Hello,
I've not had my 911 long. One of the problems it has is it backfires constantly when starting. It has a blow off valve fitted inside the air cleaner, which blew out all together on one occasion.
The cold start / Warm-up (911.606.903.00) gadget was not powered initially, but I have fixed this. This part seems to be about £400 from Porsche.
Is there any way of checking that it works correctly.
I assume the backfiring is because it is running lean on starting.
Has anyone seen this problem before?
Thanks
<MARK>
Cold Start Problem 1973 911T K-Jetronic
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mhester
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Gary71
- Nurse, I think I need some assistance
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Mark,
When your engine is cold, like first thing in the morning, take out the cold start injector and aim it into a jar. With the ignition disconnected turn over the engine and it should squirt fuel whilst you are cranking.
If this is OK then you need to start the usual search for air leaks. Round gaskets, in the vacuum system, and anywhere from the metering head to the cylinder head.
Hope you get it sorted.
When your engine is cold, like first thing in the morning, take out the cold start injector and aim it into a jar. With the ignition disconnected turn over the engine and it should squirt fuel whilst you are cranking.
If this is OK then you need to start the usual search for air leaks. Round gaskets, in the vacuum system, and anywhere from the metering head to the cylinder head.
Hope you get it sorted.
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mhester
- DDK Fanatic
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Gary,
Over the weekend, I disconnected the Thin pipe from the cold start device to the main injector distribution point.
Nothing came out of the cold start device, but allot of fuel came out from the Injector mechanism.
I then tried to block this off.
Should fuel also come out of here, or should fuel only flow into it?
I then checked out the electrical side of the cold start, and that had stopped working again. I then ran out of time, so I'll try again later this week.
Thanks
<MARK>
Over the weekend, I disconnected the Thin pipe from the cold start device to the main injector distribution point.
Nothing came out of the cold start device, but allot of fuel came out from the Injector mechanism.
I then tried to block this off.
Should fuel also come out of here, or should fuel only flow into it?
I then checked out the electrical side of the cold start, and that had stopped working again. I then ran out of time, so I'll try again later this week.
Thanks
<MARK>
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Bruce M
- Me and DDK sitting in a tree! KISSING
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- Joined: Fri Aug 27, 2004 1:07 pm
to clarify (from a vague memory).
The cold start injector, only runs for a brief time (ten seconds or so).
a termocouple on the block cuts it out after that (using the small internal heater or a hot engine to open the bimetalic contacts) .
The warm up device reduces the fuel pressure on the top of the fuel distributer. This allows the air metering flap to travel further for a given air volume therfore increasing the amount of fuel delivered to the injectors and richening up the mixture. The warm up unit bleeds off petrol when the engine is cold and returns it to the tank (sometimes via the fuel distributer on later versions).
Hope this helps
The cold start injector, only runs for a brief time (ten seconds or so).
a termocouple on the block cuts it out after that (using the small internal heater or a hot engine to open the bimetalic contacts) .
The warm up device reduces the fuel pressure on the top of the fuel distributer. This allows the air metering flap to travel further for a given air volume therfore increasing the amount of fuel delivered to the injectors and richening up the mixture. The warm up unit bleeds off petrol when the engine is cold and returns it to the tank (sometimes via the fuel distributer on later versions).
Hope this helps