Technical StarShip losing power/cruise issue?

[RocketDad]

I run a charity called STEAM Co. to encourage kids to be creative and fly to schools around the UK in #StarShip22 which has a few issues and SpaceX say it’s out of warranty!

Old folk see an old motorhome on a 2007 Ducato 2.8 diesel - but kids have more imagination as you can see in this film I made with McLaren: http://bit.ly/SponsorXfilm

I’ve been getting a loss of power when driving along

If I take foot off accelerator it’s fine again

The gap between this fault has been getting shorter from once every ten mins to once or twice a minute sometimes

I’ve noticed when it happens the after market cruise control (two three button clusters on dashboard) doesnt work

It cleared itself for a few days and cruise worked again

Now the fault is back

Any ideas that can help keep me on the road?

And in the sky?

Would be really grateful

 

[cris1117]

Brake pedal has a switch that knocks off the cc when you touch the brake I believe it also cuts the fuel down, you could try lifting the brake pedal with your foot and see if the cc starts working again or just replace the switch its way up at the top of the pedal ,(look for the wires) so you will need to stand on your head in the foot well.

 

[marcostig]

Well done for what you are doing hopefully someone with more know how than me can help you out.

 

[Anthony489]

Hi

With factory cruise control, as soon as the brakes are touched the system is disabled, and you have to manually intervene by pressing the resume button if you want it to work again. This is done for obvious safety reasons, and I imagine the aftermarket version will work in the same way. So if you had a faulty brake pedal switch, i.e. brake lights coming on whilst driving along even though not actually braking, the cruise would be disabled, which doesn't sound like the symptoms you describe.

Since there seems to be some link-up between the bad behaviour and the cruise control, I would be inclined to temporarily disable it by isolating its wiring (usually plugs and sockets) and see if the problem stops. There may be a multiway connector interposed between the throttle pedal sender and the existing vehicle loom, it occurs to me that a bad or loose connection here could cause the symptoms you describe. Do you have any details of the cruise control manufacturer ? Was it professionally fitted ?

I'm personally not a big fan of cruise control as there always seems to be too much traffic in my part of the world to use it for any length of time, but I appreciate that it can have its uses. Some types have the option of a speed limiter, which may be more useful.

 

[RocketDad]

Brake pedal has a switch that knocks off the cc when you touch the brake I believe it also cuts the fuel down, you could try lifting the brake pedal with your foot and see if the cc starts working again or just replace the switch its way up at the top of the pedal ,(look for the wires) so you will need to stand on your head in the foot well.

Thanks for that. I will have a look.

It’s all been okay for the last few days and then started playing up again and is now okay.

By your reckoning it may be a dodgy switch which is on the way out of course.

I’ll have a look in a wiggle and see what’s going on.

 

[Communicator]

Brake pedal has a switch that knocks off the cc when you touch the brake I believe it also cuts the fuel down, you could try lifting the brake pedal with your foot and see if the cc starts working again or just replace the switch its way up at the top of the pedal ,(look for the wires) so you will need to stand on your head in the foot well.

I hope that is an easier task than on the x244. If I remember correctly Ocwobio described it as "a bitch". Not room to stand on head, but you have to lie on the floor with your head under the pedals. On my x244 there was insufficient room to withdraw the switch.

 

[RocketDad]

I hope that is an easier task than on the x244. If I remember correctly Ocwobio described it as "a bitch". Not room to stand on head, but you have to lie on the floor with your head under the pedals. On my x244 there was insufficient room to withdraw the switch.

Not managed to look yet - not least as it’s been behaving for a couple weeks of weeks

Not sure this explains the loss of power problem which occurs even when CC is turned off

Could the CC and/or that switch affect the engine when turned off?

 

[Communicator]

I hope that is an easier task than on the x244. If I remember correctly Ocwobio described it as "a bitch". Not room to stand on head, but you have to lie on the floor with your head under the pedals. On my x244 there was insufficient room to withdraw the switch.

Sorry folks, I should have looked more closely at the initial post. While the vehicle is described as a 2007, a 2.8 engine is mentioned.
This suggests that the vehicle is a late registered x244 model, the production of which ceased in 2006.

 

[cris1117]

Not sure this explains the loss of power problem which occurs even when CC is turned off

Yes it would brake switch still cuts fuel, did you try lifting the brake pedal with your foot when the cc stops working and try cc again.
If the above works it will prove it is a faulty switch but it may still be the switch even if this trick dosnt work.
The switch cuts the fuel down every time the brake is applied, I had this on my Fiat diesel car don't bother with wd40 it doesn't help.

