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1.4 (75) battery light and PAS gone then back on.


Lupo Tom Lupo
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Hi all,

This is my first post and it's long overdue, the wife's Lupo has had a few problems in the past but this one has stumped me.

She told me she was driving along when suddenly the power assisting went and the battery light came on, she also said she thought the throttle pedal wasn't responding to her input too and the revs dropped but she said she might have imagined the last symptom as she was panicking but the battery life definitely came on and PAS definitely went.

My first thought was evidently the serpentine belt had snapped but when she told me that she turned the engine off and on again and everything back went to normal I knew it couldn't be that, I checked it and the belt is present and VERY tight, it won't budge at all but spins freely when the engine is running.

I am yet to ask her if at the time it was raining heavily as all I can guess is it was smashing down and perhaps she drove through a puddle and water splashed up and got all over one of the pulley's or the belt or something as the car has no undertray underneath it (unsure if Lupo's actually come with undertrays).

Does anyone have any suggestions because God forbid the next time this happens she's approaching a sharp bend.

Thank you all in advance, I'm glad to be here as I love these little cars and I figure that to be quite the compliment as my daily driver is a TT Mk1 with over 400bhp. Can't wait to get on the wife's insurance next year and take it for a drive!

Cheers :)!

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6 minutes ago, Rich said:

A TT with a diesel is the way forwards.

Definitely a perplexing issue.

So no pas, alternator or revs.

Sounds to me as if the engine cut out 

That's the thing, she did say she panicked so my suspicion is she probably put her foot on the clutch and pressed the accelerator rather than the brake, I've seen her do that before when panicked... Whilst she wasn't concentrating she likely construe this as the accelerator pedal doing nothing.

I mentioned it because it's what she said but I'm not entirely convinced the engine did anything out of the ordinary. Equally, ifI assume it was only the PAS and battery light that occurred you have to assume it's the serp belt which makes no sense when the belt is fine and very tight.

Is my hypothesis of the belt or pulley getting a soaking causing it to temporarily slip a possibility or is that a fairly far-fetched scenario?

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Yeah, lupos come with undertrays to protect the pulleys/belts as they're so close to wheel. 

My guess is same as your's... belt slip caused by water spray. Unusual, especially if it's as tight as you say it is.

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Okay so I've spoked to her and along with these symptoms she said that whilst driving randomly the accelerator pedal would definitely do nothing. I.E. She would be doing 30mph in 3rd gear and then she could put her foot to the floor and it would do nothing and then all of a sudden come back to life... Does this suggest what has been mentioned? I.E. Dodgy ignition switch causing engine to cut out which temporarily disables all functions such as power assisted steering etc?    

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yeah could be. but there's also an ignition relay near the fuse box below the steering that can cause identical symptoms/problems too. Not easy to access, but an easy fix if it is that. unplug it and plug in a replacement if it is that.

unlikely to be the crank sensor, as the computer (ECU) would throw a fault light. so most likely ignition or power related.

checked battery terminal? but unlikely.

so my guess is ig switch or relay.

you don't have a fault/check engine light on the dash (I'm guessing)?

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17 hours ago, mk2 said:

yeah could be. but there's also an ignition relay near the fuse box below the steering that can cause identical symptoms/problems too. Not easy to access, but an easy fix if it is that. unplug it and plug in a replacement if it is that.

unlikely to be the crank sensor, as the computer (ECU) would throw a fault light. so most likely ignition or power related.

checked battery terminal? but unlikely.

so my guess is ig switch or relay.

you don't have a fault/check engine light on the dash (I'm guessing)?

I will check the battery terminals to make sure the connections are tight, haven't done that in a couple of months but there is no corrosion or anything like that.

No EML and no fault codes as I had it on a friends fault code reader only last week to be pleasantly surprised that since we bought the car there has been not a single code stored.

After checking the battery if all is well I will take your excellent advice on the ignition relay, do you recommend a branded part (like for example important sensors we always buy Bosch or some kind of OEM part) or will anything that's the correct fitment be suitable?

I found the following, does this seem correct:?

