Idle oddness

[clivvy]

I cant find my old thread I did about my weird idling thing, but recently, i started to discover some things that might lead to some answers.

firstly, the issue. imagine car sat, idling away. all of a sudden (but at regular intervals) it will feel to slightly drop, then carry on. Sometimes its worse, I think from cold, and certainly seems to get much better when warm.

The thing I noticed, was when I pressed my passenger electric window button UP, even though the window was UP, it did it. Each and every time I did this, the thing seemed to drop-its like a drain on the battery or something?

What could this be, battery, or alternator, or wiring? I have fitted new positive lead to starter, new main earth from engine to chassis. If it matters, the two smaller earth cables that attach to the engine block near the dip stick are bolted together rather than one each in the bolt holes (theres two).

At one point I did wonder if it does the idling thing when I have my breaks on due to an issue I had AFTER jetwashing a little bit underneath-holding the break pedal down made it do it much more dramatically...

any ideas?!:bow

 

[makeitfit]

Could it be some sort of sudden load on the alt.:nenau I know mine will drop revs as the cooling fan comes in , then picks up as it catches up with itself:augie
What about putting a voltometer (avail from Wallace n Gromit) on the battery and wait for it to do it again. Have a spy at the readings

Have you got air con? If so does that have fans or motors trying to do something?

 

[clivvy]

yeah it does SEEM like a sudden load, but WHAT?ive got nothing special running when it does it, and it does it when cool more (so cant be the fan can it?) no air con either. the odd thing is, it did it worse when applying the breaks, at idle, after a little bit of jet wash underneath....does it when trying to bring the windows up even though they are up, which I know can happen anyway, but the effect is exactly the same as if i sit there and do nothing....

ill try the voltage thing, might call upon Jim to help me as im USELESS with the voltmeter, i simply dont know how to use it!!

 

[makeitfit]

Maybe you've got a vacuum pipe leak some where and when you soaked it you got a temporary seal:nenau
Similarly, when the engine warms up the pipe gets softer and may then leak possibly, maybe,I know nothing :augie

 

[clivvy]

dunno mate, but keep the ideas coming!

 

[ocelot]

I cant find my old thread I did about my weird idling thing, but recently, i started to discover some things that might lead to some answers.

firstly, the issue. imagine car sat, idling away. all of a sudden (but at regular intervals) it will feel to slightly drop, then carry on. Sometimes its worse, I think from cold, and certainly seems to get much better when warm.

The thing I noticed, was when I pressed my passenger electric window button UP, even though the window was UP, it did it. Each and every time I did this, the thing seemed to drop-its like a drain on the battery or something?

What could this be, battery, or alternator, or wiring? I have fitted new positive lead to starter, new main earth from engine to chassis. If it matters, the two smaller earth cables that attach to the engine block near the dip stick are bolted together rather than one each in the bolt holes (theres two).

At one point I did wonder if it does the idling thing when I have my breaks on due to an issue I had AFTER jetwashing a little bit underneath-holding the break pedal down made it do it much more dramatically...

any ideas?!:bow

Really sounds like an earthing issue, are the terminals clean and the hole to which they attach clean? The basic explanation is;
When a device like a window operates, current flows from the supply, in this case, a battery, through a fuse, through a relay and then to the motor. If the earth is poor, the current finds another path and that can cause a voltage drop elsewhere. As your engine is changing RPM, I's suggest that the problem is within the engine bay, OR, somewhere near the ECU.
Try removing and cleaning every earth you can find, including those near the ECU. Maplins do a great switchcleaner, alternatively, use coke (cola) or white vinegar. When the problem is found and resolved, use waterproof grease to cover the terminations..............
I'm not that far from you (Liverpool) so if you want to drop over this way one day, I could have a look, I have a good multimeter.....

Regards and happy hunting.

Dave

 

[clivvy]

Dave, thanks very much indeed for that offer, if I cant get to the bottom of it, and you dont mind, ill pop over!

anyway, I think you may be right. I have already had to replace the big earth wire from the engine block to chassis-it was corroded, thats ok BUT the two small ones that are part of the wiring loom, they are both attached together into the same bolt hole...i bet its that, isnt it?? if so, i need a screw/bolt to fit one to its own bolt hole, this is where the dip stick is by the way...

what do you think?

if i could fix this id be VERY pleased indeed!

 

[clivvy]

ok, bit of an update.

i checked my earthing cables so thats one from the engine to chassis, the bigone, and two from the wiring loom. the wiring loom ones were connected together, so i have seperated them and fixed them to the two points on the negine block, and two points on chassis, gave them a clean too. I also removed my stereo, as its one of those cheapo imports and was never fitted right, turns out theres about 3 iso adapters to make it fit, and the cables were snagged and bare in places, so that might even have contributed. I have driven very little so havent noticed if its any better, but ill certainly know more tomorrow when i drive to work.

 

[clivvy]

well, it doesnt seem any better, might even be worse not sure. is ther eany way i can test to see if its an earthing issue, such as simply detaching the earth wires from the chassis, or is that silly?

also, what about th eMAF, is it possible that the AMF could cause me some idle issues/?

