ECU wiring connectivity

[durtkillon]

I need help mapping out the connectors for my ECU wiring harness. There are three spade connectors that branch from the same place the two pin connector for the aux. air regulator comes from. How do I identify these? They are all in the coil area and very close to the oil pressure switch.

There is also a three pin connector than I cann't find a home for. It is near the throttle body area. Please check this diagram I made out if you can help me. The five connections I'm having trouble with are identified with question marks. Here is the link: http://communities.msn.com/Porsches914/shoebox.msnw?action=ShowPhoto&PhotoID=3

[This message has been edited by durtkillon (edited 08-06-2001).]

[This message has been edited by durtkillon (edited 08-06-2001).]

[pbanders]

Jeff Bowlsby is your man for this question.

Brad Anders

[scotty914]

sounds like the three wires are grounds ( at least on my 1.8 )

and might the 3 prong conn be the throttle possition plug or there is a 3 prong plug on the reg board


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scott thacher
75 1.8 on the road again
75 under rust
(fine german rust)

[durtkillon]

The three spade connectors each have two wires connected to them. I don't know if this helps. It doesn't seem likely that there are three grounds with two wires each in such a tight location. Where do these grounds connect? Is there a way to verify if they are grounds?

By the way... This is a 1972 model I'm working on. I'm installing a stock FI. The PO had carbs on it before.

[bowlsby]

Something doesn't addd up...has the harness been modifed? Or did you forget a connector? I think you may also have the aux aur regulator confused with the cold start valve. The CSV has a fuel line, the AAR does not.

It sounds like you have a 1972-73 EA/EB engine code harness (1.7L), it may or may not be the engine you have.

The Aux Air Reg does not attach to the FI harness, but the regulator plate harness from the 12 pin connector on the regulator plate. Please verify.

Using your numbers and diagram:

1. Not the fuel pump - I suspect it is one of the fuel injector plugs for cyl 3 or 4, and if so, you need two of these in that area of the engine bay. The fuel pump does not connect directly to the FI harness. Please verify.

2. Pressure sensor (MPS) 4 pole

3. Head temp sensorm but it is a long male connector on the harness, female on the sensor itself.

4, 5, 6 3 pairs of 2 white wires into shared female wire terminals - they are grounds

7 Cold start valve near throttle body, check for fuel line attaached to that valve to verify. 2 pole

8 Thermotime switch on engine tin, single female connector on your harness

9 3 pole is the trigger switch on the distributor.

10 Throttle position switch on throttle body - 5 pole on your harness

11, 12 Fuel injectors for cyl 3 & 4

13 Not Aux Air Regulator,. but temp sensor 1 mounted to air plenum. The AAR has 1 red wire feeding it 12 volts and 2 air hoses, its mounted to the engine, but not to the air plenum.

Let me know if you need further help or repairs.

[bowlsby]

It took me so long to reply, you beat me to it!

The 3 pairs of 2 white wires are in fact grounds. They connect to a 3 spade (male) connector on the upper rear bolt of the engine case. They also will work bolted to 1 of the bolts of the throttle body, assuming your air plenum is grounded to the case.

Terminal 11 on the ECU conncector (25 pin) will be one of the ground wires and it is shared with the middle terminal (of 5) on the throttle position switch, which you can verify. The other 2 pairs of wires go, 1 wire each, to each fuel injector and the only way to verify it to use an ohmmeter to one side of each fuel injector housing connectors.

Now lets see if you've posted another question already.



[This message has been edited by bowlsby (edited 08-06-2001).]

[durtkillon]

You are right! I mis-traced the fuel pump. I was looking at the injection wires. I updated the drawing. You may want to take a look for accuracy. http://communities.msn.com/Porsches914/shoebox.msnw?action=ShowPhoto&PhotoID=4

My spade connectors, by the way, are all female. I have found a few funky junctions that connect the wires. The harness appears to be original.

As I was correcting the wiring, I broke the connections at the cold start valve. Is there a way to re-pin these connectors? They look like standard spade/butting connections, but I can't back them out. Any tricks or do I have to buy a new ECU harness?

[bowlsby]

Looks much better, but...

13 Not Aux Air Regulator,. but temp sensor 1 mounted to air plenum. The AAR has 1 red wire feeding it 12 volts from the regulator plate harness, not the FI harness, and 2 air hoses, its mounted to the engine, but not to the air plenum. TS1 is mounted to the air plenum, 2 pole connector like the fuel injectors, on the FI harness.

The broken wire terminals and other harness parts are nearly impossible to find, they are very specialized. If you are just having minor problems like that it is more economical to repair, but as far as I know, I am the only one repairing them. You can send your harness to me to repair, or as an option I can supply a new rebuilt one if you prefer. Contact me offline.

bowlsby@aol.com

[durtkillon]

Thanks for the help. I updated the drawing again. For those that refer to this in the future, the incorrect drawings were deleted, so they will not load. Here is the correct drawing for future reference. http://communities.msn.com/Porsches914/shoebox.msnw?action=ShowPhoto&PhotoID=5

[bowlsby]

There is a section on the following website that may be of help to anyone needing to wring out their fuel injection harness:

http://members.rennlist.com/pbanders/djetparts.htm

(Thanks Paul!)

[Dave at Pelican Parts]

Your last diagram is correct, as I understand it.

The metal contacts were available as of last year (early) from Beck-Arnley. I have posted part numbers for them before, but do not have them handy right now. Jeff has the correct parts (possibly even better-fitting than the B-A parts), and the good crimping tool which will give you a good joint that is small enough to fit into the plastic plug (the housing).

The metal contacts have a "barb" on them, which pops into place in the plastic plug. You can reach in with a ground-down "tweaker", or other small but stiff implement, and depress the barb. That will let you slide the contact out of the plug.

1/8" barbed female spade connectors will work in the plug, but the fit is less than perfect and they may not make contact. The correct size is metric and fits better.

Bottom line--you can replace the parts, with the degree of success depending on the exact parts you find and the care you take with the work. Jeff can do the job right, period.

--DD

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Pelican Parts 914 Tech Support

A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling