I am in the middle of converting my new 90 speed density harness to work with my cars 1985 wiring. I want to change the pin outs in the c100 connector of the engine harness to match up with the cars 85 wiring from the bulkhead. Below I have a picture of the c100 from 85 and 90. A couple of the pin outs have me confused about where to put them.

A7 from the 90 harness is called "Emission Control". There is no spot in the 85 wiring that has so, so do I just ignore it?

F8 on the 85 is labeled for the charging system. On the 90 it is Air bags. So should I remove the air bag wire from that harness and replace it with the G8 pin out on the 90 harness which is called starter and charging system/coolant fan relay?

G4 is not used on the 85 bulkhead but it on the 90 and is for the fuel pump relay. How do I go about adding this to the 85 wiring so the fuel pump still works?

I have read the tech section about this swap but still couldn't answer these questions. I would really appreciate any help. I have two attached pictures of the wiring pin outs.

 

A7 is an ignition power to control the evap and other emission equipment. It believe it comes from the gauges fuse.

F8. Yes. move the wire. I believe F8 on the 85 is to the volt gauge which also energizes the alternator.

G4. On the 85 harness, the fuel pump relay AND the wire to power the pump go through the C207 which is the connector under the dash on the passenger side.

 

Thanks. So A7 just gets left alone? So for the G4 pin, how do I go about matching them up to work with each other so I get my fuel pump to work? Sorry, this is all confusing to me.

 

NP. I converted a v6 harness into my car (cheaper, same ecm just need to modify a couple of things).
A7 can be used to power your evap can, egr solenoid and your AIR valves. You can also use it to power anything you want that is ignition hot. Make sure you don't overload the circuit or tie too many things on it.
The fuel pump is tricky. On your car, the fuel pump power wire is in the C207. on the SD harness it is on the C100, opposite ends. You either need to modify the engine harness so that wire is run to the C207 OR modify your dash/interior harness to runt he wire to the C100. As you have the engine harness out, its easier to modify that one. I have a bunch of info at home that I can post when I did my swap.

 

That info would be great. Thanks

 

Here is the c207:
85-87

Pin “A” = brown wire from ECM pin “A2" connector “C1" to pin “C” of ALDL
Pin "B" = Fuel Pump Diag (ALDL pin G)
Pin “C” = brown/white wire from pin “13" connector “C2" (ses light) of inst. Cluster to pin “A5" connector “C1" of ECM
Pin "D" = Fuel Pump Feed/power
Pin “E” = white/black wire from pin “B” of “ALDL” to pin “A9" connector “C1" of ECM(Diag)
Pin "F" = Eng Control FUse
Pin "G" = Gauges Fuse
Pin “H” = tan/black wire from TCC solenoid to pin “F” of ALDL (automatics only)

Pin “J” = orange wire from ECM pin “A8" connector “C1" to pin “E” & “M” of ALDL
Pin “K” =brown wire from ECM pin “A10" connector “C1" to pin “F” of VSS buffer

Pin “M” = black/white wire ground to back of each cylinder head(To ALDL pin A)
Pin “N” = orange/black wire from ECM pin “B10" connector “C1" to pin “B” og gear selector switch (auto only)
Pin "P" = TCC switch (disengage the TC)
Pin "R" = Cold Start (Crank Fuse)

C221
Pin "A" = Injector Fuse 2
Pin "C" = Fuel Pump/Fan Fuse
Pin "D" = Injector Fuse 1

C207 - 88-89
Pin “A” = brown wire from ECM pin “A2" connector “C1" to pin “C” of ALDL
Pin “B” = Injector Fuse
Pin “C” = brown/white wire from pin “13" connector “C2" (ses light) of inst. Cluster to pin “A5" connector “C1" of ECM

Pin “E” = white/black wire from pin “B” of “ALDL” to pin “A9" connector “C1" of ECM(Diag)
Pin “F” = pink/black wire from “ECM-IGN” fuse to pin “A6" connector C1 of ECM & pin “B” of ESC module
Pin "G" = Injector Fuse
Pin “H” = tan/black wire from TCC solenoid to pin “F” of ALDL (automatics only)

