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1970-1995 Range Rover Classic
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Discussion Starter #1
Recently I've been experiencing power loss under hard acceleration from a stand still and also going up hill. The engine isn't stuttering, it has a rough idle, and it throwing codes left and right. My Rover is LHD and what ever is wrong is on the left side of the engine. I did a compression test on cylinder 1 and I was told it should be about 85 psi in the cylinder, it's lower than that. Does that mean all the cylinders on that side have a lower compression rate now as well? I was told to unplug the injector for the 1 cylinder as all Im doing is dumping into a cylinder that won't burn it. After I unplugged it, it ran a little better. I'm wondering what could've caused this and also would a changing of the head & gasket do the trick?

Thanks In Advance,
 

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1970-1995 Range Rover Classic
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Discussion Starter #4
Thanks for the replies guys; Sid, I have spark coming from the distributor to the wire, But now that you've mentioned it, I didn't check if the plug was sparking, I only assumed if it was coming from the dist. it was making its way to the spark plug, I'll check for spark at the plug in the morning. keithdixon, Im getting various codes ranging from multiple cylinder misfire to 02 codes to clyinder 6 misfire to air fuel ratio. I was trying to say this sudden power loss was due to a bit of bad gas I bought. My rovacom is at a friends, once I get it back, I'm hoping to get a clearer picture of what's going on. Also I'll reset the adaptive values on it and see if that does something.
 

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1970-1995 Range Rover Classic
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Discussion Starter #6
allyv8 said:
Think I'd be looking at why the compression is so low on that cyl, until the engine is an efficient air pump reseting adaptions is a waste of time.
Thanks Ally, So basically I'm back to looking at a possible head gasket replacement. (I think)
 

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All you need to do is check all the ways that pressure can escape from that cyl,if the one next to it is low too its a strong chance of head gasket.Have the rocker cover off and make sure the valves are fully closing.Its a nice simple engine to work on so shouldnt be too much hassle. :D
 

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1970-1995 Range Rover Classic
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Discussion Starter #8
allyv8 said:
All you need to do is check all the ways that pressure can escape from that cyl,if the one next to it is low too its a strong chance of head gasket.Have the rocker cover off and make sure the valves are fully closing.Its a nice simple engine to work on so shouldnt be too much hassle. :D
Thanks Again, Ally. I guess what you're suggesting that I do is remove the rocker and manually turn the engine? My next question is; if they arent fully closing that means new heads? If they are fully closing, my guess is that I have a more serious issue. My neighbor recommended pulling a spark plug and pumping air into the engine. Depending on where the air was escaping from would, more or less, define what kind of problem I'm having. When I tried that, it was coming from the plenum which, according to him, wasn't as bad as if coming from the oil cap or causing the water in the reservior to bubble.
 

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984.6HSE said:
My neighbor recommended pulling a spark plug and pumping air into the engine. Depending on where the air was escaping from would, more or less, define what kind of problem I'm having. When I tried that, it was coming from the plenum which, according to him, wasn't as bad as if coming from the oil cap or causing the water in the reservior to bubble.
I guess that would suggest problem with inlet valve then - did you make sure piston was in correct position so both valves would be fully shut ?
 

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Discussion Starter #10
AMcK said:
984.6HSE said:
My neighbor recommended pulling a spark plug and pumping air into the engine. Depending on where the air was escaping from would, more or less, define what kind of problem I'm having. When I tried that, it was coming from the plenum which, according to him, wasn't as bad as if coming from the oil cap or causing the water in the reservior to bubble.
I guess that would suggest problem with inlet valve then - did you make sure piston was in correct position so both valves would be fully shut ?
Not sure. Im in the process of pulling the rocker off. Then I guess I should rotate the engine while pumping air into a cylinder, maybe even each cylinder, to see where the air escapes from. Any other ideas are greatly appreciated.
 

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1995-2002 Range Rover P38A
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Hi

If you want to do this pressure test with air, make sure that the engine is with the piston in top at the cylinder you want to test with both valves closed. The reason why is because the air pressure will push the piston down if not in top, and in bottom position of the piston there is always a valve open from where the air will leak into the intake or exhaust. There is also a position where the piston is in top with both valves open.

Low compression can be caused by damaged valves or valve seats, worn piston rings, leak from head gasket and even a crack or hole in the piston.

Good luck.

Regards

Jos
 

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Discussion Starter #12
Jos Geuze said:
Hi

If you want to do this pressure test with air, make sure that the engine is with the piston in top at the cylinder you want to test with both valves closed. The reason why is because the air pressure will push the piston down if not in top, and in bottom position of the piston there is always a valve open from where the air will leak into the intake or exhaust. There is also a position where the piston is in top with both valves open.

Low compression can be caused by damaged valves or valve seats, worn piston rings, leak from head gasket and even a crack or hole in the piston.

Good luck.

Regards

Jos
Thanks Jos. Im like 2 seconds from biting the bullet and hopefully taking all the guess work out of the equation by just replacing the head and gasket.
 

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Discussion Starter #13
Here's an update. Hopefully I can get away with just replacing the gasket and bolts. [attachment=0:34r70bri]DSC01944.JPG[/attachment:34r70bri]
 

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