economy gauge

[stevie-b]

merc 190e auto 1988,the economy gauge reads in the red when engine is switched off,the car is also a bad starter when cold,could the two be connected,cheers

 

[Hal Fisher]

My economy gauge goes into red end when I shut off ('85 500sec).

Your hard start problem is probably one of two things: The Idle Speed Controller or the Idle Speed Valve. There has been plenty written on this issue so do a search to see the proper ways to test and where to get the part the cheapest.

Hal

 

[bdylan]

Economy guage

I have a 1985 190E. The Mercedes dealer tells me it is normal for the guage to show red when the engine is switched off.

I also have a starting problem when the engine is cold.
Any info would be helpful.

Regards

RE

 

[classicsl]

economy gauge problem

I also have a problem with the economy gauge on my 88 (107) 300 SL. When coming to stop the needle drops to the bottom, but then rises back up to about 25% across when at a halt. is this something to do with the tick over speed of the engine as it does feel a little rough on the break pedal

 

[mike65]

Cold start could be any one of the following

Dirty Throttle body esp butterfly valve
Failed engine temp sensor (should say water temp sensor!)
Failed/blocked cold start valve
Failed OVP relay (unlikely)
Blocked/damaged vacume pipes
Failed Aux Air Device.
Maybe O2 lamba sensor if you have CAT.

You'll need to do a search here and give more details if you can.


Mike.

 

[classicsl]

thanks for that mike. its just had its B service last week so much of the things you mentioned would have been checked or cleaned out as part of the service wouldnt they? its going back to the same place to be checked out

 

[pulse]

of now this thread is old but here i go.

i just got my sec 500 back from service and notice that the economy gauge is at the extreme end of red, whether engine is on or off. i also think i got a big backfire (not 100%). i will be taking car back to garage but is it a major problem that its stuck in red?

 

[paulcallender]

The economy gauge is actually a vacuum gauge, which isn't quite economy but that's a different issue. In the red = no vacuum = full throttle. In the white = lots of vacuum = closed throttle. So, if its in the red, its reading no vacuum, which means 1) the gauge isn't connected or its vacuum line is disrupted, or 2) its connected but you have a massive vacuum leak somewhere. This would affect running! Its possible that the gauge isn't connected, and the resultant (not so huge) vacuum leak caused by its non-connection, affects your running.

 

[tom7035]

I think Paul has hit the nail on the head, and I would be sure to mention this when you take it back to the garage. Sounds like rather sloppy servicing to me, too.

 

[pulse]

thanx for that guys, i thinks its the gauge i't connected as it was working before taking it in. question is, do i now let them near the engine to fix damaged valve ?

 

[tom7035]

I wouldn't condemn the garage entirely. I've often forgotten to connect up the odd wire or tighten a jubilee clip or something after working on the car myself. If in fact they've just forgotten to reconnect (or inadvertently disconnected) your vacuum gauge maybe they'll be on their toes next time!
We're all human after all and as such liable to err!
Cheers.

 

[paulcallender]

I wouldn't condemn the garage entirely. I've often forgotten to connect up the odd wire or tighten a jubilee clip or something after working on the car myself. If in fact they've just forgotten to reconnect (or inadvertently disconnected) your vacuum gauge maybe they'll be on their toes next time!
We're all human after all and as such liable to err!
Cheers.

Agree, but make it clear that they "owe you one"!

 

[pulse]

i went in this afternoon and guy apologised and quickly got it connected even though they were busy and due to close at lunchtime. Little things like that keeps customers coming back.

 

[tom7035]

Well done pulse and thanks for getting back to us - and a coconut to Paul for his diagnosis!

 

[shirubaby]

I also have a problem with the economy gauge on my 88 (107) 300 SL. When coming to stop the needle drops to the bottom, but then rises back up to about 25% across when at a halt. is this something to do with the tick over speed of the engine as it does feel a little rough on the break pedal

I too have exactly the same behaviour with my vacume guage. and I have a w124 300ce... although, when I bought it, it wasn't working at all...major vacume leak in the tube running from the manifold to the economy guage. now that it's repaired (with a rubber mating pipe)... I still dont' know why the vacume guage is 25% across when idling. In my w126 500se, the needle is all the way to the left (highest economy) in idle.

what the fault? is there a fault? can anybody help?