Sudden short total power loss

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paultv
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Wed Aug 16, 2017 1:56 pm

Bit odd this,

Six weeks ago set off from some lights and suffered a half second total power loss - like someone has pulled the sparks -

I was away a while, and the misses reported a repeat single event of the same nature - popped out to get some oil today and had two of these events, one on each leg of the journey. The first one today lasted a bit longer, but less than a second.

Haven't spotted what the tacho does, but all ancillary gear stays alive, and no warning lights on the dash light at all -

any thoughts on this?
CPS is six months old - DME relay is pretty new, battery good, all fuses seated well -

Paul :-)
4th May 1990 325i Convertible.

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Speedtouch
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Wed Aug 16, 2017 2:13 pm

Worn AFM resistive track or dirty TPS confusing the ECU, maybe...
///M aurice
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Brianmoooore
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Wed Aug 16, 2017 6:33 pm

What the tacho. does is the first thing you need to note. Without knowing that, any diagnosis is pure guesswork.
One thing you can check, since the TPS has been recently changed, is whether its cable has come adrift and is getting intimate with the back of the water pump pulley.
Speedtouch
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Wed Aug 16, 2017 6:53 pm

That'll be the CPS, not the TPS, Brian. :wink:
///M aurice
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
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Brianmoooore
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Wed Aug 16, 2017 7:07 pm

Speedtouch wrote:That'll be the CPS, not the TPS, Brian. :wink:
It will indeed!
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paultv
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Wed Aug 16, 2017 7:46 pm

Nope, all wired in with new plastic channel- but I'll keep an eye on the tacho - just feels like you turned of the ignition for half a second -

Paul :-)
4th May 1990 325i Convertible.

BMW E30 Cabriolet Best Mod Ever:

https://bmwe30cabriolet-wdm.blogspot.com/
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chainslack
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Sun Sep 17, 2017 4:03 pm

I had similar a few days ago - Was intermittant so went around tapping the relays with the end of a screwdriver to recreate the fault.

Tried the alarm box, fuel pump relay then the main ECU relay - Bingo. One tap and could stop the engine dead, brief wiggle and could restart it again.

Replaced the relay and all is good again.
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paultv
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Mon Sep 18, 2017 8:59 am

Update: I cleaned the main socket on the bulk head a couple of weeks ago, as well as the socket under the inlet manifold and have had no issue since. So yeah probably an electrical gremlin under the hood.

Paul :-)
4th May 1990 325i Convertible.

BMW E30 Cabriolet Best Mod Ever:

https://bmwe30cabriolet-wdm.blogspot.com/
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Doobit
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Thu Sep 28, 2017 9:52 pm

I had the same thing. Split second loss of power 30s after starting her up and accelerating away, Happened a couple of times over the weekend. Gave her a few blasts over the next few days and the problem has gone away.
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Contours
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Fri Sep 29, 2017 2:25 am

I sometimes wish that a problem might cure itself and go away but unfortunately not. It is that the condition which is causing it has not occurred at this time.
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