My ZT has lost all its oomph!! and shudders a lot! [Archive]

The_Monk

11th December 2006, 17:54

Driving home tonight I went to accelerate through 2nd to 3rd and I thought I had changed into 3rd and put my foot down. However the gear stick must have got stuck half way between as the revs shot up and the car went no where! I quickly remedied and pulled away. When I came to stop at the end of the dual carriage way I went to pull away in first and the car shuddered like nobody's business, pressed the clutch in and increased the revs a bit but nothing. Putting the clutch in and slowly (I mean very very very slowly) raising the clutch the car pulled away. There was no acceleration through the gears and then when I tried to pull away there was a jolt, i felt it through the car and the car was very sluggish to pull away! Everytime I pull away the car is shuddering and there is absolutely no power.:eek:

Got home and popped the bonnet to be confronted with click click click with the engine noise which I've never noticed before!

What have I done to my car? I'm letting it cool for an hour or two then going back out to see if its still the same! It's not the dreaded vis valves is it?

lildevil

11th December 2006, 17:58

Hi

From what I have read it sounds like VIS Valves, there is lots of info on this. I will try and search for some threads for you to read. However I may be completely wrong, a very bag shudder that could possibly engine mount as well.

If my info is incorrect somebody please feel free to correct me

Regards
Tom

loupus666

11th December 2006, 18:02

Shuddering on taking up drive normally indicates clutch, see if the clutch release bearing is noisy at tickover by listening carefully & then depress the clutch to see if any noise dissapears..... I can`t see why it would suddenly start after a fluffed gear change......could the ecu have gone to safe mode after excessive revving?

Good luck......I`ll check later to see how you got on
Mark

lildevil

11th December 2006, 18:03

If it is vis valves this might help you:
http://www.the75andztclub.co.uk/forum/showthread.php?t=904&

Regards
Tom

Chilljohn

11th December 2006, 18:06

sounds like the manifold / vis motor thats exacly what happend to mine

The_Monk

11th December 2006, 18:08

If it is vis valves this might help you:
http://www.the75andztclub.co.uk/forum/showthread.php?t=904&

Regards
Tom

I searched that thread before posting up but the click click seems to come from that silver motor thing (sorry dont know what its called) next to the motor infront of the ringed bit in the photo. My dad has a 75, same engine so I might get him to pop the bonnet and listen to his engine.

Chilljohn

11th December 2006, 18:09

meant to say the time ot get really worried is when it sounds like this

http://media.putfile.com/Mg-ZT-190-Vis-Fail-Noise

ps do you mean the alternator ?

The_Monk

11th December 2006, 18:13

meant to say the time ot get really worried is when it sounds like this

ps do you mean the alternator ?

Could be, I really dont know, I bought the Haynes Manual yesterday so when it arrives I'd be able to tell you exactly, although waiting till then might kill me.

The_Monk

11th December 2006, 18:15

meant to say the time ot get really worried is when it sounds like this

http://media.putfile.com/Mg-ZT-190-Vis-Fail-Noise

ps do you mean the alternator ?

Doesn't sounds anything like that. It literally is a click click, like when kids put playing cards between the spokes on their bikes and ride slowly.

Chilljohn

11th December 2006, 18:17

yu can rest a bit easier then lol thats the noise of the manifold being rather broken !!!

Ken

11th December 2006, 18:21

meant to say the time ot get really worried is when it sounds like this

http://media.putfile.com/Mg-ZT-190-Vis-Fail-Noise

ps do you mean the alternator ?

Sounds like my 114 :lol: That sounds horrible

Ken

The_Monk

11th December 2006, 18:25

Got to go out in about 20min so I'll drive it round a few miles and report back, might be first thing in the morning though.

Chilljohn

11th December 2006, 19:07

Sounds like my 114 :lol: That sounds horrible

Ken

lol it did but £700 later all is smooth and quiet again :)

The_Monk

12th December 2006, 06:47

Ok here is what's happened. Dad came home and I told him what had happened, he started the car and popped the bonnet and had a listen. He was then convinced there was a burning smell. I had a sniff and although the was a funny smell I wouldn't have said it was burning, more of a warm smell coming again from that silver motor bit! Took my Dad round the block and the car seemed fine, no shudders no loss of power, everything was great! Popped the bonnet and there was still a funny smell?!?

