Still not starting
Discussion
So following on from my distributor replacement and subsequent intermittent start and run issues, My attention has turned to the fuel side as I have noticed that sometimes when I turn the ignition on the fuel pump does not run and then stop. If I turn the ignition on and off a dozen or so times then the pump will run and I can start the car for a few minutes until it dies. Then if I turn the ignition back on pump doesn’t run etc etc. Relay wise I have two silver Bosch relays in white connectors and one brown relay in a blue connector. I have replaced each to no effect. I have also undone the connections behind the passenger seat that go to the rear of the car and given them a good clean up with contact spray. I’m aware the immobiliser could be an issue plus I need to check the actual pump and connections. Can anyone think of anything else I should be looking at?
Cheers, Col
Cheers, Col
You need to go back to basics with a fault like this, if you suspect the fuel pump circuit then it needs to be tested.
A test lamp will be needed but you can rig one up using a headlamp bulb, something that will put a good load on the circuit and is also a helpful visual of what’s going on.
There is an inertia switch in the circuit which can usually be found under the glovebox/pouch drop down flap, but these rarely give problems.
A temporary rewire of the pump may also help you out just to eliminate the circuit as there are multiple joints in it.
A test lamp will be needed but you can rig one up using a headlamp bulb, something that will put a good load on the circuit and is also a helpful visual of what’s going on.
There is an inertia switch in the circuit which can usually be found under the glovebox/pouch drop down flap, but these rarely give problems.
A temporary rewire of the pump may also help you out just to eliminate the circuit as there are multiple joints in it.
Just beaten to it.
Start by fitting a separate power and earth direct to the pump. You can use a separate battery if that is more convenient.
You can then hear that the pump is running and staying running before you try and start the car. You can happily leave it running to check that it is not going to die, after all that is all it is doing if you go on a journey for many hours
Report back once you have completed this test.
Steve
Start by fitting a separate power and earth direct to the pump. You can use a separate battery if that is more convenient.
You can then hear that the pump is running and staying running before you try and start the car. You can happily leave it running to check that it is not going to die, after all that is all it is doing if you go on a journey for many hours
Report back once you have completed this test.
Steve
666 SVT said:
Thanks people, I’m hoping to try and get it up in the air at some point today or tomorrow and I have a large spare leisure battery I can power the pump directly from and take it from there depending on the results.
Col
Don't forget to add a correct rated inline fuse to the positive jumper cable between battery and pumpCol
Is it any easier to test at the relay ?
Penelope Stopit said:
........Is it any easier to test at the relay ?
Yes but several of the possible fault points are in the route from relay to pump.Having said that if,as you suggest, you first test at the relay you can further trace the fault forwards or backwards from that point.
So, identify the fuel pump relay as having the following wire colours. white/green, purple/white, blue/purple, 2x white/orange, white/purple, black.
The black and white/purple are from the same pin (87). With the relay removed apply +12v to to this contact on the relay base. If you are using a separate battery apply the negative to a good earth point on the car.
Steve
Steve_D said:
Yes but several of the possible fault points are in the route from relay to pump.
Having said that if,as you suggest, you first test at the relay you can further trace the fault forwards or backwards from that point.
So, identify the fuel pump relay as having the following wire colours. white/green, purple/white, blue/purple, 2x white/orange, white/purple, black.
The black and white/purple are from the same pin (87). With the relay removed apply +12v to to this contact on the relay base. If you are using a separate battery apply the negative to a good earth point on the car.
Steve
Right so I’ve just been out and located the pump relay as per your wire description (thanks) and I removed the relay and applied +12v to the base at pin 87 and the pump fired up straight away and continued running no problem? So am I correct in thinking that pin 30 supplies the +12v to the relay that should then come out at 87? If so does this positive feed come from the immobiliser or elsewhere? Getting there slowly now I think?Having said that if,as you suggest, you first test at the relay you can further trace the fault forwards or backwards from that point.
So, identify the fuel pump relay as having the following wire colours. white/green, purple/white, blue/purple, 2x white/orange, white/purple, black.
The black and white/purple are from the same pin (87). With the relay removed apply +12v to to this contact on the relay base. If you are using a separate battery apply the negative to a good earth point on the car.
