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Erratic idiling when umder electrical load


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#1 Neilc

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Posted 21 December 2009 - 02:03 PM

Hi I have a problem with my 1999 (T) 1.6cc Focus which is really puzzling me and my mechanic.

The car starts and drives lovely and during the day ticks over normally at lights and junctions etc, maybe taking a bit longer than usual to come down to idle but not excessive.

The problem is as soon as I turn on an electrical item (Fan blower, Heated screen, Head lights etc)the idle speed dips dramatically if I turn on all at once it has even been known to stall, but most times it just about saves itself and then returns to just below normal idle speed.

Obviously during the recent cold spell I am using all the electrical items mentioned above.

The local auto ecectrician has checked the alternator output and it is fine.

This is getting on my nerves, So any advice appreciated.

Neil C

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#2 stef123

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Posted 21 December 2009 - 03:03 PM

im having similar issues and im very puzzled by it. when i let the revs return to normal idle it drops slightly then picks itself back up to 750rpm or there abouts. but if im using lights, heater etc it drops dramatically and the car shakes very slightly then returns to 750rpm.

my car is now on its 4th coil pack this year, when the last one was changed the battery was changed also as this is known to cause electrical gremlins. it lasted for 8 weeks but im back to square one again. ive tested the alternator output and its fine.

i can only think its an electrical issue that playing havoc with my coil pack but im f*cked if i know what it is. in the past ive changed the ICV(which did help) also checked thoroughly for vacuum leaks.

#3 artscot79

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Posted 21 December 2009 - 03:26 PM

im having similar issues and im very puzzled by it. when i let the revs return to normal idle it drops slightly then picks itself back up to 750rpm or there abouts. but if im using lights, heater etc it drops dramatically and the car shakes very slightly then returns to 750rpm.

my car is now on its 4th coil pack this year, when the last one was changed the battery was changed also as this is known to cause electrical gremlins. it lasted for 8 weeks but im back to square one again. ive tested the alternator output and its fine.

i can only think its an electrical issue that playing havoc with my coil pack but im f*cked if i know what it is. in the past ive changed the ICV(which did help) also checked thoroughly for vacuum leaks.

have you had the voltage regulator checked the focus is known to have weak earth points and doesnt like excessigve loads focus hacks has info on it it requires using heavy duty earth cable and upgrading them all the car shouldnt stall though the revs should drop but the violtage regulator will make it pick back up to anywhere between 680-750rpm use the dash diagnostics and go to the battery readout it will read 14.7 or so idling with no electrics then turn the electrics on 1 by 1 and watch it the voltage with everything on shouldnt drop below 12 if it does then voltage regulator or the alternator is a t fault if it stays at 12 or more they are fine also whatever the readout is when you use the gas the reading should increse

#4 stef123

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Posted 21 December 2009 - 03:33 PM

have you had the voltage regulator checked the focus is known to have weak earth points and doesnt like excessigve loads focus hacks has info on it it requires using heavy duty earth cable and upgrading them all the car shouldnt stall though the revs should drop but the violtage regulator will make it pick back up to anywhere between 680-750rpm use the dash diagnostics and go to the battery readout it will read 14.7 or so idling with no electrics then turn the electrics on 1 by 1 and watch it the voltage with everything on shouldnt drop below 12 if it does then voltage regulator or the alternator is a t fault if it stays at 12 or more they are fine also whatever the readout is when you use the gas the reading should increse


even under load the alternator voltage still remained quite high so i can only presume its ok.

i did consider making up some earth cables. from the battery to body and the battery to engine. atleast that way if any of my earths are weak i should have eliminated them.

engine running im seeing 14.4 volts, under loads im about 14v IIRC.

cheers for the suggestions so far.

#5 artscot79

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Posted 21 December 2009 - 03:40 PM

even under load the alternator voltage still remained quite high so i can only presume its ok.

i did consider making up some earth cables. from the battery to body and the battery to engine. atleast that way if any of my earths are weak i should have eliminated them.

engine running im seeing 14.4 volts, under loads im about 14v IIRC.

cheers for the suggestions so far.

try this site they explain the earth issue better than i its a well known problem especially if you have a big install etc it cant cope try the link http://www.focushack...e...ce&ht=Audio / Video / In-Car-Entertainment

#6 mintalkin

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Posted 21 December 2009 - 03:58 PM

also check the battery terminals and get the battery drop tested.

#7 stef123

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Posted 21 December 2009 - 04:12 PM

i think to be fair the battery on my car should be fine, it is only 8 weeks old but...

i have just been out with the old multimeter and made an interesting discovery. i scratched a few bits of metal on the egine and took a reading between them and the battery. the lowest reading i got was nearly 40 ohms.

at the moment ive not got any crimps for 4awg cable although i do have the cable but ive got 2.5mm cable and crimps so i will use them for now and see if i can get this high resistance down.