Auto Car Van Boat Immobiliser Alarm Ignition Cut Off Relay 12V 30A Amp 5 Pins

s-l1600.jpg

£4.35 Delivered seem about right?

Is there a guide on accessing the location of the ignition relay or any more tips you can offer other than the ones you've kindly already detailed? "near the fuse box below the steering wheel"

Thank you :)

Edited by Lupo Tom Lupo
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There's four T25 screws holding a panel on which covers the pedal, once that is removed then you can see all the relays in the top corner.

I'd probably be pikey and go raid a few relays from a scrappy, nice selection of genuine which always seem to last longer.

It is very like a TT in a few ways so you should be fine.

Specsman, the spokesperson for best turbos occasionally comes on here too.

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49 minutes ago, Rich said:

There's four T25 screws holding a panel on which covers the pedal, once that is removed then you can see all the relays in the top corner.

I'd probably be pikey and go raid a few relays from a scrappy, nice selection of genuine which always seem to last longer.

It is very like a TT in a few ways so you should be fine.

Specsman, the spokesperson for best turbos occasionally comes on here too.

Which top corner? Accelerator for top left corner or clutch for top right corner?

Should the ignition switch look like the picture I attached further up or this one?

s-l1600.jpg

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  • 2 weeks later...

Hi all,

I have ordered both a new ignition relay and ignition switch.

I phoned around some breakers and they seemed bemused when I mentioned the ignition relay as if it didn't exist. A couple of other places wanted silly money sadly for such a small cheap little part so I ended up ordering the one I found on eBay.

I have also found a way to make the car cut out... If you put the clutch in whilst driving and rev the car to 5k rpm it will then cut out within 30 seconds.. ignition off and on and you're away again no problem, this is the only way I have found to make the car cut out, otherwise it can go for days / weeks without cutting out.

Does this point to one component over the other? I am going to replace the ignition relay first as it's the easier part and then try rev'ing the car high (when engine is warmed up) and see if it still cuts out within 30 seconds. If it doesn't it seems we may have our culprit.

Let me hear your suggestions on the logic behind why reving the engine would make it cut out not immediately after doing so but within 30 seconds? All I can think is more revs means more voltage sent through the relay resulting in it conking out after being overloaded but I'm purely spitballing outloud.

Let me know!

Cheers :)

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Oh, great problem! I love these sorts.... :) clutch and revs... cutting out... completley unrelated. Got me thinking.... Mmmmm.

It could be volts, but once warmed up the battery pretty much sits at 14.4v. Try and reproduce it with all the electrics on. Fan, lights, demister etc.

ok, this might be a stab in the dark. Clutch switch has wiring that is on the same loom that the ignition relay is on a few cm away. When you declutch, switch mounting moves, tugging slightly on the harness that goes into the back of the relay. The added tension caused by the pedal being pressed causes the wire to act like a guitar string that vibrates perfectly when you rev the engine. The added vibration causes a harmonic ringing of the contact inside the relay which then disconnects the power. Engine cuts out. Mad idea?

Or coukd be crank sensor, but i can't think of a link to the crank sensor and the clutch action...

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I've had similar symptoms to this on a Honda before. Would cut out occasionally on turning left. It turned out to be a loose wire shorting out as it touched the engine bay. Can't remember which wire though, probably something attached to the battery.

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1 hour ago, Tripod said:

I've had similar symptoms to this on a Honda before. Would cut out occasionally on turning left. It turned out to be a loose wire shorting out as it touched the engine bay. Can't remember which wire though, probably something attached to the battery.

That's another good one! Bet there was a lot of head scratching at first.... i wonder if @Rich is reading this? He's got some good stories i bet???

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Okay guys,

Today I got around to fitting the relay, although I actually didn't... I'm going to need further instruction on where to find it as above the pedals all I saw were a plethora of relays, wiring and duct tape heaven. There was nothing that resembled the relay I purchased so I'm rather confused.

There seemed to be a white harness in the top corner but half of the harness had nothing in it.

Slightly confused...

Edited by Lupo Tom Lupo
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Pic would help, then we can say stuff like "the third across, next to the green and red thing..." :)

Relay is a square black thing that plugs in. You want to look for the same number on the top, like 137A or something...

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