Technical MK2B HGT - Variator, Cam Sensor, Crank Sensor, & Dipping revs ?

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Technical MK2B HGT - Variator, Cam Sensor, Crank Sensor, & Dipping revs ?

sHAYM4N

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Hi all, think I posted on this one a few times but my HGT's been back in the wars so just after a bit more advice. These seem to be dropping like flies at the moment so really hoping I can sort this one out. Still have brakes to sort with it but other than that and a bit of corrosion on the advisory still think its too tidy to not push on with.

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Since I got it 3 years back it's always had a very intermittent problem with stalling out when slowing down to junctions (Can usually save it if I pre-empt with the foot on the accelerator to catch it - always with the clutch depressed.

It's also had the common noisy variator issue which I've always been waiting to sort. Cam belt was supposedly done on 30k in 2012, and its now just ticked over to 50k so guessing needs looking at too.


With the stallouts, the rate at which the revs drop often is a sign too - they seem to be falling faster when it happens, faster they fall more likely it is that Im going to have to catch it. So does seem air related. Can be fine for months - then play up every other junction for a few weeks. Always spoilt the fun..

Cant state any of this for certain as just when I think Im finding a common factor it throws the opposite - but most common times it can seem to happen are...

1. Winter
2. Having to slow down fast
3. Uphill seems more common, but could be my imagination - has defo happened on both & flat.

Obviously first recommendation I've been given is the throttle body. All cleaned by both myself and checked at the garages as fine (They even struggle to replicate it, only had one garage it happen to on a test ).

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Last year unrelated I guess but it refused to spark at all - called AA out and it turned out to be Cam Position phase sensor. Carb spray did nothing - 30 minutes later it decided to fire up out of nowhere.

AA guy told me best to get it somewhere as these things once they happen always tend to come back. Took it to a fiat specialists in Leeds. Drove perfectly fine on the 25 mile trip like nothing had happened. AA guy said it probably wouldn't fire up again, but wanted to check once I parked it up. It did and it didn't stop again

Garage said it all checked out fine so nothing to do there - so they looked at this stallout problem whilst I had it in. They test drove it all week and put it down to the breather hose on the Throttle body being split in 3 places (think it had already been sealed with tape - but guess it must have come undone. The resealed it and said it had been fine for them.

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Brought it back and it was just as bad if not worse on the way back they did mention that the seal may not hold out & I might have to get a custom one moulded as its not manufactured anymore. All still seems well sealed, but did buy a spare Throttle Body from a breakers as well with the hoses in case. (It has been behaving more with this recently, so never swapped the hoses out).

Anyway last week engine warning light came on again, got it back (was only a couple of miles) but refused to spark again. Got an ODB2 scanner and the cam sensor error was back. Same thing happened as last time - AA guy couldnt get it going - was like that for about 4 days - then decided to spark on the morning I was expecting to have it towed to the garage.

Warning light still on.

So now its at another local alfa/fiat specialist, he has the old diagnostics machine - and the cam sensor is showing as permanent, crank sensor intermittent which he expected to see as this is normally what stops it from firing - not the cam. Also said crank sensor may also be showing up if my battery was a bit low as it has been with trying to get it to fire.

So I have it booked in for crank/cam sensor replacement, variator replacement & timing belt to be redone. Obv pricey now as a variator alone is fetching £300 Hes also warned me not to expect this to fix any of the stalling out problem as hes sure thats not related either.

Said he could fit the TB from the breakers and retune it to the engine if its still happening too with an ECU reset.

Parts hes said hes happy for me to source if needs be, to try either the Variator repair kit - which is obviously cheaper at £20 but at the risk it does nothing at all & have to pay labour again getting to the bloody thing, but also advised trying to get OEM parts rather than after market too as they dont tend to last out as well. I know its a pain getting hold of these things now so can understand him letting me trying to find them too .

