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Posted by: brooks944 Oct 21 2015, 05:09 PM

My 1.8 L-jet was running poorly and thanks to a member I found out the AFM connector was disconnected, yes I'm clueless about the 914. It ran better after connecting, but would not start when cold with the connector plugged in. It would start with it connected when warm. It started for a couple of days with it unplugged. After starting I would plug it back in and it ran better than it has since I got it about a year ago. I left it plugged in and tried to start without any luck. Have tried for the last couple of days, both with and without it connected. Still no start. What should I do next?

Thanks,
Rick

Posted by: Jeff Bowlsby Oct 21 2015, 05:42 PM

Start by becoming familiar with L-Jet by reviewing the manuals. L-Jet is an easy system to learn and diagnose once you understand how it works:

http://bowlsby.net/914/Classic/zTN_Man12.pdf
http://bowlsby.net/914/Classic/zTN_Man15.pdf

Posted by: brooks944 Oct 22 2015, 04:32 PM

Thanks Jeff, you have the best FI reference material. I did have a guy come by today who is a body guy and mechanic, very nice to come to my house. He suggested we hook up a wire from the positive on the battery to the hot on the coil. Car started right up. When the wire was off, the car died. Really don't want to change the ignition switch again, what a pain! Suggestions on where to check next?

Thanks,
Rick

Posted by: Jeff Bowlsby Oct 22 2015, 05:13 PM

Double relay or connections to it.

Posted by: brooks944 Oct 22 2015, 05:15 PM

Thanks Jeff, I will check those. I do have another relay that I put I yesterday to check and it didn't help so it must be connections?

Posted by: Jeff Bowlsby Oct 22 2015, 05:31 PM

Its a place to start anyway, no promises that's the issue.

Posted by: Dave_Darling Oct 22 2015, 06:46 PM

I don't believe the double relay powers the coil. It powers the FI brain and the fuel pump, but not the coil.

The power to the coil comes from the ignition switch, and goes through the main wiring harness and the relay board. It gets tapped to provide a signal for a couple of the round relays on the relay board as well--though those aren't used by the L-jet system.

Time to check the power on that circuit. You can tap in through the relay connections (though I forget which exactly those are). Check the electrical diagrams for which relay socket connections are on that circuit, and see if they have voltage when the key is on.

--DD

Posted by: timothy_nd28 Oct 22 2015, 06:52 PM

Posted by: timothy_nd28 Oct 22 2015, 10:32 PM

At the relay board, you have 2 main connectors. One being a 14 pin connector while the other is 12 pin. You want to check pin 8 at the 14 pin connector for 12vdc with the key on. If full voltage is present, then continue to pin 7 at the 12 pin connector, you should also have 12 volts at this pin with the key on.

If you fail to get a full 12 volts at pin 8 at the 14 pin connector, then I would clean the spring loaded terminals for fuse #8 and the fuse,, then recheck the voltages. If that fails, then I suspect the ignition switch to be at fault.


It's not good to leave the key on with the engine not running. This could ruin your points or electronic pointless module. When I usually leave the key on while performing tests, I usually disconnect the negative wires on the ignition coil, which will isolate that from the circuit, thus avoiding any electrical damage.

Posted by: brooks944 Oct 23 2015, 10:48 AM

I am not versed with electrical testing. To test either pin on the 12 or 14 pin, I put the positive end of my meter on the pin and the negative to any convenient bare metal, correct. Also, do you have to have the ignition switch turned as if starting or just power on?

I really appreciate everyone's help, the car won't turn over now. Still hear the fuel pump, but not turning over. I'm starting to think ignition switch. I replaced it last year.

Posted by: Kansas 914 Oct 23 2015, 12:36 PM

QUOTE(brooks944 @ Oct 23 2015, 10:48 AM)

Posted by: brooks944 Oct 23 2015, 12:41 PM

Thanks Kansas. Where is the best place to get a switch (although I'm still unsure that's it)? Got the last one from a well known place where I get a lot of mail order parts, but it was the $5.00 cheap one (Meser something was the brand). Also called the local Porsche dealer and they can't get them.

Posted by: Kansas 914 Oct 23 2015, 12:50 PM

QUOTE(brooks944 @ Oct 23 2015, 12:41 PM)

Posted by: timothy_nd28 Oct 23 2015, 01:01 PM

Don't worry about testing, it's a good chance it is the ignition switch. It could also be a weird coincidence that the seat belt interlock relay is causing issues with the starter voltage, but doubtful from what you are explaining.

I would replace the cheap switch with a better one, then report back

Posted by: brooks944 Oct 23 2015, 01:16 PM

Thanks, where is the best place to get the switch. I called the local Porsche dealer, they can't even get one.

Posted by: Kansas 914 Oct 23 2015, 02:29 PM

QUOTE(brooks944 @ Oct 23 2015, 01:16 PM)

Posted by: brooks944 Oct 28 2015, 03:30 PM

Thanks everyone. I got the new oem switch in today and installed. No luck!!! Checked the relay under the passenger seat and it's already been bypassed. What next?

Posted by: brooks944 Oct 28 2015, 03:32 PM

Oh, it doesn't even turn over now, all other electrical stuff seems to be working.

Posted by: timothy_nd28 Oct 28 2015, 06:50 PM

Can you post a pic of your relay board?

Posted by: brooks944 Oct 29 2015, 05:02 AM

Relay board picture:

Posted by: timothy_nd28 Oct 29 2015, 09:20 AM

Remove the lonely yellow wire (has red circle around it) and insert this wire into either rear terminal circled in green

Posted by: brooks944 Oct 29 2015, 01:57 PM

Tried it in both of the rear one, not turning over and the fuel pump does not come on.

What do I check next?

Thanks!

Posted by: timothy_nd28 Oct 29 2015, 02:08 PM

Okay, leave that yellow wire plugged into one of the rear terminals. With your voltmeter, put the positive lead on pin 1 of the relay boards 14 pin connector (should be a yellow wire). Put the black negative meter lead on the negative battery post. Set the voltmeter to volts DC, and have an assistant turn the key to start, while he or she is doing this, observe for 12 volts on the voltmeter.

Posted by: brooks944 Oct 29 2015, 02:32 PM

Do I put the positive from the voltmeter on the pin or on the wording harness?
Thanks,
Rick

Posted by: timothy_nd28 Oct 29 2015, 02:36 PM

Yep, I would pull off the 14 pin connector, and insert the meter lead right there on pin one of the wiring harness side. You could also take off the connectors cover carefully, and probe pin one with the connector still attached, your choice.

We are looking for 12vdc only when the key is in the "start" position. So this voltage will be momentary.

Posted by: brooks944 Oct 29 2015, 04:39 PM

Thanks it may take a day or two to test, I will let you know the results. Really appreciate the help.

Posted by: brooks944 Oct 29 2015, 05:19 PM

The wires to the coil also look pretty fragile, plus after one starting attempt one of them felt hot. Is that normal?

Posted by: brooks944 Nov 2 2015, 03:50 PM

One of the 914World local experts came by yesterday to diagnose and the problem was a bad wire from the seat belt buzzer bypass to the starter. Easy fix. Had it done before the F1 race.

I appreciate everyone's help and especially a local guy and his 914 buddy spending about 3 hours of their time on a Sunday to help a novice! This is a great community.

Thanks all,
Rick

Posted by: rhodyguy Nov 2 2015, 05:01 PM

There is a small wire near the interlock relay screwed to the floor that provides a ground. Check it. With someone else trying the key there should be voltage at the yellow wire on the starter to chassis ground with your multimeter.