Broken down possibly ignition

[jeremy 68]

Basically the car will fire up and run/rev when the ignition key is in the starting position, but the minute you let go of the key the car just dies. Help greatfully appreciated.

[welshpug 1,621]

yep, sounds like the ignition switch has burnt out its contacts, you'll need to hotwire it or replace the ignition switch.

[Anthony 1,000]

Assuming this is an 8v, it could be the tachymetric relay that's failing.

 

The relay is switched in two ways - when there's voltage on the starter solenoid wire, and from the ignition coil pulse.  Possibly it's working on the former but not the later, which would explain why it runs while the key is held in start.

 

Easy way to temporarily bypass the relay and prove the issue is to use a length of wire to join the three thick wires (one brown, two white) to power the fuel pump and injectors constantly and then start the engine.  If it then runs normally, it'll be a relay or wiring issue.  Remember to unplug it after testing otherwise it'll flatten the battery.

[jeremy 68]

Thanks for both replies. Yes it is an 8v. Anthony are you talking about the wires coming from the ignition barrel or at the tachymetric relay. Reason I ask is these are the wires I have coming the ignition going to two separate plug connectors.

First plug yellow, orange, white x2

Connected to red, tan, light green, and light blue.

Second plug two white one connected to yellow the other to red

These are easy to get to so didn't want to get to the tachymetric relay unless I have to. Thanks

[jeremy 68]

Ok I've had a prod around and discovered the wires Anthony at the tachymetric relay. What can I say other than the beer is going to you. I just bridge them with a bit of wire whilst keeping the relay connected and she ran like a dream. Thank you so much. 

[Anthony 1,000]

Good show Replace the relay and hopefully that'll fix it - most faults like this are down to the relay but I have seen instances where the loom is breaking down and causes it (wiggling the loom in the right place usually makes it run again briefly if so)

[jeremy 68]

Already wriggle the loom and it didn't make any difference. This may sound daft but I assume the brown wire was a live feed into the relay and the white ones out. Just to clarify that I was bridging the relay with live feeds as opposed to providing additional live feeds to the relay to compensate for a faulty sensors some where else in the car. Sorry to ask so much.

[welshpug 1,621]

yes the brown wire is a permanent live from the shunt box.

[jeremy 68]

Yes but should the white wires be sending a live to the relay or from the relay?

[jeremy 68]

Half way there. One new relay installed, the car will run but not idle as you need to keep your foot on the gas and no revs showing on the counter, any suggestions?

[jackherer 543]

Check the fuses in the glovebox, there is one that covers items including the rev counter.

[jeremy 68]

Where I'm at.... my general consensus is that either a wire or sensor is at fault. My understanding is that the tachemetric relay keeps supplying a live feed to both the fuel pump and injectors when the car is running this it does by receiving signals from various sensors located off the engine/fly wheel. As the rev counter is not receiving a signal either then the tachemetric relay assumes the engine has stopped so the relay stops sending an output, however If I keep my foot on the accelerator I guess at about 1000tpm then all is ok.

Although I have had a thought does the airflow meter send a signal when the accelerator is not pressed acknowledging it is idling?

[jeremy 68]

Problem solved a lead on the coil had come off.

[welshpug 1,621]

that would do it!