Could it be the Vecta?

[philwaters]

Hi,

 

Been having a very intermittent problem with my x/flow. It doesn't matter if it is hot or cold, wet or dry or how long its been running.

Basically it will just cut out on me, typically when changing gear or holding steady rpm (i.e. not under acceleration - yet). I coast to the side of the road and try to start it and it just turns over with no hint of a spark at all. I then get out the car, curse and smile at the people in their reliable cars. Wait about 2 minutes, climb back in the car and it starts first time, nothing having changed.

 

The cut out is far to fast to be connected with fuel starvation and the in-line filter shows the supply is there. I am assuming that it must be electrical.

Having such a simple system with no real ECU etc, I'm at a loss as to what to check. This is made worse by the fact that up until yesterday morning it hadn't done it since May! It fixes itself so quickly that you can't get the bonnet off in time to test anything.

I am now beginning to wonder if it might be the Vecta playing up. Does anyone know what circuits this acts on on a x/flow car and how easy it is to bypass. If I don't de-accitvate it it won't turn over so one circuit is the starter/solidnoid, any others? I am thinking that I could put a hidden by-pass switch on the car so that if/when it does it again I can flick a switch and see if it restarts straight away.

 

Or does anyone have an other possible ideas?

 

 

 

Phil Waters

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[Chairman Roger]

Phil

 

Sounds like a classic Vecta problem. I had exactly the same on my VX and it finally dumped my on the roadside in France. The Vecta unit is a black cylindrical tube about 2" dia and 5" long (usually under the dash) which is stuffed full of electronics and then "potted" in resin. Because of differing rates of expansion between the various mediums used, fractures can occur inside the potted unit. When the unit warms up a connection is broken and when it cools the conection is remade.

 

Remove the Vecta !

 

You can do it yourself if you are careful and look at which wires have been broken in to but it is not a quick job.

 

Roger

[philwaters]

Thanks Roger,

 

The Vecta isn't cutting out and returning to the flashing red light when the engine cuts out, which is why I posted the question. It stays green as if all is well. Is it possible that the vecta can be in the 'happy' state and still be cutting off a circuit somewhere?

Also, I presume that the initial damage is caused by the heating and cooling of the unit over time. I have found that it does not seem to matter what the conditions are like for it to fail. The haggis trip was very hot and it did it there whilst yesterday morning was overcast and drizzling.

 

Phil Waters

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[Chairman Roger]

Phil

 

Remove the Vecta anyway. Even if it is not the cause of your present problem (and I'll bet it is) it will let you down eventualy !

 

R

[stevefoster]

I am pretty sure my Vecta is only operating on the starter soleniod hot wire! So it's effectiveness can be questioned....

The fuel pump, ignition and ECU all get power separately.. did I miss anything needed for a carb'd engine?

 

One day I will get around to hot wiring the solenoid to prove this. Probably at the roadside when stranded....

 

[Chelspeed]

My Vecta was originally wired to cut power to the coil +ve and the starter solenoid. Check this by putting ignition with vecta dead (red light flashing) check for 12V at coil +ve (ie the side of the coil not connected to the contact breakers). Then arm the vecta (green light) and recheck it.

 

If your's is wired like this then rig up a second 12V supply to the coil +ve via your hidden switch to see if it's this causing the problem.

[philwaters]

Thanks Chelspeed,

 

I'll check that when next out to have a tinker.

 

 

Phil Waters

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[domster]

Just a thought, but try changing the coil (with another xflow nearby?) and take it for a spin.

 

You may find that the coil is breaking down when it gets hot, and then cooling to allow you to restart.

 

Rgds

Dom

[Pierson Broome]

Hi Phil - how are you doing?

 

On a similar theme to the coil breakdown, I've seen a newly-installed 3D-mapping unit interfere electrically with the coil due to it's proximity, causing it to breakdown and hence cease provision of a spark. Relocation of the unit cured the problem.

 

You haven't had any such upgrades or similar perhaps, have you? Just a thought.

 

Pierson

[philwaters]

Hi guys,

 

I haven't added anything to the car electically that has co-incided with the problems. I do have a friends old coil so I could swap that over and run that for a while or carry it with me so I can swap it when it conks out on me next. The trouble is that may be in another 3 months time - it is so intermittent. Also, by the time I get the bonnet off, it starts first time anyway so I wouldn't know if it was the swapped coil helping or not.

 

I will check to see if the Vecta operates on that circuit, make up a by-pass for it and also carry the spare coil. If I get the money together for my planned engine change then hopefuly the problem will disappear.

 

Thanks for all your help.

 

Phil Waters

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