Technical Abarth Loose Connection Issues

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Ditto, actually, may give up for the night now.

I think its best if I don't drive the car until this is sorted now.. Back to squeezing in the g/f's Cinq & dropping her at work I think ... even if I do feel like Mr Bean squeezing myself into it

Is it worth me getting the alternator replaced - got a couple of pretty good local garages near me, though neither one wanted to take on the electrical fault finding when this problem first surfaced - one look under the bonnet appeared to scare them off

 

[Argonought]

re: Abarth - Earth Lead? [AND coil pack]

Yeah, this scared me - only flickered to the 28 reading for a fraction of a second, but thats enough.. generally bouncing to around max of 21 when the error occurs - which is still pretty bad

I didn't actually ask but I assume the voltage reading you originally read from Battery negative to engine earth was massive 7-14 volts rather than just 0.5 volt or so

It would seem there's no earthing connection between the engine and the chassis of the car at all when the fault occurs. There's a real puzzle here as the earths you've installed don't seem to be making any connection (like you connected your earth lead to something which looks metal but is actually plastic).

Basically you need to connect the engine to the car chassis with an earth cable and I reckon the fault should go (as I keep saying ) but of course there should already be an earth cable that does this job but at the moment it's only very poorly connected

The clue should be in the wiring diagram :chin:

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Existing battery - engine earth lead looks okay, though I will give it another close inspection tomorrow. Could not budge it where the connection attaches to the engine underneath though - nut was locked solid.

If this is the case, why would I see no difference (as I didn't), when running a 'quick and dirty' earth using a jump lead earth from a suitable spot on the engine to the battery? Puzzling!

Currently the only additional earth on there is the one I ran to the alternator, which also has not made a difference.

Head spinning on this one

So, should I run an earth from the engine to somewhere on the chassis maybe?

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]

Ok A couple of quick checks you can do and then it's going to be alternator off and have it checked out or replaced. But before you do, you can check if there is an abnormal resistance (bad contact) between the battery and the alternator.

Engine off and allowed to shut down completely for 5mins if you've just been running it

Then, check the resistance between the battery positive and the alternator positive. A hi resistance could be a bad contact at the starter solenoid A20. Worth checking the terminals at the starter solenoid too as this is the one weak link in the chain from the battery to the alternator

Then check the earth line. Again, engine off for these checks
Check the resistance between the battery neg and a good contact point on the body of the alternator

Both should be near zero resistance. If they are then it's alternator off and have it checked out time. A lot of good car spares places used to have alternator test rigs but i don't know whether they do now. Certainly, an auto electricians should be able to test it for you

Oh yes, wiring diags
Here you go

Alternator is A 10
Body computer is M1
E50 is dash charge warning light
H1 is ign switch

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Okay, will do that when I get home from work tomorrow.

... and if they check out then its an Auto Electrician (if I can find a good one locally)

Just checked out a couple of places online for new Alternators - c£108.. not too bad on comparison to what Fiat were talking earlier for extended diagnostic replacement Body Computer & ABS units Actually, thinking about it wouldn't a dodgy alternator show up via Examiner or am I overestimating what it does?

Anyway, off for a hot bath, some food & then shortly to bed.

Will post any progress tomorrow evening

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]

wouldn't a dodgy alternator show up via Examiner or am I overestimating what it does?

Ha! One would hope so but main power electrics is best tested with the most basic of gear ie a £5 multimeter

 

[Argonought]

re: Abarth - Earth Lead? [AND coil pack]

So, should I run an earth from the engine to somewhere on the chassis maybe?

Yes; this is exactly what you should do (effectively you've already done this, in theory, as you've connected both the engine and the chassis to battery negative - this is just doing the same thing indirectly).

To put it another way; the chassis, the engine and the negative terminal of the battery should ALL be at the same potential (same voltage give or take a fraction of a volt)

I'm not sure about the alternator housing though. It's quite possible this is insulated which means connecting an earth lead to it may have no effect. Either way, you want to take great care what you connect to in this area although I suspect the problem IS in this area.

Even if connecting the engine to the chassis does cure the problem you still need to track down the original earth which has failed.

