Voltage to Cold Start Valve Plug question

[mike65]

My cold start enrichment valve seems to have stopped working, I unplugged it this morning and the start up was the same as with it plugged in. So question is how to I check if the plug is getting current, I have a standard multimetre I just don't know how to use with confidence!

Should run the black lead to the plug pins (there are two) and the red to the battery positive terminal? And check the voltage (12.5v I think)?

This may be a very simple problem to solve but I need help!

Mike.

 

[Myros]

is it going to be needed in this weather?

Mike, might it just be out of its operating range. I'm reading 29.9 celsius here.

 

[mike65]

Its very hot I know, but the starting is poor since whatever happened, happened. I'm not sure I can blame the weather for this.

I went out to try and check, there are two contact pins in the plug one gave 12.58v the other 0v, I then measured the pin wires from the back of the plug (theres a handy tear in the rubber) and they both read 12.58 v. So i'm now wondering if the plug itself is broken. Pity its so ****** hot out there I cant be arsed to cut the rubber away and start fiddling with the plug assembly.

Mike.

 

[TimN]

Isn't the supply thread through the cold start valve and then earthed by a temporature sensor. Therefore if you remove the plug from the sensor and earth it directly it should start okay. If it does then it isn't the valve it is the sensor that is faulty.

 

[mike65]

The water (engine) temp sensor was replaced only last year and all the symptoms which came with the old sensor (bad starting hot or cold/cronic idling etc) are not presnt this time. Its just the hard start on cold engine otherwise it runs fine.

I'm sure there should be current to both plug pins I'll try a few things tomorrow...I hate auto electrics.

Mike.

 

[paulcallender]

There's current for 3-4 seconds during startup.

It is a useful test to remove the cold start valve and observe it working. You can remove it, then reconnect the electrical and fuel connections, sit in the car and check for electrical operation, fuel delivery and spray pattern all in the one check. Top tip: de-energise the ignition, so the car doesn't inadvertently start. Also, ensure there are no ignition sources. Your successful test would produce a quantity of finely atomised, easy to ignite fuel.

When I had start problems I had the bonnet off, which made it easy to see. You might need an assistant, or arrange to view it through a gap or underneath the bonnet.

 

[mike65]

Further to my checking, I was wrong about the wires going into the plug, one is dead - thats definite. So I have a broken wire which is purhaps not surprising, 15 years of under bonnet heat must take its toll and I has been moving the wiring loom about just before this problem occurred.

Mike.