 

[badger]

does it have aircon? could be electric cluctch cutting in.
or on second thoughts, the ecu controls the diesel heaters, which come on and off after car is running, so could be these?

 

[macabethiel]

Idle Oddness

I think you are just suffering from various loads at low engine RPM kicking in and altering the engine note & idle speed pretty normal I would say and nothing to worry about.

Vacuum loading if you pump the brake pedal, alternator load when you operate the electrics. Slight air leak on inlet manifold all possible variables that might explain your idle issue?

When the engine is hot and the battery is charged up less of an impact. Is your battery in good condition ?
A twelve volt battery as you know consists of 6 X 2.1 volt batteries in series. A fully charged battery should measure at 12.6 volts and mine never drops below 12.4 volts if I check it when the car has stood overnight. (If you have a gell battery different rules apply.)

I am a fan of charging my battery with a battery conditioner on a regular basis to reduce sulphanation effects. A less than good battery will always be making the alternator work harder than it needs to. I am a C-Tec charger fan but to be honest the generic one I got from Aldi at a fifth of the price seems just as good !

 

[clivvy]

no air con. the idle thing happens from cold right through to warm. i think it might be a bit better when warm, but does still do it. its almost like its just about to go and stall them within a split second its ok, but liek that overy few seconds, its really odd. perfectly fine when driving, and doesnt do it if i raise revs to say 800. i do believe it idles well below 750 but i have no way of telling for sure.

battery is in good condition, although i havent measured the charge so ill do that this weekend, i know the guy i bought the car off mentioned hed changed the battery trying to fix another issue.

brakes, i can literally pump them when the car is running at idle, is that right? pump them up till a bit hard then it seems to release, then i can pump again. brakes seem to work fine though, passed MOT no problem..

 

[briggie]

no air con. the idle thing happens from cold right through to warm. i think it might be a bit better when warm, but does still do it. its almost like its just about to go and stall them within a split second its ok, but liek that overy few seconds, its really odd. perfectly fine when driving, and doesnt do it if i raise revs to say 800. i do believe it idles well below 750 but i have no way of telling for sure.

battery is in good condition, although i havent measured the charge so ill do that this weekend, i know the guy i bought the car off mentioned hed changed the battery trying to fix another issue.

brakes, i can literally pump them when the car is running at idle, is that right? pump them up till a bit hard then it seems to release, then i can pump again. brakes seem to work fine though, passed MOT no problem..

could it be the diesel pump timing ?

 

[clivvy]

interesting Pete, diesel pump timing, how do i get that checked/adjusted??

 

[tezzer]

diesel specialist and it could be expensive, :thumb2

 

[clivvy]

how much is expensive? in fact, forget a fix, how much is a new pump, £400 or something? how easy to fit? id be surprised if its that though, it really does go well when driving

 

[macabethiel]

My R3mR had been fitted with a new battery when I bought the vehicle two years ago but it just was not a high enough spec.

 

[clivvy]

My R3mR had been fitted with a new battery when I bought the vehicle two years ago but it just was not a high enough spec.

hmm..in that case ill check it this weekend, perhaps ill get lucky and the battery isnt suitable..!

 

[CHASTER]

no air con. the idle thing happens from cold right through to warm. i think it might be a bit better when warm, but does still do it. its almost like its just about to go and stall them within a split second its ok, but liek that overy few seconds, its really odd. perfectly fine when driving, and doesnt do it if i raise revs to say 800. i do believe it idles well below 750 but i have no way of telling for sure.

battery is in good condition, although i havent measured the charge so ill do that this weekend, i know the guy i bought the car off mentioned hed changed the battery trying to fix another issue.

brakes, i can literally pump them when the car is running at idle, is that right? pump them up till a bit hard then it seems to release, then i can pump again. brakes seem to work fine though, passed MOT no problem..

Those idle revs seem fairly low, lower than mine. I get about 800min cold and no aircon on .
Could it be that your tick-over is so slow, during idle, that your fuel pump isn't getting up to pressure and atomising the diesel properly. You say the engine runs OK when on the road and under load etc. This might reinforce this probability of inadequate fuel pressure/atomisation at low revs.
I believe that the idle speed can be adjusted at the injector pump but I've never done it.
Perhaps some more experienced guys will be along to say if it possible---or alternatively , if my thoughts are a load of spherical ones.:naughty
Anyway---Good luck.

 

[clivvy]

Thanks Chaster, you make a valid point, ive asked the same question before, but theres uncertainty about how idle is handled, some say its ECU and not adjustable...!! personally, tome, it feels liek the idle needs adjusting, because if i ever so slightly press the pedal, to raise revs to about 800 (as good as my guess can be) its perfect, when i let go, it drops and does the same thing...NEVER stalls or anything like, just jumps (whole car wobbles), yet its still slight, its weird.

id love to know how to adjust the idle, but i darent take it to a garage for it doing if its difficult...