Go Back   The 75 and ZT Owners Club Forums > The 75 and ZT Owners Club Forums > Technical Help Forum
Register FAQ Image Gallery Members List Calendar Mark Forums Read
Notices

Reply
 
Thread Tools Display Modes
Old 21st December 2007, 00:34   #1
Johnny2R
Gets stuck in
 
Rover 75 CDT Club Tourer

Join Date: Apr 2007
Location: Norwich
Posts: 712
Thanks: 98
Thanked 47 Times in 24 Posts
Default Immobiliser mischief?

I bought my Rover 75 CDT in July 2006 and, after some initial problems with injectors, it has been a delight. Three times in that period, though, it has completely failed to start, and the worst and most serious instance was a couple of days ago. When I say failed to start, I mean it turned over OK, but nothing more, not so much as a cough. Normally it starts straight away without a problem.

Now, each time this complete non-starting has occurred, I believe I have, immediately prior to the non-start, done something slightly different from normal as regards unlocking the car - maybe accidentally re-locking it and then immediately unlocking it again, or something like that. Each time, the car has eventually just sprung back into life as if nothing had happened.

The other day, I had been for a short walk, then got back into my car and felt sleepy, so, deciding a short snooze might be in order, I pressed the button to lock all the doors. I then realised I probably wouldn't be able to sleep so decided to head off anyway and attempted to start the car, but no joy. I immediately thought "Ah, it's that old immobiliser mischief again", so did every permutation of locking, unlocking, getting in and out, etc, I could think of, but it still wouldn't start. I thought it must be something different this time, so called out the recovery people. Anyway, the guy couldn't work out what the problem was and could only determine that no power was getting to the under bonnet fuel pump (certainly I wasn't hearing the normal burring noise before starting). I took a look to see if the ECU was wet but the plenum was dry as a bone. Anyway, just after I'd put the ECU back into place, the recovery guy tried the ignition on and off three times in rapid succession, and bingo, it sprang back into life as if nothing had happened.

Now, it strikes me that this is likely some kind of immobiliser quirk, some bug to do with some sequence of actions which causes it to misbehave (unless there is some other explanation which someone can think of). Has anyone else come across such an immobilisation problem? And is there some way of effectively resetting the immobiliser, some sequence of key fob presses perhaps, that tells it to pull itself together and stop being silly?
Johnny2R is offline   Reply With Quote
Old 21st December 2007, 08:35   #2
raykay
I really should get out more.......
 
Now Other Manufacturer

Join Date: Nov 2006
Location: Co. Kerry
Posts: 2,786
Thanks: 16
Thanked 310 Times in 283 Posts
Default

The immobiliser inhibits the starter motor so if the engine is turning over, it's not that. (If you have the message centre, it tells you when the engine is disabled). If there is no power to the fuel pumps it could be the fuel pump relay.

Last edited by raykay; 21st December 2007 at 08:37..
raykay is offline   Reply With Quote
Old 21st December 2007, 08:54   #3
JohnDotCom
*
 
Rover 75 FaceLift Tourer CDTi 170BHP Auto ConnSE 2005 Model Starlight Silver

Join Date: Nov 2006
Location: Abergele
Posts: 28,735
Thanks: 0
Thanked 6 Times in 5 Posts
Default

Most common Problem of Non Starting is CAM Sensor.
JohnDotCom is offline   Reply With Quote
Old 23rd December 2007, 08:23   #4
lee79
Avid contributor
 
lee79's Avatar
 
MG ZT-T 190

Join Date: Aug 2007
Location: Hinckley
Posts: 102
Thanks: 0
Thanked 0 Times in 0 Posts
Default

i am having this problem now, twyce its happened. starter motor turns, wuring from the rear lasts about 3/4 seconds(may be sender unit ). then after 20 od attempts starts up...runs ok when started no problems there.
so to be dim.....whats this sensor and where is it?



happy christmas too:xmas-smiley-009:
lee79 is offline   Reply With Quote
Old 23rd December 2007, 15:35   #5
Departed
Retired
 
--

Join Date: Jan 2007
Location: --
Posts: 3,785
Thanks: 0
Thanked 4 Times in 4 Posts
Default

Immobilser and locking aren't actually linked (other than they both live inside the key head).

The alarm / locking transmits when you press they fob. The immobilser has a transponder chip which only transmits when it's in the ignition lock. The ECUs that receive the signals are different too.

So sorry, the theory doesn't stack up, and as pointed out an immo lockout also prevents cranking.

So cam sensor, fuel pumps, or glow plugs. If it's OK when cold, but always fails with a hot engine, I'd plump for cam sensor too.
Departed is offline   Reply With Quote
Old 30th December 2007, 13:50   #6
Johnny2R
Gets stuck in
 
Rover 75 CDT Club Tourer

Join Date: Apr 2007
Location: Norwich
Posts: 712
Thanks: 98
Thanked 47 Times in 24 Posts
Default

Quote:
Originally Posted by lowedb View Post
Immobilser and locking aren't actually linked (other than they both live inside the key head).

The alarm / locking transmits when you press they fob. The immobilser has a transponder chip which only transmits when it's in the ignition lock. The ECUs that receive the signals are different too.

So sorry, the theory doesn't stack up, and as pointed out an immo lockout also prevents cranking.

So cam sensor, fuel pumps, or glow plugs. If it's OK when cold, but always fails with a hot engine, I'd plump for cam sensor too.
The odd thing is that 99.9% of the time the car starts without a problem. As I said, this problem has occurred just three times in the 18 months I've owned the car. In each case I've done something unusual with the unlocking immediately prior to attempting to start, hence my suspicion that it was something related. Surely if I had a faulty cam sensor or the like, I'd get regular problems starting, wouldn't I? There is normally no problem whatsoever starting.

