Very Intermittant fault

[Fubar]

Hi all, First time poster. Picked up my shiney 2.0l Diesel Tourer 4 months ago. 1.5 of those months it's been at garages under warenty repair. Got it back the other week and the problem's still arent resolved.

Previous owner had a (car) break down and was eventually fixed after a month in the garage - the injectors being diagnosed as problomatic and them getting overhalled.

Now, despite everything below. A lot of the time it runs absolutly fine. No problems, no rattle, perfect start... etc.

I've read a lot on what the problem could be, and I'm wondering if it's more than one. Here are my symptoms from the beginning, including prior to getting it to a garage:

• Un-stable idle, on bad days this can be +/- 100 revs. Worse when hot.
• On clutch down, revs reduced, overshot the idle point and almost stalled.
• Occasional problem starting first time. Especially when warm.
• Driving along at 50 in 5th (long trip), engine stopped twice in short succession. Couldn't get it started second time - towed home.
• AA guy clamped diagnotics on it and it was reporting 0rpm on cranking and didn't fire up. Later gave accurate reading and fired up fine.
• Drove fine without cutting out again while I got it diagnosed by Viking garage of hampshire as a 'Inter control unit CAN bus failure'.
• Took it to garage for warrenty repair - before leaving, started engine on second attempt but it sounded rattly innitially. Did an experemental rev, but it just wouldn't go above around, 2000. Then suddenly shot up to the red line, pulled foot off the accelerator, revs dropped and car almost stalled.
• Got it to the garage and was told that the CAN bus wouldn't cause engine stoppage and that he would do his own diagnostic.
• Diagnoses a fuel pressure sensor and orders a new one.
• [Lot of politics - month goes by without getting part - car is returned to car salesman without my knowing. Someone tells him it sounds like the injectors, so he takes it to another garage.]
• Other garage fixes car and it's returned to me.
• On the day I pick it up, I have two non-starts (fired up a little hesitantly second cranking).
• Contact garage directly to discuss what work was done. He said he found a fault with the glow plug / starter control unit and got it fixed. I asked if it would have caused the engine stop. He says he was never told the engine stopped, and didn't diagnose for it. Did, however, diagnose for cam, crank and pressure sensor. Not injectors.
• Got the car booked into the garage again for leakback + spray pattern test. But symptoms have continued.
• Engine revs dropped agian on clutch down and almost stalled.
• un-even revs.
• pulling away seems to sap engine power unless I really gun it.
• Total inability to start it (still turned over, but didn't fire). Had to leave it in a carpark for an hour, then started first time.

Now, this is my first Rover, so I'm not used to them, I don't know if these are signs of problems, but here they are:

• Engine only really starts pushing me back in my seat when I hit 2000 rpm. Before then, it really doesn't feel (in my mind) like a 2.0l BWM engine.
• My old car was really noisy. So I appreciated how quiet this one was by comparison. However it sounds like it's getting louder - although I could just be getting used to it.
• There seems to be some components moved and tied back with cable ties under the bonnet. Mainly pipes and tubes. Will try and get pictures.

Now, I'm a system design engineer by trade, just not automotive. Looking at it, I figure it could be one or more of the following:


Injectors - causing fuel rail pressure drops. Although would they cause this level of intermitancy?
MAF - could explain poor starts, un-even revs and lack of power below 2000, but I un-plugged it with no change.
Cam sensor - would explain the lack of starting, but was told it was checked. May do the old magnet on bonnet test myself.
Crank sensor - Would explain the stopping, possibly lack of starting and uneven revs as well as the AA diagnostic. But I was told it was tested and ok.



As stated above, these faults are intermittant and I still drive it to work every day (10-15 min journey), but I have some long ones (Scotland) planned soon and need to be confident in its reliability.



Is there anyone out there who has more experience able to advise where my fault could be, used OBD tester and it's not come back with anything. Top contendor is still the injectors considering their history.


Cheers guys. I love this car and despite peoples insistance, I have no desire to take it back.


Sam.

[Fubar]

Oh, and it's got a hair over 70,000 on the clock.

[Mike Noc]

Find someone with a T4 diagnostic who knows how to use it Sam. That will show all the sensors in real time as well as logged fault codes, and should pinpoint the fault or faults you are experiencing.

Could well be a low pressure fuel supply problem or a combination of what you have listed, but cheaper in the long run to correctly diagnose the fault rather than start throwing new bits at it.

My last session on a T4 cost around 30 quid and was well worth it.

Mike

PS With 70,000 on the clock you have plenty in reserve - mine's got 315,000 on the clock and still going strong.

[HarryM1BYT]

I would suggest

1. injectors - do a leakback test, you can check this yourself as descibed in this forum.
2. Check the plenum and ECU for water.
3. While you are in the plenum, check the condition of the glow-plug relay.

[Fubar]

Hi guys, thanks for the speedy replies.

Times are tight, and as the salesman has agreed to continue work under warrenty, so I don't really want to spend anything... yet.

The garage I'll be taking it directly to is a rover place so has T4 kit. I'll see if he can check fault codes and the likes while I'm there. He'll also be doing the leakback, so I will wait till that's done.

Viking cleared out the drains, but the previous owner did have the ECU fixed for water damage. Will re-check them tonight.

Is the glowplug relay the only specific component for controlling them. Is it just a DC relay driven from the main ECU, or connected to the CAN bus? Where abouts is it in relation to the ECU?

Cheers,
Sam.

[rich17865]

Unless the glow plug relay is faulty and causing other problems, I am under the impression that these engines will start fine in almost all weathers without using the glow plugs.

I am sure someone will correct me if I am wrong

[Mike Noc]

Spot on Rich you don't need the glowplugs to start but if the relay (which is a relay combined with an ECU) gets waterlogged then I've read that it can cause CAN bus problems.

The glowplug relay sits next to the ECU - easy to spot once the covers are removed.

Mike

[Fubar]

Ahhh, so it's an embedded controller + relay. Awsome. I can check that out.

Previous water damage would make it a likely contender. However, what Rich said about them starting without glow plugs (I guess the're there just to smooth it out?) makes me think that my lack of starting itsn't caused by that. Especially as it's what was (allegidly) fixed.

Don't suppose there are any mods with respect to fitting a water alarm in the penulum? might be worth fitting one to a light/buzzer on the dash.

[HarryM1BYT]

Originally Posted by Fubar

Is the glowplug relay the only specific component for controlling them. Is it just a DC relay driven from the main ECU, or connected to the CAN bus? Where abouts is it in relation to the ECU?

Cheers,
Sam.

The relay is right next to the ECU. It is not a simple DC relay, it is a rather fancy special electronic one which I suspect contains at the very least a timer circuit, perhaps a temperature circuit too. Whilst the car will happily start in most conditions without need for the glow plugs to be operative, if the relay is faulty the car wlll not start.

Someone provided a photo on the forum, of the internals of the relay, where the relay had suffered water damage.

[HarryM1BYT]

Originally Posted by Fubar

Don't suppose there are any mods with respect to fitting a water alarm in the penulum? might be worth fitting one to a light/buzzer on the dash.

It is a fairly simple circuit to sense contact with water, but you can buy battery operated water (flood) sensors for installing under washing machines. Maybe adapt one of those to run from an ignition supply? Its sensor would need to be protected from the normal flow of water into and out of the plenum, so it only senses a build up of water though.