Range Rover P38 Power Loss

jacckk · Post by **jacckk** » Thu May 14, 2015 5:46 pm

Hi,

I've got a P38 with a GEMS 4.6 engine in which feels like it is down on power and also has a slightly rough idle. I recently rebuilt the engine with a top hat liner block because my old one cracked. Even with the previous engine it never had much power so I don't think it's a mechanical problem. Everything in the engine is pretty much new such as rods, pistons, crank, cam, lifters etc. I can't remember what cam it was at the minute but I got it from v8developments and they said it would work 100% with my GEMS ecu without having to dial it in.

Other things I've already tried/replaced/tested:

Tested compression, all cylinders were around 155psi.
Tested fuel pressure - seems OK.
New plugs, leads, coil pack.
New o2 sensors
New MAF
Swapped TPS, IAC, engine management ECU with some ones I had lying about - no difference.

Has anyone got any ideas of anything else I can try out to try and figure this out?

Thanks

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ChrisJC · Post by **ChrisJC** » Thu May 14, 2015 9:04 pm

Have you read out any fault codes?

Are the brakes seized (including the handbrake)?

Have you tried a different one to see if that feels any faster? Try a 0-60 sprint.

Chris.

jacckk · Post by **jacckk** » Thu May 14, 2015 9:41 pm

Forgot to mention there are no fault codes ever appear.

I don't think the brakes are seized. All were checked recently when I changed the pads and I the front calipers.

No I've never tried a different one. I'd like to though. I think it feels reasonably ok at full throttle it just feels like it's lacking power on hills and at part throttle.

jacckk · Post by **jacckk** » Sat May 16, 2015 11:01 pm

It's getting dynoed on Friday so that should be interesting.

I was thinking about checking my cam timing. Is there any reason I can't do this when the engine is in the car? As far as I can see all I need to do is make something to stop the piston via the spark plug hole, take a rocker cover off to measure lift via the pushrod and stick the dial gauge on the front pulley. Is there anything I'm forgetting?

ChrisJC · Post by **ChrisJC** » Sun May 17, 2015 6:40 am

I believe you are right about measuring cam timing just by removing a rover cover.

Chris.