Cut out and non start - have you seen this before
Discussion
Hello Gentlemen,
Has anyone seen this before?
https://youtu.be/c1OgsyZOrFQ
https://youtu.be/pN8ZghPAQE4
My car has been playing up recently and has cut out a few times and normally restarted straight away but a couple of weeks ago it cut out several times at roundabouts but restarted again and after filling up with fuel it wouldn't restart, it was turning over but not firing, but instead was making a buzzing noise and the rev counter was flipping back and forth at the same time while the ignition was on as in the above videos. I called the RAC and the chap seemed to think it was a crank sensor but after doing some research he discovered it didn't have a crank sensor but believed there is a sensor in the distributor? He disconnected the large rectangular black multiplug next to the ignition coil and reconnected it and the buzzing stopped and so did the rev counter but could of been a coincidence. He eventually got it started as it was flooded after several previous attempts to start it, drove it home and to my specialist the next day and it hasn't cut out since, recently it has been struggling to idle properly as it hunts for a few seconds before coming to a smooth idle, has recently had a new stepper motor but could be another issue. Has anyone ever experienced the above? My specialist has never seen this before and at the moment it's not cutting out which is typical and making it hard to diagnose the fault, any help would be much appreciated, thank you!
Has anyone seen this before?
https://youtu.be/c1OgsyZOrFQ
https://youtu.be/pN8ZghPAQE4
My car has been playing up recently and has cut out a few times and normally restarted straight away but a couple of weeks ago it cut out several times at roundabouts but restarted again and after filling up with fuel it wouldn't restart, it was turning over but not firing, but instead was making a buzzing noise and the rev counter was flipping back and forth at the same time while the ignition was on as in the above videos. I called the RAC and the chap seemed to think it was a crank sensor but after doing some research he discovered it didn't have a crank sensor but believed there is a sensor in the distributor? He disconnected the large rectangular black multiplug next to the ignition coil and reconnected it and the buzzing stopped and so did the rev counter but could of been a coincidence. He eventually got it started as it was flooded after several previous attempts to start it, drove it home and to my specialist the next day and it hasn't cut out since, recently it has been struggling to idle properly as it hunts for a few seconds before coming to a smooth idle, has recently had a new stepper motor but could be another issue. Has anyone ever experienced the above? My specialist has never seen this before and at the moment it's not cutting out which is typical and making it hard to diagnose the fault, any help would be much appreciated, thank you!
That buzzing noise is odd, it's also very regular and almost sounds like it could only come from some sort of speaker?
Are you sure its not coming from your alarm siren, does your siren work?
If the siren is sick you could just be hearing it making a muffled buzzing noise in the same rhythm it would if it was screaming properly? Just a guess really as the noise is very odd indeed, I can't think of much else in the engine bay area other than a sickly siren that might potentially make such a consistent regular electronic buzz sound like that?
The only other thing I'd add is the rev counter shows engine speed by taking a pulse signal from the distributor, the ECU also needs this signal to run the fuel pump consistently beyond the short priming pulse you hear when you first turn the ignition on and disengage the immobiliser. The rev counter therefore sees the engine speed pulse after its first passed through ECU.
The immobiliser itself interrupts two circuits, the feed to the starter motor solenoid and the ECU, so if the immobiliser was faulty it could be switching the ECU on and off which would have the effect of the rev counter pulsing up and down as in your video, now with the immobiliser and alarm units paired it could be it's activating the siren too which if sickly could make a muted electrical buzz rather than the scream you'd expect.
It's all just a guess mind
Are you sure its not coming from your alarm siren, does your siren work?
If the siren is sick you could just be hearing it making a muffled buzzing noise in the same rhythm it would if it was screaming properly? Just a guess really as the noise is very odd indeed, I can't think of much else in the engine bay area other than a sickly siren that might potentially make such a consistent regular electronic buzz sound like that?
The only other thing I'd add is the rev counter shows engine speed by taking a pulse signal from the distributor, the ECU also needs this signal to run the fuel pump consistently beyond the short priming pulse you hear when you first turn the ignition on and disengage the immobiliser. The rev counter therefore sees the engine speed pulse after its first passed through ECU.
The immobiliser itself interrupts two circuits, the feed to the starter motor solenoid and the ECU, so if the immobiliser was faulty it could be switching the ECU on and off which would have the effect of the rev counter pulsing up and down as in your video, now with the immobiliser and alarm units paired it could be it's activating the siren too which if sickly could make a muted electrical buzz rather than the scream you'd expect.
It's all just a guess mind
The noise appears to be coming out of that relay strapped to the loom (maybe a make shift hot start mod) should not be buzzing either but who knows what owners do to these cars and how? could be a failing ignition module causing your running problem but from over here who can tell? Oh I get it now that relay appears to be connected to your tacho looking at that second vid WTF is going on there? someones been playing 
I would try to get a savvy owner that lives near by to have a looksie most are an helpful bunch
but who knows what owners do to these cars and how? could be a failing ignition module causing your running problem but from over here who can tell? Oh I get it now that relay appears to be connected to your tacho looking at that second vid WTF is going on there? someones been playing I would try to get a savvy owner that lives near by to have a looksie most are an helpful bunch Edited by Sardonicus on Thursday 24th November 14:05
I had the whole hunting, cutting out at roundabouts and junctions on my S previously and not starting up for a few minutes after cutting out....intermittently.
I found a leak on vac advance and bad connections to the tacho.
Alarm / immobiliser could also be playing up as others have said.
I've had buzzing from relays when the battery has not been great.
I found a leak on vac advance and bad connections to the tacho.
Alarm / immobiliser could also be playing up as others have said.
I've had buzzing from relays when the battery has not been great.
Sardonicus said:
Oh I get it now that relay appears to be connected to your tacho looking at that second vid WTF is going on there? someones been playing
It could be an attempt to cure the TVR bouncing tacho needle problem, running the tacho wire through the relay coil has been done/suggested many times as a potential cure for this ?ukdj said:
It could be an attempt to cure the TVR bouncing tacho needle problem, running the tacho wire through the relay coil has been done/suggested many times as a potential cure for this ?
Yes it could 
but its more than just using the relay coil windings as the pulse damper there are also other components involved i.e a transistor and some resistors to function correctly and this looks definitely a Heath Robinson set up 
my advice to the OP'er is to pull this monstrosity out of the circuit and go back to stock wiring set up Edited by Sardonicus on Friday 25th November 10:51
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