Slow Starting 91 S2
#31
I changed my FPR too and still did not speed the starting. I am fairly convinced that the M198 (1.7KW starter) option will help in speeding up starting. Anybody has this one on their S2. And I definetelly heard that standard 944, 944S and 944T can start quick so this is definetelly a S2 trade mark.
#32
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Join Date: Aug 2008
Location: Folsom/San Luis Obispo CA
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My take: More volume + more compression + same starter = slower start
How many times around does an engine (porsche or otherwise) typically go before it starts?
How many times around does an engine (porsche or otherwise) typically go before it starts?
#33
+1. S2 DME wants to get couple times the TDC position before it fires up the engine. My engine started on third or fourth... But there is always the way-way-way-way-<ignition>-wrum!! effect.
23tml? Congrats on your new baby!
23tml? Congrats on your new baby!
#34
I've had to jump mine off before and even with the starter spinning a little faster, it still takes 4-6 cranks to start, and this is in all situations: cold start and re-starts after parking for a little bit, so it isn't a starter problem.
If anything it's a fuel issue, but I personally don't mind letting the engine spin several times before it actually starts. It gets your engine oil flowing a little before it's completely running, which isn't a bad thing.
If anything it's a fuel issue, but I personally don't mind letting the engine spin several times before it actually starts. It gets your engine oil flowing a little before it's completely running, which isn't a bad thing.
#35
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There is just no example anywhere in the modern fuel injected automovtive universe where an engine turns over more than a couple of times before firing. Either something is not strong enough (starter), or holds/builds pressure fast enough (FPR/fuel pump) or there is a lack of juice (battery, poor ground/contacts). On other cars I have had this condition was related to the cold start sensor or something similar.
i have premature let go syndrome in spite of being trained to keep my hand grasping the key longer than usual because of my S2 ownership.
maybe i need KeyVitra to stop me from letting go prematurely.
wake up guys, the OP posted a legit question, it was answered, now you are digging around for answers.
By the way, did you know that in a fuel injected rotary motor, namely the GSL-SE of 84-85 you are supposed to step on the gas twice to prime the motor. imagine that, a fuel injected motor and you prime it with a pump on the gas pedal before turning the key. says so in the owners manual.
#36
Three Wheelin'
I just put an early starter in my late (85.5) and it starts much faster. 2nd or third crank. The old starter was not in good shape, so I'm sure it contribute to this, but the early starters are certainly larger so I suspect they may be higher powered and get the engine up to speed faster.
#37
Another factor that could make the starter lethargic is that in my S2 the battery is in the boot. The wire to the starter will be longer then when the battery is in the engine compartment. The longer wire will contribute to less energy getting to the starter.
#39
and you're right about the wire. Here's a tip to battery movers....look at a wire rating chart for the wire ratings. If you're increasing the length, you're increasing resistance therefore you're going to need a bigger wire. I know things as such is common sense to a lot of folks in here, but by reading some of the responses in this forum, I'm sure a few don't have a clue.
#40
Voltage drop lost in the wire running from the batttery in the boot to the starter is about 0.24 volts, In a 12 volt system that is a 2% loss... not much at all.
Why? 4 awg wire has a resistance of 0.000815 ohms per meter. Putting the battery in the boot will add lets say 2 meter or 0.00163 ohms A starter will draw between 100-150 amps.
Voltage drop in wire = 150 amps * 0.00163 ohm
=0.2445 volts
Why? 4 awg wire has a resistance of 0.000815 ohms per meter. Putting the battery in the boot will add lets say 2 meter or 0.00163 ohms A starter will draw between 100-150 amps.
Voltage drop in wire = 150 amps * 0.00163 ohm
=0.2445 volts
#41
Agree with this calculation. Well 2% loss is hardly anything to worry about.
So M198 option (1.7KW starter) may be the only way to speed up starting without having to modify the DME internal program. Noticed that the 968 which has basically the same engine as S2 only comes with a 1.7KW starter. I wonder why? Also agree that the engine will still have to crank 4 times or so but with a faster speed the starting will feel more normal.
So M198 option (1.7KW starter) may be the only way to speed up starting without having to modify the DME internal program. Noticed that the 968 which has basically the same engine as S2 only comes with a 1.7KW starter. I wonder why? Also agree that the engine will still have to crank 4 times or so but with a faster speed the starting will feel more normal.
#42
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Will the 1.7kw starter bolt into the S2 engine without interference? Does the larger starter require a larger/higher cranking amp battery than what is recommended for the S2? I have noticed the S2 has a very small area for the battery (I replaced it and cleaned all terminals while to improve starting time).
Interesting item to note: as my car is a low mileage S2 the PO had a trickle charge bypass clamped on the negative terminal to keep the battery topped up when not being driven. Good idea but when you turned the trickle charger switch off (integrated on the clamp) it had significant parasitic impedance. When the car was running the voltmeter on the dash read only 12.25-12.5V even when running down the freeway. I removed the trickle charge bypass and the voltage jumped up to 13-13.5V while running. Lesson learned here; remove that trickle charge bypass clamp, if you use one, whenever you plan on driving the car.
Interesting item to note: as my car is a low mileage S2 the PO had a trickle charge bypass clamped on the negative terminal to keep the battery topped up when not being driven. Good idea but when you turned the trickle charger switch off (integrated on the clamp) it had significant parasitic impedance. When the car was running the voltmeter on the dash read only 12.25-12.5V even when running down the freeway. I removed the trickle charge bypass and the voltage jumped up to 13-13.5V while running. Lesson learned here; remove that trickle charge bypass clamp, if you use one, whenever you plan on driving the car.
#43
Will the 1.7kw starter bolt into the S2 engine without interference? Does the larger starter require a larger/higher cranking amp battery than what is recommended for the S2? I have noticed the S2 has a very small area for the battery (I replaced it and cleaned all terminals while to improve starting time).
#44
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My NA has always taken 4 to 5 revolutions to start. If the car is hot, and you run into the house or the store for a second, sometimes it will start on the second revolution.
On a cold day (under 32F) it still takes 4-5 revolutions, but it is slower. It has always been that way since new. The HD megatron plus interstate batteries always helped and worked better.
On a cold day (under 32F) it still takes 4-5 revolutions, but it is slower. It has always been that way since new. The HD megatron plus interstate batteries always helped and worked better.