Car trying to pull away with no throttle in first gear

[Hedgetrimmer]

My car is trying to pull away in first gear without using the throttle. It idles at 800rpm in neutral but seems to be idling between 1000-1500 in first gear hence it is trying to engage first. The revs seem to rise more when changing gear.

It's only started doing this from yesterday. The clutch was replaced recently and it has been operating perfectly since.

I am using a FD DBW and this is set to the fastest change point. I have noticed some extra slur in the gear change.

Any thoughts?

 

[lozcb]

My car is trying to pull away in first gear without using the throttle. It idles at 800rpm in neutral but seems to be idling between 1000-1500 in first gear hence it is trying to engage first. The revs seem to rise more when changing gear.

It's only started doing this from yesterday. The clutch was replaced recently and it has been operating perfectly since.

I am using a FD DBW and this is set to the fastest change point. I have noticed some extra slur in the gear change.

Any thoughts?

Possibly clutch drag/slippage one for the SD2/3 i think , settings should really be checked/ reset after around 500 miles after a new clutch is fitted


regards loz

 

[Hedgetrimmer]

Hi Loz. I would tend to normally agree however it hasnt happened progressively. The car was totally different on Saturday morning and the clutch was fitted 2000 miles ago.

 

[Gixerboy]

Suggest checking the throttle body is clean, & no intake air leaks, pipe dislodged.
If it is hunting, with the revs touching 1500rpm the clutch may legitimately start to engage.
Cheers
Dave

 

[Hedgetrimmer]

Thanks Dave. When the revs drop to 800rpm in first gear it disengages so I think the revs are definitely clausing the clutch to engage. It seems strange that the engine builds revs when stationery rather than sticking open but I'll take a look.

I have also experienced a wet carpet on the passenger side which I have now rectified (cleared out the drain plug for the AC) so I am hoping that the problem is not linked.

 

[Emtee]

Hi Hedgetrimmer, maybe fit the DBW bypass and see if that makes a difference to begin with?

 

[Hedgetrimmer]

Hi Emtee, many thanks for the advice. I installed the bypass and this removed the problem.

This suggests that one of the original soldered joints may have broken. I think 3 joints were "t" junctions ie where information was being taken from the main loom to be used by the DBW box, and one of these my be the culpret. The other solder joints are in line therefore fitting the bypass would probably still generate the same problem.

I doubt that the DBW unit or its loom are at fault.

 

[Emtee]

Hi Emtee, many thanks for the advice. I installed the bypass and this removed the problem.

This suggests that one of the original soldered joints may have broken. I think 3 joints were "t" junctions ie where information was being taken from the main loom to be used by the DBW box, and one of these my be the culpret. The other solder joints are in line therefore fitting the bypass would probably still generate the same problem.

I doubt that the DBW unit or its loom are at fault.

Glad you're closing in on the cause HT. Easy enough to check the loom, though you may crick your neck in the process. Just remove the liner above the pedals and get in there with a torch.

 

[Hedgetrimmer]

All of the solder joints are fine on the loom. The wires were still very well solder together so the problem may now be the FD box itself. I think the box will now need to be tested by Jeff which is a bit of a pain.

 

[mjheathcote]

Where are you based?
Maybe there is an owner near you with a DBW module who you can swop with to see if the same problem persists?

 

[Hedgetrimmer]

I am base dup in Newcastle and Maserati's are pretty scarce up here. I'll have a word with Noor to see if he knows of any cars up here or I may drop down to see him in Bolton in the coming weeks as I is running a DBW on his own car.

 

[Emtee]

Hi HT,

From what I know of the DBW module, I believe it increases the signal to the throttle pedal potentiometer, and also alters the signal 'curve'.

Is there any play in your throttle pedal? Can you put your foot behind the pedal and lift it slightly towards you? If yes does it then stop the creep?

If this is the case the pedal rest position might be slightly too low and dropping into the slow drive position?

Just a thought but an easy one to check at least.

You could also try the same with your brake pedal to make sure the brake light plunger switch at the top of that pedal is also sending the correct signal. Again very easy to check.

Regards, Miles.

 

[Hedgetrimmer]

Never thought about that Miles! The DBW does enhance the first part of the travel significantly so I better check the movement of the pedals. I check it tomorrow as I have a few drinks to soften the impact of my good lady watching the X Factor.

 

[Emtee]

I have a few drinks to soften the impact of my good lady watching the X Factor.

You and me too mate, though with mine it's SCD. Both vomit inducing torture!