Drove it too my friends house which gave it a good couple of mile run in and when I got there checked under the bonnet and the smell had gone!

Woke up this morning and the car started fine from cold, and was responsive as I accelerated up through the gears.

Now question is, what's going on? Was it all just some sort of freak thing to make me panic, or is there something about to go wrong on the car. I would get the car checked in but the car seems normal and if there is an intermittent fault it probably wouldnt show any way, am I right? So should I put it down to freakiness and wait till it happens again and panic, or pester a garage loads until they find a fault, which then might mean mucho mulah for no reason other than the garage's pockets.

lildevil

12th December 2006, 17:43

sounds like the manifold / vis motor thats exacly what happend to mine

So for once I managed to give some helpful and correct advice?

From what I have read it sounds like VIS Valves, there is lots of info on this.

Regards
Tom

Simon

12th December 2006, 20:50

The little silver thingy (as you describe it) is the alternator.

Depends on what smell you are smelling. There are two types of electrical smell. One that smells of warm metal and is kind of a 'nice' smell. The other is the white-smoke-of-death smell.

Once you see or smell the white-smoke-of-death then all hope is lost with regard to electrical components.

If the alternator is burnt out then it will no longer be recharging the battery. I'm not sure it would cause a juddering in the car but this following set of events could have happened:

Alternator suffers a catastrophic and sudden failure.
Battery is no longer being charged because of alternator failure.
ECU detects major drop in battery voltage and goes into an 'emergency limp-home' mode (basically, minimal power usage, default all settings to standard)
Once home and car is switched off, battery has time to "recover" and the emergency program is reset.
Starting the car since has proved fine as battery still has sufficient power to run things normally.Well. That's my theory, anyway.

I'd say test alternator using multimeter and see if its generating anything as the next step. Report back your findings....

:lol:

The_Monk

13th December 2006, 09:06

Where do I put the leads to test? Dont want to blow myself or anything else up! Is it just across the terminals on the alternator?

Simon

13th December 2006, 23:28

Yeah. Test across the alternator first, then try and trace the wires back to the battery (this may be impossible to complete due to where the wiring goes in the engine bay).

If all that checks out okay then the alternator is also okay. I say check the wiring just in case it has broken somewhere.

The_Monk

21st December 2006, 12:14

Quick update, car seems fine now, spent ages finding the multimeter only to drop it down the stars and break it! Great eh! (luckily 4.99 from maplin!). However was reading through the Haynes Manual and it suggests a poor air intake could account for the loss of power. With the plastic bags the floating around one could of got stuck over the grill whilst I was driving? Happened last week but I saw it and stopped the car. What do you think, possible?

Simon

25th December 2006, 12:54

Plastic bag could have got stuck over the grille but this would only reduce air flow to the cooling fan not the air intake (the air intake is stowed safely up in the wheel-arch away from debris and water hazards).

If an object did prevent cooling of the engine then the ECU may have selected an emergency program but it seems unlikely as it would have to be a significant temperature increase and you would have been alerted way before what happens by various warning lights appearing on your dash.

If it hasn't happened again then it could have been one of these random "fluxes" in electrical systems. These entirely random occurances can upset any electrical system from a pocket calculator, microwave through to the best PC in the world. Often they are short-lived and disappear as quickly as they came and the only evidence is a "hiccup" somewhere in the sytem. Similar to what you experienced.

If nothing else seems untoward then I'll let it go and continue to keep an eye on things. Hopefully though, nothing bad will come of it.

The_Monk

1st January 2007, 10:46

mantianak

1st January 2007, 12:19

A while back I too experienced something similar to Monks problem. I was flooring it on a dual carriage way when after dropping a gear for an easy roundabout all power seemed to disappear. The lack of power reminded me of a choke that's left on for too long on an old car and it floods the engine while driving. Or when I drove my old Laguna after leaving it for a month unused, it had power dips which later turned out to be a knackered battery and alternator!
Several thousand miles later, my 75 still hasn't had a power dip again. The only explanation I could think of (bearing in mind I know little of these things) is that it was incredible low on petrol and the engine was starved a little as the fuel gushed about on the roundabout.

