TVR Chimeara immobiliser
Discussion
Hi guys I am in a bit of a pickle at the moment. Not had my TVR 500 on the road for a couple of years due to lots going on building custom motorcycles since I retired. I regulary start the TVR and drive out on the drive with her ticking over until the fans cut in and then give it a polish and drive it back in. A few months ago I tried to start it and no fuel pump prime or turn over from the starter. I have jacked the car and the pump works on a direct supply. All the lights work on the dash and all other electrics work and even tried a brand new battery, so I’m assuming the immobiliser?? I had planned recommissioning it for the summer and maybe just maybe selling end of season but now can’t even get her over the road to my main garage with the ramp... any advice or clues on how to get her running again would be greatfully received.......
TBH, it's all too easy to blame the immobiliser.... and while there are known issues with the way TVR wired it I urge caution as making assumptions is not the way to diagnose a fault.
Question: Does the stepper motor buzz (key on - key off), this tells you if the ECU is getting power..... which is important as the ECU controls the fuel pump (amongst other things).
Just last weekend I fixed my mates no-start Chimaera that has not been driven for many months, the car would crank but would not start, there was also no tell tale three second buzz from the fuel pump when the key was moved to position one and the immobiliser fob button was pressed.
"It's the immobiliser" my mate said... but I was sure it wasn't as the stepper motor was buzzing when I cycled the key on and off, you see the ECU controls the stepper motor as well as the fuel pump, and the immobiliser is just an interrupter switch on the starter solenoid and the ECU circuits.
So because I could hear the stepper motor I knew the ECU was getting power via the immobiliser, which told me it wasn't an immobiliser issue. Now, as it was highly unlikely the fuel pump circuit within ECU itself was at fault I went straight to the fuel pump relay hanging in the footwell (blue socket), the test being to bridge relay input (terminal 30) to the relay output (terminal 87) with a jumper cable.
The fuel pump immediately came to life and the car started for the first time in months like it had been started only minutes before, this had to mean the fault was with either with the trigger going to (terminal 87) or the ground (terminal 85). Using my test meter I put the positive to terminal 87 and the negative to the battery (known good ground), the test proved the issue was an open circuit on the ground, this lead be to the fuel pump ground switch........ otherwise known as the inertia switch
With the elastic glove pouch flap dropped (two screws) to gain access to the inertia switch, I reached up and applied one press to the inertia switch, as soon as I felt it click I knew I'd solved the no-start issue. The really odd thing was the car was driven into my mate's lockup many months ago without any issue whatsoever, the car had not been subject to shock to trip the inertia switch but had just sat there perfectly still for months on end.
The inertia switch is of course just an interrupter switch on the fuel pump's ground circuit, inside the switch is nothing more complicated that a ball held by a magnet, any significant shock will dislodge the ball and break the ground. I believe the magnet in my mate's 23 year old inertia switch is getting weak and maybe he stalled the car putting it away which jolted the ball off the magnet?
The truth is we will never know but hopefully the above story helps to prove why its so important not to make assumptions and why you should always....
1. Understand how the system works in the first place
2. Follow a systematic/logical diagnosis process
Hope the above helps, Dave
Question: Does the stepper motor buzz (key on - key off), this tells you if the ECU is getting power..... which is important as the ECU controls the fuel pump (amongst other things).
Just last weekend I fixed my mates no-start Chimaera that has not been driven for many months, the car would crank but would not start, there was also no tell tale three second buzz from the fuel pump when the key was moved to position one and the immobiliser fob button was pressed.
"It's the immobiliser" my mate said... but I was sure it wasn't as the stepper motor was buzzing when I cycled the key on and off, you see the ECU controls the stepper motor as well as the fuel pump, and the immobiliser is just an interrupter switch on the starter solenoid and the ECU circuits.
So because I could hear the stepper motor I knew the ECU was getting power via the immobiliser, which told me it wasn't an immobiliser issue. Now, as it was highly unlikely the fuel pump circuit within ECU itself was at fault I went straight to the fuel pump relay hanging in the footwell (blue socket), the test being to bridge relay input (terminal 30) to the relay output (terminal 87) with a jumper cable.
The fuel pump immediately came to life and the car started for the first time in months like it had been started only minutes before, this had to mean the fault was with either with the trigger going to (terminal 87) or the ground (terminal 85). Using my test meter I put the positive to terminal 87 and the negative to the battery (known good ground), the test proved the issue was an open circuit on the ground, this lead be to the fuel pump ground switch........ otherwise known as the inertia switch
With the elastic glove pouch flap dropped (two screws) to gain access to the inertia switch, I reached up and applied one press to the inertia switch, as soon as I felt it click I knew I'd solved the no-start issue. The really odd thing was the car was driven into my mate's lockup many months ago without any issue whatsoever, the car had not been subject to shock to trip the inertia switch but had just sat there perfectly still for months on end.
