2004 Rover 75 CLUB LE 4D Sedan V6 auto - Immobiliser
 

Hello,

Unfortunately my lovely black Rover 75 not longer starts, or more accurately has been starting intermittently before (eventually) not starting at all.

My local Land Rover dealer is stumped, saying that the Engine Control Computer is not communicating correctly with the immobiliser when I activate the remote key. He can't fix it. I've read the thread regarding the problem of battery low voltage affecting this issue, and also the need to have two keys. The battery is in tip top condition. Now this is the strange bit; I have two keys (originals), and both work perfectly to unlock the vehicle. But the immobiliser is (apparently) not activating to allow the engine to run.

Another strange thing, as I mentioned above, is that the problem began as an intermittent problem.

Now, the service people have a computer to assess my Rover, but this apparently, is not helping to resolve the issue.

This issue really has me stuck, since support for Rover 75's in Western Australia is now almost non existent. Worse, I'm not really that technically minded.

Lastly, the engine, when running, runs totally and absolutely perfectly after a recent top end service and head gasket replacement, plus change to a metal water thermostat. I've only done 92,000 Kms after 16 years so all should be good. The service people said my ignition coils and plugs are all good, and that the engine itself is absolutely fine. They are convinced it is an immobiliser issue.

I should also mention there are no fuel leaks evident, or problems with the fuel tank.

I'm hoping someone out there has some advice, or guidance, that I may provide the local Land Rover Service Centre in Perth WA. Thankyou again ...

Hello Lewis,

Does the starter motor turn but the engine doesn't fire?

Or is the starter motor silent?

Simon

The remote unlocking and engine immobilisation are separate issues. So if your car is locking and unlocking as it should on the buttons then the key fobs are working as they should.

The immobiliser part of the key is a separate chip in the key casing that is picked up by a coil fitted around the steering lock. You haven't modifed the keys to flip keys have you? That may cause intermittent starting problems as the chip may not get close enough to the coil each time.

Take the EWS unit out and have a look inside. Not unknown for water to get in there and corrode the circuit causing the sort of problems you are experiencing. Worth cleaning the plug contacts while you are in there.

Forum member genpk is in Perth too and has his own Toaf (diagnostic computer/system). I’ve used Toaf to check on the immobiliser ecu (EWS) - genpk can perhaps provide better information to help you and the garage.

Regards

Thankyou all and SD1too for getting back. Yes, the starter motor runs perfectly and the battery is is in excellent condition. There are no engine fault warnings either on the screen at the dashboard. Or any other warnings. The mechanic says that his test computer is flagging an immobiliser fault. Thankyou Mike Noc for the info. No, my keys are both originals and have been working perfectly up to now. But that is an interesting point. The batteries in the keys have been there for a long time and I've just realized/remembered that the range of both is quite poor. I'll get the batteries changed and see what happens. Thankyou vitesse, can you tell me how I would contact genpk? Is he perhaps in the WA Rover Club? Thankyou all.

To contact Perth member genpk find one of his posts like this one: https://www.the75andztclub.co.uk/for...d.php?t=236134 and click on his name on the left hand side. Usually gives you the option to either send a PM or email to poster.

Regards

I could be way off the mark here but as the problem was intermittent initially have you checked the solenoid on the starter motor? It's a classic symptom. Firstly check the small connector is secure and secondly the solenoid contacts within the solenoid?
Taking a power source direct from the battery to the small connector on the starter motor should cause the starter motor to activate, if it does not then the solenoid is the problem.
At least it is something you can look at, not over complicated and has zero cost to prove or disprove.

Thanks for confirming Lewis. Since the immobiliser ECU inhibits operation of the starter motor (and fuelling) it would appear to be working correctly in that respect. This must also mean that the transponder chip in your key and the immobiliser ECU are communicating properly with each other.

I'd say that the next stage is to check fuelling. Place your ear as close as possible to the fuel pump under the right hand side of the rear seat cushion and ask an assistant to turn on the ignition. Do you hear the pump running in a short burst of about two seconds?

If no, please report back.
If yes, with the starter motor turning can you hear the pump running continuously?

Simon

In a 2004 model, that sounds like classic Fuel Filter Syndrome (search term FFS).


TC

Thankyou again all,

I'll investigate your suggestions and get back. I'm suspecting that the techs here don't have much experience with Rover 75's. I'll try listening for the fuel pump and check the solenoid, although that does appear to be working at the moment because the starter does run OK. Hopefully I can eliminate the possibility of a complicated solution. By the way, shortly after I bought the car (new) the fuel tank stopped supplying fuel. The tech at the time said that a bracket had come adrift in the tank. I only remembered this on Saturday and mentioned it to the service people who said that it was not the same problem. I suppose it's not, but it struck me as that it could be that recurring. Anyway, I'll get back later this week. Thankyou again all for your thoughts..

