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Old 01-13-2002, 01:17 PM
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Question 1969 289 SEL vacuum leak problem?

My 1969 280 SEL is runing on 4 of its 6 cylinders it seems. The compression checked out with 150lbs. of pressure in all cylinders. However, no changed is detected in running when spark plug wires #1 and #2 are removed. Is this a good indication of a vacuum leak? I sprayed carb cleaner all around the affected area when the car was running and it didn't seem to change the engine beat at all. Any other tests I can run here? Many thanks.
Thom

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1967 Jaguar E-type Series I, 2+2
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Old 01-13-2002, 04:45 PM
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I suggest a test of the Injector points. Connect a 12v. light to the fuel injector plug of the dead cylinders and crank the motor, the light should pulse. If not then the injector points are at fault. Check a good cylinder to test the light. The injector points are on the side of the distributor on a plate with an electrical plug. Remove and examine them for anything like corrosion, broken bits, etc. Replace with new or McGyver if this is your cup of tea. Good luck with your repairs.
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Old 01-13-2002, 05:36 PM
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Injector points??? I didn't know that mechanical injection had such a thing. I'll take a look though. Thanks.
Thom
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Old 01-13-2002, 06:14 PM
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The car is Mechanical FI. No injector points.
Might still be an injector/pump, but I would try spark first. [ wires could be crossed on those two at the cap.]
Running on 4 must be rough....
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Old 01-13-2002, 06:41 PM
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Talking Sorry

Injector points were a few more years in the future. I did a quick consult with the manual and it showed fuel inj. It didn't say what type, man am I embarrassed.
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Old 01-13-2002, 06:42 PM
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Arthur,
The mechanic I took it to tried that already. He switched the leads for #1 and #2 and no effect. He took out his stethoscope and listened to the injectors as well and they seemed to be clicking. AAARRRGGGHHH.
Thom
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Old 01-13-2002, 08:56 PM
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Meanwhile back at the drawing board...

Lets start from the beginning, when exactly did this situation manifest itself, and was there mechanical work being done at the time preceeding this event? Has the timing been checked statically -TDC and rotor at the #1? Do you have spark on #1 and#2 visually(and Thick Glovedely)? Plugs gapped per manual?
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Old 01-13-2002, 08:56 PM
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Then it is possible you have two bad wires/resistor ends. Also could have cross arcing in cap.
I would check the firing order compared to the wires at the cap first so you know that is right, then pull each plug and work back from there.
You can substitute a known good plug wire for testing. [ can be off anything, even a FORD !!!]

You are sure about the compression?
Adjacent dead plug/cyl. could be a gasket. I would redo the comp test just for starters. Then you are sure where you are and then go to timing order.
After these are known to be on, it is gas or spark.......
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Old 01-13-2002, 10:26 PM
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In theory, cracking the cap nut loose on the pump should leak fluid if the pump is working right. But I presume your mechanic would have checked that.

A diagnostic scope check is in order. You can literally see the effect of rich/lean on the scope for each cylinder.

If your mechanic doesn't know the system well, it's unfortunately time for a more seasoned mechanic for this.

Here's some good tech info... http://www.pelicanparts.com/techarticles/911_MFI/TipMFI.htm

-CTH

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