Keatonfuller94 1 Posted February 2, 2017 Report Share Posted February 2, 2017 Hi, I have a early 1998 mk3 golf vr6 2.8 which I've owned for a year nearly. Ever since I've owned the car it's had a mind of its own wile idling, sometimes it'll sit at normal idle of 750rpm and other times it's vary from 1000-850 rpm the idle doesn't fluctuate up or down it will stay consistent at the idle it sits at so I believe that takes possibility of it being the coil pack :/ Since owning the car it has had: New 8mm leadsIridium plugs Timing chains have been replaced Aux tensioner Aux belt Alternator BatteryStarter motor K&n air induction (57i) New engine earth has been run Throttle body has been cleaned2 oil+filter changes And it's been plugged in and has no faults come up It's had loads of other things changed but doesn't involve the engine When my idle sits at a 1000 rpm or at 800 rpm if I switch the car off and start up again straight away it will then idle at 750 but as soon as I start driving again and go to stop it sometimes it'll go back to 750 or most of the time it'll sit at 850-900 It's the only thing wrong with my vr now it's it starting to do my head in lol Any ideas thanks Keaton Link to post Share on other sites
VR6Pete 1,455 Posted February 2, 2017 Report Share Posted February 2, 2017 Few things that could affect idle. - Vacuum leak (I.E to FPR, damaged gasket on inlet etc... usually spraying some carb cleaner etc... will identify any vacuum leaks in the engine bay but there are other methods too). - MAF (doesn't always throw up an error code) can throw another one on relativly cheap - I pay no more than £20 for second hand OBD2 MAF's. - Fuel Pressure - Pump maintaining flow ? FPR Ok? - Are you running stock cams? Link to post Share on other sites
Keatonfuller94 1 Posted February 2, 2017 Author Report Share Posted February 2, 2017 Still running stock cams but will be hopefully putting in 268 cams soon as I've got to get the lifters done as they knock on col start for 5 mins or so, the car it self runs smooth as, through out all driving it's literally just my idle giving me problems :/ I'll have to get it checked out with vacuum leaks and I bought a new mag from Euros the other day put it on and still no different so I sent it back and got my money back lol Link to post Share on other sites
Keatonfuller94 1 Posted February 2, 2017 Author Report Share Posted February 2, 2017 Where can I locate my fpr? Link to post Share on other sites
Keatonfuller94 1 Posted February 5, 2017 Author Report Share Posted February 5, 2017 Figured out my funny idle, i believe something isn't man enough on my motor i.e. Battery, it's when I have my hids climate control and stereo on its causes my car to rev at 850-950 and when I turn off the climate control or hids it makes the car tick over at 750 again and will always stay there so is it my battery isn't man enough for the car?? It's a Bosch battery and it's got 540cca? Link to post Share on other sites
red_rocket 10 Posted February 5, 2017 Report Share Posted February 5, 2017 (edited) Hi, That sounds normal to me. Most cars have an input to the engine ECU from the air conditioning because of the extra load it puts on the engine. Likewise, if you have got electric power steering, or sometimes even the lights. I would check the battery voltage with nothing on (greater than 12.8V if your battery is good) and then check the charging voltage with the engine running. This should be greater than about 13.8V under all conditions. You should also check the impedance of the earth straps (i.e. battery to chassis and battery to engine). You can measure the impedance directly (best to disconnect the battery) or measure the voltage across the strap (hence impedance via ohms law) when running normally. This is problem with a lot of older cars and can give weird symptoms, not just charging problems. Cheers Pete Edited February 5, 2017 by red_rocket Link to post Share on other sites
Keatonfuller94 1 Posted February 5, 2017 Author Report Share Posted February 5, 2017 Lovely cheers for the advice much appreciated, my vr6 is a/c delete, and it's had a brand new alternator and battery in the last month I do have to admit I've noticed this a lot more since I put hids on the motor, could a bigger battery help this situation? And I will check my earth from the battery to chassis, I know that the engine to chassis has been replaced Many thanks Keaton Link to post Share on other sites
red_rocket 10 Posted February 5, 2017 Report Share Posted February 5, 2017 Hi, No, the battery is just for starting really. Once the engine is running the alternator does everything including charging the battery. You need to measure voltages and impedance first to make sure everything is OK. HIDs can generate a lot of electrical noise, which could be upsetting things, especially if anything is bit marginal. Good luck, cheers Pete Link to post Share on other sites
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