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Any petrol heads out there?


pritch1
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I know its not a very exciting engine but im trying to sort a 2.25 petrol engine out and being from a diesel loving family im not brillant with them but know a little :).

So it seems that its only running on 3 cylinders and removing the number 2 ht lead shows no difference so this is the problem area, the compression tester shows 128 on this cylinder and 133 to 137 on the others surely this would not make much difference. there is also a definet spark as me and my friends right arm knows.

The question is what else could it be im going to check the valves are opening fully but im pretty certain thay are as the bloke im doing the work for has done the tappets recently. Could the fuel not be getting to the cylinder? Any bright sparks out there got a clue :rolleyes:

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You need to follow a method of fault elimination to try to determine the likely fault. If you hold the plug close to the block, do you get a good strong blue spark off it when the points open for that cylinder? Try this with more than one plug as they can break down under compression. Is the plug black or oily after it's been in the engine and it has been run for a while? Excessive oil, or indeed water in the cylinder will prevent the plug from firing, or fire late - giving the effect that it isn't working at all.

On a worn engine it's common for there to be a difference in compression between cylinders. From your reading it should still run ok in my opinion.

Also, check the firing order - two leads swapped will give the same effect as one cylinder not working.

Les. :)

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lol

plugs, leads, dizy cap, rotor arm, condensor, coil and points are all new and working properly. The affected plug appears to be white where as the others look to be running rich. is it possible that it could be a valve not opening fully? the head gasket has also recontly been changed but i guess water could be an issue? is there anyway that the one cylinder could not be getting any fuel

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The only way one cylinder could not be recieving the same amount of fuel/air - would be the valves/combustion chamber. The common inlet manifold means that all cylinders would have the potential ability to recieve the same as the other 3. Your problem would appear to be in the either the cylinder itself, or a problem with the ignition circuit.

Les. :)

(see how Nige has gone quiet?, That's because this thread has become..............................

TECHNICAL!!

Les. :)

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take off the rocker cover - a couple of screws to undo at most and look at the valve train - could be that the inlet rocker for that cylinder is broken or adjustment screw undone/broken/missing/incorrectly adjusted so that the valve is not opening.

As you replaced the cylinder head gasket, is there a possiblily you fitted the inlet manifold gasket so it block off the ports or got something like a rag in the port?

Has it just started to do this or has done it since you fitted the head back on?

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