As you have a later car i would certainly investigate fuel filter syndrome as T-Cut suggests - if you don't have a fuel filter clip fitted on later cars the fuel filter (under driver side rear passenger seat) can separate - leading at the start to intermittent starting as the filter begins to part then when the filter separates completely non starting. The fix is called the fabled orange clip (FOC) - which costs less than a fiver - it basically prevents the filter separating. A cheap fix and worth investigating.:shrug:

Thanks Yorkshire GOC, Apologies, I didn't see your post (it was on page 2!). The techs are working on the car today and I'll get back with what they find. Fingers crossed they find the problem. Still not sure how to do a 'thankyou'.

After having the fuel pump, fuel filter, all the plugs, and a couple of coils replaced the engine is now starting, however for about thirty seconds after start the engine runs roughly, then clears to run normally. I've been advised that the coolant system is over-pressurising which is causing water to wet the plugs after shutdown, hence the rough running after startup. The system is also losing coolant (200 mls per day). This (apparently) means a damaged head gasket (the second after 83,000 kms). So the solution is another gasket(s) replacement.

Thinking back, the engine suffered a leaking water thermostat housing about 6 months after the first top end overhaul. The overtemp only lasted about 30 seconds until I pulled over and shut down. And after replacing with a Kaiser housing I thought nothing more of it. But clearly, 30 seconds was enough to cause serious damage, which manifested itself about a year after the mod.

Anyway, for the sake of completion I'll post the result of the repair.

Thankyou all for your assistance and advice.

It means that you have a coolant leak. Do you see clouds of white "smoke" (water vapour) from the exhaust after first starting the engine?
The leak results from flattened 'O' rings caused by movement because the straight pipe plastic clips have not been set correctly.
I'm afraid that's an incorrect assumption. It takes a lot of abuse to cause a KV6 MLS gasket to fail.

You say that the garage renewed the fuel filter. Did they fit a complete new assembly? Does it have a clip fitted?

Has the garage performed any tests to verify the claimed overpressurised cooling system and cylinder misfiring? Is there any mixing of oil and coolant?

Simon

Thanks Simon, yes it's mystified me also. It seems just too much that I've done another gasket so quickly. I wish I was knowledgeable enough to ask the right questions at the right time! Anyway, the fuel filter was replaced, and with a new clip. I bought two of those from Rover Discounts in England and provided one to be fitted, which they say they did. The fuel pump included the whole assembly with the fuel quantity transmitter.

As for testing, the car is going into the garage in a fortnight and I'm expecting an answer shortly thereafter. They've said they'll do a test (can't remember the name of it), which I understand checks the compression. But they're pretty sure a gasket has blown again, even though there is no smoke. I actually asked that; 'why aren't there more symptoms?' And they said a gasket can be damaged without other indications or loss of power. But that the pressurized water (and water loss) is enough to indicate that.

Oh yes, I forgot, the carbon monoxide test was negative. But again, they said that doesn't necessarily mean all is OK with the gasket.

I suppose both have to be replaced, even if only one is blown. Would that be correct?

Thanks again.

Bought my current V6 from an owner for spares or repair as the garage having changed thermostat, radiator, and fan - said the only thing left causing the overheat/expulsion of coolant had to be the headgaskets even though there was no CO in the coolant. I got a very cheap car with one year old belts etc and next day solved what was a very stubborn airlock - it just needed a good burp.
Would have thought it more likely that any lose of coolant or water in the cylinder(s) was the result of failed paper inlet gaskets.
The car had repeated overheated while used by the previous owner, as the garage said after each operation that it was fixed, overheated twice on my way home despite minus 12c but is now completely reliable. Not quite the same issues as yours but trying to highlight, what was in my case, the garage's incorrect assumption that the problem was headgasket related.
Any lucky contacting forum member Genpk - a fellow owner/long term member might have more idea than this garage you are using.

Regards

:wot:
Thanks for this Mike.
OK. Did the garage open the housing to fit a new filter element, then closed it again and secured with the clip or was the complete filter assembly renewed?
Please tell us more about this pressurised water Lewis. Is it being ejected out of the expansion tank cap?
No, that's incorrect.
So your garage is claiming that combustion gases are pressurising the cooling system and injecting coolant into a cylinder (or cylinders) yet there is no carbon monoxide in the coolant? :rolleyes:

I'm sorry to say this Lewis but your garage appears to have guessed at a diagnosis (head gasket failure) then is desperately trying to find reasons to confirm it. The problem is that those reasons are eluding them.