Sleep on it - you've almost got it beat

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]

" Checking to the battery positive:
Engine | Volts 14 (normal) | Volts pumping up to between 21 and 28 when fault occurs
Body | Volts 14 (Normal) | Volts 14 (fault)"

My thinking is this you see Argo.
The alternator voltage regulator should keep the voltage no higher than say 14.6v no matter what. So there's the problem you might say, but it tries to put 14.6v above the battery base line voltage. If it's not reading the battery voltage correctly (high resistance/bad contact) then it pushes it 14.6 above that. So if it thinks the battery voltage is zero then it'll push it 14.6v above that 14 +14 =28v
So the resistance checks from battery directly to alternator are the next step to find out if there is resistance in the alternator to battery connections. Alternator earths through the alternator body so resistance checks from battery neg to alternator body is good.

But resistance checks are not so good as engine running checks
Best check is a voltage drop check with engine running from battery pos to alternator pos- should be less than 0.2v
Same thing from battery neg to alternator body -less than 0.2v

The connections from battery pos to alternator feed goes through the starter solenoid and that's the next weak link for bad contact and the next port of call


HSSB has put alternative earths from the battery neg to just about everywhere with no effect and bad earths alone won't cause high voltage

 

[Argonought]

re: Abarth - Earth Lead? [AND coil pack]

Must admit Decks, I was a bit thrown by the 28V output as didn't even think the alternator could generate that output so started to think it might be defective but the clues are already there in the table HSSB provided.

Anything connected to the chassis (body) is fine but anything which uses the engine as earth has a big problem.

The engine earth is effectively floating (but only during the fault) and engine potential drops about 7-14 volts BELOW chassis earth. Fortunately most devices use chassis earth (be fried otherwise) except for the poor fuel meter/relay which I suspect is the only thing trying to hold the two earth lines together.

I originally suggested the earth connection to the engine can be ignored because it was so tight but I could easily be wrong on this. Electrolytic corrosion could have been going on for years and this would effectively welded the connection to the engine and yet at the same time created a resistance barrier between the two metal types.

Had a look at the wiring diagram (thanks) but I notice earths are just assumed rather than being actually marked on the diagram

Should know soon when HSSB reports back :chin:

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Okay guys, progress report:

Checked resistances as per argonauts post earlier with following results:

Battery + to Alt + reads 0.01
Battery neg to good contact point on alt reads 0.0

Both near zero as you stated they should be.

then ran another earth from engine to chassis & 'tweaked' & twisted the existing engine earth a little (and sprayed with contact cleaner even though I couldn't loosen the engine end off).

Result - still getting the dipping fuel gauge / loss of City mode / Central locking switching off & onetc.. BUT voltage that was spiking at 28 is now reading steady at between 13-14v only. Checked this with engine warmed up and it stayed steady even with the fuel gauge going absolutely nuts.

Hadn't seen those last couple of posts before I tried this, so haven't done Deckchair's checks yet.. currently pouring down with rain too, which may curtail me for the evening (got no lights in the garage currently)

Do you think I've had a bit of a red herring / 2 concurrent problems here

At least its progress...

 

[Argonought]

re: Abarth - Earth Lead? [AND coil pack]

That's very disappointing result and also more than a little crazy

In a situation like this it is important to get our reference point back and that was in post # 34 Are you absolutely sure you read between 21 and 28 volts here?

If you're uncertain then I'd remove the earth lead you just installed and then check it again. One you've confirmed it's still reading much the same (under fault condition) then put the earth strap back and then check the reading again (under fault condition) and make sure it stays close to 14 volts.

If the above checks out then it most likely means you've only earthed part of the engine (sounds quite insane I know) which means you need to find the part which is still not earthed.

Keep the meter positive lead on battery positive (or nearby positive wiring if easier) and then hold the negative lead on different parts of the engine. It should show 14 volts but what you're looking for is a big jump to over 20 volts during the fault condition.

The most likely place to try is the alternator body and that general part of the engine. Measuring voltage is quite harmless so it wont do any harm to the engine but obviously take care you don't get the probe trapped in something rotating

If it turns out you were wrong about post #34 (you were day dreaming or it happened in a parallel Universe etc ) then everything I've posted since you can ignore :bang:

The thing with voltmeters is that it's very easy to read nothing when there is a voltage there but it's close to impossible to read a voltage if it's not there - so I'd be surprised if that is the case.