Pin “J” = orange wire from ECM pin “A8" connector “C1" to pin “E” & “M” of ALDL
Pin “K” =brown wire from ECM pin “A10" connector “C1" to pin “F” of VSS buffer

Pin “M” = black/white wire ground to back of each cylinder head(To ALDL pin A)
Pin “N” = orange/black wire from ECM pin “B10" connector “C1" to pin “B” og gear selector switch (auto only)

Pin “R” = purple/white wire from Crank fuse to C207, then purple wire to pin “2" of cold start switch and purple/white wire from splice to pin “2" of cold start injector.


C207 - 90-92

Pin “A” = brown wire from ECM pin “A2" connector “C2" to pin “C” of ALDL
Pin “B” = Injector Fuse
Pin “C” = brown/white wire from pin “13" connector “C2" (ses light) of inst. Cluster to pin “E7" connector “C3" of ECM
Pin "D" = B11 c1 to c8 c2 gauge cluster vehicle speed input (digital dash?)
Pin “E” = white/black wire from pin “B” of “ALDL” to pin “E12" connector “C3" of ECM(Diag)
Pin "F" = Eng Control FUse
Pin "G" = Injector Fuse
Pin “H” = tan/black wire from TCC solenoid to pin “F” of ALDL (automatics only)(upshift indicator)
Pin “J” = orange wire from ECM pin “A8" connector “C1" to pin “E” & “M” of ALDL
Pin “L” = VATS
Pin “M” = black/white wire ground to back of each cylinder head(To ALDL pin A)
Pin “N” = orange/black wire from ECM pin “B10" connector “C1" to pin “B” og gear selector switch (auto only)
Pin "P" = c1 c2 to cruise control module

The c221 is the 6 pin connector that has your fan/fp fuse and the injector hots. In the SD harness it was incorporated into the c207. The 86 should be very similar if not exact to your 85(86 pinouts were taken from my car). The 90 should be the same as the 90-92 harnesses. Check to make sure the pinouts are correct and use the above as a reference. Threw in the 88 c207 as a bonus if anyone else needs it.

 

More pics. This should point you in the right direction. PM me if you need anything else. For your fuel pump, you need to take out the wire from the 90 harness in terminal G4 on the C100 and route it to the C207 pin D under the dash. On the 90 harness it should be a grey wire that goes to the fuel pump relay. The brown/white wire in the fuel pump relay on the 90 harness then has to go to Pin C on the C221 under the dash to energize the relay.

 

I think I have most of the c100 pin-outs figured out. What other changes need to be made to the c207 connector for everything to operate correctly?

 

Take a look above at the list of c207 pinouts. Make sure that the 90 harness is the same as the 85. Three of the top of my head are to move the injector hot and fan/fp to the c221. There are a bunch of other ones that need to be moved as well.

 

This is what I've come up with for the c207 wiring.
A Stays
B ?
C Stays
D Run wire to this pin from G4 wire in the c100 connector
E Stays
F Stays
G ?
H Stays
J Stays
K ?
L?
M Stays
N Stays
P ?
R ?

The other few I need some help with.

For B, the 85 harness is listed as Fuel Pump Diagnostic Pin G of ALDL. the 90 says injector Fuse. Do I just run a wire from pin B on the 90 harness to the c221 connector for the injector fuse? if so does it go to injector fuse 1 or 2?
For G, the 85 harness has it listed as Gauges Fuse and the 90 harness is injector fuse. Do I do the same on this one as well and run a wire from pin G to the c221 again? And if so, to the injector 1 or 2 spot?
L is listed as vats on the 90 and is unlisted on the 85. Can this just be left alone?
P on the 85 harness is TCC switch and on the 90 says c1 c2 to cruise control module. Not sure what to do here.
R on the 85 is cold start/crank fuse and is unlisted on the 90. Can this be left alone?

I'm not sure what to do with the fuel pump/fan fuse wire in the c221 connector as well?

