Engine random cut out

[Jimmysan 0]

Hoping someone can help solve my problem, my car is 1996 VR6 OBDII unmodified

 

Car cuts out at any speed, generally when decelerating and when engine warm, but recently happened when cold.

 

Problem gradually got worse, cutting out more frequently and taking longer for dash lights to come back on to enable restarting the engine.

 

CEL does not come on with ignition - this means ECU is not getting power, but why would it still run for up to 10-15min?

 

Changed the crank speed sensor and fuel pump relay to no avail, throttle body was cleaned in the summer.

 

Sprayed the coil pack in the dark and got few sparks at the coilpack terminals, so changed the coil pack for new, but problem still exists.

 

Battery is good and cleaned terminals etc. But not looked under the battery tray yet.

 

Strangely when engine warm, if left indicator is activated – engine cuts off. (Also happened when reverse gear was engaged, but not happened since installing new coil pack)

 

I’m thinking next step is to have a look at the ECU, I have a small hole in the rubber that seals over the windscreen, car was left for 3 weeks getting rained on a lot, since then problem occurred.

 

Any help appreciated.

[Nex 17]

I would say it would be a plan to check your earths to make sure they are ok and just have a look at your wires to make sure there isnt a short somewhere.

[Jimmysan 0]

Yes this is my priority for tonight, just going to be difficult with no garage and in the dark! Any particular ground point to inspect?

 

Thanks

[Jimmysan 0]

Found the washer jet heater lead to left side has been cut in the past, and on the right side has not been cut but the brown cable has come loose, not sure if this is touching bare metal though, if so then the bonnet earth strap would not do it's job as it is rotten.

 

Anybody think of a reason to cut 1 of 2 washer heater leads?

 

Could this be enough to cause the engine to lose power? I've now disconnected both washer heaters and plan to fit a new earthing strap.

 

Also found that the right fog light is loose and not supported?

 

Checked grounds under battery tray, seem fine, thats as far as I got in the cold and dark last night!

 

Any comments please

[Lukey. 381]

There's a big earth on one of the gearbox bolts and the positive runs to the starter.

[Jimmysan 0]

Forgot to mention, I have scanned for codes and I get 00668 - terminal 30 low voltage, think this came up after changing the battery, but it has reappeared since clearing it few weeks ago. 

[Jimmysan 0]

battery tested when removed from car at 12.2V - this is low i know, but has been left in cold for few days- will test with engine running tonight.

 

Battery is a Bosch S4 075 - 60Ah, 540 CCA  - reading about this I believe this is slightly underrated?

 

Question is, can a semi-charged battery cause the random cut out i'm experiencing?

[Daverse 175]

maybe, if the alternator was providing enough power either. what amperage is the alternator rated to?

[Jimmysan 0]

Cleaned starter earth even though looked ok. Battery reading 14.6V when engine running, charged up to 12.5V after running engine for 5min.

I have measured 0.15V from battery neg to bonnet earth strap point with engine running lights in etc, so clearly an earth fault. But really stuck as to where this earth fault is coming from?

[mattvr6 133]

Why don't u just put a new earth in?

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[Jimmysan 0]

Which earth cable are you thinking? They look fine, the one I haven’t found is earth point on the rear of the head – can anybody help explain how this can be accessed?

 

Pulled the ECU out and all looks fine under the rain tray.

 

My problem is temperature related, once warmed up and upon cutting out, it takes 10-20minutes for the car to be restarted, which is one reason I changed the coil pack, but this didn’t fix it.

 

I have thought about changing the coolant temp sensor but can’t see how this would cut the engine completely?

 

Also, I said earlier voltage between battery neg and earth point is 0.15V – this isn’t as bad as I thought and possibly quite normal and acceptable?

[Lukey. 381]

IIRC the earth on the head is at the back underneath the plastic trim that the ht leads route along

[Jimmysan 0]

Ok thanks, the one near the throttle body is fine, I thought there was one further down on the head from reading on the net, but can't see it so maybe not.

[Ickyketseddie 89]

I had a starting problem that sounds similar, that was the temp sender but never had the cutting out issue. Not sure if that helps lol.

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[VR6Pete 1,455]

check your big multi plug on engine loom and check no water has got in, seen instances in the past where aux pump has leaked and corroded terminals on the plug...

 

I've also had a cutting out issue on my old mk3 when turning left and going over bumps.

 

It ended up as one of the pins on the ECU plug was loose.

[mattvr6 133]

Just use a new earth strap from the battery to the engine I had that problem on my mk2 easy way to rule if out

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[Jimmysan 0]

Pete, this is the one multi plug i've struggled to disconnect, there is a tab thats snapped off it but I still can't twist it off, is there a trick to this? It did seem damp.

 

When you say pins on the ECU plug are you talking about the same thing?

 

I am thinking of changing the blue coolant temp sensor but played around with the existing one last night and don't see how that can be at fault, it doesn't run without it and runs fine with it!

 

I idled the engine for about 15min last night, puttting into reverse is ok 9/10 times but sometimes cuts it, indicating left cuts it most of the time, indicating right cuts it but not as often as indicating left, strange?

 

Thanks.

[Lukey. 381]

It twists off, but its really stiff so you have to really grip it and really twist it, I thought mine was going to break first time I did it.

[Jimmysan 0]

Ok thanks, got it off, took the plastic ring and rubber seal/ring off first and twists off a lot easier. Were 3 or 4 golden brown looking female pins, so gave them a clean.

 

Main finding last night was that the rear left lighting wires had been taped up in the past because about 8 wires of one loom have clean breaks around the insulation (copper is ok), as though someone has put a guillotine across them – really strange!

 

It’s possible that the wires are shorting with each other, the reverse light is also within this cluster, and would explain why indicating left cuts the engine more than indicating right.

 

Anyway after tidying things up with electrical tape, I could not get the dash lights up i.e. the ECU was dead/immobilised for hours – left overnight and tried this morning before going to work and car starts, but this is the longest it has ever taken for a restart, so I’ve found something but made it worse?

[VR6Pete 1,455]

If it's taking ages to fire when cranking over then I'd say possibly crank sensor but doesn't explain why dash lights don't come on.

Club Chairman

[Jimmysan 0]

I have a Clifford alarm/immobilser - before I can crank the engine I have to press a button on console and unlock button on key at the same time to get dash lights on, but when the car dies it takes varying amount of time for this procedure to work.

 

Car fires fine everytime, it's this ECU timeout that I don't understand, also timeout tends to take a lot longer when engine was warm before it cut out.

[Lukey. 381]

When the dash came back on did you hear it make a sound like a buzzing or whir or anything when you turned the key to accessory?

Edited November 28, 2013 by Lukey.

[Jimmysan 0]

Yes I get the buzzing sound - fuel pump priming?

 

Occasionally the ABS pump makes a lot of noise, and sometimes I get a rather loud high pressure sound coming from under the intake manifold.

 

The secondary water pump seems tempermental - it will some times be clicking and then come to a halt, and sometimes I can knock it and it will start ticking again.

 

Can I ask why you are asking, as I don't have starting issues, only cutting out when driving issues

 

thanks

[Lukey. 381]

I meant from the clocks themselves, if you can hear that then they lost all power, then you could be looking for a break in a connection somewhere.

Edited November 28, 2013 by Lukey.

[Jimmysan 0]

No never heard any buzzing/whirring from the clocks.

 

Anyway, not tested the car since taping up the exposed wires, taking it for a drive when get back from work tonight, fingers crossed