So just wondering if anyone had any other ideas I could get him to look at whilst its in for all this work, think someone once mentioned this can also be down to a seal behind the exhaust manifold that breaks away? It was whistling for a bit around that area last winter but stopped once it had been driven for a bit. If anyone knows of a place with the OEM part numbers to search for too would be a great help.

Think the original cam sensor is a bosch for one, but there were a few versions of the variator as well with some having more issues than the newer one?

Thanks in advance for any help! :)
 
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Just a bit more on the variator...

Moved it today round to my dads whilst we sort the parts out. Started first time fine with no errors, but thought I'd do a quick vid of the variator noise as well. Probably sounds worse in this video than it does in person actually, but either way obviously not good...

https://www.youtube.com/watch?v=j9tFlG86gpw&feature=youtu.be


Heard they can still not sound great when replaced anyway? So trying to weigh whats best with all this atm....
 
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Just a bit more on the variator...

Moved it today round to my dads whilst we sort the parts out. Started first time fine with no errors, but thought I'd do a quick vid of the variator noise as well. Probably sounds worse in this video than it does in person actually, but either way obviously not good...

https://www.youtube.com/watch?v=j9tFlG86gpw&feature=youtu.be


Heard they can still not sound great when replaced anyway? So trying to weigh whats best with all this atm....

I don’t profess to know much about the Mk2b HGTs, but I had a similar stalling issue on my Mk2 HGT not too long ago. It’s a quick thing to do if you haven’t done it already but try cleaning the inside of the throttle body (think that’s what it’s called). In any case I have recycled the pic you posted indicating the part I’m on about. I cleaned mine with brake cleaner with the butterfly flap open. Be careful however not to touch or damage the sensor wire . Any foreign matter or worse yet it gets broken then you’re not going anywhere ! ☝
Spray your brake cleaner/carb cleaner onto a clean lint-free rag, and just wipe the inside of it. Then wait around 5 mins before putting things back.
I turned the ignition on in mine and pinned the accelerator pedal down with a broomstick as I didn’t have an extra pair of hands to help. Whilst the butterfly flap was open I cleaned as much up to that point and the flap itself when I released it. The dirt accumulation will amaze you. After I did that it was purring away and the stalling on deceleration had seemed to have been eliminated. Also again not sure if it’s the same on the MK2bs, some other member may know. The Mk2 Punto HGT has a ‘Variator’ kit that used to be sold on eBay which was meant to eliminate some of the issues with thy the variator noise? They’re between £20-30 depending on where you get them and how much the seller wants to flog them for, but do check and see if it’s compatible with your model of HGT. Hope that helps some
 
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Thanks yep, cleaning the throttle body was the first thing I tried unfortunately.

It already seemed pretty clean too. I have managed to get a spare from a breakers but it looks dirtier than the one I have, so may spend a bit of time cleaning that up in case its needed. My garage has said they're tricky to replace as the ECU all has to be reset to accommodate it for relearning but is doable (so last resort really) maybe worth swapping the hoses over first too I guess.
 
Thanks yep, cleaning the throttle body was the first thing I tried unfortunately.

It already seemed pretty clean too. I have managed to get a spare from a breakers but it looks dirtier than the one I have, so may spend a bit of time cleaning that up in case its needed. My garage has said they're tricky to replace as the ECU all has to be reset to accommodate it for relearning but is doable (so last resort really) maybe worth swapping the hoses over first too I guess.
I think that throttle body has an integral idle control valve . see if you can remove it from throttle body and clean it very gently do not force it's plunger in or out.
You could posdibly swap idle control valve from other throttle body to current one and see if it makes a difference.
 
I think that throttle body has an integral idle control valve . see if you can remove it from throttle body and clean it very gently do not force it's plunger in or out.
You could posdibly swap idle control valve from other throttle body to current one and see if it makes a difference.

Brill thanks will take a look on the one from the breakers should be easier to find if so!

Only other thing Ive noticed is that there is also sometimes a delay on the revs response, some days worse than others - could this also be related to that or possibly even the variator?

I don't feel it so much when driving, but when sat idle in neutral its definitely noticeable.
 
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