75 1.8 won't start, Looking for help! |
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75 1.8 won't start, Looking for help! |
brooks944 |
Oct 21 2015, 05:09 PM
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#1
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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 |
JeffBowlsby |
Oct 21 2015, 05:42 PM
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#2
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914 Wiring Harnesses Group: Members Posts: 8,505 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
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 |
brooks944 |
Oct 22 2015, 04:32 PM
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#3
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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 |
JeffBowlsby |
Oct 22 2015, 05:13 PM
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#4
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914 Wiring Harnesses Group: Members Posts: 8,505 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Double relay or connections to it.
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brooks944 |
Oct 22 2015, 05:15 PM
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#5
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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?
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JeffBowlsby |
Oct 22 2015, 05:31 PM
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#6
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914 Wiring Harnesses Group: Members Posts: 8,505 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Its a place to start anyway, no promises that's the issue.
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Dave_Darling |
Oct 22 2015, 06:46 PM
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#7
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914 Idiot Group: Members Posts: 14,985 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
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 |
timothy_nd28 |
Oct 22 2015, 06:52 PM
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#8
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
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timothy_nd28 |
Oct 22 2015, 10:32 PM
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#9
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
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. |
brooks944 |
Oct 23 2015, 10:48 AM
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#10
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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. |
Kansas 914 |
Oct 23 2015, 12:36 PM
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#11
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
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. If you replaced the switch with the Chinese made one it could very well be the switch. I have read where for some those switches last only days so months would be a real possibility. It is well worth the extra money for quality on the switch since it is a pain to replace. |
brooks944 |
Oct 23 2015, 12:41 PM
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#12
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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.
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Kansas 914 |
Oct 23 2015, 12:50 PM
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#13
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
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. I did a quick search at Pelican Parts: http://www.pelicanparts.com/catalog/SuperC..._pg6.htm#item20 |
timothy_nd28 |
Oct 23 2015, 01:01 PM
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#14
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
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 |
brooks944 |
Oct 23 2015, 01:16 PM
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#15
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
Thanks, where is the best place to get the switch. I called the local Porsche dealer, they can't even get one.
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Kansas 914 |
Oct 23 2015, 02:29 PM
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#16
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Advanced Member Group: Members Posts: 2,999 Joined: 1-March 03 From: Durango, Colorado Member No.: 373 Region Association: Rocky Mountains |
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brooks944 |
Oct 28 2015, 03:30 PM
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#17
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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?
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brooks944 |
Oct 28 2015, 03:32 PM
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#18
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
Oh, it doesn't even turn over now, all other electrical stuff seems to be working.
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timothy_nd28 |
Oct 28 2015, 06:50 PM
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#19
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Advanced Member Group: Members Posts: 2,299 Joined: 25-September 07 From: IN Member No.: 8,154 Region Association: Upper MidWest |
Can you post a pic of your relay board?
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brooks944 |
Oct 29 2015, 05:02 AM
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#20
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Member Group: Members Posts: 241 Joined: 5-September 10 From: Kingston, TN Member No.: 12,139 Region Association: South East States |
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