Help Starting problem on a V6

[Rangers1]

Hi have posted this before and was advised to change the CTS Sensor however this hasn't solved my problem.

I have a 1996 V6, which from cold starts okay. However after running or driving the car for more than 5 minutes it will refuse to start.

The strange thing is the car will start imeadeatly after running the engine however if it leave it more than 3 to 5 mins thats when the problems occur.

The starter motor turns over fine however the car simply won't start, only after prolonged turning of the ignition then suddently the car will start straight away (without spluttering etc).

The cars been to Vauxhall 3 times ( the fault never occurs when it there) There is no fault codes showing on the ECU apart from the fuel tank sensor which reads
<!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo--><!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto-->167 Tank sensor voltage low, short circuit and subsequently the fuel gauge does'nt work. <!--fontc--></span><!--/fontc--><!--sizec--></span><!--/sizec-->
<!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo--><!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto-->[/font]<!--sizec--></span><!--/sizec-->
<!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo-->[font=Times New Roman]I'm at a complete loss what to do as the problem is becoming so frequent its making the car impractical to use.<!--fontc--></span><!--/fontc--><!--sizec--></span><!--/sizec-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo-->[/size]<!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo-->To date I have changed;<!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo-->Battery, Fuel pump relay, alternator and the CTS sensor.<!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo--><!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo-->When driving the car it don't notice any problem power loss etc, the only thing that might be related is I notice the engine temperature on the dash never moves even on long journeys. However this hasn't been picked as an problem by Vauxhall.<!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto--><!--sizeo:3--><span style="font-size:12pt;line-height:100%"><!--/sizeo--><!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->
<!--fonto:Times New Roman--><span style="font-family:Times New Roman"><!--/fonto-->[size=3]I would be very grateful for any help.<!--sizec--></span><!--/sizec--><!--fontc--></span><!--/fontc-->

[Dan Willis]

I had something similar in my V6 Cav.. turned out to be the imobiliser. Odd I thought.

Other than that it sounds like something is expanding with heat - what, I don't know.

[Stupink]

When its not starting, have you done any basic tests to see why its not starting... spark/fuel etc etc. if it suddenly starts fine, it does sound an electrical gremlin.
But I dunnoooo owt about the v6.
the fuel relay and the cts you replaced with new parts i presume?

[Rangers1]

All parts where brand new and fitted by vauxhall. The fuel pump appears to be working as I can hear it outside of the car.

I'm intrested in the thought being the imobiliser as it currently doesn't work the drivers lock is worn despite the central locking working as the electric windows don't close when they are left open. However they do on the passenger side. I was looking at getting this fixed however haven't had time to sort this out yet. The other point which I didn't mention was the engine appears to start when I open the bonnet. This doesn't happen every time. Could this also indicate the problem being related to the imobiliser?

[Dan Willis]

Well mine was just peculiar. It even spent a week with an alarm specialist who, on the Friday, announced they'd fixed it. Only for me to drive a mile up the road - and die. lol.

It could well be the immobilser... but I really don't know to be honest. It's certainly worth ruling out.

[trev150]

This sounds very much like my old mk3 cav (C20XE).

It would do exactly the same as you have said above. When it plays up next make sure that you are getting voltage at the starter motor.
If you are not getting a voltage but you can hear the fuel pump running i would suggest that you bump start the car.
If it will bump start it would indicate that your immobiliser is not working.
Immobilisers work by isolating the two circuits needed to start the car.
These are

1. Fuel Pump
2. Starter Motor

Most immobilisers have the outputs (the 2 circuits) on relays. With time and use these relays give up.
All i did was to follow the feed from the starter back and found where it was intercepted and just simply linked it out and by-passed that channel. It was still immobilised but only on one channel.


Hope this helps cos it drove me crazy at the time.


Trev

[dicky]

It sounds like a spark plug problem to me.

First of all take a plug out when it refuses to start and look to see if a healthy spark is generated or if at all.

When did u last have the plugs changed?

Try to get a hotter plug usually just alternatives when u look in manuals at say halfords but actually have a different temp range than standard plugs, or could be other way round and try standard plugs.