New wheels on vito maybe caused limp mode?

[Jdhogg]

Hello and thanks in anticipation

I have check the usual thousands of threads re limp mode but nothing to do with the possible link to new wheels ,It may be co incidence but yesterday I had new alloys ( merc ) put on my 108 cito cdi with 16 inch 225 tyres and straight afterwards went into limp mode and no mount of ignition of /on will cure it.

is there a link with speed sensor / limp mode and can this be cured i dont want to put the steels back on looks great but cant leave it in limp mode either!!

Don eall the usual checks vacuum hoses on the top sensor etc and clutch pedal best i can.

Not checked underneath yet as i beieve there is another near the turbo which comes off?

as for the wheel fitting it was the norm jacked up each corner so off level could this effect anything engine on a wobble for a while???

any ideas useful


thanks in anticipation and i hope this thread in the right place thanks jon

 

[Simon_M]

I have not hear of much similar, but I sold a set of 18" C63 wheels to someone whose car had the 19" from factory and he had limp mode come on and needed some kind of STAR setting changed - very strange.

S

 

[Giantvanman]

The proof in the pudding is to put the steel wheels back, reset and go for a drive. Easy and saves a trip to get STAR checked. If it doesn't go into limp mode, you've answered the question; do I need to get a STAR setting changed when I put different rolling size wheel/tyre combo on. Good luck……..unless the resident van guru's are in attendance because they will know the answer, most likely.

 

[BIG UN]

Im not sure that swapping your tyres will put your van into limp mode. Never happened when i did mine but i needed to get it onto star to change the setting for the wheels as it obviously will effect your speedometer. Since mine has been adjusted(which took a bit of time) it is just about spot on. Hope that helps

 

[Jdhogg]

Right
Checked everything but I think maybe an issue with vacuum hoses
Does the turbo actuator get fed from the vac sensor near the wheel or the one in the engine bay next to the small paper filter ?
This one has three black pipes two at top one at the bottom one off the top to the egr and the other runs to a splitter which goes to the paper filter and on god knows where
The bottom pipe has nothing on it?

All three pipes in the sensor near the drivers wheel appear to be connected does this one feed the turbo ?

 

[Lord-WYBMAnE220]

Is the circumference/diameter of your new wheels the same as the old ?
A few percent should be OK.
Plenty of tyre size calculators on Teh Googles.

 

[Jdhogg]

hi yes not a huge difference lower profile but wider slightly..
however i believe the issue may be the transducer near the drivers wheel but would like to run it past you guys??
the actuator moves freely on the turbo and moves in and out about 10mm maybe bit more.
there appears to be about 8v constant to the electric plug on the transducer ( with ignition on)
appears to be plenty of vacuum on the in ( vac ) tube , i can only test with a motorcycle carb balancer runs off vacuum and it rises to the top...

however on the outlet to the turbo the ( out ) on the transducer there id very little hardly any vacuum not enough to register on the vac guage...

question is should the vacuum be move than whats going into the transducer? or significantly less? how does it work and is this normal operating proceedure?

thanks in advance

 

[andyboyt]

Hello,
I'm andy, a merc tech,
You said it's a 108 so it's an old shape 638 chassis, changing tyre sizes won't take it into limp mode, but I have had it before on two occasions the rear tyres were slightly bigger than the fronts, so the vehicle thinks it wheel spinning all the time, on both occasions the esp warning light didn't come on, and the vehicle was in limp mode, so make sure all 4 tyres are the same size
On the vacuum side it's critical there's no leaks, most of them have vacuum operated headlamp height adjuster. Put your lights on and move the adjuster inside the cab and see if the lights go up and down. If they do the vacuum side should be ok, the waste gate defaults open, so get someone to start the vehicle as you watch the wastewater, it should close the waste gate slowly after engine started,

 

[Jdhogg]

Hi
Thanks guys yep tyres all ok and headlights do adjust however I have checked the vacuum into the transducer on drivers side wheel and there is plenty of vacuum however next to nothing coming out into the actuator
On start up the actuator does move about 10mm then nothing
If you rwmove the vac supply doesn't move and if you replace it nothing ...
When the engine turned off the transducer ticks and whines for about 1 minute like the diaphragm is knackered ?

Hopefully this is it?
Cheers jon

 

[Jdhogg]

Problem solved

Faulty turbo transducer

Just mad coincidence went when new tyres on!

Cheers guys

 

[FraserWaters]

Hi
Just came across this old thread but I had a similar issue this morning, swopped my Vito w639 tyres on the rear for a pair of beefy 225/75/16 on steel rims but didn't do the front yet, they're 225/55/17 on alloys. I know it looks weird but i can't afford the new front's until payday.
Van drives spot on but after about 3 minutes of driving the speedo stopped working and the BAS lights came on, switch off and the same again after 3 minutes of driving. It doesn't go into limp mode as such, it still drives fine but no speedo, luckily i have a GPS speedo too.

My question is what is the allowed difference in rolling dia to stop this happening, could i put 225/70/16 up front and 225/75/16 out back? I'm a bit worried about clearance on the front when going lock to lock...

Cheers...

 

[AEMILIUS]

Hello,
I'm andy, a merc tech,
You said it's a 108 so it's an old shape 638 chassis, changing tyre sizes won't take it into limp mode, but I have had it before on two occasions the rear tyres were slightly bigger than the fronts, so the vehicle thinks it wheel spinning all the time, on both occasions the esp warning light didn't come on, and the vehicle was in limp mode, so make sure all 4 tyres are the same size
On the vacuum side it's critical there's no leaks, most of them have vacuum operated headlamp height adjuster. Put your lights on and move the adjuster inside the cab and see if the lights go up and down. If they do the vacuum side should be ok, the waste gate defaults open, so get someone to start the vehicle as you watch the wastewater, it should close the waste gate slowly after engine started,

Yes, you're right !!!!!!!! Hello "limp mode lovers" !!! Yes indeed, this limp mode drive us crazy. I just run out of limp mode because of changing the rear wheels tires. I changed all the summer tires into the winter profiles, but for the rear wheels I got some old, but still in good shape tires, but a little bit different as the front ones - the height - 65 not 55 as the front ......and our super car feels the difference ....very sensible car, dear ! So, I deserve a limp mode ! After 400 km running in this beautiful way. I had the idea to replace with the old summer profile height 55 and Bingo ! no limp mode. Conclusion, take care of the tires you put on your merc ! And, another thing..... HAPPY NEW YEAR WITH NO LIMP MODE TO EVERYONE !!!