Fast crank no start

[roberta berks]

Have a problem once and a while when car sits for a month or so.I come back to it a couple times and sometimes it finally it starts.New battery and new key battery's. No second trunk battery.Seems like it cranks faster too.Key programming?

[lewisweller]

2 hours ago, roberta berks said:

Have a problem once and a while when car sits for a month or so.I come back to it a couple times and sometimes it finally it starts.New battery and new key battery's. No second trunk battery.Seems like it cranks faster too.Key programming?

Erm im hedging a bet the battery(s) are ok if cranking is faster than normal.

Low compression can cause faster cranking and no start or hard starting symptoms. 

Would suggest doing compression test first. 

[roberta berks]

What would cause low compression on a 45k mile Cayenne that ran great?

[lewisweller]

Just now, roberta berks said:

What would cause low compression on a 45k mile Cayenne that ran great?

Ran great (past tense) or stills runs great (when it starts)?

A list of possibilities but yes a good running low mileage engine shouldn't have these problems.

 

Got any fault codes? 

 

The symptoms are too vague to narrow down a cause yet.  

[roberta berks]

1 hour ago, lewisweller said:

Ran great (past tense) or stills runs great (when it starts)?

A list of possibilities but yes a good running low mileage engine shouldn't have these problems.

 

Got any fault codes? 

 

The symptoms are too vague to narrow down a cause yet.  

Thanks.Runs great when it starts.No fault codes.

[lewisweller]

Just now, roberta berks said:

Thanks.Runs great when it starts.No fault codes.

Fuel pressure is a possibility. There is a fuel pressure regulator which is supposed to hold 3 bar after ten minutes when engine is stopped IIRC, if that fails you go to crank and don't have any fuel pressure available, hence long crank to build pressure then it starts. I remember also the fuel filter has a non return valve in it which can fail. Also fuel pumps are notorious for being a pain, weak pumps, leaky pipes, clogged suction screens etc etc. I've been inside my tank a few times and replaced all these items on my 06 ctt when I had it. 

Testing fuel pressure requires a fuel pressure test kit with correct Schrader fittings and a specific procedure. 

[roberta berks]

Sure, thank you.It does not show symptoms of hesitation or start for a second then die out that usually relates to fuel problem.(when running). Just intermediate fast crank like the key is not recognized (tried both keys). Some electrical gremlin again perhaps?That is all Ive had with this car.Car does sit for months at a time.Any other thoughts are appreciated!

[roberta berks]

16 hours ago, lewisweller said:

Fuel pressure is a possibility. There is a fuel pressure regulator which is supposed to hold 3 bar after ten minutes when engine is stopped IIRC, if that fails you go to crank and don't have any fuel pressure available, hence long crank to build pressure then it starts. I remember also the fuel filter has a non return valve in it which can fail. Also fuel pumps are notorious for being a pain, weak pumps, leaky pipes, clogged suction screens etc etc. I've been inside my tank a few times and replaced all these items on my 06 ctt when I had it. 

Testing fuel pressure requires a fuel pressure test kit with correct Schrader fittings and a specific procedure. 

 

16 hours ago, lewisweller said:

Fuel pressure is a possibility. There is a fuel pressure regulator which is supposed to hold 3 bar after ten minutes when engine is stopped IIRC, if that fails you go to crank and don't have any fuel pressure available, hence long crank to build pressure then it starts. I remember also the fuel filter has a non return valve in it which can fail. Also fuel pumps are notorious for being a pain, weak pumps, leaky pipes, clogged suction screens etc etc. I've been inside my tank a few times and replaced all these items on my 06 ctt when I had it. 

Testing fuel pressure requires a fuel pressure test kit with correct Schrader fittings and a specific procedure. 

Sure, thank you.It does not show symptoms of hesitation or start for a second then die out that usually relates to fuel problem.(when running). Just intermediate fast crank like the key is not recognized (tried both keys). Some electrical gremlin again perhaps?That is all Ive had with this car.Car does sit for months at a time.Any other thoughts are appreciated!

[lewisweller]

21 minutes ago, roberta berks said:

 

Sure, thank you.It does not show symptoms of hesitation or start for a second then die out that usually relates to fuel problem.(when running). Just intermediate fast crank like the key is not recognized (tried both keys). Some electrical gremlin again perhaps?That is all Ive had with this car.Car does sit for months at a time.Any other thoughts are appreciated

I would have thought it wouldn't crank if the immobilizer was the issue? Not quite sure. 

I'm still not sold on it not being a fuel issue perhaps. Really only testing and ruling out things will get you closer to the cause without fault codes to help guide you. 

 

[roberta berks]

1 hour ago, lewisweller said:

I would have thought it wouldn't crank if the immobilizer was the issue? Not quite sure. 

I'm still not sold on it not being a fuel issue perhaps. Really only testing and ruling out things will get you closer to the cause without fault codes to help guide you. 

 

Right.Since the car has only 45k miles and runs great when it does run without symptoms or faults,I'm leaning towards some little connector that's corroded from sitting in humid Florida.It was that when I swapped out the rear convenience module a few months ago after gremlins started appearing and fixed without a dura or piwis.Maybe alarm module since it sits on top of rear convenience,I dont know.Real PITA vehicle.

[lewisweller]

2 minutes ago, roberta berks said:

Right.Since the car has only 45k miles and runs great when it does run without symptoms or faults,I'm leaning towards some little connector that's corroded from sitting in humid Florida.It was that when I swapped out the rear convenience module a few months ago after gremlins started appearing and fixed without a dura or piwis.Maybe alarm module since it sits on top of rear convenience,I dont know.Real PITA vehicle.

Kessy module is under the dash just up above the accelerator pedal. I think the module next to the rear comfort control module is the level control module? 

[roberta berks]

4 hours ago, lewisweller said:

Kessy module is under the dash just up above the accelerator pedal. I think the module next to the rear comfort control module is the level control module? 

Sure.May look at Kessy connectors for corrosion since its easier to look at first. No air suspension in this car.Appreciate the help !