Gemini Alarm/ immobiliser issue
Discussion
Evening all,
I'll say at the outset that electrics is not my strong suit - somewhere between novice and amateur.
My 94 griff 500 has developed an odd fault. unlock the car, key in the ignition, turn to on - all fine, except no power to the ECU. The engine cranks well, but as the ECU controls the fuel pump etc etc , it doesn't fire.
About 30 seconds after ignition on, the ECU light comes on, fuel pump primes and off we go. if, once the first ignition on eventually powers the ECU, I turn the car off and on again there is still a delay powering the ECU, but its shorter in duration 5-10 seconds, maybe less.
I have a Canems set up, so no relays in the loom specifically for fuel pump. I've had the stereo and vents out and found the alarm/immobiliser. I'm not that fussed to keep it because I have a battery brain I can trigger remotely, and a battery in the boot so pretty good immobilization options anyway
Any suggestions what tests I can run to see where the problem might be?
Can i bypass the system to just power the ECU whenever the i turn the ignition on?
Thanks in advance, appreciate this topic has been covered a few times on PH, but i cant find anything for Gemini rather than Meta
I'll say at the outset that electrics is not my strong suit - somewhere between novice and amateur.
My 94 griff 500 has developed an odd fault. unlock the car, key in the ignition, turn to on - all fine, except no power to the ECU. The engine cranks well, but as the ECU controls the fuel pump etc etc , it doesn't fire.
About 30 seconds after ignition on, the ECU light comes on, fuel pump primes and off we go. if, once the first ignition on eventually powers the ECU, I turn the car off and on again there is still a delay powering the ECU, but its shorter in duration 5-10 seconds, maybe less.
I have a Canems set up, so no relays in the loom specifically for fuel pump. I've had the stereo and vents out and found the alarm/immobiliser. I'm not that fussed to keep it because I have a battery brain I can trigger remotely, and a battery in the boot so pretty good immobilization options anyway
Any suggestions what tests I can run to see where the problem might be?
Can i bypass the system to just power the ECU whenever the i turn the ignition on?
Thanks in advance, appreciate this topic has been covered a few times on PH, but i cant find anything for Gemini rather than Meta
Dave,
Thank you so much for your reply and email, I have replied.
I will go and cross check my components against the list you supplied, reliability is key to me (and a big part of why I did the install in the first place) as this is my daily driver.
Further investigation last night and it appears the fault is not with the fuel pump, but with the power supply to the ECU. When I first turn the ignition on the ECU takes about 3 mins to get power. If I turn the ignition off and back on again, it take less, maybe 10-30 seconds to get power. If I then leave it a few hours the delay between switching the ignition on and the ECU getting power is back up to 2-3 mins.
Am I about to go on fire?!
Thank you so much for your reply and email, I have replied.
I will go and cross check my components against the list you supplied, reliability is key to me (and a big part of why I did the install in the first place) as this is my daily driver.
Further investigation last night and it appears the fault is not with the fuel pump, but with the power supply to the ECU. When I first turn the ignition on the ECU takes about 3 mins to get power. If I turn the ignition off and back on again, it take less, maybe 10-30 seconds to get power. If I then leave it a few hours the delay between switching the ignition on and the ECU getting power is back up to 2-3 mins.
Am I about to go on fire?!
If there was a place TVR would hide a relay for switching power to the ECU, where would they hide it?
In the garage at the minute and I have a red and white wire, plus earth, from the ignition barrel heading into a loom and disappearing down the footwell, door side.
The white wire has some damage and exposed wire, but I'll fix that and at the moment those areas are hanging in free space.
1.5v at the red wire with ignition off, white wire then gets 1.5v with ignition on (nothing when its off).
where to these wires normally reappear so I can test resistance/voltage drop?
Thanks
In the garage at the minute and I have a red and white wire, plus earth, from the ignition barrel heading into a loom and disappearing down the footwell, door side.
The white wire has some damage and exposed wire, but I'll fix that and at the moment those areas are hanging in free space.
1.5v at the red wire with ignition off, white wire then gets 1.5v with ignition on (nothing when its off).
where to these wires normally reappear so I can test resistance/voltage drop?
Thanks
There is also a panel, behind the dashboard itself with 4 relays on it. No mention of what these are in the handbook?
I also pull fuse number 2 from the fuse board which is supposedly "battery feed to ECU" and when turning on ignition still managed to, after the now usual delay, get power to the ECU.
I'm sure once I get started I'll figure it out, but following a loom behind the dash is impossible.
Do I need to take the dash out?!
I also pull fuse number 2 from the fuse board which is supposedly "battery feed to ECU" and when turning on ignition still managed to, after the now usual delay, get power to the ECU.
I'm sure once I get started I'll figure it out, but following a loom behind the dash is impossible.
Do I need to take the dash out?!
Thanks Penelope,
Yeah 1.5v seems low, my gauge in the dash says I have 12.5v. should that be the same at the ignition? Doesn't change when the ECU springs to life - I just figured there was a relay to switch the ECU power on when ignition was engaged.
Finding it is proving impossible - there is nothing I can see through the stereo slot in the dash, or the footwells, other than this mysterious panel of 4 relays?
thanks - I did say I was a novice!
Yeah 1.5v seems low, my gauge in the dash says I have 12.5v. should that be the same at the ignition? Doesn't change when the ECU springs to life - I just figured there was a relay to switch the ECU power on when ignition was engaged.
Finding it is proving impossible - there is nothing I can see through the stereo slot in the dash, or the footwells, other than this mysterious panel of 4 relays?
thanks - I did say I was a novice!
