V6 Sudden Power Loss

My engine suffered sudden power loss for a few seconds yesterday. I'd just been opening up the taps up a twisty steep hill. The box was in 2nd gear manual mode. Just as i reached the crest of the hill the road straightens so i let the engine run up to around 5K rpm I shifted up to 3rd planted the throttle again but there was no power as I slowed I selected 2nd while gently pushing the throttle. All of a sudden the power came back and i was able to continue my commute without further problem. I've noticed a similar event a couple of times after I've negotiated sharp corners that are at an angle but never had complete power loss. It appears to be fuel surge but I can't imagine the fuel tank is that badly designed to suffer to such an extent, especially with half a tank of fuel on board.
Any ideas?

Throttle body could be sticking - I've read about them getting gunked up, just an idea

Brack said:

Throttle body could be sticking - I've read about them getting gunked up, just an idea

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All ideas are welcome as I'm all out. I've not been able to replicate it again ether

Has It ever happened in auto mode?

Hippo said:

Has It ever happened in auto mode?

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It's only done it 5 or 6 times but in a variety of transmission modes. It's difficult to tell in D because it up shifts quite early which seems to mask the power drop. I've had it happen in sport and manual shift but never as bad as Friday. But it does appear to be related to cornering speed particularly if there is steep hill at the same time. It acts like the fuel pump is picking up air which takes a few seconds to bleed through. The ECU isn't logging any faults and the MIL stays off.

How about driving down a straight road and steering left to right repeatedly to create body roll and see if you can make it happen.

Hippo said:

How about driving down a straight road and steering left to right repeatedly to create body roll and see if you can make it happen.

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I tried that on the way to work but the problem didn't occur. It's very difficult to replicate the exact situation, I even did the same route again on Saturday to try and get the power loss again but I couldn't get it to happen again. It's very irritating.

I think it's the sort of fault that needs to get worser for you to be more easily able to detect it.

Hippo said:

I think it's the sort of fault that needs to get worser for you to be more easily able to detect it.

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It doesn't do it very often 5 or 6 times since November so yeah I think leave it to see if it gets worse. Thanks for the input.

Any chance it's the Inertia fuel cutout switch? I know it's not supposed to reset itself, but maybe it's not fully locking out, then opening again.

Brack said:

Throttle body could be sticking - I've read about them getting gunked up, just an idea

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A known prblem on the KV6's - a lot of peeps fit a catch tank to reduce the crap gettin to the throttle body ( inlet manifold (Viz valves). Changing the body for a metal, rather than plastic, also helps.



Price £64.00 Postage and Packing £9.00 UK mainland only.

or a cheaper one - http://www.ebay.co.uk/itm/MG-ROVER-...CarParts_SM&hash=item43a660005a#ht_1429wt_911

FreeTaz said:

Any chance it's the Inertia fuel cutout switch? I know it's not supposed to reset itself, but maybe it's not fully locking out, then opening again.

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I've discounted that as the doors that are locked stay locked. I'm going to check the fuel pump wiring for security.

mine did the same. was found to be corroded contacts on the underside of the engine bay fuse box.

The Mad Hat Man said:

mine did the same. was found to be corroded contacts on the underside of the engine bay fuse box.

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I'll check that out. Did yours log any faults?

nope
mine would just coast to a halt/
lights worked, wipers worked.
after it stopped, give it a minute and it would start and run for a random length of time.

took ages to find it

The Mad Hat Man said:

nope
mine would just coast to a halt/
lights worked, wipers worked.
after it stopped, give it a minute and it would start and run for a random length of time.

took ages to find it

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I'll check the fuse box although my engine doesn't stop or at least hasn't stopped running, it doesn't loose power long enough. It just returns to idle. After a few seconds of mucking about it's fine again. I had thought maybe it is a CAS but that would log a fault code. Investigations will continue.

Hi Nodge,

My V6 suffered a loss of power at 40mph. got it towed back home then it started to drive.
Also would it be common fault with having an engine change? I had my V6 changed with a 2002 (85k miles) into a 2001 freelander with 95k on the clock.
I Also noticed the during kick down it picked up some speed, 50mph with 5000rpm then still keeping the revs but slowing down until you let off and go backto reular driving.

Were you able to diagnose the problem? I will take it to my mechanic who is a Gear box specialist and he will check if it is a gearbox fault / fuel pump or anything else. I will keep you updated on any findings.

Woz said:

Hi Nodge,

My V6 suffered a loss of power at 40mph. got it towed back home then it started to drive.
Also would it be common fault with having an engine change? I had my V6 changed with a 2002 (85k miles) into a 2001 freelander with 95k on the clock.
I Also noticed the during kick down it picked up some speed, 50mph with 5000rpm then still keeping the revs but slowing down until you let off and go backto reular driving.

Were you able to diagnose the problem? I will take it to my mechanic who is a Gear box specialist and he will check if it is a gearbox fault / fuel pump or anything else. I will keep you updated on any findings.

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Hi Woz
I've never actually managed to find a definitive fault although I did check all engine bay connections. The fault hasn't returned since!
The faulty my car suffered was engine power loss, flooring the throttle did nothing, this caused the car to slow and gearbox to change down. The gearbox works as it should.
I changed the engine in my V6 for safety as I bought it with an overheat damaged engine due to a leaking thermostat. I could have rebuild it but thought it prudent to swap it out. I've since checked the old engine thoroughly and discovered it could be rebuild.
Your fault sounds like a gearbox clutch might be slipping or is low in oil? It's best to get the codes read and avoid driving it to avoid further damage.
Good luck with it.

So i finally got the car back from the garage. They checked the Gear box oil and the guys took it for a spin and advised that the Gear is all good.

They found out the problem was the Crank Sensor. when the car heats up so did the sensor and started to fail and cut off the engine. Only when it cooled down did it restart. However now that the Crank Sensor has been replaced it starts all the time.

Found a new problem of running out of water. Drove back from work (26 miles) and could hear my fans working over time and not stopping even with the engine off. So i filled it with 2 litres of water and the fans slowly stopped running but lost all water.

Again took it garage hoping for the worst only to be told that the Dumb ass that fitted the engine pushed the hose too close the belt which sliced the hose. Belt (luckily) has no damage to it.

Thanks for the reply Nodge.

I hope the engine is ok? The K series will not tolerate a low water level. The liners ovetheat in seconds which damages the head gasket!
At least the CAS was easy to sort.