Electrics affect Idle (Fingers crossed its fixed)

[JBOB 0]

Ive had this problem with the idle on my 1.8 16v for ages and nothing I do seems to sort it :(

The rev needle at idle moves up and down just a little bit (2-3mm each way) which is really annoying. So i Checked the ISV and cleaned it out, checked and replaced (If needed) the vac hoses, Changed the inlet manifold gaskets (on advice from a garage) checked the microswitch and throttle cable (Think ive done more but cant remember at the min)

So last night i had most of the the electrics on and the idle was perfect, the needle was rock steady :lol: So this morning Ive checked over everything on the engine and alls fine except for the idle lol. BUT i started to turn some electrics on to see what happens.

If at idle you turn all the electrics on (Heater, lights, fogs, rear window heater) then the idle goes mental going up and down to 1.5K - 2K for about 20 sec and then settles at about 950 and is rock solid like last night. No matter how much you rev the engine it goes straight back as it should.

You have to have all of the above on for it to do this but once the idle is sorted if you turn off one of the electrics its ok but if you turn off two of them it starts to move again

So there seems to be something electrical that’s not right !!! Anyone had this before and know how to sort it

 

Thanks J

[Henny 0]

check the main earth cable which runs from the battery to the chassis just under the battery and then on to the gearbox mount to earth the engine. Also check the earth straps from the head to the bulkhead.

 

These tend to go green (or get a white powder buildup on them) which makes 'em high resistance and stops the electrical systems earthing properly causing all sorts of random problems like this...

[JBOB 0]

Thanks Henny Ill check all the earths when I get back home :D

 

You say earth straps from the head. Without looking id say i only know of one strrap from the head to the coil. Where are the others ?

[Henny 0]

that's the boogar...

 

I think there's some brown wires (earths) which go to the side of the head too, but it's a while since I've played with a valver, so I can't remember if that's G60 only, or also on the valvers...

[Bobby 0]

three earth brown wires that bolt to the same place as the head to coil strap , try give them a clean with some wire wool and bolt them back down

[JBOB 0]

I found and cleaned up (Near mirror polished :lol: )

 

Only TWO small brown wires and the coils earth at the back right of the head and cleaned at the coil end.

 

Bolt at the back of the battery and where the same earth bolts to the engine (Between front mount and starter)

 

Both connections at the alternator.

 

I made sure that everything was connected at the battery and that nothing else was loose. But TBH i couldn’t really check that the wiring was all intact as they are all covered in the plastic covers

 

Ive also replaced the air intake elbow thing that I found to be ripped :oops: (Pics below) But still the cars idle is moving the rev needle a small amount same as my first post :mad:

Have I missed an earth point somewhere that could be the cause of this ??

[stevemac 0]

Check your alternator output at idle - should be just over 14 volts. ECU doesn't like low voltages & worn alternator could be your problem.

[JBOB 0]

Faulty/worn voltage regulator on the back of the alternator ?

 

ECU doesn't like low voltage (engine at idle with worn alternator or voltage regulator) & may be causing your problems. As the engine revs increase, the voltage will stabilise & engine may run okay.

 

Check alternator output with engine at idle - should be just over 14 volts. Could even be a knackered alternator but voltage check will confirm this.

 

The alt is a recon one that’s about 11 months old so should be ok. I did get the multimeter out today and I checked the voltage between the large output bolt on the alt and the nearest earth and it was 14.2 at idle but I didn’t check at speed but 14.2 at idle sounds ok to me :oops:

 

Which part on the alt is the regulator Steve ?????????

[stevemac 0]

Regulator's at the back of the alternator but I doubt it will be faulty if you're getting 14.2v output at idle.

 

I have a spare set of G60 clocks you can try, if you like ?

[JBOB 0]

Regulator's at the back of the alternator but I doubt it will be faulty if you're getting 14.2v output at idle.

 

I have a spare set of G60 clocks you can try, if you like ?

 

Excuse the stupidity please Steve :oops: But do you think that my clocks could be the problem ??

[MillSpeed 0]

Sorry for the hijack but.......I'm having all kinds of trouble with my ECU, how low does the voltage have to drop before it starts to get upset? I'm seeing as low as 13.8v.

[stevemac 0]

MillSpeed, Not sure exactly but if your alternator is putting out less than 14v, it's likely to be quite worn. ECU senses "low" voltage & switches to emergency mode. On a G60, this involves dumping fuel into the engine causing it to run rather badly.

 

 

JBOB - as the clocks are electronic, faulty ones can sometimes cause the needles to "shiver".

