I bought today a 914 GA 2.0 1974 that was imported to France in 2015 from Oregon.
At owner control change, the car failed to test emission with a CO at idle at 9%.
I had a second manifold pressure sensor because I have another 914 and I had this piece as a spare.
Everything went back to normal and the CO went to 3%.

I have another less serious problem, when I activate the handbrake, the red light flashes, ok, but also the two green lights in triangle flashers.
Also, if I operate the right or left turn signal, the two green lights flash together.
I found in the folder of the 914 a turnlight central change bill.I think the guy made a mistake in editing.Your opinion.
CheeRS

If your car has separate Left and Right indicators on the tach and is a '74, the tach may have been converted from a '70-'73 car as the '74 had a single L<>R indicator. If it was converted then the wiring may be suspect.

You can try this test: pop out the tach and look at the wires on the indicators. If they have a common wire like shown below, remove the wire from both indicators and tape them off. Then get 2 wires and crimp a female quick disconnect spade on each. Connect these to the open spades on the indicators and connect the other end of the wires to a chassis point, screw or something.

Then try the e-brake and turnsignals. The indicators should work correctly. If so, then shorten the wires or make a pigtail like shown below. Connect the Y-spade to the ground wire of the tach.

Start by checking grounds and tail-light connectors. They get corroded very easily. I know on mine when i pull the handbrake, the 2 green turn signal lights flash. I don't know if that is how it was intended to operate though.

Good to hear you passed the emissions test and congratulations on a 2.0 914. Any photos?

Don’t throw out the bad MPS. @Chris_Foley makes a rebuild kit. Literally saving the stock EFI for thousands of these cars. See Tangerine Racing’s website.

It's easy to hook wires up on the back of the gauges in the wrong places.

That's where I'd start.

Thanks a lot, will check the wire.
Could you confirm dash turn light have to flash pulling the hand break ?

Just came back from the emission control.
Passed with 2.9 CO, now the car can take the road.
Just a little thing to fix, each time I stop the engine and start it again, idle spin between 800 and 1200 during 15mns and after return to normal.
Thinking about the additional air valve.

So I have the same problem.
It is an early US 74 with the single turn signal green light which flashes along with the red emergency brake light when the handle is pulled up.
It has done this since I can remember, maybe 15 years.
Today I thought I would fix it. I downloaded the 74 wiring diagram and started tracing everything out. All wires are the correct color code. I tried cleaning dual filament bulbs and holders, no change. Grounding gauges and bulbs independently, no change.

The only thing I might still try is another flasher. There could be cross-talk between the two circuits in the flasher relay.

I am stumped!
Let us know what to try next!

It's the turn signal relay.

I was troubleshooting my turn signal stalk a long time ago and swapped out my original 75 turn signal relay for a URO unit. Turn signal started flashing in sync with handbrake light. Thought it was weird but otherwise it was never really an issue.

If you look at the 74 current flow diagram the hazard/turn signal relay feeds to both the turn signals and parking brake light. RS Stop is correct - that is where the crosstalk is.

Click to view attachment

Below is the schematic for the '74-'76 914 with single L-R indicator in the dash. I had a '74 and installed an early tach with separate L and R indicators.

The single indicator is driven by pin C of the relay. The idea is that the tiny current from the e-brake light bulb isn't enough to trigger the secondary coil to activate C to 12V. With heavy turnsignal bulb current, the secondary coil activates C and the indicator flashes with the turnsignal. That's the theory anyway.

The only thing I could surmise is the e-brake bulb is more current (higher wattage) than OEM. The relay could be weak but usually the secondary coil becomes less efficient with age.

Spoke,
Thanks for the info. Love your LED kits!
I found a 2 Watt bulb in the emergency brake light socket of both my 914's. I was able to find a later Carrera push in socket so I could try a 1.2 Watt bulb. No change. Turn signal light still flashes. One more thing to try; check ground at the handle switch.

mzalanka,
interesting, that the URO flasher did that. I am going to look for another flasher relay to try.