As I mentioned, there was no power to the fuel pumps, which would appear to rule them out. How would a problem with glowplugs manifest itself?

Also, how do I check out the fuel pump relay?
Johnny2R is offline   Reply With Quote
Old 19th May 2008, 16:03   #7
EamonnS
Newbie
 
Rover

Join Date: May 2008
Location: Surrey
Posts: 3
Thanks: 0
Thanked 0 Times in 0 Posts
Default Is the transponder in the key active or passive?

My 75 Tourer has just started playing me up with the immobiliser. What triggers the transponder chip when it is in the ignition lock? Is this a passive transponder or does it rely on a battery in the key? Is there a way of completely bypassing the immobiliser? This is now happening with both of my keys. HELP!!!!!

Quote:
Originally Posted by lowedb View Post
Immobilser and locking aren't actually linked (other than they both live inside the key head).

The alarm / locking transmits when you press they fob. The immobilser has a transponder chip which only transmits when it's in the ignition lock. The ECUs that receive the signals are different too.

So sorry, the theory doesn't stack up, and as pointed out an immo lockout also prevents cranking.

Last edited by Simon; 19th May 2008 at 17:13.. Reason: Fixed quote
EamonnS is offline   Reply With Quote
Old 2nd January 2010, 13:39   #8
Lynneth
Newbie
 
Rover 75 Saloon

Join Date: Dec 2008
Location: Immingham
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
Default Same problem

I have had my car for almost two years and have had absolutely no problem, but twice over this festive season, I have gone to my car and it has not started.

However, thinking about it, on both occasions, I went to my car, put the key in the ignition and started it, then remembered I needed to do something, so turned off the car, did what I needed to do and and quickly returned to the car. It then would not start.

There was no engine action at all (all ignition lights came on).

On the first occasion, we left it overnight and it started normally in the morning. Today, I could not get it to start. My husband left it for a while and then it started, then it wouldn't, then it started.

I am really concerned that I am losing confidence in my car. I want to be sure that when I go to it, it will start.

Any help would be really appreciated

Thank you
Lynne
Lynneth is offline   Reply With Quote
Old 2nd January 2010, 15:59   #9
David3807
Posted a thing or two
 
David3807's Avatar
 
2002 R75 Conn SE 2.5l Auto Tourer, 2001 R75 Conn SE 2.5 Auto Saloon

Join Date: Nov 2006
Location: Gravesend
Posts: 1,897
Thanks: 0
Thanked 2 Times in 2 Posts
Default

Hi Lynne and welcome to the club.

So that a more specific reply can be given can you let us know what model you have ?? Diesel ?? Petrol ??
If Petrol what engine - 1.8 ? 2.00 V6 ?? 2.5 V6.
Automatic or manual ? How old is the car and mileage.

EAch model can have different likely causes of non starting.

However one thing common to all is the battery. If the car is over six years old and is on the original battery then its on borrowed time.

Did you notice if the headlights flashed when you tried to start the car and failed ?? The cars computer (ECU) checks the battery power level every time before starting the car. If there is not enough in the battery the ECU will not allow the starting proceedure to continue and to let you know this will get the headlights to flash at least 3 times.

If this is the case and the battery is over six years old then it could be new battery time. If the battery is fairly new then it could be that you do a lot of short journies which has not given the battery enough time to recharge properly. Think it takes about 5 to 10 miles of running to replace the energy of ONE COLD start. A decent long run (once the car is running) or useing a battery charger every now and again might cure things.

HTH
David3807 is offline   Reply With Quote
Old 3rd January 2010, 01:32   #10
Lynneth
Newbie
 
Rover 75 Saloon

Join Date: Dec 2008
Location: Immingham
Posts: 8
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by David3807 View Post
Hi Lynne and welcome to the club.

So that a more specific reply can be given can you let us know what model you have ?? Diesel ?? Petrol ??
If Petrol what engine - 1.8 ? 2.00 V6 ?? 2.5 V6.
Automatic or manual ? How old is the car and mileage.

EAch model can have different likely causes of non starting.

However one thing common to all is the battery. If the car is over six years old and is on the original battery then its on borrowed time.

Did you notice if the headlights flashed when you tried to start the car and failed ?? The cars computer (ECU) checks the battery power level every time before starting the car. If there is not enough in the battery the ECU will not allow the starting proceedure to continue and to let you know this will get the headlights to flash at least 3 times.

If this is the case and the battery is over six years old then it could be new battery time. If the battery is fairly new then it could be that you do a lot of short journies which has not given the battery enough time to recharge properly. Think it takes about 5 to 10 miles of running to replace the energy of ONE COLD start. A decent long run (once the car is running) or useing a battery charger every now and again might cure things.

HTH

Thank you so much for replying

I have a Rover 75 1.8 petrol car.

I did not see any flashing of headlights, although it was daylight on the two occasions it failed, so may not have noticed.

Also, as previously mentioned, on both occasions, the car did start with no problem, then after stopping the engine for a short while (and removing the key from the ignition), it refused the start again because of the immobiliser.

As far as travelling is concerned, I travel long distances (all over the country) as part of my work, so there is no problem with that.

The car is six years old, so not sure if the battery is the same age as the car or not. It certainly does not seem to have been a problem, and has started every single time since I bought it - until recently. The car has done 60,000 miles (it had 33,000 miles when I bought it) and is manual.

Thank you very much
Lynne
Lynneth is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 18:46.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright © 2006-2023, The Rover 75 & MG ZT Owners Club Ltd