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Discussion Starter · #1 ·
My friends 02 325ci started exhibiting crank but no start problems a little while ago. It first started happening later in the day on some days, but would be fine in the mornings. Then it progressed to every day and most mornings. A couple times earlier on I was able to get it to start by pulling the battery cable for a minute or so. When it stopped completely we pulled it to my house and I tested for fuel pressure and spark (fuel pump is about 3 years old, coils and plugs a few months old) and both seemed fine. I replaced the crank position sensor, then I ran out of time to deal with it so we took it to a shop.

They just called and said it has low compression on all cylinders. I did notice, I think right after installing the new CPS, that cranking got "easier". I think that the valvetrain system is to blame, and that must have been when it went out completely. The shop doesn't want to deal with it, just wants to swap the engine. Seems like a waste when this car doesn't leak or smoke and ran great up until now. Does anyone know what would be the likely point of failure with the vanos or timing system to cause low compression on all cylinders?
 

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E30M3 Race F10 535 R1150Rt M Coupe
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My friends 02 325ci started exhibiting crank but no start problems a little while ago. It first started happening later in the day on some days, but would be fine in the mornings. Then it progressed to every day and most mornings. A couple times earlier on I was able to get it to start by pulling the battery cable for a minute or so. When it stopped completely we pulled it to my house and I tested for fuel pressure and spark (fuel pump is about 3 years old, coils and plugs a few months old) and both seemed fine. I replaced the crank position sensor, then I ran out of time to deal with it so we took it to a shop.

They just called and said it has low compression on all cylinders. I did notice, I think right after installing the new CPS, that cranking got "easier". I think that the valvetrain system is to blame, and that must have been when it went out completely. The shop doesn't want to deal with it, just wants to swap the engine. Seems like a waste when this car doesn't leak or smoke and ran great up until now. Does anyone know what would be the likely point of failure with the vanos or timing system to cause low compression on all cylinders?
that cranking got "easier".

Unless they did something wrong? This is the key point.
Pull the valve cover and inspect/check camshaft timing against the crankshaft @ TDC.
 

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Discussion Starter · #8 ·
When car ran it was perfect. It did run once after I replaced the CPS, then at the end of the day it didn't start again. Shop has lots of good reviews on google, but I am not there to confirm they tested correctly. If I thought it was mechanical I would have tested myself. Car has almost 180k miles, but I can't confirm if the engine is original.
 

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When car ran it was perfect.
They just called and said it has low compression on all cylinders.
Shop says they were all around 30psi
The shop doesn't want to deal with it, just wants to swap the engine.
With all cylinders are in the 30psi range, it can't run perfect when it decided to run. Dump the shop and find someone to do a leak-down test on the cylinders.
What is the measured battery voltage directly at the battery?
 

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sounds like you may have cylinder wash check the spark plugs to see if they are wet with gas and make sure you have a good strong battery
 

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E30M3 Race F10 535 R1150Rt M Coupe
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sounds like you may have cylinder wash check the spark plugs to see if they are wet with gas and make sure you have a good strong battery
Yeah, I was just wondering about such... But in the warm weather have not seen it. Hence why it was out of mind.
 
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