Sterling Toad Immobiliser / Battery problem - or is it the Battery Master Switch?

[sjmmarsh]

You may have seen that on my way back from my annual service in November that I hit a bit of flooded road which went right over the car and dumped half a bucket of dirty water into the passenger and driver footwells. It is all dried out now and, last week, I thought I would take it out for a run in the milder weather.

Flat battery.

I jump started it using a leisure battery in the garage and it fired up OK - a bit lumpy as it had not run for 6 weeks, but it soon settled down to normal. When the engine came up to temperature and the fast idle cut out the engine just died. It would not restart as the immobiliser was still active. Nothing worked, so I took the battery home from the lockup to charge it up. It was holding 12.8V overnight but, at 4 years old, the voltage dropped to 12.4 when it went in the car. I still couldn't turn the immobiliser off.

New battery time - put it in the car and same result. 12.4V (turns out it is not fully charged) and the immobiliser still wouldn't turn off. I put the leisure battery across the new battery with jump leads and now the voltage in the car showed 13V (I have a plug in meter) and the immobiliser turned off and the car started no problem.

The new (Banner) is on to charge which should work (fingers crossed) but I am concerned that there is a dirty/damp connector somewhere that is reducing the voltage to the immobiliser which means at some point I could end up stranded if the battery voltage drops too far. It used to (just) start OK if the battery was only showing 12.4V and I have never had problems with the immobiliser refusing to disarm before this.

My next  test  will be to undo the immobiliser  to check for a bad earth and to check all the connectors on the ECUs on the bulkhead.

Should I be looking anywhere else?

it is a 2007 CSR 260.

Thanks 

Steve

 

[Jonathan Kay]

I think that you're very wise to check those connectors and earths. I'd include the engine block earth(s).

Then I'd want to measure the minimum battery voltage during cranking and voltage during any rough running.

And even though you now have a new battery I'd check its fluid levels.

Jonathan

[sjmmarsh]

Thanks Jonathan

The acid levels are fine. The voltage drop on the old battery was to around 8.5V (when it just started OK). The earth strap is worth looking at as well. Thanks

Steve

[Jonathan Kay]

Yes, in order to avoid components dropping out it seems as if at least 10.5 V is necessary. (The surprising thing about Sevens is that they'll often crank at what seems to be an acceptable speed while the voltage drops below that.)

Jonathan

[Tom_Arundel]

I had problems with the aerial and fob, they are worth checking (If you have them) I had to redo the aerial 

[7 wonders of the world]

The white 2 pin aerial multiplug is a known weak point, I had intermittent times when it would not disarm, eventually got it to do it in the garage and gently started lightly poking things and this was the cause, I just put a little tension on the pins and perfect - so then cut the plug out and soldered it with heat shrink, 

 

[sjmmarsh]

7 wonders - is the multi plug inside the box with the immobiliser or in the loom somewhere?

Steve

[sjmmarsh]

7 wonders - is the multi plug inside the box with the immobiliser or in the loom somewhere?

Steve

[sjmmarsh]

7 wonders - is the multi plug inside the box with the immobiliser or in the loom somewhere?

Steve

[7 wonders of the world]

on the end of the loom where it meets the coiled up aerial usually just under the steering column

[sjmmarsh]

Update - I've been waiting for the weather to get warmer as the garage was too cold to work in, particularly when fiddling with bolts to check earth connections. I've made some progress and think I have found the problem but will put a longer description here in case it helps someone else in the future. 
 

The symptoms are that, after hitting a flooded road and deluging the engine and footwells, the immobiliser would not turn off unless the voltage at the battery was fully charged. Even then, although the car would start, it cut out when the engine went from fast idle to tickover (i.e. while I was locking the garage up - just enough to do that and get in the car). After that, the car would not immobilise unless I put jump leads on the car.

Suspecting the battery (Banner, 4 years old) was on the way out, I got a new one, same result. This led me to check all the earth connections and cleaning the electrical connectors to the ECU and relays in case water had got in there. All looked ok and I got a 0.0ohm reading from the -ve battery connector to the bulkhead. Hmmm.

I checked the positive leads as best I could and while there was a small 0.1 ohm resistance, (between the positive lead and the starter motor), I couldn't see anything amiss  I put the battery back in and the car immobilised and started Ok.  I did this several times with no problem, so decided to go for a blat. I locked the garage up and .... it cut out again and would not restart.  aaaagh!

I went through the resistance checks again (battery removed of course) but this time I got a 5 ohm resistance to the starter motor. Wiggling the Battery Master Switch brought this down to 0 ohms, so at last I was getting somewhere. Battery back in,  start the car. Running ok. Tap the BMS and the engine cut out, so the problem looks like the 16 year old BMS is the problem   At that age, it is best to get a new one - other than CC have none in stock and Redline are mid stocktake and not answering the phone or email at the moment. Hopefully this will fix the problem, rather than just reveal the next layer of the onion skin!

What I think is happening is the initial start is OK but the current through the BMS is causing some arcing and increases the resistance, so any interruption causes the immobiliser to cut in and won't deactivate as there are not enough volts getting to it.

I'll confirm all is working when I find a replacement BMS  

Steve

 

 

[Andy135]

Good update. Fingers crossed a new BMS is the solution for you.

[Jonathan Kay]

Thanks for the update.

While you're waiting for the new switch how about making the old switch irrelevant by putting the output and input connectors on the same terminal?

Jonathan

[SM25T]

Redline has stock, and believe has replied to you now Steve.

[sjmmarsh]

Good idea as a temporary workaround. Long term it would just end up with a flat battery as I have no power in my garage to hook it up to a battery conditioner. 
 