Evening chaps, been a week since my last update - work and family getting in the way...
Whale tail came off this evening to reveal not very much - I was hoping to find where the power supply to the ECU came from.
What I did discover though, is that the Gemini box does not control the power to the ECU. I pulled both connection plugs from it, turned the key, just in case, and suddenly there was power to the ECU!
So, main question from this - what else could be causing this weird, variable delay in the ECU seeing power?
Writing this, I also need to check if there is actually power delivered to the ECU when it comes on - could be an issue with the ECU itself maybe?
Whale tail came off this evening to reveal not very much - I was hoping to find where the power supply to the ECU came from.
What I did discover though, is that the Gemini box does not control the power to the ECU. I pulled both connection plugs from it, turned the key, just in case, and suddenly there was power to the ECU!
So, main question from this - what else could be causing this weird, variable delay in the ECU seeing power?
Writing this, I also need to check if there is actually power delivered to the ECU when it comes on - could be an issue with the ECU itself maybe?
Evening all,
Been exercising the multimeter again. I pulled the plug off the top of the ECU and linked a bit of wire from the plug power connection (3B?) to the multimeter, and earthed the other probe on the gearstick.
Ignition on and immediately I've got a voltage reading. No delay, instant voltage.
The voltage was low, about 6-8 volts, but I had some really dodgy connections between the plug and the meter and the earth so suffered a bit of drop there I'm sure.
So given I have power to the ECU plug, could the Canems be the problem itself? How would I know - take it off and feed it directly with 12v and see if the light comes on?
We are closing in on this issue - thanks for the advice
Chris
Been exercising the multimeter again. I pulled the plug off the top of the ECU and linked a bit of wire from the plug power connection (3B?) to the multimeter, and earthed the other probe on the gearstick.
Ignition on and immediately I've got a voltage reading. No delay, instant voltage.
The voltage was low, about 6-8 volts, but I had some really dodgy connections between the plug and the meter and the earth so suffered a bit of drop there I'm sure.
So given I have power to the ECU plug, could the Canems be the problem itself? How would I know - take it off and feed it directly with 12v and see if the light comes on?
We are closing in on this issue - thanks for the advice
Chris
More readings for you chaps...
So:
1. battery voltage was 12.2v (now on charge)
2. voltage at fuse 12 was 12.1v
3. voltage at pin 3B was 12.1v
connected the battery live to pin 3A and voltage was 12v
Am I safe to assume therefore that the ECU is getting the necessary juice and the earth is also good?
Does that then point to a faulty unit? or should I take it out and run 12v across 3a and 3b to see if it turns on immediately before jumping to that conclusion?
Other interesting findings. My gear knob is a terrible place to earth to - anything between 4 and 8 volts seen on the meter when using it as the earth. I had assumed it would be well earthed?
I also stuck a fuse in position 21. Nothing happened...yet...but there is 12v there. Manual just says "battery feed to ignition" so does this mean it's been bypassed if all was working ok without a fuse in it? either way putting the fuse in hasn't fixed my ECU issue.
Think this has me beaten
So:
1. battery voltage was 12.2v (now on charge)
2. voltage at fuse 12 was 12.1v
3. voltage at pin 3B was 12.1v
connected the battery live to pin 3A and voltage was 12v
Am I safe to assume therefore that the ECU is getting the necessary juice and the earth is also good?
Does that then point to a faulty unit? or should I take it out and run 12v across 3a and 3b to see if it turns on immediately before jumping to that conclusion?
Other interesting findings. My gear knob is a terrible place to earth to - anything between 4 and 8 volts seen on the meter when using it as the earth. I had assumed it would be well earthed?
I also stuck a fuse in position 21. Nothing happened...yet...but there is 12v there. Manual just says "battery feed to ignition" so does this mean it's been bypassed if all was working ok without a fuse in it? either way putting the fuse in hasn't fixed my ECU issue.
Think this has me beaten
Right, ECU out the car.
Made up a lead to connect 3a and 3b directly to spare battery.
The problem is the ECU.
Sat there watching the LED for 3 mins then on it came, exactly as it does in the car.
I'll take it up with the supplier from here. As you say Dave, it may be a faulty unit.
Shame as it has been perfect for 9 months. For once, maybe it isnt TVR wiring that's at fault!!
Made up a lead to connect 3a and 3b directly to spare battery.
The problem is the ECU.
Sat there watching the LED for 3 mins then on it came, exactly as it does in the car.
I'll take it up with the supplier from here. As you say Dave, it may be a faulty unit.
Shame as it has been perfect for 9 months. For once, maybe it isnt TVR wiring that's at fault!!
SOLVED!
Sent the unit back to the installer, who agreed it was some internal fault.
They sent the unit to Canems who found the problem, replaced the offending bit, reloaded my map and sent it back to me...all within 48 hours.
Very nice letter from the chap at Canems too, genuinely good bit of customer service.
Plugged it in and away we go!
All that remains, is to say thank you for all the advice. There is an incredible amount of knowledge out there and people who want to share it which ultimately will keep these wonderful machines on the road.
Chris
Sent the unit back to the installer, who agreed it was some internal fault.
They sent the unit to Canems who found the problem, replaced the offending bit, reloaded my map and sent it back to me...all within 48 hours.
Very nice letter from the chap at Canems too, genuinely good bit of customer service.
Plugged it in and away we go!
All that remains, is to say thank you for all the advice. There is an incredible amount of knowledge out there and people who want to share it which ultimately will keep these wonderful machines on the road.
Chris
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