g60 bucks badly when coasting at speed

[steveo29 0]

my g60 has always bucked when coasting under 60mph

 

 

 

say for instance you see a traffic light or slower car ahead and take your foot off the gas , it will buck /jerk like a mofo until you dip the clutch

 

 

 

checked all the obvious , everything is in good order , ive also ran differant ecu chip and they all do the same so that rules out the chip

 

 

 

its stock except chip/pully , decat , carbon can delete

 

 

 

any ideas please

[stevec14 10]

HI

Have you tested out the microswitch on the throttle actuating arm? On top of the inlet manifold? The bracket that its fixed to was bent away from actuating arm on mine car ticked over better and revs better since putting back in correct place. It should be made when on idle.

I had to adjust idle screw on mine when I put switch in correct position (at back of inlet manifold).

Hope this helps

Steve

[steveo29 0]

yep switch is good..thanks for posting

[Yandards 0]

Hallo,

 

The digifant ECU is not the most refined and my G60 used to surge at certain points, the way the engine is designed to function is that when you come fully off the throttle at above 2500rpm (IIRC) it will cut all fuel to the engine, at around the 2250rpm mark it will start adding fuel again. If you have a lambda gauge you can see this in action as it will go fully lean when coming off the throttle and then start cycling showing lambda adaption at work.

 

It could be that some of the inputs into the ECU are messing up the response or that the ECU chip MAP you have is not very well suited to the mods you are running - worth checking/replacing the hose from the throttle body to the ECU is ok and is exactly 1m in length - it also has to go onto the correct outlet on the throttle body although I can't remember which one that is! Try swapping them over and see if it improves.

 

It could also be worn engine mounts (I would replace all 3 as a set).

[steveo29 0]

will see if i notice anything with the revs being 2500 or more

 

ive tried a few chips and theyre all the same with the bucking , so im fairly confident its not a poor chip

 

engine mounts are recent with a front vibratech one

[G60_Marc 0]

Throttle butterfly wedge been removed?

[steveo29 0]

Throttle butterfly wedge been removed?

 

 

no...i did try it once and it made it super jerky to drive