#8 InstructorPiggy

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Posted 21 December 2009 - 05:19 PM

yeah, get some earth cable, do a good daisy chain around the bay, bodywork to engine and back again and then to battery!!

I did it with me colt once...cured a lot of ICE problems....and I had two batterys running and a capacitor!!

Check the loom by the aux belt too...the wiring sometimes rubbs through creating a bad earth.

:)

#9 stef123

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Posted 21 December 2009 - 05:26 PM

yeah, get some earth cable, do a good daisy chain around the bay, bodywork to engine and back again and then to battery!!

I did it with me colt once...cured a lot of ICE problems....and I had two batterys running and a capacitor!!

Check the loom by the aux belt too...the wiring sometimes rubbs through creating a bad earth.

:)



sounds like a plan, i will try that tomorow and check the wiring. atleast i will get rid of the high resistance lol.

do you think the high resistance/poor earth could be the killer of coil packs and also causing me to have an erratic idle for a second?

cheers
stef

#10 InstructorPiggy

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Posted 21 December 2009 - 05:29 PM

maybe...easy way to find out...and it aint that expensive!!

Gota get it sorted really, if you getting that high resistance and it finds its way to the ECU...ooooouch

#11 stef123

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Posted 21 December 2009 - 05:52 PM

maybe...easy way to find out...and it aint that expensive!!

Gota get it sorted really, if you getting that high resistance and it finds its way to the ECU...ooooouch


very true, the only problem is trying to find a good point to fit an earth to.

#12 Neilc

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Posted 21 December 2009 - 05:54 PM

im having similar issues and im very puzzled by it. when i let the revs return to normal idle it drops slightly then picks itself back up to 750rpm or there abouts. but if im using lights, heater etc it drops dramatically and the car shakes very slightly then returns to 750rpm.

my car is now on its 4th coil pack this year, when the last one was changed the battery was changed also as this is known to cause electrical gremlins. it lasted for 8 weeks but im back to square one again. ive tested the alternator output and its fine.

i can only think its an electrical issue that playing havoc with my coil pack but im f*cked if i know what it is. in the past ive changed the ICV(which did help) also checked thoroughly for vacuum leaks.




Hi Thanks for all the advice so far, i have been reading it all through, When you changed the coil pack did it cure the problem even if only temporarily?

Also what is the ICV which you say actually helped by being changed?

My voltage at the battery stays at about 14.7 even when everything is turned on so i dont think its the alternator.

Maybe we will get some more help from users later on

Regards
Neil

#13 InstructorPiggy

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Posted 21 December 2009 - 05:54 PM

make one...find a bolt or two on engine, remove, clean off area with wet/dry paper...body work plenty places you could rub away at, put bolt/nut/self tapper in...just ensure you seal it after to avoid rust :)

#14 stef123

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Posted 21 December 2009 - 06:07 PM

Hi Thanks for all the advice so far, i have been reading it all through, When you changed the coil pack did it cure the problem even if only temporarily?

Also what is the ICV which you say actually helped by being changed?

My voltage at the battery stays at about 14.7 even when everything is turned on so i dont think its the alternator.

Maybe we will get some more help from users later on

Regards
Neil


yes the coil pack did certainly help to begin with but it was either masking the original problem for a while or the original problem takes a bit of time to affect the coil pack.
the ICV controls the flow of air when the throttle is shut basically. Idle control valve.
my alternator is doing exactly the same as yours then really, load doesnt affect its output too much. so it looks like the alternators are ok then.
im going round to my garage tonight to knock up some earths and fit them on and see if i can stop this erratic idle and flickering headlights. earth faults can throw up the weirdest of symptoms at times so lets keep our fingers crossed.

make one...find a bolt or two on engine, remove, clean off area with wet/dry paper...body work plenty places you could rub away at, put bolt/nut/self tapper in...just ensure you seal it after to avoid rust :)


i will go hunt out my emery cloth and a file. im gonna fit an earth right on the bracket that secures the alternator and also atleast one more to the bodywork, anywhere else you recommend?

i might even use a set of jump leads first to see if it makes a difference before i go making holes or pulling bolts out.

cheers
stef

#15 stef123

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Posted 21 December 2009 - 10:40 PM

ok well a bit of an update.
ive been round at the garage most of the night doing some experimenting and testing.
it appeared that all my resistance readings from the battery to each earth point were about 40ohms, ive now fitted a new earth 'loop' and removed and cleaned up all the existing earths and managed to get the earth resistance down to 3ohms. i would have taken the car out for a little drive but the battery is flat.

now the major earth problem is the 2 earths situated at the side of the screenwash filler. now i dont know about anyone else but i usually soak these when filling up the screenwash.

hopefully this will help you aswell neil but i will be back on here tomorow morning after ive got the car started.

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