I fear that you are about to waste another chunk of money after the fuel pump and sparking plugs which I suspect were perfectly ok. :o

Simon

Thanks both for the advice ...

In turn .. to question 1 ... I pretty sure they fitted the new filter element, then closed it again and secured with the clip. But I'll check with them when we return from our touring holiday in South West WA (now using a hire car!!)

Question 2. The garage said that after I drove it to the shop the radiator cap was excessively difficult to remove. When they did get it off there was a clear loss of water and the overflow tank was empty. About one liter was required to fill. I'd only driven about 30 kms max since I'd checked the water before. The next day with a stone cold engine I started it at home and the (refilled) radiator immediately started pushing the water out at a low, but noticeable rate (a fast dribble). I don't really know what that means but it seemed to confirm the diagnosis. Before I refilled it the water was about 2 cm below the fins.

Thanks on the number of gaskets to be replaced.

Question 3. Yes, that is what they are saying. There is no CO2, but water is getting in.

"I fear that you are about to waste another chunk of money" - God I hope not! When we return I'll question them further with reference to all the above. It's so weird, when the engine is up and running she really purrs happily with plenty of power, but I'm rather worried about it blowing up on me on a distant country road. But at least it's starting again.

Hi Vitesse, I'll try contacting forum member Genpk again. Thanks ...

Thanks again both ..

Thanks for your helpful and clear replies Lewis.
If that turns out to be the case then please note T-Cut's advice. He has had personal experience of doing this and reports that it's very easy to unintentionally distort the seal between the two parts of the filter housing when reassembling. Should this happen, the result is unreliable fuel pressure which could well be the reason why you have erratic running. I disagree. The same thing happens if you have an air lock* but first ....
Don't use the fins as a reference. The correct level is between the MIN and MAX labels at the bottom of the expansion tank. If the MAX label is covered with coolant then the tank is overfilled and is likely to eject coolant. Check this as a priority.
You originally said carbon monoxide but no matter! :} As I said in my last reply, your garage is making the common mistake of starting with a diagnosis then trying to make the evidence fit it. When a piece of evidence doesn't confirm their belief (the gas test and absence of white "smoke") they dismiss it. That is not the way to discover what is really wrong and repair it in a cost effective way.

By the way, is this the same Land Rover dealer referred to at the beginning of the thread? :o

:wot:
That's what your garage should be thinking!

Simon

* MGR's procedure for preventing air locks.

Thankyou both, We've just returned from down South-West so time to answer your comments...

My 75/2004 is booked in on the 23rd (Monday fortnight) and they'll do a compression test on that day. 1. Have taken note of SD1too's comments re. clip and seal, airlock, and fins. Thanks for that. 2. Yes, sorry, I meant CO, not CO2. 3. Yes, I agree. Bizarrely it worries me also that the engine is actually running quite well. I'm looking forward to the compression test result. By the way that had another technical name that I can't remember; it was the 'Something Test'.

As for the filler cap, I replaced that with an original some months ago well before all this happened. I'm sure it's OK. I didn't see any pinkish colour, and the radiator is actually original and repaired. I haven't seen any leak from it on the ground. Nevertheless I'll ask the appropriate questions and get back. Thanks bl52krz. By the way, the car is going into an engine specialist shop that repaired the heads previously (before the water thermostat housing split - I wish I'd replaced that then with the Kaiser metal one!!!), not the shop that 'fixed' the fuel filter and fitted the new fuel pump. Both have said again definitely (and independently I think) that there's a problem with the head. I guess I'll have to take that at face value for now I suppose, but I'll bug them with questions.

By the way, the specialist says he'll source the correct gasket set (avoiding the original factory gasket that caused all those historical problems) but I'm a bit nervous about that. Discount MG Rover Spares have a set at https://www.dmgrs.co.uk/collections/...t-kia-carnival

Do you think these would be OK? I am tempted to buy the set just to hand over to the specialist and see what he thinks.

Thanks both, and I'll get back as things progress!

Forgive me if I missed it Lewis but have you mentioned this before? How were the heads repaired, skimmed perhaps? Any work such as this raises another possible source of trouble.
Please see my earlier advice (post 14); the thermostat housing doesn't split although it does appear to have done at first sight. What happens is that the 'O' ring at the base flattens and pressurised coolant is emitted as a spray which coats the housing seam with residue leading to the incorrect diagnosis. The Kaiser metal parts are successful because they're rigid. You can obtain the same result by positioning the straight pipe "herbie" clips correctly.
Your specialist seems to be thinking of the Rover 825 KV6 engined cars. The 75/ZT version uses MLS gaskets which have never been problematic.
:eek: No.