Steve
Regards Col
There are two relays- when you turn on the ignition the "main" relay closes and supplies power to the fuel pump relay contacts. The pump relay coil is switched by the ecu, and supplies the fuel pump. You will hear the relays close at the same time as the ignition goes on, then the fuel pump relay should drop out after a few second if you dont start the engine. You can try swapping over the two relays as they are the same type and see if the symptoms change. If both relays are clicking away as they should its a good start. The covers will come of the relays if you want to have an eyeball at the internal contacts as they switch. The relays are not your normal 2 way ones, but switch two contacts at the same time.
blitzracing said:
There are two relays- when you turn on the ignition the "main" relay closes and supplies power to the fuel pump relay contacts. ........................
As we know there are a variety of electrical versions but all the ones I've seen the fuel pump supply does not come through the main relay it is from a permanent +12v at fuse 13.So the pump relay pinout is as follows..
pin 30, purple/white wire, perm +12v from F13
Pin 87, 2x white/orange, to Lambda sensors
Pin 87, Black wire to pump via immobiliser and inertia switch. Also white/purple to carbon canister purge valve.
Pin 86, white/green wire Ign switched +12v, F12 via immobiliser
Pin 85 Blue/purple, to ECU pin 16.
Main relay pinout is
pin 30, brown/light green wire, perm +12v from F2
Pin 87, brown/orange, to ECU pin 2, injectors, OBD
Pin 87, brown/orange, to MAF.
Pin 86, brown/orange wire perm +12v from F2 and also connects to ECU pin 15
Pin 85 Blue/red, to ECU pin 12.
Steve
Hi Col,
Common points of failure are:
1. The connector hidden behind the carpet flap behind the passenger seat
Unplug and spray with contact cleaner, re-plug and test
2. The spade connections at the fuel pump itself (+12v and ground)
Remove, clean up, re-fit and test
If this doesn't work do you still have an immobiliser?
It's important to understand the low amp trigger supplying terminal 86 on the fuel pump relay (blue socket) is supplied by the ECU, it's the ECU that runs the fuel pump for 3 seconds. The +12v supply for the ECU passes through the immobiliser, so if the path through the immobiliser has failed open circuit your ECU will not get its +12v supply, the ECU therefore will fail to trigger the fuel pump relay.
Immobiliser issues on Chimaeras and Griffiths are common because TVR wired the two immobilised circuits (starter solenoid & ECU) back to front, normally the problem manifests itself as a failure to crank although it's not uncommon for the issue to appear on the ECU circuit too. The Meta security system is made up of of an alarm control unit and a separate immobiliser unit, these two boxes are paired together, being 20+ year old 1990's Italian electronics they are not that reliable and the way TVR wired the system made things even worse.
I recommend completing the following two simple tests at the fuel pump relay itself:
3. Use a test meter to prove/disprove the presence of +12v at terminal 86 of the fuel pump relay, disengage the immobiliser and switch the ignition key to position one, use the battery as your ground for on your multimeter, your meter should show battery voltage for 3 seconds
If you fail to see +12v your ECU is not triggering the fuel pump relay, this is likely a blown ECU fuse in the fuse board (check your manual for fuse board diagram) or an issue with your immobiliser.
4. If you do have +12v, now put your ground multimeter probe on terminal 85 rather than the battery and repeat the test
If +12v is not present you have a ground issue, make a new temporary ground fly lead from terminal 85 to your battery negaitive terminal and re-test
Follow the above four steps systematically and you should find your fault.
Kind regards,
Dave.
NB: If you provide a direct +12v from the battery positive terminal to terminal 86 on the fuel pump relay, then supply terminal 85 with a reliable ground from the battery negative terminal, you should hear the fuel pump run permanently. This is a good quick way to test your wiring back to the fuel pump, if you do get the fuel pump to run this way you do now need to trace why the ECU is not triggering the fuel pump relay itself? The most likely reason is the ECU isn't getting it's +12v, and the most likely reasons for that are a blown ECU fuse in the fuse board, or the relay inside the immobiliser has failed
Common points of failure are:
1. The connector hidden behind the carpet flap behind the passenger seat
Unplug and spray with contact cleaner, re-plug and test
2. The spade connections at the fuel pump itself (+12v and ground)
Remove, clean up, re-fit and test
If this doesn't work do you still have an immobiliser?
It's important to understand the low amp trigger supplying terminal 86 on the fuel pump relay (blue socket) is supplied by the ECU, it's the ECU that runs the fuel pump for 3 seconds. The +12v supply for the ECU passes through the immobiliser, so if the path through the immobiliser has failed open circuit your ECU will not get its +12v supply, the ECU therefore will fail to trigger the fuel pump relay.
