Electrical, Wiring Harness Assistance Options

[sjhenry1075]

I hate to even post this, but I'm going to ask a bunch of few dumb questions so please bare with me. My car was painted two years ago and in my haste to drop the engine (1.7 with Djet) I did not take a lot of pictures of the wiring harnesses nor did I mark the wires. No, it they not have to be removed, but I did remove them. Yes, Huge mistake. Worst part is, the PO messed with the harness so none of the wire colors are correct.

As you probably guessed, I'm left with kind of a mess. I printed out Bowlsby's diagrams for the harnesses and the 12 point plug (which came apart during the removal process) and tested all the connections for continuity and started to put it back on the car. I few things are stumping me right now and here are my questions:

- My fuel pump no longer comes on. I looked at the wiring schematic and it shows a fuel pump wire going to the 12 pin harness, pin 12 from pin 13 of the 14 pin harness. That wire is supposed to go to the AAR valve correct?

- Is there a wire that goes from the starter to the little box in the engine compartment? It's attached to the side of the trunk and has three posts. On my Mustang it was considered the selonoid, but I'm not sure it's the same on the 914.

Do my questions make sense? I have never been good at electrical stuff. I definitely appreciate any assistance and if you want to call me a dummy that's fine too..

-

[windforfun]

Okay, so let's step back & think about this. The wiring harness doesn't have much in the way of excess length for the wires that leave it. The wires that go to the fuel pump are about 6" long.

Pull the wires off the fuel pump & measure the voltage across them with the ignition turned on. You don't have to crank the engine since the fuel pump will start first.

You've a bit of a Pandora's box on your hands & be careful not to start trying things that will do more damage. The fuel pump may now have gone south.

Post some pics of the wiring to the fuel pump. We're here to help & good luck with the trouble shooting. Above all, be patient here. Rome wasn't built in a day. "73 1.7 Djet on this end too. BTW, check the wire colors again. They can't be that messed up. I'd check mine for you, but I'd have to lift up the car. The wires in the engine well are covered. Sorry.

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[Superhawk996]

You are facing a bit of an uphill battle especially if splicing was done and color codes don’t match.

My best advice is learn to use a DMM and to read a wiring diagram if you don’t already know how. Google / YouTube are your friend. Sounds like you’re doing some basic continuity checks so that’s a good sign. (IMG:style_emoticons/default/smilie_pokal.gif)

As answer to your questions

Yes fuel pump and AAR are on a shared circuit coming through the fuel pump relay. The fuel pump relay solenoid is powered 12v + from the power supply relay. The ECU controls (provides a ground) the fuel pump relay solenoid via ECU four pin connector, pin III

Yes the starter solenoid circuit comes from the cabin through the relay board, to the starter. NOTE: the 3 pin connectors are related to the alternator and voltage regulator. Those 3 pin connectors have nothing to do with the starter.

This may help you

[Superhawk996]

(IMG:style_emoticons/default/thisthreadisworthlesswithoutpics.gif)

I’m sort of guessing what you’re asking about with respect to little box mounted to the trunk. Assume you mean the relay board in the engine bay but (IMG:style_emoticons/default/confused24.gif)

If you have some sort of aftermarket solenoid mounted in the trunk - all bets are off as to what some DAPO has done to your poor car. (IMG:style_emoticons/default/happy11.gif)

[windforfun]

CTTOI, the fuel pump wiring should have a rather unique connector on it with perhaps a rubber boot too. Simple spade lugs are not stock. Don't reverse the polarity because this will make the pump run backwards.

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

[930cabman]

The drawing from Superhawk is a great starting point. That with a VOM should get you heading in the right direction

[ClayPerrine]

The drawing from Superhawk is a great starting point. That with a VOM should get you heading in the right direction

http://www.914world.com/bbs2/index.php?showtopic=351033

[Superhawk996]

(IMG:style_emoticons/default/agree.gif) Clay (IMG:style_emoticons/default/pray.gif) - not me. I just recycle it to those in need.

[sjhenry1075]

Thank you for the advice everyone, hopefully I'll get a chance to dig into it today. In regards to the little box on the firewall, I'm attaching a pic for reference..

[dr914@autoatlanta.com]

Maybe watching this old guy will help:


https://www.youtube.com/watch?v=YLgQxpNHzIU

I hate to even post this, but I'm going to ask a bunch of few dumb questions so please bare with me. My car was painted two years ago and in my haste to drop the engine (1.7 with Djet) I did not take a lot of pictures of the wiring harnesses nor did I mark the wires. No, it they not have to be removed, but I did remove them. Yes, Huge mistake. Worst part is, the PO messed with the harness so none of the wire colors are correct.