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]


Battery + to Alt + reads 0.01
Battery neg to good contact point on alt reads 0.0

Both near zero as you stated they should be.
Ok that's good- not conclusive - but good


Next test is voltage drop between the same points with engine running as I outlined earlier. Looking for less than 0.2v difference

Any problem with voltages on the pos side i would disconnect, clean up and refit the starter solenoid terminals. In fact, I would do that anyway as all your problems seem to be in main supply voltage power and earth

Result - still getting the dipping fuel gauge / loss of City mode / Central locking switching off & onetc.. BUT voltage that was spiking at 28 is now reading steady at between 13-14v only. Checked this with engine warmed up and it stayed steady even with the fuel gauge going absolutely nuts.
The meaning of these figures will depend on where you were taking your readings which you haven't said here. Sorry to be a pain and bloody difficult, i know, to describe in detail what you're doing all the time from a distance but exactly where you were taking your readings, from where to where, is vital

Try to take readings with one lead on the pos battery terminal and the other on the engine somewhere solid bare earth (and not just across the battery) so we're getting voltage output readings and not just the battery voltage which we suspect is dropping out of circuit

If the voltage drop checks above are good then next step is removing alternator and get it checked out at a workshop for voltage regulator or internal diode problems

In the meantime you could pull the plugs on the body computer and remake them just by reinserting. You may not need to pull them right out, just enough to score up the contact surfaces

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Hiya,

Sorry, family life has interrupted my tale somewhat this evening, but should be able to resume the frustration tomorrow evening.

Absolutely certain about readings in earlier posts - watched it jump around @ 21V, 24V, up to 28V in tune with the 'gremlin' - was only the briefest of readings each time, but it was definitely there. Plain as day stayed at 13-14V tonight too - and I was stood there checking for quite some time G/F was standing next to me writing down the readings for me on both occasions and she saw it too -surely can't both be losing it that bad . I am starting to get to the point where I doubt my own sanity on this though, so fair play for checking

I'll remove the new lead and take the car out for a good spin tomorrow to get properly warmed up , then test when stationary (though I did let the car idle up to normal running temp this evening). Only thing I did different with this new earth was take from the other side of the engine to the 'standard' earth & direct to the chassis rather than back to the battery...

I'll also try to get V readings from different parts of the engine... and the alternator body again...
This is incredibly frustrating - and must be for you guys too , Feel like the fault keeps popping up & contradicting itself every time I make any kind of progress and think I've ruled something out.

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]

Keep at it! Chin up, you're doing well and the more info you give the better,

Your battery is like a big smoother in the circuit you see, a large capacity reservoir in the pipeline smoothing out the power (pressure) so the water pressure is always available at a steady pressure. Your voltage can't go to 28v when the battery is in the circuit so the fact that it DOES means the battery is dropping out of circuit (open circuit, someone blocked the pipe) and your system is being run momentarily by the alternator which is a mad waterfall with surges and splashes of pressure (voltage) all over the place

So I'd get to these connectors on your starter solenoid and make them all 100% and carrry out the checks above when you're fresh.

Hey, it's got to be better than maybe paying £900

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Cheers Deckchair. Sun is shining, so will get back on it when I get home this evening.

Might be a dumb question, but can tou remind me where I'd access the starter solenoid.. Don't remember exactly where it is located - though its probably been staring me in the face

Abarth engine bay is just so packed tight access can be difficult...

Ta

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]

The solenoid is actually on the starter but i haven't any piccies for the 2.4. Just follow one of the thick leads down from the positive battery terminal and it won't be far
Here it is on a 1.6

Don't worry about the smaller wires there as you haven't a problem with starting or the solenoid itself, just the big jobby power leads

 

[Argonought]

re: Abarth - Earth Lead? [AND coil pack]

HSSB, from what's happened so far there are only two possibilities. Either:

1. You've got a bad earth (which is now partly fixed) or
2. You've got a bad earth (now fixed) AND another fault - let's hope not

I'm not a great believer in multiple faults so I reckon it's still No. 1

Here's a few tips on earths.

Normally if it feels and looks sound then you can trust it but in a situation like this then you shouldn't trust any earth strap. With the fault you have, they are easy to verify though.

With black probe on battery negative, study the earth strap and decide which part of the engine the strap is fixed to, now hold the red probe against this part of the engine (don't hold directly onto the earth strap). If you get a zero volts reading then you might be holding it against painted metal so be prepared to scratch through to bare metal and try again. If during the fault condition the meter shows nothing higher than 0.5 volts then you can mark this earth as good (make a report in your notebook).