@Spoke - I have your EP26 relay due to plain ole exterior LEDs. I also have an LED in the turn signal socket and have found that the e-brake and single turn signal both light up when the e-brake is pulled. Doesn't really bother me but just wondering what's up with that.

Originally I had an inoperable brake warning light and when I pulled the gauges, I found that a PO had disconnected both brown lines (one from the MC and one from the e-brake switch) to that socket.

I did some testing and found that the best way around it was to simply run a new ground from the warning lamp to the e-brake switch. This took the master cylinder out of play - and it might well be that the MC reset switch needs to be hit - but I couldn't get to it. Works fine now (with the MC out of the loop) with the exception of the single turn signal flashing with it.

The EP26 does not have the secondary coil so the single turnsignal indicator will flash with the e-brake lamp. Not much can be done with that. Porsche in their infinite wisdom decided to use the flasher for turnsignals and e-brake/MC warning.

Of course Porsche is not so bad as Triumph who for the Spitfire used a flasher for the 4ways and another flasher for the turnsignals...

That's cool - just as long as things are working as they should - that's what I prefer and if the turn signal indicator is supposed to flash with the e-brake lamp while using an EP26 well....then i'm happy.

Reviving an older thread to thank Spoke for the jumper fix above (post #2).

This worked fine for me to fix the simultaneously flashing L & R indicator lamps. However, I'm thinking I may be masking a different issue because:

Unlike the OP, my car is an early '73 (9/72 build) and the tach is supposed to have separate lamps.

Before the hack, the wiring was as shown in the photo (but the common wire is blue/white) and exactly matched the '73 wiring diagram. This is a very original car with no signs of prior wiring changes.

I don't know if my brake indicator was also flashing bc I later found out it had been disconnected by a PO! However, my other symptoms were different:

The twin blinking lights were very dim and testing showed that they were acting in series - i.e. 6v each. Removing either bulb turned the other off as well.

Neither lamp would flash when the emergency switch was pulled. (No prob with exterior lights.)

Now everything seems to work as it should, but I have a hunch there still is something in the flasher relay and/or switch that was/is not right.

I can do some more diagnostic work but wondered if this makes sense to any wiring experts out there.

Thanks,

Ron

I was wondering if Spoke had a picture of the combo gauge to go along with this. I bought both Prospero's 74 diagrams and they still have double indicators showing in the gauges.

Thanks If you will?
Kevin

@nivekdodge

Here's the schematic for cars with the early tach with separate L and R indicators.

Shouldn’t there be a diode somewhere in that diagram?

@arbitrary

This is pretty much the schematic for the early tach and the 911 up to '84. I think there is a diode associated with the turnsignal stalk but that is for the Euro-park feature when the turnsignal stalk is active with the engine off. That is separate from the turnsignal circuit.

[quote name='Spoke' date='Sep 8 2022, 01:42 PM' post='3027976']
[quote name='arbitrary' post='3027957' date='Sep 8 2022, 12:26 PM']
Shouldn’t there be a diode somewhere in that diagram?
[/quote]


@arbitrary

This is pretty much the schematic for the early tach and the 911 up to '84. I think there is a diode associated with the turnsignal stalk but that is for the Euro-park feature when the turnsignal stalk is active with the engine off. That is separate from the turnsignal circuit.
Thanks bur i was looking for the late combo gauge from a 74

@nivekdodge

Check Post #9 to see if that's what you're looking for?

I think it will Thanks Bunches

As I understand the situation, the 1974 harness was supposed to work with just a single turn signal indicator in the Tach, and no diodes in the wiring. However it also seems that some early 1974 cars got the older 1973 Tach with the dual indicators; for this Tach, the two indicators were wired with a jumper so that both would blink together.
As for the handbrake activating both the indicators and the brake warning, I would guess that there is a separate wiring issue that is causing this to happen; both involve the flasher relay and could involve the hazzard switch.