Replacement is now on order with Redline. [edit - it arrived less than 24 hours later - now I just need to find time to fit it]
 

Steve

[sjmmarsh]

Having got the new BMS and fitted it, all seems to be OK but I'll know better when I do a proper test (it was raining today, so didn't run it that long in the garage...

The new one is a much tighter fit and less sloppy in its action, but think part of the issue is down to the design. The key on the left is the old one, the key on the right is new. The big difference is the amount the pin protrudes on the new one - also it is in a blind hole rather than one that goes right through. The old switch still feels a bit sloppy with the new switch, so I think a new BMS was the right way to go. 
 

https://1drv.ms/u/s!AlrS6KK8r-4KgpobFRMKfdR0Q0k05g

https://1drv.ms/u/s!AlrS6KK8r-4KgpochIBwh8_Vejf12Q

... the pictures don't work for me. I need to remember how to work round the limitations on here.....

Steve

https://1drv.ms/u/s!AlrS6KK8r-4KgpochIBwh8_Vejf12Q

https://1drv.ms/u/s!AlrS6KK8r-4KgpobFRMKfdR0Q0k05g

 

 

[Jonathan Kay]

[sjmmarsh]

Thanks JK 

I followed your helpful  links and realised that things had changed a little since I was a very regular user of blatchat. My problem was that I was using the other image upload facility (ringed in yellow) rather than the new (to me) one in blue. The insert image icon is commonly used on other forums and web editors, hence being puzzled why the same links don't work on here. If I have got it right you will see the image below. 
 

 

The other photo I was trying to upload shows that one key is blind and the other has a through hole for the pin. 
 

[Jonathan Kay]

Image showing fine.

There are now three methods for showing images inline: linking to them on another server, the shortcut upload (blue above), and the original upload (yellow above). The shortcut upload is quick and now widely used, but it automatically limits the resolution: not a problem for most images but can make eg text unreadable.

The original image was on Microsoft OneDrive. For most external servers there's a way of finding the URL of the image without all of the navigation elements needed in albums and galleries. I add the workflow for these to the Forum User Guide thread. But this one defeated me, so I had to download and upload.

Jonathan

PS: Standing offer to help anyone with image management on this site.

[sjmmarsh]

Thanks JK. 
 

I tried to be helpful when the switch to the new website happened in 2014, but that was mainly on identifying workarounds to some of the issues, including using Google site: parameters to find things that otherwise seemed lost.  
 

The shortcut upload had me perplexed - I just couldn't get it working from my iPad (despite trying several image sites) and didn't want to have the hassle of transferring from iPAd to PC then uploading to my own sjmmarsh.f2s.com website and linking to that one as it is really clunky!

Steve

[sjmmarsh]

Thanks JK. 
 

I tried to be helpful when the switch to the new website happened in 2014, but that was mainly on identifying workarounds to some of the issues, including using Google site: parameters to find things that otherwise seemed lost.  
 

The shortcut upload had me perplexed - I just couldn't get it working from my iPad (despite trying several image sites) and didn't want to have the hassle of transferring from iPAd to PC then uploading to my own sjmmarsh.f2s.com website and linking to that one as it is really clunky!

Steve

[Golf Juliet Tango]

Far more issues with Apple products. I have had no picture attachment issues with either Android or PCs or uploading from phone attached a PC.

[sjmmarsh]

Final update.

it was an onion skin problem. Having replaced the BMS, the immobiliser turns off fine and the car starts and sounds fine in fast idle. However when off fast idle the car would not respond to the throttle properly. It was very lumpy and when I blipped it, the engine died,

Suspecting the throttle bodies as the issue (and remembering the heavy dousing the car got which started all this), I pulled both connectors to the throttle bodies and reseated them. That seemed to fix things, so went for a blat - finally!  All seemed fine, so I put the car in the garage..... only it wouldn't go into reverse... the gearstick would not depress, so couldn't shift it to the left into reverse. 

Time for lunch and to consult the blatchat tech archives. This directed me to the quick shift rebuild in the May 2020 Low Flying. It looks likely that the gearstick had rusted into the spherical bearing  

Back up to the garage, put some WD40 down the gearstick, waited 5 mins and gave it a thump. Success! I now have a car that goes backwards as well as forwards.

Hopefully you won't hear any more on this saga. I could tell you about the problems I am having with my Defender... but that is for another forum!

Steve

 

 

[sjmmarsh]

One last post. 
 

As I have replaced the BMS, I decided to take it apart (drill out 4 copper rivets) to see what the problem was. The pictures of what I found are attached. 
 

Essentially when you insert the switch and twist, it pushes the plunger down which bridges the copper contacts and also depresses the switch at the bottom, which is a push to break (pair 1) and push to make (pair 2).  The idea of the switch is that when the BMS is inserted it connects the ignition switch to the power (2) and when it is disconnected it shorts out the alternator through a resistor to prevent a voltage spike to the ECU. 

if you look at the close up of where the key is inserted you can see that the pin has worn a groove in the plastic, which is why it felt sloppy, However, the copper contacts are bright and clean - like new (not bad for 16 years old). Testing the switch at the back it turns out that this was not working properly, requiring it to be worked several times before it would turn on/off cleanly. The two problems combined explain why the car would not immobilise as the key was vibration sensitive and the resistor wasn't switching out properly, so pulling the voltage down that the immobiliser saw.

so, despite looking in relatively good condition, the BMS is best consigned to the bin, along with the key which, over time, will wreck the next BMS it is used in!

Steve