Saxo VTR. Trouble starting when hot.

[SSaxo1978]

Hi all, first and foremost, Im 31.

I got hold of a Saxo VTR as a runaround but its developed a problem.

The car starts and runs fine from cold. It will run for as long as you like until you turn it off. Then it wont start for 10mins.

It just turns over and doesnt fire up. If left for 10mins, it starts straight away and again, runs for as long as you wish until switched off.

I've disconnected the immobiliser, changed the crank sensor, the coolant temp sensor, the coil pack and also ran a wire from the battery to the fuel pump but it still wont fire unless left for 10mins?


Anyone got any ideas or know anything else I can try tomorrow?

[CitroJim]

Hi all, first and foremost, Im 31.

Whilst I appreciate the median age for VTR ownership is 17 and three quarters, there's no shame in having a VTR at 31 you know. I had a 205GTi at 45..

Anyway, welcome to the forum

One of our neighbour's lad had a VTR with exactly this problem but it was very intermittent. It baffled me for a log time and I even ran a Lexia across it a couple of times with no conclusion. It happened off and on for ages and he sold the car/lost his licence before any firm conclusion was reached.

You've swapped all the obvious bits. It really only leaves the MAP sensor now. As yours is a pretty concrete fault, I'd be checking the there is a supply to the injectors and that thy do in fact "fire" when the fault is apparent. Also check you have a good, fat spark as well. If these tests pass then I'd swap the MAP sensor. If there is no life at the injectors or no spark then the first suspect is the double injection relay.

The fuel pump not running is a bit of a red herring as explained in your other thread. If there is pressure in the fuel rail, the engine will fire even if the pump is not running. As said, as soon as the ECU "sees" a running engine it'll fire up the pump...

[SSaxo1978]

Thanks for your reply.
I just didnt want anyone thinking I was young whippersnapper without having checked the obvious.
Its a good little car. Cheaper than running a 2.3 Impreza everyday.

I was on another site and posted the same questions and all I got was '' is there petrol in it'' and ''if its not starting, then its your starter motor''

I've had a read at the Haynes and everything seems to be pointing to the relay now. It seems there are two in the one case that control the fuel pump, ECU and all sensors.

I have heard it 'click' while under the bonnet after I've been trying to start it.

I'll open up the relay tomorrow and take note of the positions, run the car until the fault appears then have a look at the relay again.

Just out of interest, if I change the relay and the fault still persists, will an ECU change be next?

Its strange that it seems to be heat related. Or will the fault in the relay lie in the heat of the copper?

[CitroJim]

The relay has a few diodes inside but before trying to open it, check it is/is not being properly energised by the ECU when the fault is apparent before blaming the ECU...

Yes, two relays in one housing - hence it's name - "Double Injection Relay"

I've never opened one but they look a tad unfriendlily to open. Best to get another if this is the proved root cause. They're similar right across the range and scrappies will be full of 'em...

Replacing the ECU will be a load of grief due to the immobiliser... I hope and trust it is something external.

We'll always try to give sound advice here You'll never hear on here the kind of suggestions you've had from others... "Is there petrol in it.."

[SSaxo1978]

I opened the realy. Nothing visibly wrong.

Car started ok, ran it, turned it off, wouldnt start.

I opened the relay again and turned the ignition on and both are closing, car still wouldnt start.

I even taped them shut, reconnected the battery but the car still wouldnt start.

Looks like I'm on the lookout for an unlocked ECU

[SSaxo1978]

***UPDATE***


Fuel pump was at fault. Very low pressure.

A 2nd hand one from a scrappys did the trick.

[CitroJim]

Wow! Wonderful!

Normally a pump is a remarkably reliable bit of kit...

One to file away for future reference. Thanks for updating this thread with the solution