the box will last a long time. I will follow the instructions.

So they test each one and add a resistor that gets the correct value? It would be to simple to just add a resistor. Hopefully I don't have to buy another one any time soon.

 

Got the O2 harness and passenger seat out yesterday. Tonight I changed the CTS and IAT. Then pulled the main harness through the firewall. Hooked up the TFI, injectors, IAT and CTS. So far it's going pretty good. Took a short video then my phone died. Hope to pull the power harness tomorrow.

 

I think I am making this harder than it should be. I was trying to not cut up my factory harness. I bought a box of wiring harness connectors off eBay it has most of the ones I will need and have been studying the factory wiring diagram trying to figure out what I need and what goes where. If I didn't want to keep the A/C water temp and oil pressure gauge it would be lot easier. I think the fuel pump power runs through the engine harness as well.

I have been thinking about going to the junkyard and looking at the other late 80's fords to see if there is a factory harness I can weed out. The smarter thing to do would be cut up the one I have.

 

Yeah,just use the one you have.

 

It's all in the manual, but there are some things you need to know before hand.
On the fuel pump, the stock ECU grounds the relay. The holley send s 12v+. One way is to power the pump directly with the Holley. Other way would be to ground the FP wire up near the stock ECU then send that 12v+ back into the stock 12V+ feed for the pump via the stock ECU Relay.

The stock water temp and oil pressure don't go through the stock ECU. They do get run into the harness. They come back out of the harness over by the brake MC. You look for an 8 pin connector with a R/W and a W/R wire. R/W is water temp, W/R is oil pressure.

 

Quoted for truth. We do this to every fox we holley swap or coyote swap. Oreillys has the push over connectors with a 6" pigtail. They call them cigarette lighter repair pigtails. Tach wire is one of the green wires going to neg side of the coil. You'll need to run the alt wire out of the same harness the temp and press wires come out of. It will keep the battery light off.

 

Thanks Disney Lincoln, that confirms what I have been reading.

Nxcoupe, would you weed out the stock harness. Or pull it and start with the needed pigtails and make a harness for the coil, sensors, tach, a/c, fuel pump. Is the dash powered though the green connector by the eec?

The OP, WT, tach, AC, coil go through the black and gray connector at the driver side by the dash.

I have the 1989 factory wiring diagram. I have been studying them. I am dangerous at best when it comes to wiring. My biggest complaint about the diagram it just shows you were it goes. Some times it would be nice to know if it was +, -, in, out, trigger, etc. But I guess the experts know what's what. I have to slowly track it down.

 

Def leave it in. You just stated you're not great with wiring so that is quite an undertaking wiring an entire car and not burning it to the ground. Most guys I see yank all the wiring and start from scratch end up giving up on the project or it turns into a clapped out race car. Ford spent millions designing those harnesses, use their money and leave it be. Just tap into the harnesses.

 

Is that how you do them when you do the Holley install?

 

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I have already pulled the harness out. That was step one of the instructions. I said I was not good, maybe what I should have said was I don't have alot of experience.

Even if I cut it down and put it back in I would like to understand what I am doing. Hopefully I can learn something from this.

I think I have run and gauges mapped out (I need to redraw it so it's clearer). Need to look at a/c some more.

 

I think this will run the A/C. Ford powers the AC relay from the eec relay and both relays use same ground, is the Holley ok with that or should I add another relay

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Ok with what? Outputs shouldn't power over an amp of draw. The eec dosen't control a/c on a fox.

 

Will there be excessive load or noise? The way I understand the 12v+ out of the eec relay goes to both the a/c relay and fuel pump relay (on the trigger side? I plan to trigger the FP relay with the Holley green wire.) The ground used is the one that connects to the body then the battery.

 

That a/c relay you keep talking about is the WOT cutout relay for the a/c. It turns the compressor off at wot. It can be activated by one of your outputs, yes. The green wire can activate the factory fp relay as well because that green wire is designed for 5 or so amps.

 

Even though my car is a hodge podge of parts I still want to be able to go back in the future. I went to the junkyard and got an engine wireing harness out of an 88 t-bird. Other than capping off a few wires and adding the relay fo #ad
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r the coil. I think it about done.

The white wire from the TFI harness goes the coil (-) the factory wire to the eec has a resistor in it. Should I keep it with the Holley or cut it out?

 

Cut it out. Unless the holley instructions specify it, don't do it, is a good rule of thumb to follow

 

So I finished thinning and repining the T-bird harness. Got the Holley hooked to the factory power wires on the harness. Pulled the h+pipe drilled and welded in two new bungs and plugged the old two and one of the new ones.

I figured I would try both the left and right bank and see which one is leaner.

I need to put the H-Pipe in and hopefully crank it!

 

I have not done a good job of keeping my thread update. It fired up on the wizard tune easily but. The AFR was showing lean but it smelled rich, I could hear an exhaust leak. I didn't get the H-Pipe back on the header correctly. Second fire up went well, after correctly installing the h-pipe.

I have driven it a few times and it feels pretty good I really enjoy the data logging.

I got the A/C kick working I didn't change it from a ground to a 12V+ input once I realized that it's working as it should.

As far as hardware next I want to get a wheel speed sensor and the two step hooked up.

I would like to work on the timing table and maybe play with the AFR target table. The timing table the wizard spit out is very blocky. There is a base tune in the computer software that has more of a flowing timing curve. I have been thinking about trying that one. Anyone have and experience with the two tables? Can these table be exported to excel?