Now you can move onto any other earths leads that are visible and apply the same procedure.

Of course if you do get a higher voltage (certainly 5.00 volts or more) then it means the earth strap is defective and should be replaced (or just add another earth lead if you like as a quick fix)

All this is in addition to post #51 but it will be useful if you think you've located a dodgy earth connection.

I hope you've got a digi camera handy as we'll be expecting a nice photo of the dodgy connection when you find it tonight

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Okay,

Been in about an hour and been back on the Stilo for most of that - refreshed now

Reminder on state of play when I started: all additional earths to standard that I had put on I have now removed apart from one to the Alternator (as I have this gut feeling about it). Main engine earth had been cleaned as best I could without removing it (liberal dose of electrical contact cleaner) as I can't shift the thing!

Started car - ran perfectly normally - no sign of gremlin
Let car run up to normal temperature - no sign of gremlin
Got hopeful
Checked earthing against various parts of engine/ body as advised in last couple of posts - all read 0.01V or thereabouts with no fluctuation.
Took car on a 10 mile test drive - gremlin re-occurred 4 times when in motion (seemingly mainly when braking or turning right for some reason). Would not occur when idling stationary (normally worst time)
Brought car back to house, bonnet up, left idling 10 mins - no sign of gremlin. Measured Voltage from various bits of the engine and all steady around 13.98v, with occasional drops to 13.5, but 'gremlin' wasn't showing at any point

Something has obviously changed, probably related to the engine earth - all I can think is that the contact cleaner has done some good, but how since it wasn't actually used directly on the contact surfaces?

Short of hanging off the bonnet while the cars in motion I can't now measure whats going on with Voltage when the problem occurs - could not get it to happen when the car was still (complete reversal of previous experience there, normally worst possible period!)

I really do think I have had 2 problems here - an earthing one that seems (maybe temporarily?) sorted or at least improved by something I've done, and a possible further intermittent issue - the 'gremlin'. Maybe Fiat weren't far of the mark in fingering ABS / Body computers?

P.S. Dumb as it sounds, I can't pinpoint the starter from the engine bay (I know, I know!) - I can't identify where a number of the big power leads go to follow them since they disappear under the fuse box on top of the D4 area and everything coming out of there seems to be in plain black wrap - and pretty inaccessible from above, so I'm going to whip the car over the pit & see what I can from underneath, and then maybe take the battery out & check under that fuse box.

Oh, and my lovely G/f has decided the car is actually possessed / cursed and is currently working out where best to sprinkle some holy water from Lourdes to cure it... Think I need to keep her away from the electrics

Just to add - have regained some of my usual good humour now, but this is making me feel & look such a fool. I keep following the good advice given here (which I appreciate immensely!!), I'm darn sure I'm doing it right, and yet results keep seeming to contradict one another on different occasions.

 

[HSSB]

re: Abarth - Earth Lead? [AND coil pack]

Right, 2nd load of testing for the night - couldn't get into my garage with the pit as someone had parked in front of entrance - long story, but have 2 garages - 1 out front, and 1 around the back, but can't drive direct to the garage out back from the front of the house (no through road), so have to go out.. round about 2 mile of country lanes, and then back in via a connecting estate... Pain in the backside when you are trying to get something done quickly..

Anyway got the multimeter out, and the gremlin was present at idle speeds again (in force this time).

Checked voltage - again remaining relatively constant at around 13.98v even when gremlin acting up - no repeat of the 28v we had earlier, but I am absolutely certain that really did occur
Checked body - battery earth - reading 0.01v steady throughout
Checked engine - battery earth and that was fluctuating jumping from 0.01v at normal running to between 0.05v and 0.11v with each 'blip'

So, is that acceptable variation, or am I back to an engine earthing problem from that? Trying to rule out as many of the apparent red herrings as I can , one at a time...

 

[Deckchair5]

re: Abarth - Earth Lead? [AND coil pack]


Checked voltage - again remaining relatively constant at around 13.98v even when gremlin acting up
But from where to where? And is this the same place as you saw the 28v appearing?

To check voltage when car is moving you can improvise and use an old something you don't need any more that plugs into your cigar lighter, chop the wires and securely connect your multimeter leads to the wires

I have a sharp intake of breath whenever you mention voltages like 28v so it would be nice to never see those again

It's a pity the Stilo only winges and fires warnings when there's a low voltage and says nothing when there's a high voltage