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Intermittent Ignition Question

 
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GeneT95  



Joined: 07 Nov 2019
Posts: 2
Location: Chesapeake, Virginia

PostPosted: Fri Nov 08, 2019 3:44 am    Post subject: Intermittent Ignition Question Reply with quote

Have a 931. Very intermittently when I attempt to start, there is no response from the key. I've had the car maybe 8 months and in that time it has happened 3 times. Luckily twice, it started eventually. The third time, I had to push start it the 'old' way. I at first thought it was a 'hot' start issue but the last time it did it it was a 'cold' start. So here is my question.

I originally thought perhaps the Flywheel sensor or starter connections were fouled. So I cleaned the sensor connections at the DITC and the starter. It starts now but given that the problem is very intermittent, it's obviously hard to tell if I fixed it or not. It otherwise runs perfectly once started and it has never shut off while running.

My question is this - if the flywheel sensor was faulty, intermittently so, would I still be able to push start the car anyway? I figured no unless flywheel movement caused the sensor to have electrical changes that overcame its less than optimal connection to the DITC.
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bureau13  



Joined: 07 Sep 2017
Posts: 176
Location: South Florida

PostPosted: Fri Nov 08, 2019 4:57 am    Post subject: Re: Intermittent Ignition Question Reply with quote

I assume you mean it doesn't crank or anything? Accessories still come on though, right?

I have had this exact problem, and would have sworn it was an ignition switch failing (yours still could be) but for me, every time it started happening more frequently I ended up having a dead battery soon thereafter. So, for my car at least, a dying battery will trigger this scenario.

GeneT95 wrote:
Have a 931. Very intermittently when I attempt to start, there is no response from the key. I've had the car maybe 8 months and in that time it has happened 3 times. Luckily twice, it started eventually. The third time, I had to push start it the 'old' way. I at first thought it was a 'hot' start issue but the last time it did it it was a 'cold' start. So here is my question.

I originally thought perhaps the Flywheel sensor or starter connections were fouled. So I cleaned the sensor connections at the DITC and the starter. It starts now but given that the problem is very intermittent, it's obviously hard to tell if I fixed it or not. It otherwise runs perfectly once started and it has never shut off while running.

My question is this - if the flywheel sensor was faulty, intermittently so, would I still be able to push start the car anyway? I figured no unless flywheel movement caused the sensor to have electrical changes that overcame its less than optimal connection to the DITC.

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1982 931
1986.5 Silver 928S
2007 Hummer H3 (Daily Driver)

Past lives (I miss them all):
2004 RX-8 (Wrecked)
1993 RX-7 (Sold)
1987 RX-7 Turbo II (Sold)
1985 RX-7 GSL (Stolen)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1793
Location: MI

PostPosted: Fri Nov 08, 2019 5:38 am    Post subject: Reply with quote

The ignition switch itself fails often..
I've had mine not crank or not stop cranking, that last cranking stage of he key switch messes up..

Sprayed the crap out of the key tumbler with WD-40 and worked the key in and out and through the switch turning it a lot, spray some more, exercise it some more, fixed..

If you aren't even hearing the solenoid on the starter hit when you turn the key, I'd be suspicious of the ignition switch itself..
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GeneT95  



Joined: 07 Nov 2019
Posts: 2
Location: Chesapeake, Virginia

PostPosted: Fri Nov 08, 2019 6:56 am    Post subject: Reply with quote

Thanks. I've been meaning to pull the switch, but really didn't want to do that. I also thought of the ignition switch as the intermittent problem as I hear nothing when it fails to start yet have aux power (sterio etc).

Even though it push started, I know pushing it to get it started may have nothing to do with it Actually fixing the problem, i.e. ignition switch, but just coincidence. Guess I'll run it to ground and check/clean the switch to just to be safe.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 1828
Location: Somerset, UK

PostPosted: Fri Nov 08, 2019 9:31 am    Post subject: Reply with quote

Fasteddie313 wrote:
The ignition switch itself fails often..
I've had mine not crank or not stop cranking, that last cranking stage of he key switch messes up..

Sprayed the crap out of the key tumbler with WD-40 and worked the key in and out and through the switch turning it a lot, spray some more, exercise it some more, fixed..

If you aren't even hearing the solenoid on the starter hit when you turn the key, I'd be suspicious of the ignition switch itself..


Its nothing to do with the ignition barrel + key......its the switch at the bottom of the barrel that fails. New are easy to swap out and cost $10 at a VW heritage specialist.

......Or its the solenoid on the starter or crusty wiring on the starter.
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peterld  



Joined: 10 Dec 2006
Posts: 740
Location: Noosa Heads QLD Australia

PostPosted: Fri Nov 08, 2019 3:22 pm    Post subject: Reply with quote

+1 to what he said. Known problem areas for the entire 924/944 range.
Particularly the plastic switch, which fortunately is a cheapish VW part.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 1793
Location: MI

PostPosted: Fri Nov 08, 2019 10:42 pm    Post subject: Reply with quote

Carrera RSR wrote:

Its nothing to do with the ignition barrel + key......its the switch at the bottom of the barrel that fails.


Right, but I flooded it so much I must have got the switch too because it fixed it..
That day it wouldn't stop cranking even with the key out and I had to run panicking to pull the battery cable to stop it.. Yeah that sucked..
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