Engine doesn't start
12-31-2017, 01:51 PM
#1
Engine doesn't start
The car was working perfectly until last week but today the engine won't start. Battery looks good however when I turn on the header lights, it flashes. So I connected the battery with my friend's car using a wire to check whether its a battery issue and the engine started perfectly. However, as soon as I disconnected the wire, header lights started flashing and the engine lasted about 3 mins and then the car started shaking and it went off.
What do you guys think the problem is?
It's Porsche Carrera 993 1994 with 20k miles on it.
What do you guys think the problem is?
It's Porsche Carrera 993 1994 with 20k miles on it.
12-31-2017, 08:01 PM
#3
RL Community Team
Rennlist Member
Rennlist Member
A fully charged battery should be at about 12.3 to 12.5 volts at rest.
A running car should show 13.5 to 14+ volts at the battery terminals while running.
If you charge your battery overnight with a 1.5 to 2.0 amp charger it should start your car in the morning unless it is flat dead.
Remove and clean the battery connections and reattach.
Charge the battery overnight check standing voltage in the morning as over 12 volts, if not you likely need a new battery.
Make sure your alternator belt is adequately tensioned, as not to slip.
Start your car and measure the running voltage, if too low investigate the alternator and its connections.
Just some thoughts
A running car should show 13.5 to 14+ volts at the battery terminals while running.
If you charge your battery overnight with a 1.5 to 2.0 amp charger it should start your car in the morning unless it is flat dead.
Remove and clean the battery connections and reattach.
Charge the battery overnight check standing voltage in the morning as over 12 volts, if not you likely need a new battery.
Make sure your alternator belt is adequately tensioned, as not to slip.
Start your car and measure the running voltage, if too low investigate the alternator and its connections.
Just some thoughts
12-31-2017, 08:23 PM
#4
Race Director
A fully charged battery should be at about 12.3 to 12.5 volts at rest.
A running car should show 13.5 to 14+ volts at the battery terminals while running.
If you charge your battery overnight with a 1.5 to 2.0 amp charger it should start your car in the morning unless it is flat dead.
Remove and clean the battery connections and reattach.
Charge the battery overnight check standing voltage in the morning as over 12 volts, if not you likely need a new battery.
Make sure your alternator belt is adequately tensioned, as not to slip.
Start your car and measure the running voltage, if too low investigate the alternator and its connections.
Just some thoughts
A running car should show 13.5 to 14+ volts at the battery terminals while running.
If you charge your battery overnight with a 1.5 to 2.0 amp charger it should start your car in the morning unless it is flat dead.
Remove and clean the battery connections and reattach.
Charge the battery overnight check standing voltage in the morning as over 12 volts, if not you likely need a new battery.
Make sure your alternator belt is adequately tensioned, as not to slip.
Start your car and measure the running voltage, if too low investigate the alternator and its connections.
Just some thoughts
at 12.3, you are about 50% discharged. At 12v, you are like 75% discharged
12-31-2017, 08:47 PM
#5
Rennlist Member
Steve is right, as always
problem with open circuit battery voltage is that it doesn't show sulphated cells and other degradations that raise cell internal resistance
when you go to pull some current, the bad cell voltage collapses
problem with open circuit battery voltage is that it doesn't show sulphated cells and other degradations that raise cell internal resistance
when you go to pull some current, the bad cell voltage collapses
Steve has the correct First step
12-31-2017, 08:49 PM
#6
Burning Brakes
12-31-2017, 09:29 PM
#7
RL Community Team
Rennlist Member
Rennlist Member
My car, that has a three year old battery in it, runs at 12.5 volts just after turning the engine off. It then drifts down over sever days but always seems to be able to start my car.
Andy
Trending Topics
01-01-2018, 02:33 AM
#8
RL Technical Advisor
I am in full agreement however most batteries only achieve 12.7 when they are nearly new and most batteries with a flat 12 volts will be able to start a car unless it is well below 40 degrees outside.
My car, that has a three year old battery in it, runs at 12.5 volts just after turning the engine off. It then drifts down over sever days but always seems to be able to start my car.
Andy
My car, that has a three year old battery in it, runs at 12.5 volts just after turning the engine off. It then drifts down over sever days but always seems to be able to start my car.
Andy
You may have some resident electrical maladies preventing you from reaching full voltage such as some high resistance connections.
01-01-2018, 02:09 PM
#9
The battery is only 9 months old. I thought that battery’s job is only to run the motor. That’s not the case in the car as I did run motor using a wire and it ran for few mins then went off.
I did a quick research and thought the issue is in the DME relay so I bought a new one and replaced the one I was using. But still having the same issue. When I try to switch the car on it only clicks.
I did a quick research and thought the issue is in the DME relay so I bought a new one and replaced the one I was using. But still having the same issue. When I try to switch the car on it only clicks.
01-01-2018, 03:33 PM
#10
Something lost in translation here don't understand what header lights are and what kind of wire? Jump leads? Common fault is battery earth strap. If the car starts and runs with a slave battery then the battery is faulty. If the cars starts and runs for a few minutes then dies and will not restart for a while I'd be looking at the crank sensor, which can fail open circuit when hot and then work again when cooled down. Take it in and get the engine harness checked it should have been replaced by now on factory recall.
01-01-2018, 05:11 PM
#11
Technical Guru
Rennlist Member
Rennlist Member
The clicking means your battery cannot provide enough power to turn the starter over. Something is either drawing too much current during standby or your alternator was not charging the battery while the engine was running.
01-01-2018, 05:19 PM
#12
Rennlist Member
How did you connect your friends battery?
im gonna guess you did + to + and then connected - to your cars chassis
in this way your friends battery had a low impedance to chassis but your battery strap is no good to run on its own
im gonna guess you did + to + and then connected - to your cars chassis
in this way your friends battery had a low impedance to chassis but your battery strap is no good to run on its own
01-01-2018, 05:28 PM
#14
The battery is only 9 months old. I thought that battery’s job is only to run the motor. That’s not the case in the car as I did run motor using a wire and it ran for few mins then went off.
I did a quick research and thought the issue is in the DME relay so I bought a new one and replaced the one I was using. But still having the same issue. When I try to switch the car on it only clicks.
I did a quick research and thought the issue is in the DME relay so I bought a new one and replaced the one I was using. But still having the same issue. When I try to switch the car on it only clicks.
01-22-2018, 04:49 PM
#15
Thank you guys for the all the help. My issue was battery and the alternator. I replaced the battery and now it is working perfectly. The alternator belt is pretty and cracked so when starting the engine, it doesn't hold the pulley properly. I want to replace it, however the alternator shaft is stripped, I couldn't hold it from turning. What do you guys do in this case?