Immobiliser issues on Chimaeras and Griffiths are common because TVR wired the two immobilised circuits (starter solenoid & ECU) back to front, normally the problem manifests itself as a failure to crank although it's not uncommon for the issue to appear on the ECU circuit too. The Meta security system is made up of of an alarm control unit and a separate immobiliser unit, these two boxes are paired together, being 20+ year old 1990's Italian electronics they are not that reliable and the way TVR wired the system made things even worse.
I recommend completing the following two simple tests at the fuel pump relay itself:
3. Use a test meter to prove/disprove the presence of +12v at terminal 86 of the fuel pump relay, disengage the immobiliser and switch the ignition key to position one, use the battery as your ground for on your multimeter, your meter should show battery voltage for 3 seconds
If you fail to see +12v your ECU is not triggering the fuel pump relay, this is likely a blown ECU fuse in the fuse board (check your manual for fuse board diagram) or an issue with your immobiliser.
4. If you do have +12v, now put your ground multimeter probe on terminal 85 rather than the battery and repeat the test
If +12v is not present you have a ground issue, make a new temporary ground fly lead from terminal 85 to your battery negaitive terminal and re-test
Follow the above four steps systematically and you should find your fault.
Kind regards,
Dave.
NB: If you provide a direct +12v from the battery positive terminal to terminal 86 on the fuel pump relay, then supply terminal 85 with a reliable ground from the battery negative terminal, you should hear the fuel pump run permanently. This is a good quick way to test your wiring back to the fuel pump, if you do get the fuel pump to run this way you do now need to trace why the ECU is not triggering the fuel pump relay itself? The most likely reason is the ECU isn't getting it's +12v, and the most likely reasons for that are a blown ECU fuse in the fuse board, or the relay inside the immobiliser has failed
666 SVT said:
I’ll root about for a wiring diagram and try and find out what voltages should be on that relay base and where they come from, Then I can test it with the meter. Probably be Sunday now before I get the chance.
Col
Has car standard ECU?Col
Have you found a decent diagram?
Would be a pain to be testing through circuits, finding possible faults then find circuits not standard
ChimpOnGas said:
Hi Col,
Common points of failure are:
1. The connector hidden behind the carpet flap behind the passenger seat
Unplug and spray with contact cleaner, re-plug and test
2. The spade connections at the fuel pump itself (+12v and ground)
Remove, clean up, re-fit and test
If this doesn't work do you still have an immobiliser?
It's important to understand the low amp trigger supplying terminal 86 on the fuel pump relay (blue socket) is supplied by the ECU, it's the ECU that runs the fuel pump for 3 seconds. The +12v supply for the ECU passes through the immobiliser, so if the path through the immobiliser has failed open circuit your ECU will not get its +12v supply, the ECU therefore will fail to trigger the fuel pump relay.
Immobiliser issues on Chimaeras and Griffiths are common because TVR wired the two immobilised circuits (starter solenoid & ECU) back to front, normally the problem manifests itself as a failure to crank although it's not uncommon for the issue to appear on the ECU circuit too. The Meta security system is made up of of an alarm control unit and a separate immobiliser unit, these two boxes are paired together, being 20+ year old 1990's Italian electronics they are not that reliable and the way TVR wired the system made things even worse.
I recommend completing the following two simple tests at the fuel pump relay itself:
3. Use a test meter to prove/disprove the presence of +12v at terminal 86 of the fuel pump relay, disengage the immobiliser and switch the ignition key to position one, use the battery as your ground for on your multimeter, your meter should show battery voltage for 3 seconds
If you fail to see +12v your ECU is not triggering the fuel pump relay, this is likely a blown ECU fuse in the fuse board (check your manual for fuse board diagram) or an issue with your immobiliser.
4. If you do have +12v, now put your ground multimeter probe on terminal 85 rather than the battery and repeat the test
If +12v is not present you have a ground issue, make a new temporary ground fly lead from terminal 85 to your battery negaitive terminal and re-test
Follow the above four steps systematically and you should find your fault.
Kind regards,
Dave.
NB: If you provide a direct +12v from the battery positive terminal to terminal 86 on the fuel pump relay, then supply terminal 85 with a reliable ground from the battery negative terminal, you should hear the fuel pump run permanently. This is a good quick way to test your wiring back to the fuel pump, if you do get the fuel pump to run this way you do now need to trace why the ECU is not triggering the fuel pump relay itself? The most likely reason is the ECU isn't getting it's +12v, and the most likely reasons for that are a blown ECU fuse in the fuse board, or the relay inside the immobiliser has failed
Sorry Dave your test at 3 is not correct.Common points of failure are:
1. The connector hidden behind the carpet flap behind the passenger seat
Unplug and spray with contact cleaner, re-plug and test
2. The spade connections at the fuel pump itself (+12v and ground)
Remove, clean up, re-fit and test
If this doesn't work do you still have an immobiliser?
