3.2 wiring dilemma, where does yellow #4 dme wire go? Options

[brp986s]

3.2 DME schematic shows a yellow wire from the ignition switch to position #4 on the DME box. But that's for a 911 and this is for a 914 so I don't have that switch and don't know what that wire has and under what condition.

I thought it might be the same as the yellow wire to the starter solenoid. When I make that connection the engine won't start with the ignition switch, but if I use my remote starter switch across the starter relay with key "on", the engine will start and run fine. Anybody know what's going on here (besides my not knowing wht the heck is going on) ? (IMG:style_emoticons/default/hissyfit.gif)

[Cap'n Krusty]

Sounds like you may be picking up power from the wrong terminal of the ignition switch. There is one pin that has power during cranking and running, and one that has power only when running.

The Cap'n

[Jeffs9146]

I ran a relay from my fuel pump wire to power my ignition module on my 3.0L!

[jcd914]

The 2 3.2L diagrams I looked at both show the yellow wire to pin 4 of the DME control unit as coming from the T50 on the ignition/starter switch, same as the yellow starter wire on a 914. The yellow wire is just a signal to the DME that the engine is cranking.

Make sure you still have your ignition power from the ignition/starter switch while cranking. The T15 circuit in the ignition/starter switch should have power when in the ON position as well as the crank position. Some ignition/starter switches have a X circuit that has power when in the ON position but does not have power when in the crank position.

Jim

[brp986s]

Sounds like you may be picking up power from the wrong terminal of the ignition switch. There is one pin that has power during cranking and running, and one that has power only when running.

The Cap'n

I'm actually making the connection at the starter, not the switch. I've confirmed the DME box is getting the start signal at DME #4. When using my remote starter switch it only serves to confirm that DME #4 is getting what it already has. But the engine only starts with remote and not key. That's what is crazy about it. (IMG:style_emoticons/default/wacko.gif)

[jcd914]

Sounds like you may be picking up power from the wrong terminal of the ignition switch. There is one pin that has power during cranking and running, and one that has power only when running.

The Cap'n

I'm actually making the connection at the starter, not the switch. I've confirmed the DME box is getting the start signal at DME #4. When using my remote starter switch it only serves to confirm that DME #4 is getting what it already has. But the engine only starts with remote and not key. That's what is crazy about it. (IMG:style_emoticons/default/wacko.gif)

Someplace you have to be connecting to the ignition switch because the DME needs power that is controlled by the ignition switch. Typically the ignition switch energizes a relay that supplies power to the DME control unit. It is the power from the ignition switch to operate the relay that we are questioning whether it is connected to the correct terminal on the ignition switch. I believe the yellow wire just signals cranking so the DME will turn on the fuel pump.

Jim

[Series9]

Here:

[jim912928]

On my iPhone so too hard to search. I have a thread dedicated to wiring a 3.2l motronic...including placement of my dme and wiring into the fuse panel etc. I put my dme under the passenger seat and tapped into the yellow wire that comes from the ignition switch and resides under the passenger seat that ties into that seat belt/ignition switch mess. Yellow ties into yellow...nice and clean. Of course this only works on the model years that had that "safety feature".

[jim912928]

Found the link:

http://www.914world.com/bbs2/index.php?sho...7&hl=Wiring

[John]

Sounds like you may be picking up power from the wrong terminal of the ignition switch. There is one pin that has power during cranking and running, and one that has power only when running.

The Cap'n

I'm actually making the connection at the starter, not the switch. I've confirmed the DME box is getting the start signal at DME #4. When using my remote starter switch it only serves to confirm that DME #4 is getting what it already has. But the engine only starts with remote and not key. That's what is crazy about it. (IMG:style_emoticons/default/wacko.gif)

I have ALWAYS followed the 911 wiring diagrams EXCACTLY!. That means that the yellow wire from the ignition switch is the yellow wire from the ignition switch (not the starter). The ONLY problem I have EVER run into electrically is the connection of the two flywheel sensors plugged into the wrong position. I have been running 3.2 conversions since 1986.

You can find the correct circuits by following the PORSCHE wiring diagrams. Heck, each terminal is LABELED with the SAME numbering scheme. One of the things I truly love about old Porsches.

Good luck in your endeavor, but please contact me if you have any questions, I may be able to help.

[Series9]

Here:

Edited to seem less picky (IMG:style_emoticons/default/smile.gif)

[brp986s]

Mr. O'brien, your diagram is great. I thank you all for your responses. This place is great. I'm off this Fri and will have another crack at it.

[jim912928]

Joe...I'm not debating the solution....I actually used your diagram and the 911 and 914 wiring diagrams to do mine. The thread I created only showed real pictures of where and how I used that diagram. I'm guessing you didn't even look at it to understand that. Man this place can get picky at times when all we are just trying to do is help this guy.

Done venting...brp986s, look at the diagram as it is very good and spot on. If you want pictures of how I implemented that diagram go to that thread.

[Series9]

Joe...I'm not debating the solution....I actually used your diagram and the 911 and 914 wiring diagrams to do mine. The thread I created only showed real pictures of where and how I used that diagram. I'm guessing you didn't even look at it to understand that. Man this place can get picky at times when all we are just trying to do is help this guy.

Done venting...brp986s, look at the diagram as it is very good and spot on. If you want pictures of how I implemented that diagram go to that thread.

Sorry, I wasn't trying to be picky. I couldn't get your link to work last night, but it's working now. (IMG:style_emoticons/default/beerchug.gif)

Oh, and that diagram is not "mine". It was given to me a long time ago. I don't know the original creator, but I share it because it was shared with me.

[ChrisFoley]

Does anyone know how to wire a Carrera tach in a 914 with the 3.2L?
The 8 pin connector on the back is labeled 1-8, not much help if you don't have the correct wiring diagram.

[Series9]

Does anyone know how to wire a Carrera tach in a 914 with the 3.2L?
The 8 pin connector on the back is labeled 1-8, not much help if you don't have the correct wiring diagram.

Yes.

Signal on #2
12v+ on #5
Ground on #6

[ChrisFoley]

Thanks Joe!

[brp986s]

North Hollywood Speedometer will convert a non-DME tach for $160. May help with keeping visual consistency across gauges.

[brp986s]

This is baffling. DME#4 is getting +10.0 V while cranking, but it won't start. If I disconnect the starter and turn key to start then dme#4 gets 12+ V. I thought maybe 10V wasn't enough so I tried connecting another battery in parallel. DME#4 now gets 11V but still won't start. There is no fuel pressure. I put in another dme relay. Won't start. The fuel pump is new. If I bypass the dme relay to operate the fuel pump the engine won't start. But, putting key to "on" and jumping 12V to dme#4 with no other assistance, the engine will start and run every time. Further confounding matters, I got a generic automotive relay to supply 12V to dme#4. The fuel pump will turn on, but the starter won't operate! Preparing to go Goober with push button switch. Ugh.

[Steve]

I guess I was lucky. I just took the Haynes 914 and 911 manual and figured it out on my own. After putting the whole thing together the car wouldn't start. I was all ready to tow it to Hergesheimer's when a friend said to sleep on it. I got up the next day checked the fuel pressure and it was twice what it was supposed to be. The problem was I pinched one of the fuel lines putting the tank back in. I replace the line and it started right up and has run great ever since. That was 10 years ago.