Engine Cutting Out (immobiliser i think)

[chassis 33]

The Chim has cut out on me 3 times in the past week, all under similar circumstances...so its story time with Iain...

Start the car, drive for maybe 2mins everything is fine, engine cuts, no splutter just dead. Try cranking it over, occasionally fires once on the starter but nothing otherwise.

The first 2 times, i parked up, opened the bonnet wiggled (engine) bits about, cranked, wiggled some more, checked for a spark, etc etc eventually fires and runs as if nothing had happened.

This afternoon, the same thing happened, except instead of getting out of the car just try cranking a coplue of times, and i noticed the alarm LED in the centre of the dash flashing...pressed the remote twice to set and unset the alarm, everything runs.

The questions are, can a normally functioning immobiliser only partially immobilise the engine, ie the ignition circuit, cos my understanding is that it stops the starter too? If thats isnt the case if could be an immobiliser fault, if not its could be any number of electrical faults.

Also if it isnt too much of an emotive subject, where is the immobiliser kept, and canit be permanently disabled? Probably best not post that on on the forum, please contact me though. The immobiliser and alarm are getting ripped out as I prep the car for the track over the winter, but until then i still need to use the car!

Its a 95 M'plate with the later chassis and a serp. engine if that makes a difference.

Regards
Iain

[Graham]

ok then first things to check.


when you first start the car listen for the fuel pump to prime then stop. it primes for a bout 5 seonds to get the fuel rail upto pressure.


then go for a drive.


when it stops, turn ignition off then back on again. do you hear the fuel pump prime. if you do its not fuel pump/imobaliser problem look elsewhere.

if the pump doesnt prime, then remove the ecu access panel in the passenger footwell ( the ecu and wiring will then probably fall on the floor)

find the 2 relays.

when you trn the ignition on do they both click. one ( the black connector i think) should just click on, the other ( blue connector) should click on ( you should here the fuel pump priming) and then off ( the fuel pump should stop)

If the relays are working fine, then the problem is probably a corroded conector onthe fuel pump ( in front of the nearside rear wheel)

if the relays dont click then its the imobaliser, or possibly a relay issue


you can swap the relays to test as they are both the same


try that
G

[david beer]

My immobiliser would cut out the ignition only, usually when the dash was hot. There are three seperate circuits, the other two being the starter solenoid and fuel pump. Yes they can be over ridden, i had to do mine on a country lane.

[tvr+bubblecar]

Graham - Good advice - my similar problem last week was the connector at the fuel pump

Good luck
Chris

[chassis 33]

Cheers for the replies, the thing that gets me is that it happens after a similar period of time, shortly after starting and (so far at no other time), which to me is something a little more sinister than a failing relay or bad connector.

I'll try to take more note of what runs and doesnt run next time.

Regards
Iain

[GreenV8S]

Lots of good suggestions so far, also check the plug between the ignition switch and the main vehicle loom, under the steering column cowling. Sometimes these can overheat and corrode, causing intermittant power loss which resets the immobiliser.

[the dodger]

Mine was caused by pitted/corroded contacts at the ignition module on the side of the dizzy. This caused random, intermitant cutting out but also random intermitant firing up again! Connector contacts replaced in the socket (by the alarm specialist I had called thinking it was the imobiliser) and all OK since (2 yrs).

[z_chromozone]

Graham said:

ok then first things to check. when you first start the car listen for the fuel pump to prime then stop. it primes for a bout 5 seonds to get the fuel rail upto pressure. then go for a drive. when it stops, turn ignition off then back on again. do you hear the fuel pump prime. if you do its not fuel pump/imobaliser problem look elsewhere. if the pump doesnt prime, then remove the ecu access panel in the passenger footwell ( the ecu and wiring will then probably fall on the floor) find the 2 relays. when you trn the ignition on do they both click. one ( the black connector i think) should just click on, the other ( blue connector) should click on ( you should here the fuel pump priming) and then off ( the fuel pump should stop) If the relays are working fine, then the problem is probably a corroded conector onthe fuel pump ( in front of the nearside rear wheel) if the relays dont click then its the imobaliser, or possibly a relay issue you can swap the relays to test as they are both the same try that G

The inner workings of one of my relays had come apart resulting in a piece of insulation getting in the way of the contacts. I gave it a shake and it fell out with the top off, I have never had another problem.

Z