Getting seriously banana now....

[AussieAub]

Getting seriously banana-ed off with the Disco now.
Looking for ideas....

At the end of last year I had an issue with a slight stuttering when taking off, which quickly cleared as the motor was running.
Come to a set of lights, etc, and the stuttering started again on take off only then cleared.
Took it up to a mob in Perth who stuck it on the machine and got MAF sensor errors.
Bought and installed a new MAF sensor early this year. Same problem.

Back to workshop who then thought it was the CATS gone/going.
Put the CATS off for a week or three until I could get done.
Back up to workshop again this morning who say there are no error codes reported, and smell of bad eggs.
Has to be the CATS I was told.

Off to an exhaust centre this arfo, just got back from having a new pair of CATS fitted (not OE parts due to cost), and the problem is STILL there. Tried to call workshop but they knocked off at 5:00.

Now I'm pulling my hair out on this (what I have left) and just seems like I'm pouring money into this motor for the sake of it.
I'm now down a small fortune, and still no closer to the motor running right.

My next thought would be leads and plugs, but I was assured I had new ones installed when workshop did the engine rebuild last year.
Any thoughts? PLEEEEAASSSEEEE.....!!

Cheers,

..:: KIEREN ::.. :mad:
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[4bee]

It is possible the plugs have sooted up since the rebuild if the MAF was faulty. Have you had them out & inspected them?

Are they the correct heat range plugs for your car?

Has anyone stuck a probe up the zorst to check for overfuelling?
Have you a genuine Dizzy cap & rotor arm fitted?

After market ones seem to be notorious for "missing" problems.

[Blknight.aus]

plugs, leads, dizzy, coil, and the amp. In that order as previously mentioned.

Cats dont cause bad running unless they are clogged up and then that tends to cause loss of top end power that gets progressively worse.

from the list of also rans...

sticking valves
dirty injectors
sluggish fuel pump
clogged fuel filter (should get worse as time progresses)
bad earths
intermittent vacuum leak
dirty fuel
plugging air filter
bad electrical connection to an injector

of course some of those are more or less applicable depending on exactly how its doing what its not supposed to do.

[AussieAub]

Thanks for the post 4bee.

It is possible the plugs have sooted up since the rebuild if the MAF was faulty. Have you had them out & inspected them?
No I haven't. The motor was only rebuilt approx 4 months or so ago. Would the plugs have got the bad in an practically new motor that quick?


Are they the correct heat range plugs for your car?
Have no idea, how would I know by inspection? Though expect with DA being a LR specialist centre, I doubt they would have put the wrong ones in....


Has anyone stuck a probe up the zorst to check for overfuelling?
Really not sure on the exhaust probe thing, think diagnosis is just going by the code readers.


Have you a genuine Dizzy cap & rotor arm fitted?
Not a clue on the dizzy or rotor either, but again, I would have thought they should know?

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[AussieAub]

Cats dont cause bad running unless they are clogged up and then that tends to cause loss of top end power that gets progressively worse.


Thanks for the input Dave.
Whilst the guys at the exhaust shop said there were no audible rattlings in the CAT, the "line of sight" through them wasn't clear and they did show signs of beginning of failure/breakdown. Once it pulls through that initial pulling away stuttering, the rest of the rev range/powerband seems fine at the mo.

I suppose plugs and leads are my next step, once I can find out if they were actually replaced at the rebuild.

Question though Dave, wouldn't alot of those problems you listed show up on the code reader? From what I've been told, there were no errors....

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[PhilipA]

You know, what you describe is a typical failure mode of the Throttle Position Sensor,(TPS).
They are like a volume control ie a variable resistor and they wear most just off idle.
Seems to be about the only thing not covered.
Regards Philip A

[Peppercorn]

I had a problem like that once and it cost me a small fortune and a lot of frustration. It also taught me a BIG lesson.

The leads that we use today are carbon and designed to live for about 12 months!!

You may be lucky and see them live longer but generally 12 months is about when they start to play up.