 

All changes are done on the 90 harness to match the 85.
Pin B needs to be unpinned and put in the c221. Does not matter which injector bank.
Pin G is the same as above, does not matter which one.
Pin L Yes. Your car does not have VATS
Pin K you need to run a wire from the 85 harness c207 to the ecm so that it can get the vehicle speed.. I cannot remember the pin at the moment, but can check.
Pin P. Pin H on the 90 harness has to go here.
Pin R Yes it can be left as is. The 90 harness does not have a cold start circuit.

You will need to run a wire from fuel pump/fan pin on the c221 all the way to the fuel pump relay on the firewall near the c100. This energizes the relay.

On the 90 harness at the fuel pump relay you will see a short red wire that just hangs off the relay. This is the fuel pump diag port. If you really want, you can run a wire from this to Pin B. It is not needed, just depends on how far you want to convert the harness.

 

I really appreciate all the help so far. I'll be starting on this later and see where I get.

 

I'm looking where you say that pin h from the 90 harness should go to pin p on the 85 harness. Pin h for 90 is listed as tcc and for 85 it is also tcc according to austin thirdgen.org http://www.austinthirdgen.org/mkport..._1985_C207.txt
So I was thinking should I just leave that one alone?
Next, for the vss, for 85 it is pin k. Should I run pin d or p from the 90 harness there?
As for the fuel pump fan wire in the c221, do I run it to pin a of the fuel pump relay to energize it?

 

Woops.. your right.
Pin P on the 85 harness is the TC disengage. This is when the brakes are applied. Pin H is for TCC troubleshooting from the aldl port

For the VSS, you will need to run Pin K on the 85 harness to terminal b10 on the 730 ecm. This is how the ecm gets its vehicle speed.

On the relay, pin a is the fused hot from the battery, e goes to the fuel pump, and d and f are to energize the relay. d looks like it goes to the ecm and f is the ignition hot. I beleive the wire in the c221 goes to pin f.

 

Great. I'll try and finish getting this wired up and put into the car to see how it all works. thanks

 

Pin f is a black and white wire that looks like it is a ground. Should I run the c221 wire to pin d which is the green and white wire? Also what should I do about pin p? The 85 harness has it listed as tcc switch and the 90 harness is cruise control. My car is a manual, (no tcc), and it doesn't have cruise control either. So can they stay hooked up like they are, or should I pull both pins?

 

Yes. The ecm supplies the ground so that it can activate the relay.
Unpinning both is fine.

 

So does that mean it goes to the black or green wire? Thanks again.

 

Take a look at this.

http://www.austinthirdgen.org/mkport...ta_sensors.jpg

 

I hooked the fuel pump / fan wire from the c221 to the green and white wire. The fuel pump is not turning on when I turn the key forward. What are some things that I can look for to find my problem?

 

I don't believe the ecm is getting power (no check engine light coming on). Do the speed density harnesses have the two pigtail connector plug in by the battery to power the ecm or do they get it there a different way?

 

I got the ecm and everything working. The only issue I have now is that when I turn the key forward the fuel pump stays running and won't turn off after two seconds like it is supposed to. I am trying to figure this out myself but have been unsuccessful so far if anybody has any ideas.

 

Can you take a pic of how the relay is wired and tell me where each wire is connected?
I will try to take a pic tonight and show you how mine is wired up.

 

Well I don't know exactly what happened but everything is working as it should now. Well see if it goes back to staying running. Thanks for all the help again.

 

This problem with the fuel pump staying running somehow seems to be intermittent. Its now doing it again. I'm not sure if the pump is constantly getting power to it or not. The battery will be dead to if it sits for a while. I should also note that I installed a racetronix hot wire kit as well if that possibly has anything to do with this problem.

 

I forgot to post back. I did get everything figured out. The only wire that I didn't do anything with is the A7 wire for the emission control. You said that it runs off of the gauges fuse. How do I go about adding it to that circuit? Do I splice it into the wire that goes to the gauges fuse in the fuse box? Or is there another way? Thanks again.

 

A7 from the c100 put it to pin G on the c207. Pin G goes to the gauges fuse on an 86 harness.

 

Great! Thanks.