no crank/no start
08-20-2016, 11:42 PM
#1
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no crank/no start
I took my ’80 A/T to the local auto parts store this morning to pick up some oil. When I hopped back in to leave, I turned the key, and just got a click at the starter relay; no crank. I had the battery tested, it was good. I tried to jump it with a battery pack. No change. I checked the grounds, and they were clean. I switched the horn relay and starter relay, the horn worked, but still no crank. I checked post 86, turned the key, and had 12 V. I jumped the yellow wire from the 14-pin to the jump post, still no crank. I tested U7 at the CE Panel, shifting from park to drive and back, but saw no change in voltage. I jumped post 87 and 30, the engine cranked easily. I suspect I have a failed neutral safety switch. Does this sound correct? Is there anywhere else I should look?
On the bright side, my lovely wife was kind enough to bring me my tools. While I was waiting I had at least seven people of all ages approach me, ask me about the car, tell me how much they love the 928, or tell me about their memories of the 928. One we was showed up in Boxster. Lastly, the information I found on this forum was excellent. I can’t thank you all enough.
On the bright side, my lovely wife was kind enough to bring me my tools. While I was waiting I had at least seven people of all ages approach me, ask me about the car, tell me how much they love the 928, or tell me about their memories of the 928. One we was showed up in Boxster. Lastly, the information I found on this forum was excellent. I can’t thank you all enough.
08-21-2016, 07:03 AM
#3
Rennlist Member
The plug connector for that switch should be near the spare tire well. They can be in need of cleaning.
I'd also be replacing the bat ground strap.
They fail in a most subtle/diabolical way, passing just enough electrons to show 12v at various test points throughout the car, but fail when you draw a load, like moving a seat or turning the key. Then, with no warning, maybe just a vibration, tweaking or slight ambient temp change, work again.
I'd also be replacing the bat ground strap.
They fail in a most subtle/diabolical way, passing just enough electrons to show 12v at various test points throughout the car, but fail when you draw a load, like moving a seat or turning the key. Then, with no warning, maybe just a vibration, tweaking or slight ambient temp change, work again.
08-21-2016, 07:52 AM
#4
Electron Wrangler
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Yes - on an '80 you don't actually have a starter relay, the ignition key directly drives the starter - however it drives it through the starter blocking relay. The sole purpose of this relay is to provide the starter transmission interlock (neutral safety switch). when you jumper 87/30 on this relay you just disable that interlock.
Check the wiring in the spare tire well above and in front of the batter box (WRT vehicle).
Alan
Check the wiring in the spare tire well above and in front of the batter box (WRT vehicle).
Alan
08-21-2016, 11:05 AM
#6
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" I jumped the yellow wire from the 14-pin to the jump post, still no crank."
If you did that correctly, you just eliminated all of the switches, relays and wiring from the situation.
All that is left is a lack of power to the starter, an intermittently failing starter solenoid or worn/sticky starter brushes.
If you apply power to the yellow wire down to the solenoid and the solenoid clacks but no starter, clean or replace the brushes.
If there is no clack, clean every connection from the positive post thru the starter and chassis to the negative post, including both ground cables and connections. While you are under there, check and clean the solenoid guts.
If you did that correctly, you just eliminated all of the switches, relays and wiring from the situation.
All that is left is a lack of power to the starter, an intermittently failing starter solenoid or worn/sticky starter brushes.
If you apply power to the yellow wire down to the solenoid and the solenoid clacks but no starter, clean or replace the brushes.
If there is no clack, clean every connection from the positive post thru the starter and chassis to the negative post, including both ground cables and connections. While you are under there, check and clean the solenoid guts.
08-21-2016, 05:07 PM
#7
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" I jumped the yellow wire from the 14-pin to the jump post, still no crank."
If you did that correctly, you just eliminated all of the switches, relays and wiring from the situation.
All that is left is a lack of power to the starter, an intermittently failing starter solenoid or worn/sticky starter brushes.
If you apply power to the yellow wire down to the solenoid and the solenoid clacks but no starter, clean or replace the brushes.
If there is no clack, clean every connection from the positive post thru the starter and chassis to the negative post, including both ground cables and connections. While you are under there, check and clean the solenoid guts.
If you did that correctly, you just eliminated all of the switches, relays and wiring from the situation.
All that is left is a lack of power to the starter, an intermittently failing starter solenoid or worn/sticky starter brushes.
If you apply power to the yellow wire down to the solenoid and the solenoid clacks but no starter, clean or replace the brushes.
If there is no clack, clean every connection from the positive post thru the starter and chassis to the negative post, including both ground cables and connections. While you are under there, check and clean the solenoid guts.
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09-27-2016, 10:18 AM
#8
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Roger sent me a new neutral safety switch. I removed the old NSS and installed the new one following the WSM directions. The connector was amazingly clean. The car started and all was good, expect now it will not start again.
It started I believe a half dozen times. I noted corrosion on the relay and on the board, so I cleaned both with deoxite and a wire bush, reinstalled the relay, and the car started again. A couple days later, it would not start again, pulled the relay out of the socket and did not fully reset it. The car started. A few days later, no start again. I figured I had loose connection and corrosion. I pulled the CE panel, cleaned and tightened the connections and cleaned the grounds. I still have no start. I get 11.5 V at the U7 with the key turned and the relay installed. I bench test the relay and it works. Switched it with horn relay, horn works, but no start. If I remove the relay, U7 = 0 V. If I shift to P to R to N to D, U7 voltage goes from 11.5 V to 10.3 V to 11.3 V to 10.3 V V? Should it not go to zero in D and R? Should it not close the relay if there is current and start anyways? I have continuity from the NSS to U7 and the car starts when I jump 30 and 87. Is there anywhere else I should look?
It started I believe a half dozen times. I noted corrosion on the relay and on the board, so I cleaned both with deoxite and a wire bush, reinstalled the relay, and the car started again. A couple days later, it would not start again, pulled the relay out of the socket and did not fully reset it. The car started. A few days later, no start again. I figured I had loose connection and corrosion. I pulled the CE panel, cleaned and tightened the connections and cleaned the grounds. I still have no start. I get 11.5 V at the U7 with the key turned and the relay installed. I bench test the relay and it works. Switched it with horn relay, horn works, but no start. If I remove the relay, U7 = 0 V. If I shift to P to R to N to D, U7 voltage goes from 11.5 V to 10.3 V to 11.3 V to 10.3 V V? Should it not go to zero in D and R? Should it not close the relay if there is current and start anyways? I have continuity from the NSS to U7 and the car starts when I jump 30 and 87. Is there anywhere else I should look?
09-27-2016, 10:38 AM
#9
Team Owner
did you check the ground connection behind the RR interior liner? in the hatch
05-22-2017, 02:26 AM
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thanks all for comments
the car was repaired at Porsche dealer
they replaced battery alternator and positive negative cables in the engine bay
today they tried the car it started
but I told them that because something cool down or battery recovered - same as before leave a few days starts ok
they need to run the car for extended time them check if alternator when hot fails meaning battery not get charged
I'll ask them check all the wiring - could be some short somewhere
the car was repaired at Porsche dealer
they replaced battery alternator and positive negative cables in the engine bay
today they tried the car it started
but I told them that because something cool down or battery recovered - same as before leave a few days starts ok
they need to run the car for extended time them check if alternator when hot fails meaning battery not get charged
I'll ask them check all the wiring - could be some short somewhere