The inertia switch is of course just an interrupter switch on the fuel pump's ground circuit, inside the switch is nothing more complicated that a ball held by a magnet, any significant shock will dislodge the ball and break the ground. I believe the magnet in my mate's 23 year old inertia switch is getting weak and maybe he stalled the car putting it away which jolted the ball off the magnet?
The truth is we will never know but hopefully the above story helps to prove why its so important not to make assumptions and why you should always....
1. Understand how the system works in the first place
2. Follow a systematic/logical diagnosis process
Hope the above helps, Dave
Thanks Dave for that information. Odd thing now is you prompted my memory this happened before and I replaced the relay and away she went. My initial thoughts were the relay again so I changed it but no joy. I will go through the other items you mentioned and check that inertia switch as didn’t know that existed. Thanks again for giving me a few clues much appreciated I will have another look at the weekend
TMS500S said:
Thanks Dave for that information. Odd thing now is you prompted my memory this happened before and I replaced the relay and away she went. My initial thoughts were the relay again so I changed it but no joy. I will go through the other items you mentioned and check that inertia switch as didn’t know that existed. Thanks again for giving me a few clues much appreciated I will have another look at the weekend
My pleasure Trace it back, be systematic and above all don't be tempted to make assumptions.
Do not skip testing steps in the chain or jump to conclusions
Test the relay and establish if it really is getting +12v in the first place and if it is whether the earth circuit is good, many a healthy relay has been replaced because the relay and it's wiring was not methodically checked with a multimeter first.
If you trace the fault back you can only ever eventually bump into the fault, keep in mind the immobiliser is just an interrupter switch on the starter solenoid and ECU live feed circuits, it's unusual for both circuits to fail at the same time but it does happen.
If you do find the immobiliser is where the problem sits then send me a PM and I will send by return my step by step immobiliser bypass instructions, but do complete your multimeter tests first rather than simply assuming it's the immobiliser.
Good luck with it, Dave.
Hi Dave
I Checked the stepamotor and it did not buzz when the ignition was on and the immobiliser disarmed..
Took down the glove pocket and found nothing behind it but did find another button under to the left side of the steering column identical to the boot button located on the other side of the column. Pressing this did nothing and not sure if this is not the switch, what it does? But I certainly could not find a switch under the glove pocket.
Checked the pump relay and there was power to trigger the pump to pin 30 reading 12.65 volts but no other live terminals with ignition on and immobiliser button pressed . I Did the live feed test to the relay from the battery to trigger the relay and the pump primed continually. However the engine would not turn over.
I have the hot start kit fitted so used a crocodile test lead and took a live feed to trigger the small relay ( small red lead) on the kit and as soon as I put a supply across it the engine turned over. So then put the pump on prime using another set or test leads and then turned the engine over from the hot start relay but did not fire up so I’m assuming there is not power to the ECU.
I Checked the stepamotor and it did not buzz when the ignition was on and the immobiliser disarmed..
Took down the glove pocket and found nothing behind it but did find another button under to the left side of the steering column identical to the boot button located on the other side of the column. Pressing this did nothing and not sure if this is not the switch, what it does? But I certainly could not find a switch under the glove pocket.
Checked the pump relay and there was power to trigger the pump to pin 30 reading 12.65 volts but no other live terminals with ignition on and immobiliser button pressed . I Did the live feed test to the relay from the battery to trigger the relay and the pump primed continually. However the engine would not turn over.
I have the hot start kit fitted so used a crocodile test lead and took a live feed to trigger the small relay ( small red lead) on the kit and as soon as I put a supply across it the engine turned over. So then put the pump on prime using another set or test leads and then turned the engine over from the hot start relay but did not fire up so I’m assuming there is not power to the ECU.
ChimpOnGas said:
Hi Tony,
The first thing I would do is get rid of that hot start kit, it does nothing to help and just adds another failure point.
Then PM me and I'll let you have my completely reversible immobiliser bypass instructions.
Dave.
Hi dave could i have a copy of your bypass instructions please The first thing I would do is get rid of that hot start kit, it does nothing to help and just adds another failure point.
Then PM me and I'll let you have my completely reversible immobiliser bypass instructions.
Dave.
Cheers matt
You'll need to PM me
Over 200 TVR enthusiasts helped to date, years after creating them I'm still getting requests for my bypass instructions on almost a weekly basis.
Happy to help but as per my instructions you mustn't just assume every starting issue on these cars relates to the immobiliser.
Over 200 TVR enthusiasts helped to date, years after creating them I'm still getting requests for my bypass instructions on almost a weekly basis.
Happy to help but as per my instructions you mustn't just assume every starting issue on these cars relates to the immobiliser.
