Map hose conection. bad idle

[Alan Mullins]

I am trying to get my GTIR to idle, when i do get it close it hunts very bad. The only way it will idle roughly is by lowering the master fuel to 65. Just noticed today that the idle rises when you put your foot on the brake, does this mean i have the map sensor hose in the wrong place? It is hooked into the throttle bodies, Each butterfly has a fitting so i have all four in series and then into the LEM. Is this wrong any help would be great. Alan.

[Simon]

Hi Alan

On the GTiR you are best to configure the ECU to be spanned off TPS. At idle running MAP the signal will not be the best.

[Alan Mullins]

I am running tps Does the TPS need to set at 20-220 or is 20-100 ok? Regarding the hose where the map vacum comes from, Is that in the right place? Will it effect the idle? Thanks, Alan.

[Simon]

That should be fine for the map hose as long as it is on the engine side of the butterflys.

20-220 will just expand how much of the map you are using. Either will work.

To see if it is the map signal effecting the idle you can run with it unplugged. Just be sure to block the hose so that the idle remains low.

[Alan Mullins]

I have run with the map hose unplugged and the idle does not rise when i put my foot on the brakes. It was hooked up between the butterflys and the engine, Does this mean i need to hook it somewhere else Or is it a set up issue? Alan.

[Simon]

It could be that the map signal is being effected due to the vacuum assisted brakes. It might be causing the ECU to change the fuelling hence raising the idle slightly.

The idea is to find a stable map signal. However on the GTiR with multi butterfly this is almost impossible.

This is one area the G4's excel at with their ability to have 4 and even 5d mapping.