M47Rman

1st January 2007, 16:20

Was changing my side lights today (oh those ones off ebay I suggested in the other thread, they look naff!) I popped the bonnet looking to see how to change them and noticed that the air intake pipe had half fallen off the filter! Not sure if it had anything to do with what happened but I hope other bits of my car are not half hanging off! :eek:

Happy New Year Everyone! All the best for 2007!

Well
this now sounds like a classic collapsing intake (shannon) duct. This happens when the engine is demanding high levels of air flow into the engine, and the pipe feeding the air in collapses. This leads to a complete loss of power. Only when the pipe has at least partially recovered its shape, will the air flow be restored and the engines power return - or of course the pipe could be forced off the air cleaner box, and hey presto the air intake has found a new route, thus bypassing the problem duct! The pipe falling off would also explain why the problem has not re-occurred.
HTH
Andy

Simon

1st January 2007, 18:09

Well
this now sounds like a classic collapsing intake (shannon) duct. This happens when the engine is demanding high levels of air flow into the engine, and the pipe feeding the air in collapses. This leads to a complete loss of power. Only when the pipe has at least partially recovered its shape, will the air flow be restored and the engines power return - or of course the pipe could be forced off the air cleaner box, and hey presto the air intake has found a new route, thus bypassing the problem duct! The pipe falling off would also explain why the problem has not re-occurred.
HTH
Andy

Collapsing shannon duct. Are these possible to collapse? I've taken mine off (see previous thread about modifying the air intake - actually Andy, you know all about that thread, but for those who don't it's now been mentioned)... Er... where was I? Oh yes....

The shannon duct is very stiff and to collapse it would require huge amounts of pressure. Either the entrance to the duct became blocked thus causing the engine to suck the air out of it completely and allowing atmospheric pressure to collapse the tube OR the tube had just become blocked and then (as you suggest) perhaps has become detatched or maybe the blockage was removed somehow.

Of course, this is speculation as to what happened. It's worth taking both the passenger-side headlight inspection pannel off and the under bumper quater pannel to inspect the shannon duct on your car. It should look like it does in this thread http://www.the75andztclub.co.uk/forum/showthread.php?t=1365 (skip through to post number 11)

Hope that helps! :lol:

mantianak

1st January 2007, 18:50

Simon

1st January 2007, 18:54

My shannon duct looks just like that! When I get around to it I'm going to replace it with some of that aluminium looking flexi tube.

If what you guys are saying about it collapsing, wouldn't it be more likely that the rubber tube connecting the air filter box to the air intake would collapse? It is flexible rubber.

With a degraded shannon duct, cracked or with gaps in the underbelly pan, water could get easily sucked into the duct (especially if you enjoy splashing through puddles as much as I do!) causing power loss. When the car is left for a while the engine heat will evaporate the waters clogging the filer. With the engine off the ducts, air filters will warm up without the constant air flow.

Now I thought about it really need to get mine sorted out.

Where's the best place to have a duct/tube sucking cold air from?

A few people including myself have debated long and hard about this. The above thread http://www.the75andztclub.co.uk/forum/showthread.php?t=1365 deals with me fitting a new pannel filter plus modiffying the air intake. The mod is okay BUT DO NOT DRIVE THROUGH PUDDLES as it allows water intake into the engine which would lead to very expensive-sounding noises :panic:

I've since added to the modification which I will be writing an aditional post in the above thread about very shortly.... ;)

The_Monk

1st January 2007, 20:18

Simon

1st January 2007, 20:25

I think I need to inspect the rest of the tube just in case, do I need to remove the bumper to access all the tube? I have to say fitting it back on with the jubilee clip it seemed quite substantial and hardly likely to crush, but stranger things have happened!

If you have bendy arms then bumper removal is not needed. Remove the lower pannel from underneath the corner of the bumper (four screws IIRC) remove this pannel and look up. Best done on axle stands so you can get underneath the car.

If you do not have bendy arms or would like unrestricted access (plus an awfull lot more light to see what your doing) then it's bumper off time....

The_Monk

1st January 2007, 20:58

If you have bendy arms then bumper removal is not needed. Remove the lower pannel from underneath the corner of the bumper (four screws IIRC) remove this pannel and look up. Best done on axle stands so you can get underneath the car.

If you do not have bendy arms or would like unrestricted access (plus an awfull lot more light to see what your doing) then it's bumper off time....