As you probably guessed, I'm left with kind of a mess. I printed out Bowlsby's diagrams for the harnesses and the 12 point plug (which came apart during the removal process) and tested all the connections for continuity and started to put it back on the car. I few things are stumping me right now and here are my questions:

- My fuel pump no longer comes on. I looked at the wiring schematic and it shows a fuel pump wire going to the 12 pin harness, pin 12 from pin 13 of the 14 pin harness. That wire is supposed to go to the AAR valve correct?

- Is there a wire that goes from the starter to the little box in the engine compartment? It's attached to the side of the trunk and has three posts. On my Mustang it was considered the selonoid, but I'm not sure it's the same on the 914.

Do my questions make sense? I have never been good at electrical stuff. I definitely appreciate any assistance and if you want to call me a dummy that's fine too..

-

[Superhawk996]

Thank you for the advice everyone, hopefully I'll get a chance to dig into it today. In regards to the little box on the firewall, I'm attaching a pic for reference..

Yup - DAPO’s been there so I guess you weren’t joking when you said wiring has been molested.


The presence of this added solenoid was meant to solve intermittent hot start issues 914s are notorious for. Based on the way this one was done and the size of the wiring, it is a sign that it was done poorly. The OEM Bosch solenoid draws about 24 amps. The wiring from that solenoid is too small to be of much use.

Here’s how to do it properly

http://www.914world.com/bbs2/index.php?sho...p;mode=threaded

Be advised: added hot start solenoids are a Band-Aid that usually temporarily mask other underlying issues such as:

Failing ignition switch, large voltage drops in the OEM yellow stater wire due to age & corrosion, failing and/or missing ground strap between engine and transmission, failing battery cables (either + or neg.).

If it were me, I’d take it out and fix the underlying issues while you are in the process of cleaning up and sorting out your other fuel pump issues.

[windforfun]

Maybe watching this old guy will help:


https://www.youtube.com/watch?v=YLgQxpNHzIU

I hate to even post this, but I'm going to ask a bunch of few dumb questions so please bare with me. My car was painted two years ago and in my haste to drop the engine (1.7 with Djet) I did not take a lot of pictures of the wiring harnesses nor did I mark the wires. No, it they not have to be removed, but I did remove them. Yes, Huge mistake. Worst part is, the PO messed with the harness so none of the wire colors are correct.

As you probably guessed, I'm left with kind of a mess. I printed out Bowlsby's diagrams for the harnesses and the 12 point plug (which came apart during the removal process) and tested all the connections for continuity and started to put it back on the car. I few things are stumping me right now and here are my questions:

- My fuel pump no longer comes on. I looked at the wiring schematic and it shows a fuel pump wire going to the 12 pin harness, pin 12 from pin 13 of the 14 pin harness. That wire is supposed to go to the AAR valve correct?

- Is there a wire that goes from the starter to the little box in the engine compartment? It's attached to the side of the trunk and has three posts. On my Mustang it was considered the selonoid, but I'm not sure it's the same on the 914.

Do my questions make sense? I have never been good at electrical stuff. I definitely appreciate any assistance and if you want to call me a dummy that's fine too..

-

Come on George, you don't look a day over 30. Great video BTW. Thank you very much.

BTW, what's the PN for those relays? I assume you sell them. @dr914

(IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif) (IMG:style_emoticons/default/biggrin.gif)

[windforfun]

George got me curious so I uncovered my relay board which I haven't done since 2007 when I replaced the voltage regulator with a new Bosch transistorized one from AA.

There's a spare fuse with a color that's different from the main fuse. The filaments appear to be the same size.

The three URO relays are very neatly wrapped with orange tape at the bottom.

Is this factory stock? TIA.

(IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif) (IMG:style_emoticons/default/confused24.gif)

[Superhawk996]

Is this factory stock? TIA.

Not stock.

The fuses should be a 25A and a 15A. Was not uncommon to find 25A put in place of the 15A to serve as spare. If the 25A blows, you’re walkin’ assuming you don’t have a 25A up in the main fuse block that you can use.

URO is not the OEM supplier of original relays. Wehrle was OEM supplied relay.

[sjhenry1075]

I want to thank everyone for their replies and assistance. I was prepared to fully diagnose the issue, multimeter and schematic in hand. I climbed under the car, looked up and yup, you guessed it, the fuel pump harness was unplugged (IMG:style_emoticons/default/headbang.gif)
Yeah, I'm an idiot. At least now I know that's the very first thing i should check. Thank you again for your time and patience!!

[930cabman]

Don't think you are alone, more than one of us has, ___________ you fill in the blank

[windforfun]

Well at least you didn't short out your battery with a wrench that was too long. I burned my hand & destroyed an Optima battery. The wrench went flying & almost broke my garage door window. Optima replaced my battery for free. I didn't tell them what happened & they assumed it failed prematurely. I guess it was still under warranty.

So not only am I a dumb shit, but I'm also a liar.

"Everything I say is a lie." This is a line out of an old Star Trek episode entitled "Veeger" IIRC.

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