Hi
I have been having some troubles with my 2006 Automatic.



It started a while ago with the engine not starting properly and me having to crank for quite some time before anything happened.
I exchanged the crankshaft sensor (for Bosch 0261210170 – equivalent to 0031532728) which didn’t do the trick. I then changed the Camshaft sensor (for Bosch 0232103114 – equivalent to 0041536928). That didn’t do it either. I re-soldiered the Relay control unit – didn’t help – still had to crack for a good while before it started. Then, after some fault-finding and reading, I decided to change the fuel filter – from a non-branded to one to Bosch. It did the trick – the car start every time now at first try. My guess is that the valve in the filter gave up.



However, I now noticed a new problem.



If I put my foot down all the way down the tranny does not shift up unless I let go of the gas. It will come to around 4300-4400 revs and stay there and the car stays at whatever speed I am going. Unfortunately this happens at any speed (and gear). If I take the foot off the gas it upshifts as normal at that point.
If I am driving normally and decide to speed up it shifts down one step as it should but then it hits the magic 4400 and sticks in that gear unless I let go a bit.
When I use the “manual” it all works fine and upshifts as and when I decide but still does not seem to go above 4300-4400 revs.

I guess my questions are:
Any idea what this could be?
Is it related to the sensors I exchanged and if yes then which one?

The thinking here is that these are for a SLK320 but not necessarily for a crossfire but I struggle to see how it would affect it.

Thanks for any help.

 

Your problem is the max 4400 RPM, holding the pedal down should shift up at about 5200 RPM, but since it isn't getting there, no shift.
I have no idea why 4400 is your limit.

 

Only thing that comes to mind here.. wheel speed sensors.. much as your car will rev limit if your not rolling forward.. "burnout" in water .. same reason dyno pulls are a problem..

 

Look for any codes set, they are a great help. The CEL does not have to be on. My guess is the electrical plate and the solenoids.

 

Would that be the same limiter as when your in neutral and rev the motor..?

 

Mrmiata - My guess was that the problem is with some kind of sensor . However, my line of thought was that it had to do with the two I exchanged.

Onehundred80 - Hmm the engine light did not come up but that I could still check the fault codes. Hmm will standard OBD fault checker show gearbox faults or do I need the special one for that?

 

After a day of testing I might finally have found the issue
I drove on the motorway and started testing driving in manual. I shifted down to 3rd and accelerated hard. If I put the foot all the way to the bottom the car would max out at around 4500 revs. If I let go slightly, just before that tick point it would accelerate slower up to 6000 etc. That happened in 2 and 3 - gears I tested. I assume this sounds like a fuel pump issue - is my assumption correct?