Weekend Jobby Me Thinks! Great!:o

M47Rman

3rd January 2007, 18:45

Collapsing shannon duct. Are these possible to collapse? I've taken mine off (see previous thread about modifying the air intake - actually Andy, you know all about that thread, but for those who don't it's now been mentioned)... Er... where was I? Oh yes....

The shannon duct is very stiff and to collapse it would require huge amounts of pressure. Either the entrance to the duct became blocked thus causing the engine to suck the air out of it completely and allowing atmospheric pressure to collapse the tube OR the tube had just become blocked and then (as you suggest) perhaps has become detatched or maybe the blockage was removed somehow.

Of course, this is speculation as to what happened. It's worth taking both the passenger-side headlight inspection pannel off and the under bumper quater pannel to inspect the shannon duct on your car. It should look like it does in this thread http://www.the75andztclub.co.uk/forum/showthread.php?t=1365 (skip through to post number 11)

Hope that helps! :lol:

Hi Simon
You are quite right that the shannon duct is unlikely to collapse IF, it is in good condition, and has not been mis-shapen or squashed in any way, either during original assembly, or by a subsequent owner who just squashed the pipe in any old how. If the pipe profile gets squashed (particularly likely at any point where it bends through a tight angle), then it loses its structural stiffness, and becomes more likely to be sucked flat. Just thought it might be worth a look, if nothing else to tick it off the list!
Incidentally, although it is unlikely to happen with our shannon duct, due to the fact that the entry point is clipped to the body, on Rover 600 L series diesel models, there was a huge problem in service, and on test cars, with massive power loss. The only thing showing up on diagnostics was a huge drop in airflow at the AFM. we changed all sorts of pipes, ducts, filters etc, all to no avail.
The problem? At high speed the inlet end of the shannon duct was being sucked ON TO the cars inner wing, as it was not fixed in any way. I seem to remember it was just tucked under the battery tray!:eek:
Andy

Simon

3rd January 2007, 19:26

The problem? At high speed the inlet end of the shannon duct was being sucked ON TO the cars inner wing, as it was not fixed in any way. I seem to remember it was just tucked under the battery tray!:eek:

That's shocking! Hopefully the production cars were sorted ;)
You're right though, a quick inspection will soon prove/disprove the shannon duct as a possible cause for the loss of power.

mantianak

26th January 2007, 22:56

If anybody is still interested in this thread I would be greatfull for some help.

This evening on my way home from work I had this prolem again (lack of power, feels like a manual choke on a old car). It's been months since the first and only time I experienced this.

I decided to experiment.

Idling, the engine ran as normal
Flooring it in 1st gear, as normal.
flooring it in 2nd, 3rd (didn't try 4th or 5th, not enough road), power loss at low end of revs.

It seemed the power dip happened only when between 1.5 to 2.5 revs. Once running higher it pulled as it normally does.

My 1st gear sometimes makes a squeeling sound and as I understand it, that is to do with the clutch. I don't hear the engine reving as normal with the power dip so I'm guessing it's not the clutch. Or am I wrong?

Simon

26th January 2007, 23:05

Definately interested in this thread - we're all out to help each other ;)

I must admit I've not noticed this on my KV6 so I don't think it's a trait of the engine or anything. Mine seems to get-up-and-go at most revs.

Maybe something else is putting excesive load on the engine? Have you tried the above experiment with both a full load (ATC, heated window, full lights etc) and then doing the same with no electrics at all?

mantianak

26th January 2007, 23:16

No, I haven't tried that.
It i only the second time it's done it to me. The first time I assumed water had got in my degraded shanon duct. Today the weather was dry, although cold.

I have a in-line sealed air filer that has increased the 75's responsiveness (and sounds mean over 4k revs). I've had it for about 7 months so I don't think it's that.
I also have what I think maybe an issue with a delayed feeing of revs. I don't know if the 2 problems are connected but it feels like it revs a second after I tap the pedal, difficult to pull fast on a roundabout without revving too high.

I'll have to see how it is tomorrow. If like last time the problem wont show for another month or so.

MartinW

27th January 2007, 07:07

I was hugely embarassed to find that my 160 was sluggish pulling away from junctions in second and especially third gears. It seemed ok in 1st, but unless the revs were up, it seemed to have just lost its get-and-go!

