Curious annoyance, -- I have a theory; what is yours? |
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Curious annoyance, -- I have a theory; what is yours? |
Dave_Darling |
Apr 4 2022, 09:49 PM
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#1
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914 Idiot Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
I have a small annoyance that I've been putting up with when trying to start my 914. It's been this way for years, BTW. I have a theory about what is going on, but I am interested to hear yours.
My car can be hard to start. It will crank and not catch. After one or sometimes a couple of ~15 second tries at starting, it will cough when I turn the key off again. The next try it starts up. So, any theories about what is causing this? I see two primary paths for this sort of failure; fuel or spark. --DD |
76-914 |
Apr 4 2022, 10:34 PM
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#2
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Repeat Offender & Resident Subaru Antagonist Group: Members Posts: 13,509 Joined: 23-January 09 From: Temecula, CA Member No.: 9,964 Region Association: Southern California |
Are you saying that the instant the key returns to the on position it coughs like it wanted to start? If so I'd be curious as to the voltage at the coil when cranking.
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Dave_Darling |
Apr 5 2022, 12:27 AM
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#3
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914 Idiot Group: Members Posts: 14,991 Joined: 9-January 03 From: Silicon Valley / Kailua-Kona Member No.: 121 Region Association: Northern California |
Sounds like fuel to me. How long does it take you to build proper rail pressure? Also what motor/injection? Fuel pressure comes up within the first few seconds of cranking. The car is a 2.0 liter (1974) with D-jet injection. Are you saying that the instant the key returns to the on position it coughs like it wanted to start? If so I'd be curious as to the voltage at the coil when cranking. That is correct, when I turn the key off it gives one cough as if there was a single combustion event. After it does that it will start normally. I am suspecting the ignition as well, but I haven't yet measured the coil voltage when it is in its failed state. I hadn't considered the ignition switch; that is a good thought!! --DD |
Root_Werks |
Apr 5 2022, 10:16 AM
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#4
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Village Idiot Group: Members Posts: 8,337 Joined: 25-May 04 From: About 5NM from Canada Member No.: 2,105 Region Association: Pacific Northwest |
Sounds like fuel to me. How long does it take you to build proper rail pressure? Also what motor/injection? Fuel pressure comes up within the first few seconds of cranking. The car is a 2.0 liter (1974) with D-jet injection. Are you saying that the instant the key returns to the on position it coughs like it wanted to start? If so I'd be curious as to the voltage at the coil when cranking. That is correct, when I turn the key off it gives one cough as if there was a single combustion event. After it does that it will start normally. I am suspecting the ignition as well, but I haven't yet measured the coil voltage when it is in its failed state. I hadn't considered the ignition switch; that is a good thought!! --DD (IMG:style_emoticons/default/agree.gif) I was thinking ignition switch. Another test you can do is not detent the start position 100%. Sounds weird to do, but there is about 3-4 degrees of rotation in the "start" position the switch makes contact. The full rotation is the most worn area. I've done this test on a number of older VW's and Porsches. Go full start rotation, let it back off a degree or two. Most times the engine lights right up = bad/worn out switch. |
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