so im adapting an s4 n/a harness to work with an s5 turbo motor. I of course am changing to new s5 injector pigtails. My question is: how do i know which injector clip on the harness goes to which injector? also there appear to be 6 injector looking clips but there obviously only four injectors are the other two for emissions equipment that i no longer have? how do i tell the difference between the 6?

Also i deleted my BAC valve, cant find any info on if im supposed to cap off the coolant lines at the thermostat housing and rear iron or run a line between the two?

 

Wire color(s). Look at an N/A wiring diagram at the back of a series four FSM that will display the EM harness connectors and wire colors. - Hint: On the S4 N/A harness, the primary fuel injector clips come off of the same branch and the secondaries come off of their own separate branch... As opposed to the S4 turbo wiring harness where the front primary and front secondary fuel injector clips are on the same branch and the rear primary and rear secondary fuel injector clips come off of the same branch.

Four for the fuel injectors, of course. One for the BAC valve. One for the water thermo sensor. (You absolutely need the water thermo sensor and fuel injectors to be hooked up.)

The BAC valve clip is blue... I THNK. Which would mean that the water thermo sensor clip would be green. I cannot remember. You should be able determine which is which between reading the wire colors in the series four FSM.

You can either cap them or route them to one another.


-> FREE Online Factory Service Manual: '88 FSM

 

omg thank you for the fsm link! been unable to find one, will be extremely helpful!

would you suggest capping them or routing them to eachother? there isnt too much pressure behind them when they are capped?

 

so the fsm isnt as helpful as i thought it would be. if it says injector (f-s) i assumed that meant front secondary, correct? LG/W and B/Y means? are those the colors of the wires? light green/white? black/yellow?

sorry if i sound like an idiot just not sure how to read it. and yes i read the intro that says how to read the fsm...

 

The Factory Service Manual is pretty helpful when used properly.


I have had mine capped for quite some time now. No issues.

Correct. (F-S) Front Secondary, (F-P) Front Primary, (R-S) Rear Secondary, (R-P) Rear Primary

Wire colors are in the FSM somewhere. I know that in the '87 FSM they're in section 15 "Body Electrical System; Introduction" (15-4)

CODE > COLOR

B > BLACK
Br > BROWN
G > GREEN
L > BLUE
Lb > LIGHT BLUE
Lg > LIGHT GREEN
O > ORANGE
R > RED
Y > YELLOW
W > WHITE

Examples: BrB is going to be BROWN with a BLACK stripe. BW is going to be BLACK with WHITE stripe.

 

Did the wiring harness colors change throughout series 4? My wiring harness came out of an 87 but I am unsure if it was a high or low impedance car.

 

Dors it have a resistor box? If so its a low imp car.

 

is that the little box down by the passenger headlight? i think it did... will this harness not work?

with whatever harness i use, does the polarity matter on the new injector clips?

 

^ Yes.

You can simply just remove the solenoid resistor pack.

 

Thank you again dwb87. I was up late last night reading and saw that I have to combine all five wires together that go to the low impedance box?

And how do I determine the polarity of the injector pigtails? And does the 87 low impedance harness have the same color wires that I see in the 88 fsm? Can't locate the early 87 fsm :/

 

bump

 

so i can not for the life of me find and 86-87.5 engine wiring harness diagram.

I cannot figure out which injector is which, all i can find is the 88 fsm which doesnt match the low impedance harness at all..

 

Figured that stuff out, Haynes Manuel came in handy for once as soon as I found a microscope..


New question, I'm concerned about having too much fuel pressure at idle with the walbro 255 and stock fuel rails, pulsation dampner, and stock fpr.

Can I run an aftermarket fuel pressure regulator with my stock fuel rail set-up?

 

you'll have to take the stock fpr off the rail in order to run an aftermarket Fpr.

 

Cut it off and re-tap the rail to whatever size fitting I need or does the stock fpr come right off? I didn't think to check it out when it was all apart. Once it's all hooked up what's a good psi to be at?