Simon

Hi SD!too, yes sorry, the head gaskets have already been replaced once, at 78,000Km. At the beginning of this thread I'd simply not thought to mention it because the idea of a second head gasket failure was inconceivable. But yes, there was a previous failure; the engine stopped producing sufficient power and the temperature shot right up while on the freeway. Anyway, it was repaired and all seemed good, even after the thermostat housing failure (and overtemp) about a year later. The engine specialist put it down to a wrong head gasket fitted at manufacture. There was no evidence that the cooling system had failed (although there was a previous repair which had been done during a previous service, when a minor leak had been discovered (no overheating had occurred on that occasion). Sorry, should have mentioned that but it just didn't occur to me as relevant. Do you think it could be? ... I guess the heads were skimmed; that's what is always done when a gasket is replaced, right?

Talking of the thermostat housing, they told me that the housing had split along a 'plastic weld'.

OK, so the head gaskets at Discount MG Rover Spares are wrong. Thanks, I won't buy them. Actually I'll let the repairer source those.

Thanks again SD!too ... I'll get back when I know more in 10 days.

Hello SD1too. Finally managed to book in my Rover to a repair shop. I'll take it there in a couple of weeks. Since my last post I've only driven it a couple of times for a short distance, not more than a kilometer. Weirdly, the engine starts easily and runs perfectly now, with plenty of response, power, and the engine temperature normal. However, after each drive the next morning I found oil in the coolant, a very slimy layer. Pulling it out I brushed it over a surface and it's definitely engine oil. The first time I've seen this. At all other times during this problem the coolant has been perfectly clean.

I guess this means that a gasket really has failed ...

Too bad, this will make head gasket replacement mark II ... !!

As I've said before Lewis, I doubt that very much. It takes a lot of abuse to destroy an MLS head gasket but of course it depends upon the quality of the previous work in that area.

On the KV6 the oil cooler sometimes fails resulting in mixing. Also some owners have found that a damaged inlet manifold gasket has the same effect.

If I were you, as your engine starts easily, runs perfectly with plenty of response and power, I would cancel your garage booking and drive it regularly. Any fault symptoms should then become more apparent and easier to diagnose.

Simon

OK, thanks for the advice Simon. I appreciate it. I'll consider my options again.

Hi SD1too. Well, it appears you were almost certainly correct. Eventually, after oil was contaminating the coolant more and more, the repair shops (X2) emphatically advised that the head gasket was damaged, even though I suggested a number of times that the oil-water heat exchanger (which they called the 'oil cooler') may be the culprit. Both shops denied this. So the original shop replaced the head gaskets, saying both were damaged (who really knows).

Oil then reappeared in the water. To make a long story short, it transpired that the oil cooler was indeed damaged, and leaking oil into the coolant. Indeed, oil started leaking onto the road from the oil cooler! After replacement of the oil cooler (by a different shop) I was advised that the oil would continue to appear in the coolant for a while due to oil contamination in the cabin heater circuit, which apparently is a monster to remove and wash out.

Anyway, I'll see what happens. The engine is running well after its second head gasket job!! And the oil contamination seems decreasing. Thanks again for your advice and suggestions ...

Thank you very much Lewis for your kind words and for updating the story.
Indeed it is, and there is an alternative to removal; repeated flushing of the cooling system with an additive likely to absorb the oil residue. This is best done by bringing the engine up to normal operating temperature each time so that the thermostat opens and every corner is reached. :D

Simon

Thanks again Simon, I'll get that done after the rains finish. In the meantime I've been removing the oil with blotting paper at the water filling point. Using heaps of paper so the oil is decreasing with every 10 km's or so. In the meantime I've got a problem with my ABS faulting after heavy rain and flooding roads, but I'll use a different thread for that. Lew

Hi Simon, and all others who have assisted with this. Since my last post the car has been running really, really well and nicely, albeit oil is still being removed by the dipping paper into the radiator tank method. Looking back on it I wished I'd pushed the oil cooler theory (as you suggested) more strongly with the repair shops involved, but thems the breaks! (And they weren't listening anyway) Anyway, after two head gasket replacement efforts I decided to sell the car. Which was a pity 'cos I loved it, and it looked great with its new refreshing black paint job. It was such a yank! I got a really good price for it, and I did it properly, telling the new owner the lengthy and unending history of unserviceabilities with my loved 75. So thanks again all! The new owner is actually displaying it at British car shows in the south-west of Western Australia!!! He loves it too. Cheers and signing off ....

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