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914World.com _ 914World Garage _ Curious annoyance
Posted by: Dave_Darling Apr 4 2022, 09:49 PM
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
Posted by: JamesM Apr 4 2022, 10:08 PM
Sounds like fuel to me.
How long does it take you to build proper rail pressure?
Also what motor/injection?
Posted by: 76-914 Apr 4 2022, 10:34 PM
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.
Posted by: jcd914 Apr 5 2022, 12:07 AM
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.
I had an old VW Rabbit that did this.
Was a bad ignition switch, no power to the 15 circuit while cranking.
Sometimes I could turn the key far enough to start cranking and then back off slightly and it would catch and start.
Jim
Posted by: Dave_Darling Apr 5 2022, 12:27 AM
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
Posted by: euro911 Apr 5 2022, 04:56 AM
I had the same issue on the 'BB' ('75 w/2056) and on my '70 Ghia. Replacing the ignition switches took care of it.
Posted by: wonkipop Apr 5 2022, 05:57 AM
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.
I had an old VW Rabbit that did this.
Was a bad ignition switch, no power to the 15 circuit while cranking.
Sometimes I could turn the key far enough to start cranking and then back off slightly and it would catch and start.
Jim
yeah. i'm going with you jim.
50 years of rammin that key in.
Posted by: mate914 Apr 5 2022, 06:08 AM
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
I remember being a very young man 17 or 18 at a east coast ramble with John Dunkel from Rennlist. Pelican Parts sent you over as a Porsche 914 Guru. I looked up to you and wished I had your knowledge.
Now, twenty two years later I always carry two ignition switches. The switch will crack and only partially work.
Twenty mins to change.
Good luck,
Matt
Posted by: DRPHIL914 Apr 5 2022, 07:35 AM
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
Dave,
i first thought ignition switch, but, 4-5 years ago i had this problem
and my MPS was failing electronically . so check the mps too, not jus vac, but resistance values on the input leads
-AND this year it happened , the pump would prime then not prime. - it was my fuse / relay board in engine compartment that was shorting out on the injection/pump circuit.
.
Posted by: maf914 Apr 5 2022, 08:00 AM
Now, twenty two years later I always carry two ignition switches. The switch will crack and only partially work.
Okay, sorry DD (Dave), slight hijack. I have replaced my ignition switch twice in the past after experiencing mystery progressive starting failures.
Several ignition switches are available with prices ranging from $60 to $6. Are there any that are recommended? Below are a few examples.
https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=ignition+switch
https://914rubber.com/ignition-switch-1
Posted by: mate914 Apr 5 2022, 08:10 AM
Now, twenty two years later I always carry two ignition switches. The switch will crack and only partially work.
Okay, sorry DD (Dave), slight hijack. I have replaced my ignition switch twice in the past after experiencing mystery progressive starting failures.
Several ignition switches are available with prices ranging from $60 to $6. Are there any that are recommended? Below are a few examples.
https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=ignition+switch
https://914rubber.com/ignition-switch-1
I have had the aftermarket ones from PP and AA. I have never tried the 914rubber ones. Next time I buy I will try 914 rubber.
Matt
Posted by: mate914 Apr 5 2022, 08:13 AM
[quote name='mate914' date='Apr 5 2022, 10:10 AM' post='2993281']
[quote name='maf914' post='2993278' date='Apr 5 2022, 10:00 AM']
[quote name='mate914' post='2993256' date='Apr 5 2022, 04:08 AM']
Now, twenty two years later I always carry two ignition switches. The switch will crack and only partially work.
[/quote]
Okay, sorry DD (Dave), slight hijack. I have replaced my ignition switch twice in the past after experiencing mystery progressive starting failures.
Several ignition switches are available with prices ranging from $60 to $6. Are there any that are recommended? Below are a few examples.
https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=ignition+switch
https://914rubber.com/ignition-switch-1
[/q
I have had the aftermarket ones from PP and AA. I have never tried the 914rubber ones. Next time I buy I will try 914 rubber.
Matt
[/quote]
You can clearly see the crack after removing if switch is bad. If you see no crack problem is most likely not that.
Posted by: Root_Werks Apr 5 2022, 10:16 AM
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
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.
Posted by: ClayPerrine Apr 5 2022, 10:41 AM
Dave,
You have to face it.. your car is scared of you. It heard what you have done to other 914s over the years, and doesn't want to run for fear of you doing something bad to it.
Clay
Posted by: 930cabman Apr 5 2022, 11:13 AM
Somewhat of a consensus here pointing to the ignition switch. Try a hot wire to take the switch out of the equation.
Or could be a poor connection along the line or weak coil
How does she pull under power? uphill WOT
Posted by: Spoke Apr 5 2022, 01:04 PM
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.
After cranking and letting off the starter to turn the key off, you pass by the RUN position which is when the engine coughs. So as you discontinue the cranking, the key goes: START -> ON -> OFF.
Will the car start if after an abortive cranking, what if you stopped at RUN instead of going completely to OFF?
Posted by: Dave_Darling Apr 6 2022, 01:38 AM
You have to face it.. your car is scared of you. It heard what you have done to other 914s over the years...
I've done far worse to this car than I ever did to Ed's or Joe's!! Heck, I dropped intake valve seats on two separate occasions, and that's not even counting the crank shaft having a good 1/8" of end play back when!!
Consensus seems to be the ignition switch. Spoke's explanation makes it even clearer; that sounds by far the most likely problem. I'll have to check the switch once I have access to the car again!
--DD
Posted by: Chris914n6 Apr 6 2022, 11:10 AM
Similar issue for me once. Even made a video of it. http://www.914world.com/bbs2/index.php?showtopic=316353&hl=
Posted by: ClayPerrine Apr 6 2022, 11:16 AM
Dave.. you can test the theory by putting a remote starter button on it and use it to start the car. If it works, then you definitely have a bad ignition switch.
And stop abusing the poor 914!!!!!
Clay
Posted by: r_towle Apr 6 2022, 04:20 PM
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.
--DD
I left you alone for years.
Have you considered that maybe it’s diet related, or maybe some CBD will help?
Posted by: 914_teener Apr 6 2022, 05:06 PM
I'd spray a little bit of Windex on the CHT.
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