Obviously it's hard not being there but I'd like to bet your leads are dodgy! It certainly sounds like they re the culprit!

Start it up at night time and see if you can see any sparks flying around the Distributor Cap or anywhere that they are near the engine. Either way, they are one of the cheapest places to start!

[AussieLandRover]

Oxy sensor's could be stuffed this was an issue with my old 98 falcon which had the same problem stuffed cat put new one on ran better but had the same issue put new oxy sensor in all fixed.

[2 rocks]

Hi Kieren
Look this is a really dumb question from an oiler-driver who knows jack about the V8's (except 10 years ago I had to do my valley cover 3 times :( ), but...

Are they fly by wire too? And if they are could it be some issue/confusion with the early part of the throttle input-response causing the ECM to mess up?

BTW - what time were you at workshop today? I was there about 10:30-ish...

Cheers
Mike

[AussieLandRover]

I had a problem like that once and it cost me a small fortune and a lot of frustration. It also taught me a BIG lesson.

The leads that we use today are carbon and designed to live for about 12 months!!

You may be lucky and see them live longer but generally 12 months is about when they start to play up.

Obviously it's hard not being there but I'd like to bet your leads are dodgy! It certainly sounds like they re the culprit!

Start it up at night time and see if you can see any sparks flying around the Distributor Cap or anywhere that they are near the engine. Either way, they are one of the cheapest places to start!

Either that one might not be sitting in position correctly on the cap that was an issue with my disco when I brought her.

[justinc]

The D2 has no dizzy, cap or rotor as it has coil packs, and closed loop fuel injection, bosch Motronic to be precise. It can be plugged in to a Bosch real time engine analyser etc for a second opinion if you need it. I'm going with the plug leads personally, the D2 engines are supposed to have Platinum plugs which are good for at least 80K.
Also, fuel pressure and volume are critical for these engines, and your comment about rotten eggs smell means that the cats are doing their job. It actually sounds like the misfire is spark related as the smell gets worse when a rich mixture is encountered, IE unburnt fuel.
JC

[AussieAub]

Oxy sensor's could be stuffed this was an issue with my old 98 falcon which had the same problem stuffed cat put new one on ran better but had the same issue put new oxy sensor in all fixed.

Thanks AussieLandRover!
This is my prob though. There's been lots of "could be this, could be that" issues with the Disco, and when it gets replaced, prob still there! Its an expensive way to find problems!

Since buying the car last June/July, I've spent an f-in fortune on it, had the engine rebuilt under warranty, spent more on top of that, and still no fix!

Really getting on my t!ts now - not you, the Disco! ;)

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[Blknight.aus]

ditto, I thought the TPS problem was a TD5 or better problem....

[AussieAub]

The D2 has no dizzy, cap or rotor as it has coil packs, and closed loop fuel injection, bosch Motronic to be precise. It can be plugged in to a Bosch real time engine analyser etc for a second opinion if you need it. I'm going with the plug leads personally, the D2 engines are supposed to have Platinum plugs which are good for at least 80K.
Also, fuel pressure and volume are critical for these engines, and your comment about rotten eggs smell means that the cats are doing their job. It actually sounds like the misfire is spark related as the smell gets worse when a rich mixture is encountered, IE unburnt fuel.
JC

Thanks Justin.
I'm going to get onto the phone to DA first thing and find out about these leads, wether they were new or not.
So, looks like I've blown another several hundred dollars on a pair of new CATS when I may not have needed to....:mad:

Cheers for the input,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[DRanged]

Take the car out at night. If it is missing at idle stop and pop the bonnet. See if you can see any of the leads "arcing". Make sure it is nice and dark when doing this.

It might just help and it costs nothing to do.
If you are handy with an Ohms meter you can also measure the resistance in the lead as well.

Good luck
justin

[Tank]

Does it have an Idle Air Control valve (IAC) as fitted to the rear of the earlier model plenums, sounds like it to me, Regards Frank.