[JBOB 0]

"shiver" That’s the word ive been looking for :lol: Ill keep the clocks in mind Steve but Id have to find some 16v ones as I dont think the G60 revs as high as the valver :( Might borrow them from you just to check though :D

 

Well ive had a good look over everything today and have read that the idle should be about 950 but mine is shivering around 1050. So i did the 16v setup that I found on the net (engine hot with the red/black coil wire detached) but I found that the idle screw is wound all the way IN so wont let me adjust the idle down any further :( If I detach the ISV the revs drop right down nearly stalling and stays down if I plug it back in so could it be a faulty ISV ????

 

While the engine was warm i tried turning on all the electrics like in my first post but it makes no difference now the rev needle now just shivers :lol: also if you get really close (But not too close :lol: ) to the exhaust or engine you can hear a very slight missfire/jump along with the revs shivering :(

[MillSpeed 0]

Your ISV sounds like it's ok. When you un-plug the ISV with the engine running it shuts off the ISV control unit, so plugging it back in without shutting the engine off first won't make any difference. Try unplugging it, then shutting the engine off, plug it back in and re-start the engine. It should fire up normally. I have the same problem with the rev counter, although mine jumps every now and again rather than 'shivering'. Have you noticed the rev counter shivering at higher RPM's?

[stevemac 0]

Sorry J, for some reason I thought your's was a G60 . :oops:

 

Maybe I should pay more attention . :morning: & learn to read. :lol:

[JBOB 0]

Sorry J, for some reason I thought your's was a G60 . :oops:

 

Maybe I should pay more attention . :morning: & learn to read. :lol:

 

:lol:

 

Anymore ideas though Steve im stuck :oops:

[stevemac 0]

I hate electrical problems m8.

 

Logically, it appears that your problem is definitley electrical. Personally, I would bite the bullet & take it to an autoelectrician. I suspect that you either have a bad earth somewhere, damaged wiring or have spliced into the wrong circuit while fitting some kind of accessory. I'm no expert when it comes to electrics though . :oops:

[JBOB 0]

Right I haven’t had time to sort an electrician yet as Im just moved house :roll: which also means that im on dial up til Monday when BT turn my BB on :roll: Its so slow :lol:

 

The problem is still there but ive been advised that it could be the Hall sender causing the problems but TBH i dont know what symptoms a dodgy Hall sender would cause :oops: Ive also been told that its easier to change the whole dizzy than it is to change the HS alone :roll:

The good thing is though that a mate down in London has a brand new VAG 16v dizzy still in its box and only wants £40 I haven’t a clue how much these are from VAG but id bet its more than that :lol:

 

So can anyone say that the HS could be causing the probs and should I get the new dizzy :D

[stevemac 0]

Can't see how a faulty hall sender could affect the rest of the electrical system ?

[JBOB 0]

I was told that if the Hall sender is faulty then it can cause idle problems once the engine has warmed up. Have i been told a load of BS :lol: My cars idle does seem to be worse once warm !!!!

Im gonna get a sparky to look at it as soon as I get paid, moving house is expensive :lol:

[stevemac 0]

If the revs drop too low while idling - this can cause the alternator output voltage to drop. Output voltage will come back to the correct level & stabilise as soon as the revs reach the correct idle speed or above.

 

Faulty hall sender (amongst many other things) could be the cause. Faulty hall sender will cause running problems right accross the whole rev range.

 

To diagnose the hall sender as the problem without physically checking the car, is at best, an educated guess.

 

 

Not sure where your rev counter will take it's signal from - could be the hall sender, if so, it could be a faulty hall sender or the wiring to/from it. This wouldn't necessarily cause your other electrical problems though.

[JBOB 0]

Thanks Steve what would I do without you :D Bet your glad you dont live in Leeds anymore as Id probably be round most weekends :lol: :lol:

 

Ive got a local sparky to come and have a look on Monday. Ive also spent most of this afternoon cleaning ALL (That I can find) of the electrical connections and checking the wiring then went to check the idle and found that it still shivers :lol: but turning all the electrics makes no difference anymore :roll: :roll: So im gonna buy the dizzy seeing as its only £40 and then see what the sparky has to say :D

[stevemac 0]

No worries J - you'll have to let us know what the problem was, once you get it fixed.

[Bobby 0]

same as above was gonna suggest you can try my spare dizzy if you want before you buy one.

[JBOB 0]

same as above was gonna suggest you can try my spare dizzy if you want before you buy one.

 

Thanks for the offer Bobby but Ive bought it today :lol: Should arrive tomorrow and ill try to find some time over the weekend to get it fitted :roll: £40 inc del brand new still in its VAG box cant be a bad deal that 8) Ill let you guys know how I get on :D