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T Hutch
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2 Posts
Discussion Starter #1
Just purchased a 1988 525e that has travelled around 340,000 kms.
Car is in very good condition - Runs well when warm - But is hard to start, rough idles until warm and will cut out.
I have read through the many threads and am trying to come to grips with all the various abbreviations.
I am a mechanical engineer and was brought up on a wheat and sheep farm - i have a bit of an idea about cars.
The mechanic disconnected what i think was the cold start valve to see if it made an difference.
It did not - I had a similar problem with the first 525e that we had.
Any thoughts as to where I should begin?
 

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Registered
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278 Posts
Hi ya. Check your temp sending unit. Not the one that sends to the gauge, but the one that sends signal to ECU. I have had the values the sending unit was giving so far off, the car acted like you describe.
 

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Bimmerfest Founder
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15,712 Posts
Welcome to Bimmerfest! I've moved your question to our 5 Series forum, you'll get more help in here.

Tim
 

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catso
Joined
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3,160 Posts
Just purchased a 1988 525e that has travelled around 340,000 kms.
Car is in very good condition - Runs well when warm - But is hard to start, rough idles until warm and will cut out.
I have read through the many threads and am trying to come to grips with all the various abbreviations.
I am a mechanical engineer and was brought up on a wheat and sheep farm - i have a bit of an idea about cars.
The mechanic disconnected what i think was the cold start valve to see if it made an difference.
It did not - I had a similar problem with the first 525e that we had.
Any thoughts as to where I should begin?
The 1988 528e sold in the USA does not have a cold start valve, but does have an Idle Air Control valve that can get gummed up and malfunction. It's not hard to remove and clean, but with that much mileage it may not function properly even after a good cleaning. Also inspect the passages and rubber boots connected to it and the throttle body. Clean the passages if they are blocked or very dirty. Everthing that's made of rubber is subject to deterioration and leakage so you may need to replace the intake boots and vacuum hoses too.
 

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T Hutch
Joined
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2 Posts
Discussion Starter #5
What is gorm?

Thanks Redman - I will use your info. when I get a chance.
My 525e cut out on the weekend when going up a reasonable slope - Restarted OK - Did it a few times until I was off the sloping ground - Once back on the bitumen the car performed without a fault for the 1 3/4 hour drive home.
Have also noticed that the car will stall when I back over the entrance to our drive way which puts the car on a reasonable slope - Has anyone got any ideas about this problem?
Plan to replace all the vacuum hoses as soon as I can with the aim of seeing whether it will solve the rough idling on start up problem that I have.

I am also considering doing a 'diesel transplant' into the 525e - I plan to obtain a 524td from somewhere outside Australia to do this - The 524td was never sold in this country as the diesel quality was poor - Does any one know if this is possible to do?

Regards,
Trevor from Down Under.
 

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catso
Joined
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3,160 Posts
Thanks Redman - I will use your info. when I get a chance.
My 525e cut out on the weekend when going up a reasonable slope - Restarted OK - Did it a few times until I was off the sloping ground - Once back on the bitumen the car performed without a fault for the 1 3/4 hour drive home.
Have also noticed that the car will stall when I back over the entrance to our drive way which puts the car on a reasonable slope - Has anyone got any ideas about this problem?
Plan to replace all the vacuum hoses as soon as I can with the aim of seeing whether it will solve the rough idling on start up problem that I have.

I am also considering doing a 'diesel transplant' into the 525e - I plan to obtain a 524td from somewhere outside Australia to do this - The 524td was never sold in this country as the diesel quality was poor - Does any one know if this is possible to do?

Regards,
Trevor from Down Under.
I don't think it would be very easy to replace a gas engine with a diesel; fuel system, computer, ignition, possibly even cooling system etc. would all need to be changed. The slope issue makes me think fuel system, but the symptoms seem like a crank position sensor or something electrical. Intermittent problems are usually the hardest to diagnose.
 
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