 

[Communicator]

Not managed to look yet - not least as it’s been behaving for a couple weeks of weeks

Not sure this explains the loss of power problem which occurs even when CC is turned off

Could the CC and/or that switch affect the engine when turned off?

As I have stated in the previous post, the vehicle is an x244 2,8jtd, possibly of 2006 manufacture.

The cruise control on the 2,8jtd is initiated by a switched 12V to the ECU. The supply to the brake pedal switch is separate,and not subject to the cruise control on/off selection.

The extra contact on the brake pedal switch, which opens when the pedal is pressed, is part of the cruise control installation. As suggested it cuts the power when the brake pedal is pressed. Whether this only happens when cruise control is selected is an unknown, as it would not matter either way, once the ECU has recognised the existence of cruise control. (When added there is alearning process, as the ECU does not immediately illuminate the cruise control icon.)

Developing this argument, it is quite possible that the ECU could cut the power whenever the brake pedal is pressed, or have I missed something? Loss of the 12V brake pedal signal at the ECU would then result in loss of power. An intermittant connection at the brake pedal switch would duplicate this signal.

To illustrate the connections, I am attaching my modified copy of eLearn diagram E5060. Please note that while I used the designated fuse, F27, it is common to apply a loop at the bake pedal and use F28. Any loose connections could create the condition.

Apologies for the inverted diagram, which I should re-scan and save, but good practice for looking at the pedal switch.

 

[RocketDad]

As I have stated in the previous post, the vehicle is an x244 2,8jtd, possibly of 2006 manufacture.

The cruise control on the 2,8jtd is initiated by a switched 12V to the ECU. The supply to the brake pedal switch is separate,and not subject to the cruise control on/off selection.

The extra contact on the brake pedal switch, which opens when the pedal is pressed, is part of the cruise control installation. As suggested it cuts the power when the brake pedal is pressed. Whether this only happens when cruise control is selected is an unknown, as it would not matter either way, once the ECU has recognised the existence of cruise control. (When added there is alearning process, as the ECU does not immediately illuminate the cruise control icon.)

Developing this argument, it is quite possible that the ECU could cut the power whenever the brake pedal is pressed, or have I missed something? Loss of the 12V brake pedal signal at the ECU would then result in loss of power. An intermittant connection at the brake pedal switch would duplicate this signal.

To illustrate the connections, I am attaching my modified copy of eLearn diagram E5060. Please note that while I used the designated fuse, F27, it is common to apply a loop at the bake pedal and use F28. Any loose connections could create the condition.

Apologies for the inverted diagram, which I should re-scan and save, but good practice for looking at the pedal switch.

Really appreciate all this. Thank you.

Don’t know if it makes any difference but I the cruise control appears to be an after market kit as it has two three button pads stuck to the dash board

I can imagine it works in a similar way with brake pedal switch but would it still be able to control the engine if turned off?

 

[cris1117]

Think you're missing the point the brake switch switch controls the fuel delivery to the engine so when you brake it cuts the fuel to save fuel, it also controls the cc so it is irrelevant if the cc is on or off or even not fitted.

The fact that the cc is playing up is just an indication it could be the switch.

 

[Communicator]

Think you're missing the point the brake switch switch controls the fuel delivery to the engine so when you brake it cuts the fuel to save fuel, it also controls the cc so it is irrelevant if the cc is on or off or even not fitted.

The fact that the cc is playing up is just an indication it could be the switch.

In the interests of accuracy, I have to disagree, but remain open to logical argument.

As far as I can see, the pinout for the Bosch ECU does not show any connection to the brakelight switch other than that used when CC is fitted, i.e. pin A54. On my 2.8jtd, this pin was originally left unconnected. It was only connected to +12V when I fitted cruise control, for which a change of pedal switch was necessary. There is no connection from the brake pedal switch to the ECU, other than this one.

It is therefore relevant whether CC is fitted or not. I accept that this may be different on other vehicles or engines.

My understanding is that in normal driving, when you braking, you normally take your foot of the accelerator , to operate the brake pedal. Without the additional connection CC would increase power to compensate for the drop in speed due to braking, hence the need for the additional input from the brake pedal which is normally +12V, and which is removed when braking. This could conceivably also be caused by a wiring fault. Whether or not the ECU has to see CC on at pin A53 before cutting injection, is a moot point. Possibly on my vehicle, I could try removing F27, and see whether it has any power.