F-Tar

Hey guys!

I have a friend that owns an 325d E91 2007, just sat down and did some coding and i noticed the rev limit scale for cold engine was way above rev as it should be for driving som KM. Rev limiter in KOMBI seems to be stuck somehow, it will never ever go down at full engine temp (Bottom), It always stays in 4000 section.

I've never heard myself that this would be an issue, In my M54 the scale goes down to the bottom after a 10-15min driving in atleast 10C temp outside. KOMBI stores no errors, nor DDE. (M57 engine)

And i'm sorry for posting this at a 5series forum but e90post won't let me post nothing. The cluster is the same for a 3/5ser that has iDrive so it's pretty much the same thing.

So has anyone of you guys ever heard about the rev limiter scale (upon engine start) never reached the bottom? Not even after driving for like 1 hour? If you don't get me, let me post a pic.

Thanks.

tom_il

Are you sure it is movable ? On the E60/61 LCI they have taken away this feature. Probably they did the same on the E90/91

F-Tar

Hi.

Yes im positive, i mean.. Why would they put it there for no good reason? Then if it's not ment to be functional it's better of not having any cold engine scale at all! This is a E91 pre-LCI btw.

Redtwin

Mine never fully retracts even when the car is showing 93c coolant temp. I think it sticks at 4500 RPM with 4 little lines showing on the scale.

Car is an '06 535d.

F-Tar

Hmm, maybe and probably cus it's never able to reach full engine temperature.. Atleast 100C should be operating engine temperature. All those lines should be at the bottom.. But when you start the car for the first time of the day.. Are those lines futher up? Then goes down to stop when it's 4 lines left? Faulty engine thermostat can do this.. But in this 325d there was no errors stored in ECU.. Plus that the lines (scale) never ever moves. Not even when turning engine and ignition off!

Redtwin

I had brand new original BMW main and EGR thermostats fitted a month ago. The thermostat is set to open at 88c (it's printed right on thermostat) so not sure why you think 100c should be normal operating temp?. Maybe the petrol models run at that temp, but never heard of a diesel E60 doing so unless it had cooling problems.

When the car is first started from cold all the lines are showing up around 4000 rpm on the tacho. When fully warm...or I should say, as warm as it is going to get, the lines drop down to about 4800 and there are 4 showing.

Faulty thermostats won't show any errors. What coolant temp does that 325d run?. Even when my thermostats were bad and I only got 65-70c the lines would still move. On my car the lines drop about halfway when I reach 60c.

I am just going off memory, I don't sit watching and counting the lines when I am driving.

F-Tar

Hmm.. maybe i'm misstaking with a different car.. I remember there was an operation temp of 100C, think it was in a 2013 caddy. In my 530 the engine temp is around 100C, but as you say, gasoline engines might have an higher operating temp than bmw diesels. Short Circuit should throw error but if it's stuck there are no errors. I still wounder why your lines stop when it's four left. In my 2004 they drop to the bottom. And in 325d they never moves, stange things.

I never had the chance to look up the coolant temp on 325d, i started with the research afterwards, if this was an common issue or no.

Maybe it's his thermostat that needs to be changed. It's not good for the engine not getting at operating temp. But as said, not even when ignition off the lines get's to the bottom. So that's really odd.

Redtwin

What would short circuit and show an error?. The Kombi?. If it is just the temp dial that is faulty that wouldn't be important enough to cause an error.

I don't worry about 4 lines showing on my gauge, I check the coolant temp and as long as it is over 88c, I am happy. Those little lines are only a rough guide anyway.

If his diesel won't reach that temp his thermostats needing changing. That is way more important than the lines on the kombi.

F-Tar

The thermostat. No.. KOMBI does not store those kinds of errors, but DDE/DME does. It's not nessecerly to cause an warning light to turn on.. But most of the BMW's out there has errors stored in ECU which not causing a warning light. Most common in my opinion is the aux water pump, it always fails without any errors on dash, but still stored in ECU.

I always follow those small lines, if they're not in the bottom i cannot put any pressure on the engine.. I wan't full temp before i start to play around.

Yes, ofc it is. But if the thermostat is stuck it will show no errors, if it has some kind of short circuit an error occurs in DDE ECU. But that is also very easy to diagnose, you will not get any hot air into ur car if the engine isn't getting at operating temp. Also this error is diagnosed all because these small lines cus the won't reach bottom, i guess they're pretty inportant after all.

But still, weirdest thing is that why those lines won't go to the bottom even when igition off and car locked.

Redtwin

There is nothing electric in the thermostat to short and cause an error. Many diesel BMW drivers know first hand that failed thermostats give no indication of their failure until things start to go very wrong in that the DPF no longer regenerates and eventually blocks costing serious money to sort. Even the heater still blows warm air.

70c coolant temp is enough to keep the cabin warm, but not enough to allow DPF regeneration.

I don't know what more I can say about the small lines. Mine don't go to the bottom even when the coolant is showing 95c...a full 7c above the operating temp of the thermostat. If yours do, great, we have very different engines in our cars. I would rather check the actual temp of the coolant to know when it is up to full operating temp rather than rely on lines. Your friend's 325d is proof enough that those lines should not be relied on as his don't work.

Why don't they work?. My guess is that the mechanism that moves the dial is faulty or the dial has somehow become detached and no longer moves.

If that happened to my car I would do absolutely nothing about it. It is just another gauge (the MPG swing-o-meter is the other) that doesn't give accurate information. I am sure you know the newer LCIs don't even have that temp gauge.