So in desperation, as the Shell Optimax would only clean downstream of the injectors, and not the sensors etc in the inlet, I went and purchased some carb cleaner, and removed the air inlet hose from the throttle body and applied the cleaner directly to the inlet plenum. I did this for a good few minutes repeatedly adding the cleaner at varying engine revs.

A subsequent test drive revealed that all was restored to normal. I think the sensors get gunged with oil fumes and consequently the engine gets a bit flat.

mantianak

27th January 2007, 07:56

That's a good Idea. I've only used the valve cleaner in the fuel and not into the body itself.

Did you use carb cleaner or injector cleaner? I've seen that Redex stuff and it comes for different engine types.

I've seen an oil breather on another thread. Do you think this would prevent oil vapour gunking up?- Or would that cause more damage not having any oil vapour going into the air inlet?

Countach

27th January 2007, 10:08

How many miles have you done?

If you have contaminated fuel (or a blockage in the fuel filter) then you can get problems due to momentary loss of power.
I use a fuel treatment additive (redex) once a year just to clean the fuel system.

Check the air filter, anythings possible!

mantianak

27th January 2007, 12:36

The milage is 90,000.

The problem seems to have gone now. Same as the last time it happened. I do put Redex in every so often but I think I'm going to give Martin's idea a go.

MartinW

27th January 2007, 14:17

It was carb cleaner I had lying around from an SU overhaul.

Simon

27th January 2007, 19:50

Can vouch for carb cleaner too!

Following Martin's recommendations I sprayed a healthy dose into the open throttle body. Light squirts every few moments - too much and the engine will stall because the carb cleaner stops the oxygen getting in too! ;)

The_Monk

28th January 2007, 18:13

Simon

31st January 2007, 12:57

You need to remove the upper section of the airbox.

There are two screws along the upper section (next to the battery box). You will also need to undo the rubber hose from the throttle body, this is held in place by one of those metal-band things that tightens up with a screw (poor explanation - sorry!). The picture highlights the three screws (upper ones next to battery and the one hiding inbetween the engine block and the airbox)

http://www.donottumbledry.co.uk/mg_img_bin/IMG0311.jpg

Once these screw undone - the one for the throttle body WILL NOT COME OFF, so do not attempt to take it off. You may also find the upper two do not completely remove from the case, but this is ok.

The upper box lid will then be free to be moved. There are two lip-type holding clips along the lower edge that will need to be wiggled free, the two pipes (big one you just took the undone the screw for and the little push-fitted one above it) will pull off the throttle body. This may stage will require a fair amount of tugging and wiggling things around bit eventually it'll come free.

Once off, place to one side and you will be presented with an open throttle body. Start up your engine. (Yes - it will noisey without the airbox cover in place).

You will see the throttle cable entering the throttle body which you can use to adjust the engine speed. Pull the cable to get a fast idle and simple point-and-squirt carb cleaner into the open end of the throttle body. It may be a good idea to put an old rag under the open end to catch the oil that (will) come out.

Keep squirting carb cleaner in short burst at various engine speeds for a few minutes and then leave the car to idle so the rest of the cleaner can work it's way out.

Once done, you may like to use car cleaner to clean out the rubber pipe on the airbox before you reassemble.

Hope this helps!
:)

GreyGhost

31st January 2007, 13:02

If you don't mind Simon I will copy your post and enter it into a new thread in the How To section. :)
Easy access for all then.:)
I will of course attribute it to you.

Thanks

Simon

31st January 2007, 13:11

GreyGhost

31st January 2007, 15:31

No probs at all there GG... In fact, I see you have just done that! ;)

If you would like a better write-up with more detailed pics then let me know and I can arrange it. The post on this thread was done rather quickly...! :)

that will be very decent of you. Post it in there yourself and I or Keith will check it over and lock it.

The_Monk

1st February 2007, 19:18

Top Notch! I will be having a go the weekend! Thanks

mantianak

3rd February 2007, 20:38

I can confirm the VIS butterfly valves problem.
My car had the odd power loss when heavily accelerating so I tried the carb cleaning approach. That seemed to give a bit more power but the power dips were then transformed into jumping power loss.
After visiting Lates, it turns out it's due to the VIS motors not working. There's a link somewhere to how it can be repaired (I'm too tired to look now, maybe it's been posted, I've not looked) or it will cost about £130 (for me anyway) to buy new ones.