Hi Chimpongas. I have just had my first ever breakdown of my Chim 500 in 8 years of ownership , it took nearly 6 hours to get relayed home, what a day. It appears that I have no fuel pump feed. Immobiliser remote allows cranking and sparks but the pump does not prime. AA man had checked and replaced pump relay to no avail. A separate live feed to the pump did switch it on I assume immobiliser is not allowing pump to prime etc. Please can you help with procedure to bypass the immobiliser as I am at a loss now and cannot get it even over to my garage to get the dash top off. You ask other peeps to PM you but I cannot find how to do so. Thanks in anticipation of your reply.
Semaj,
Be very careful following advice from Penelope, he does not have a TVR and is well known as posting completely irrelevant nonsense on here when not cutting and pasting other owners information. To have the fuel pump running continuously even for a trip to the garage is far from ideal.
Why he lurks on here is a mystery to many owners.
Send me an email and I can give you a wiring diagram for the immobiliser, from that an easy job to bypass the bits you want to.
Be very careful following advice from Penelope, he does not have a TVR and is well known as posting completely irrelevant nonsense on here when not cutting and pasting other owners information. To have the fuel pump running continuously even for a trip to the garage is far from ideal.
Why he lurks on here is a mystery to many owners.
Send me an email and I can give you a wiring diagram for the immobiliser, from that an easy job to bypass the bits you want to.
semaj said:
Hi Chimpongas. I have just had my first ever breakdown of my Chim 500 in 8 years of ownership , it took nearly 6 hours to get relayed home, what a day. It appears that I have no fuel pump feed. Immobiliser remote allows cranking and sparks but the pump does not prime. AA man had checked and replaced pump relay to no avail. A separate live feed to the pump did switch it on I assume immobiliser is not allowing pump to prime etc. Please can you help with procedure to bypass the immobiliser as I am at a loss now and cannot get it even over to my garage to get the dash top off. You ask other peeps to PM you but I cannot find how to do so. Thanks in anticipation of your reply.
Loubaruch said:
Semaj,
Be very careful following advice from Penelope, he does not have a TVR and is well known as posting completely irrelevant nonsense on here when not cutting and pasting other owners information
Why do you post lies about me hereBe very careful following advice from Penelope, he does not have a TVR and is well known as posting completely irrelevant nonsense on here when not cutting and pasting other owners information
You have sent me an email in the past and amongst other things we discussed diagram drawing software
I offered to help you with the drawing of diagrams in any way possible
You know that I am heavily involved in testing and verifying automotive electrical systems amongst other things which are many
I am very concerned about the fact that you contacted me by email and now hand out abuse in my direction here in this forum
Loubaruch said:
Semaj,
Why he lurks on here is a mystery to many owners.
It is none of your business what I do with my timeWhy he lurks on here is a mystery to many owners.
Loubaruch said:
Semaj,
To have the fuel pump running continuously even for a trip to the garage is far from ideal.
Having posted your vitriol here you then show the world that you are lacking in knowledge about the fuel system fitted to the OPs vehicleTo have the fuel pump running continuously even for a trip to the garage is far from ideal.
The world now knows that you aren't in a position to judge anyone
The fuel pump of a correctly functioning system does run continuously once the engine has started
Am very worried about the comments you post to the TVR forums about me
Am more worried about you contacting me by email
Don't know what I can do
Have reported you in the past
I know you won't reply, you never do
At least others will have read about my concern and am no longer on my own with this problem
Please don't contact me by email in the future, I am scared about you contacting me
Hi All
Can Anybody help me ? My TRV Chimera won't start and the immobiliser touch key LED has stopped "blinking" where you press your fob into. I've had a search on the net and it suggests that the immobiliser has gone U/S.
From information found on line it states the immobiliser is under the dash, behind the radio. I've got the dash top off and the radio out and cannot find the immobiliser ..... I've looked in every nook and cranny and even persuade my wife to push her arm through the radio hole and grope about to see if she can find it in there ....... but no joy ?
Two questions :-
1) can anyone suggest where else the immobilser may be hiding
2) can anybody pleeeeeease send me details on how I can bypass it
Can Anybody help me ? My TRV Chimera won't start and the immobiliser touch key LED has stopped "blinking" where you press your fob into. I've had a search on the net and it suggests that the immobiliser has gone U/S.
From information found on line it states the immobiliser is under the dash, behind the radio. I've got the dash top off and the radio out and cannot find the immobiliser ..... I've looked in every nook and cranny and even persuade my wife to push her arm through the radio hole and grope about to see if she can find it in there ....... but no joy ?
Two questions :-
1) can anyone suggest where else the immobilser may be hiding
2) can anybody pleeeeeease send me details on how I can bypass it
chewyKwak said:
................Can Anybody help me ? ...........
Main problem is as a new PH member we will be reluctant to give out info on the security of our cars. I'm sure you can understand this.However, where in Hampshire are you? Reason I ask is that you could come in and visit me at Southways Automotive in Fareham.
Convince me you are an owner and I will show you what you are looking for and where. Call me on 01329 446694 to confirm I will be there when you plan to visit.
Steve
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