It's important to understand the low amp trigger supplying terminal 86 on the fuel pump relay (blue socket) is supplied by the ECU, it's the ECU that runs the fuel pump for 3 seconds. The +12v supply for the ECU passes through the immobiliser, so if the path through the immobiliser has failed open circuit your ECU will not get its +12v supply, the ECU therefore will fail to trigger the fuel pump relay.
Immobiliser issues on Chimaeras and Griffiths are common because TVR wired the two immobilised circuits (starter solenoid & ECU) back to front, normally the problem manifests itself as a failure to crank although it's not uncommon for the issue to appear on the ECU circuit too. The Meta security system is made up of of an alarm control unit and a separate immobiliser unit, these two boxes are paired together, being 20+ year old 1990's Italian electronics they are not that reliable and the way TVR wired the system made things even worse.
I recommend completing the following two simple tests at the fuel pump relay itself:
3. Use a test meter to prove/disprove the presence of +12v at terminal 86 of the fuel pump relay, disengage the immobiliser and switch the ignition key to position one, use the battery as your ground for on your multimeter, your meter should show battery voltage for 3 seconds
If you fail to see +12v your ECU is not triggering the fuel pump relay, this is likely a blown ECU fuse in the fuse board (check your manual for fuse board diagram) or an issue with your immobiliser.
4. If you do have +12v, now put your ground multimeter probe on terminal 85 rather than the battery and repeat the test
If +12v is not present you have a ground issue, make a new temporary ground fly lead from terminal 85 to your battery negaitive terminal and re-test
Follow the above four steps systematically and you should find your fault.
Kind regards,
Dave.
NB: If you provide a direct +12v from the battery positive terminal to terminal 86 on the fuel pump relay, then supply terminal 85 with a reliable ground from the battery negative terminal, you should hear the fuel pump run permanently. This is a good quick way to test your wiring back to the fuel pump, if you do get the fuel pump to run this way you do now need to trace why the ECU is not triggering the fuel pump relay itself? The most likely reason is the ECU isn't getting it's +12v, and the most likely reasons for that are a blown ECU fuse in the fuse board, or the relay inside the immobiliser has failed
Pin 86 is an ignition switched supply via F15 and the immobiliser so should stay live not go off after 3 seconds.
The next test 4 going from 86 to 85 should produce the 3 second pulse.
Steve
Thanks guys, lots of good information to try tomorrow when I get the chance. To answer a couple of questions people have asked, The car still has the Lucas 14CUX ECU with a non standard map and five position resistor switch for the different fuel maps. I have also tried another ECU which made no difference. The car is a 95 but is factory non cat as it was supplied to Southern Ireland from new so no Lambda sensors to worry about off the fuel pump relay. As the pump worked fine with the +12v supplied from the battery direct to the fuel pump relay base pin 87 I can now assume the wiring to the pump and the pump itself is fine. Hopefully tomorrow going through the aforementioned tests will prove fruitful and I can get her up and running again?
Thanks again.
Col
P.S. Steve I’ve sent you a PM for those diagrams
Thanks again.
Col
P.S. Steve I’ve sent you a PM for those diagrams
Your next piece of homework then is to probe pin 86 compared to a good earth. kill immobiliser and turn on ignition which should give you +12v.
If OK then turn off and again connect your meter across pin 86 and pin 85. When you again kill the immobiliser and switch on the ignition you should get +12v for about 3 seconds.
If OK then when the pump has stopped go straight to cranking the engine and you should get your +12v back. This will be proving a number of things like the ECU is getting power, the ECU is switching and asking for fuel, It is proving that the ECU is seeing an ignition spark signal.
Last test for now is put the relay back in and connect meter between the back of pin 87 and a good earth and do the same tests.
Report back and we will mark your work.
Steve
If OK then turn off and again connect your meter across pin 86 and pin 85. When you again kill the immobiliser and switch on the ignition you should get +12v for about 3 seconds.
If OK then when the pump has stopped go straight to cranking the engine and you should get your +12v back. This will be proving a number of things like the ECU is getting power, the ECU is switching and asking for fuel, It is proving that the ECU is seeing an ignition spark signal.
Last test for now is put the relay back in and connect meter between the back of pin 87 and a good earth and do the same tests.
Report back and we will mark your work.
Steve
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