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Bibi
 
Join Date: Jan 2010
Location: France
Posts: 35
Problem with K-jet

Hi,

Before explaining, my engine start extremly good, No problem, But :

Before starting my engine, I hear my fuel pump turning.
I changed relay pump, my front fuel pump, my connection near head of Kjet is ok.
normally my fuel pump should not turn.

When my engine is hot, everything is ok, my fuel pump turn just when I start.

And when I start after stop engine one hour, my fuel pump turn intermittently, So I start immediatelly, It's not good for them.

Do you know what is the problem ?



Last edited by The frenchi; 06-23-2010 at 11:42 AM..
Old 06-23-2010, 10:41 AM
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Location: Central Washington State
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If your car is properly wired the fuel pumps should not run until the fuel metering plate/control arm is deflected enough to activate the electrical switch connected to it. Cranking the engine and drawing air across the metering plate will delfect it and start the pumps running. I believe the switch is normally closed, and opens when the arm deflects enough.

You may want to check the connections on that switch, at the back of the fuel distributor. Pull the electrical connection (green plug, or is it blue?) to the switch. If everything is operating correctly, pulling the plug will cause your pumps to start running. If they're already running to begin with, then dirty connections or faulty switch may be the cause....or, the metering plate control arm is hanging up and not fully returning to rest when you shut the car off.
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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-23-2010, 01:38 PM
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Bibi
 
Join Date: Jan 2010
Location: France
Posts: 35
Thank for answer.
My electrical connection is blue.
I'll test my switch and my connection.
And I give you news !!
Is it possible to change the switch ?

I'm afraid to have to set the metering plate control

Old 06-24-2010, 10:17 AM
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Quote:
Originally Posted by The frenchi View Post
Thank for answer.
My electrical connection is blue.
I'll test my switch and my connection.
And I give you news !!
Is it possible to change the switch ?

I'm afraid to have to set the metering plate control

Yes, the switch can be replaced...though I have never done that myself.

Check to make sure your metering arm is moving freely, and lubricate it at the pivot point (sorry, I can't tell you exactly where to lube it at, but others on this forum may have pictures). From your symptoms I'm betting it's just not returning fully to rest when the engine is cold and eventually loosens up when things get hot and expand.
Or, don't even worry about it. It won't cause any problems with the pumps running for a couple seconds before you actually start the car.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-24-2010, 10:37 AM
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Here's a great picture of the inner workings of the fuel distributor. It looks like the pivot point for the metering plate control arm is behind that shaft end with the circlip holding it in place. But I'm not sure if that's where you lube it or not.

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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 06-24-2010, 11:47 AM
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Bibi
 
Join Date: Jan 2010
Location: France
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Ok, thank
In case of accident if my fuel pumps continue to turn, it can be a cause of fire.
And I like when everything works well.
Before setting my metering plate control, I would try to lubricate the pivot point, I didn't know it was possible.
If someone can say me how lubricate....it will be cool
Old 06-25-2010, 08:42 AM
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Bibi
 
Join Date: Jan 2010
Location: France
Posts: 35
Quote:
Originally Posted by mark houghton View Post
Here's a great picture of the inner workings of the fuel distributor. It looks like the pivot point for the metering plate control arm is behind that shaft end with the circlip holding it in place. But I'm not sure if that's where you lube it or not.


Could you post again this picture but in an other resolution , I don't manage to read the text
Old 06-26-2010, 10:27 AM
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Just so you know that picture is of a 4 cylinder BMW, Saab, Audi, or Volkswagon CIS unit. This one pictured has an airflow meter that swings upwards and the opposite direction to the one on a 930.
It's also missing alot of fuel head parts in this diagram/picture and the diaphram and orifice's are different than a USA lambda head but it's better than nothing.

I've never heard of anyone trying to lubricate the pivot bearings on the airflow sensor arm. Some people probably have and you could spray something thin like WD40 with the long straw attachment at them from the inside.
I wouldn't try to remove the circlips and covers over the bearings on the outside.

It would be very difficult to see what you're doing while the airflow housing is installed on the motor.
If all the fuel lines are off the fuel head than there's only 3 - 13mm nuts holding the housing onto the intake manifold and 3 screws hold the fuel head onto the housing.
If you use spray lube at the bearings, taking the fuel head off may be the best way to reach them.
Old 06-26-2010, 12:44 PM
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Bibi
 
Join Date: Jan 2010
Location: France
Posts: 35
So I work to find my problem.
My electrical connection is ok.

When I pull up the metering plate control, my fuel pump stop.
And when I drop in his initial position, my fuel pump turns.
So : Maybe my switch is broken or set wrong.
Or my metering plate control is set wrong.

How can I disassemble the switch I didn't find...

And How can I set the metering plate control...but that will change my CO setting....


Thank for answer
Old 07-01-2010, 09:21 AM
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Turbofrog
 
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Are you pulling the metering plate or the connector plug?

If metering plate then that is how it should work but yours does not freely come to up position by itself so it needs to be freed or lubrigated somehow.

If you are pulling the plug, there are two connectors on the back of the engine bay. Are you sure they are on correct connectors, although that might prevent the engine to start at all?
Old 07-01-2010, 07:08 PM
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Quote:
Originally Posted by The frenchi View Post
So I work to find my problem.
My electrical connection is ok.

When I pull up the metering plate control, my fuel pump stop.
And when I drop in his initial position, my fuel pump turns.
So : Maybe my switch is broken or set wrong.
Or my metering plate control is set wrong.

How can I disassemble the switch I didn't find...

And How can I set the metering plate control...but that will change my CO setting....


Thank for answer
Well you seem to be narrowing down the problem. At least we now know that your switch is functioning, but it doesn't appear that your control arm is returning to full rest and triggering the switch.
Two possibilities that I can think of. One, the air flow sensor plate is binding or rubbing on the side of the cone and may need to be re-centered. You should be able to pass a 0.1mm feeler gauge around the circumference of the plate to assure proper clearance between the plate and cone. You could loosen the center mounting screw and move the plate until it's centered. Or, the other possibility is that the control plunger in the fuel distributor is gummed up and sticking, not letting the control arm return to its full rest position. You would have to remove the fuel distributor to get to and clean the plunger.

I personally have not made those adjustments or removed the distributor, but it seems pretty straightforward. An invaluable resource is Bentley Publishers Bosch Fuel Injection and Engine Management book, written by Charles O. Probst.
__________________
Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 07-01-2010, 07:19 PM
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Bibi
 
Join Date: Jan 2010
Location: France
Posts: 35
So, how can I do to re-centere my plate control ?
Or How Can I clean the control plunger ?

Thank
Old 07-02-2010, 08:08 AM
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