Help needed

[Tyron760]

Originally Posted by aardvarkash10

I don't know what the long resistor does, but its not dim/dip voltage reduction.

Oh yes it is!

[ThePurplePanther]

Just to slightly drag this back the problem OP started it with (I know, sorry - btw good to learn what all those resistors do in the bay so not complaining).

If you wanted to I will be in warminster this weekend so you could try my icv from a known working car to see if the symptoms change/disapear.

PM me if you want to try it.

PP

[Laird Scooby]

While i remember it, pulling the vacuum hose off the FPR at idle and the engine speed increasing is a sure sign it's running too lean - almost certainly an air leak.

Like i said originally, check the hose between the MAF and throttle body for splits and security - also check the hose between the EICV and the inlet manifold for the same.

[Gareth2510]

All air hoses are good no leaks & vac lines were all replaced not long ago. Heres one. the idle control valve is drawing 11.5 volts at the plug when i twist the throttle should that voltage drop ie when coming off idle cos mine stays the same no reaction from the tps to icv.

[Gareth2510]

Originally Posted by ThePurplePanther

Just to slightly drag this back the problem OP started it with (I know, sorry - btw good to learn what all those resistors do in the bay so not complaining).

If you wanted to I will be in warminster this weekend so you could try my icv from a known working car to see if the symptoms change/disapear.

PM me if you want to try it.

PP

hello have sent a pm but as im new on here im unsure if you got it. That would be great i do have one coming but unsure of condition just borrowing to test. If it works il let you know on here before the weekend. Post code is ba12 9eb & house number 87. Many thanks.

[Laird Scooby]

Originally Posted by Gareth2510

All air hoses are good no leaks & vac lines were all replaced not long ago. Heres one. the idle control valve is drawing 11.5 volts at the plug when i twist the throttle should that voltage drop ie when coming off idle cos mine stays the same no reaction from the tps to icv.

There should be a feed of battery voltage to the idle control valve on a blue-yellow wire, other wire goes to the ECU and is red-black.

However that's for a 1995 model, not sure if they changed to a different idle control valve on later models.

Was that reading taken with the engine running?

[Gareth2510]

No just on po2 of ignition. I thought as you press the throttle the tps clicks telling the ecu to come off idle stopping voltage to the icv.

[bob12]

Originally Posted by Rversteeg

According service manual TP0005071 the reduced low beam (dim-dip) system was introduced in the UK only, starting from 1996.
"Reduced low beams for the UK:
The dimdip or reduced low beam is a new system for all vehicles. A resistance of 0.9 Ohm is used to lower the supply voltage to the headlights to about 9V."
You won't find this system outside the UK

FYI - (although off topic ... again) I have dim-dip fitted as standard on my Feb 1990 745 Facelift.

[TonyS9]

It is firing and supplying fuel, but you have not enough air or fuel.

Fuel pressure reg is a likely cause but pull the vac pipe off and check for fuel leakage or change in engine note.

Check for air leaks, throttle body gummed up (clean with intake cleaner).

[Laird Scooby]

Originally Posted by Gareth2510

No just on po2 of ignition. I thought as you press the throttle the tps clicks telling the ecu to come off idle stopping voltage to the icv.

That's a permanent feed to the EICV, without checking the diagram again i can't remember if it's ignition switched or permanent from the battery, it doesn't change with varying engine conditions. The switching is done on the other side of it by the ECU.

The TPS tells the ECU when the throttle is either at idle position or at full throttle, it alters timing, fueling etc from these signals and possibly might switch the earth return to the ICV off when not idling.

Originally Posted by bob12

FYI - (although off topic ... again) I have dim-dip fitted as standard on my Feb 1990 745 Facelift.

I have had dim-dip on all my 7xxs as well Bob, a 1987 740, 2 x 1988 740s and a 1988 760, all estates, auto and GLE spec although the best equipped is the 760GLE as it came with standard air-con.

Ash doesn't know what he's missing having never had to diagnose and fix a nasty dim-dip system!