[AussieAub]

Take the car out at night. If it is missing at idle stop and pop the bonnet. See if you can see any of the leads "arcing". Make sure it is nice and dark when doing this.

justin

Just done this, and there does seem to be a very slight blue flash on the passenger side banks (approx 3rd plug from front). Not 100% sure though. Saying that, the missus rev'd the car in the dark, with my head under the bonnet, and there was a very distinctive "clicking" that came from where I thought I saw the blue flashes.

The reason I say not sure, is that when looking directly at the spot, I couldn't see anything, but when my focus was just off, I could see some extremely slight irregular blue flashing.

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[AussieAub]

Does it have an Idle Air Control valve (IAC) as fitted to the rear of the earlier model plenums, sounds like it to me, Regards Frank.

Sorry, have no idea Frank!

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

[Blknight.aus]

Just done this, and there does seem to be a very slight blue flash on the passenger side banks (approx 3rd plug from front). Not 100% sure though. Saying that, the missus rev'd the car in the dark, with my head under the bonnet, and there was a very distinctive "clicking" that came from where I thought I saw the blue flashes.

The reason I say not sure, is that when looking directly at the spot, I couldn't see anything, but when my focus was just off, I could see some extremely slight irregular blue flashing.

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com/)

thats your leads breaking down.

[justinc]

Like Dave says, that is a classic lead breakdown. They don't last long on these vehicles as the heat around them is pretty extreme.

JC

[catch-22]

When you say shuttering, are you sure it's motor related? Could it be coming from the box as you say it only happens when taking off? Or is it rough at idle?

It may be an intake vacuum leak...

[chazza]

My D1 suffered from HT leads breaking down; I replaced three sets over about 60 00km before replacing them with Gasmaster leads and it hasn't played-up since then (70 00km) along with the Iridium sparking plugs that I fitted.

Now I don't know if these leads will be suitable for a D2 (Justin will know) but I highly recommend them,

Cheers Charlie

[Pedro_The_Swift]

Leads are a bitch to change,, (oh yes they are!!)
Buy quality and do it right the first time!!

2 seconds to check a plug,,

I bought NGK Platinums for mine,,
I would strongly recommend using ONLY NGK plugs.



I HOPE its not a coil pack,,
for your sake---

[AussieAub]

When you say shuttering, are you sure it's motor related? Could it be coming from the box as you say it only happens when taking off? Or is it rough at idle?

It may be an intake vacuum leak...

Yes, it is a little rough at idle too....

Cheers,

..:: KIEREN ::..
2000 Disco II Auto V8
AussieAubs Disco Page (http://aussieaub.blogspot.com)

[BMKal]

Hi Kieren.

From your description of what you saw and heard under the bonnet when you checked for arcing between leads at night, and as both Justin and Dave have already said, it definitely sounds like leads to me. I'd be going out and getting a set of the recommended leads, and replacing them straight away.

Would also probably pay to check that you are runnning the recommended spark plugs, as I have found before that running incorrect plugs, while maybe not having any immediate detrimental effect on the engine performance, may contribute to early failure of the leads.

[PhilipA]

Uh, I do not know what ACTUAL effect it has , but on Motronic engines you are only supposed to use OE type plugs, because the Motronic measures the flux of each plug as it is fired and detects misfires by the voltage feedback. So just be careful on plugs and leads.

It also adjust the injection duration based on this info, and "balances" the cylinders by differing the injection duration.. The late 4.0 and 4.6 engines are even not dynamically balanced to the same smaller tolerance than the earlier engines as this cylinder balancing is supposed to achieve the same effect.

BTW the Motronic has an infinite IAC, which is EXACTLY the same as the IAC on my BMW M3, so I have a spare for my M3.
Regards Philip A

[BST4X4XFA]

Hi there Kieren,

Seems to me your dico is driving you up the wall:eek:. Have you heard from DA if they used new leads?:mad: If you need a hand to measure your leads I could drop in sometime this week after work with a multi-meter.
Give me a call.
Jurgens