KV6 power loss
 

Hi everyone,

I have an on going, intermittent, annoying fault with my ZT-T that i purchased a few months ago.
The car is running petrol or LPG and the fault occurs with both fuels.

I've recently taken the car off the road to do a bit of work on it due to this fault.
I guessed at the vis motors and was right, the balance flap had snapped, the balance motor was dead and the power motor relays were dead.
The auxiliary belt was looking tired and i figured the cam belt may as well get done too.
And what a sh** that was to do!
Whilst i had the inlet off i fitted a new cam cover gasket and iridium spark plugs (rear only i've still got the front to do.

So, a new set of relays for the power motor, a new balance motor, a good second hand
butterfly valve/flap and a home made VIS tester later......the vis sytem is working but i still have the same intermittent fault.
More often than not it happens when im going up hill, noise...lots of noise but no power. When it's running well it flys.
Here are 2 videos, the first is the car running well, the second is just noise. i'm not full throttle in either just being a little enthusiastic with the pedal.

https://youtu.be/4VV_WDpBOT8

https://youtu.be/NpGitcYGYXM

so, what do you think it could be?

Jeepers! I would avoid repeating that particular test too much. Have you checked the engine oil? Did you do the timing yourself?

TC

If TC has Jeepers...I'll go with cripes!

Paul,

That sounds rather bad eh and I too would be wary of testing it whilst it is making that sound.

So it did the same before all the work you have carried out?

It sounds like mahoosive intake roar on the footage but I'm assuming it can't be that...and intermittent and more on load uphill?

Could it be something transmission related...clutch/DMF really protesting? Would that give a noise and no power behaviour folks?

Or a main engine or box mount gone that is allowing movement and the noise to occur?

Any other bangs or clonks on pulling away or under load Paul?

Hope you sort it.

Jonty

EDIT: p.s. You say the balance butterfly / flap had snapped...there isn't a piece of something left floating around inside the manifold is there?Vibrating like a reed in a musical instrument giving an intake buzz? I'm grasping at straws there.

thanks for the reply.

This reason i started all the work was because of this fault.
The car starts perfectly, doesn't smoke or rattle or bang.
It does have the odd whiff of burnt oil but i think that is the front cam cover gasket spitting oil on to the manifold.
engine oil was changed a few months ago when i bought it, the level is currently about half way between min and max.
I've reset the ecu today and taken it out for a test again. Temperature doesn't seem to affect it, it did this from cold.
At really low revs when this fault occurs the car runs fine ,all be it like an old woman on the way to a church jumble sale.
revving just makes noise and no power, too much revving causes it to splutter, yesterday the fuel pipe popped off but that might just have been incorrectly fitted.
so, after driving like an old lady for 10 miles the fault went away and the pedal feels lighter, the car bursts into life and i drove like i'd stolen it. Then, i slowed down and changed into 2nd at a small island, pulled away gently and the fault is back for the rest of the journey, 2 miles or so.

also, rev range.... anything above 2k gentle acceleration produces this noise, drive it with barely any throttle and it will happily rev past 3.
3.5k with gentle acceleration causes a splutter.
i don't think it's a timing issue as the fault comes and goes.

oh and the original flap broken cleanly, i guess these were designed to fail to safety, the shaft snapped in a cone shape and stayed inside the motor.

How do you mean?

TC

ignition on, press pedal 3 times, ignition off, disconnect battery for 5 minutes, ignition on, press pedal 3 times, ignition off.

i've borrowed autocom from a friend to look for any fault codes. NONE.
i've manually reset everything i can with the software, throttle position, air sensors etc.
i've just got back from testing it again and it's still the same.

i don't know if it's just me but the pedal feels heavier when the fault is present, or could it be an issue with the throttle body?

You can't reset the ecu like that, that's like resetting the IACV on a 1.8 only you press the throttle 5 times, nothing to do with the ecu

i've read, i think on this site or maybe xpower, that this is the procedure to reset iacv and throttle position etc values. either way it did nowt to cure my intermittent fault.

I've spoken to a mechanic friend, he thinks it's either not enough air or the cat blocked.
I've removed the inlet again to check I haven't missed anything before I order a new cat.

If the cat was blocked would I get a fault?
If it was air starvation would I get a fault?
I can't see how it can be starved of air.

Anyone know if the internal flaps of the manifold can do something weird and give such an odd fault?

Can anything be dislodged and jamming / choking the engine?

Paul, you said you already did the VIS motors and have had the manifold off recently...is that right? Did it all seem OK?

Have you tried running the car with the airfilter box open or disconnected to see if the fault is upstream of the throttle body? i.e. filter or pipework (e.g. Shannon tube). Could there be something problematic there like a blockage or collapse of the Shannon tube?

No idea about blocked cat :shrug:

Jonty