Idle problem :-(

[vwmk3jon]

Still no closer to getting the G back on the road :-( Still won't idle right!

The cars idling very rough (so i'm told) when it gets warm. 2 different chips have been tried (for my spec) plus a turbo chip. No luck.

Injectors have been changed and its cured it a little bit. Idles ok, revs up but when it comes down it wont idle.

larger map sensor had voltage checked and its fine.

Batterys completely flat.

Anyone got any ideas?

[quiksilver_jake]

isv? prob not but though id say?

[PeteG40]

if battery isn't flat then the alternator may not be charging and therefore sensors wont read right and it'll be in limp mode.

[vwmk3jon]

Well i'll have to see if i can get another alternator to try, once the cars back here.

[samg40]

Well no the first step would be to check the voltage with a multimeter when the engine is running. There is a post on here somewhere with the correct voltages you should see when certain conditions are applied. Chucking money and new parts at a problem isnt always the best route to fixing something.

[vwmk3jon]

But i've got an inkling that it does need a new one.

[vwmk3jon]

toothed belt snapped on the way home and it ran 100times better!?

[PeteG40]

sounds like it might no be correctly mapped for the air going into it if its idling sh1t.  However idling and running are two different things!

Here's what i'd do.

1. Check the mechanical cam timing to ensure the cam is dialed in right.
2. Check the resistance of the blue temp sender, co pot and hook up a air/fuel ratio meter to check the lambda is functioning.
3. Check the throttle switches on the throttle body are working correctly and its clicking the idle switch
4. Remove and clean the isv
5. Ensure the ignition components are new or good condition - eg plugs, leads, coil, dizzy cap, rotor arm.
6. Ensure the alternator is putting out the correct voltage
7. check the ignition timing with a timing light to ensure its at an appropriate base setting.
8. Ensure any dewedging is sealing correctly and the idle screw on the throttle isn't in a silly position.

If then its sh1t, I would suggest it may be a map/map sensor problem.

[vwmk3jon]

Cheers Pete.
I'll get onto them shortly to see whats what.

My mate had a fiddle last night and if we disconnected the hose to the ECU, it seemed to run better although it obviously wouldnt run over 3000rpm and the revs bogged down major when i came to a junction.

Apparently the map sensors been checked 3 times (voltages measured etc) and its fine. My battery light is flickering now. We bodged what was left of the belt back on to charge the battery up and its still doing it so i'll look at the condition of the alternator 1st.

[hayesey]

what map sensor are you using and do you know that the map you currently have in there is suitable for it?

where has the map you have come from?

[vwmk3jon]

Map sensor is a 250kpa jobbie and Phil got the map from Steve Pitt.

[vwmk3jon]

I think one of the factors of the car not idling is lack of oil (as i found out today :-()

I've put 2 litres back in and gonna top it up with 2 more litres tomorrow and hope the bottom end hasnt seized! Is it totally game over if it has?

[Max]

Have you checked for an oil leak, I am sure the car would have been topped up with oil!

[PeteG40]

they only take 3.25 litres....

[vwmk3jon]

we've checked where the car sits overnight - clear
where its parked at work - clear
and i've had a look underneath but cant see anything apart from where the charger seal went when Phil was testing it.