1996 C180 revs jump from 700 to 2000

[jayo70]

Hi, Ive read through previous posts and there are a few similar things but not sure if they are related so please forgive me if im asking something that has been discussed before Im a newb. and dont really know a lot about engines, or anything else come to think of it.

I just bough a manual '96 c180 very happy but was having difficulties with hill starts and reversing so spent a little time running it through its paces and noticed a few possible problems. Like I said I know pretty much nothing so would appreciate anyone's help.

When I start the engine the revs go straight up to 1200 and then back to 500ish where they hold but the idle can be a little rough.

When its out of gear and I press the accelerator, nothing happens for a bit but then the revs jump to 2000 with a minuscule increase in pressure on the pedal, its almost impossible to hold the revs anywhere in between.

She drives ok a little bit snatchy when pulling off in 1st, either very slow or over revving it takes alot of control to move off gently.

When doing a hill start, reversing or any sort of clutch control, unless you hold the revs too high, they shoot up to about 1700 and then down to under 500 and then the engine generally stalls.

At high speeds and higher revs its perfectly good just seems to have this low rev problem

Just bought the car today so would be very very obliged if anyone could
a) tell me if Ive got a turkey, and/or
b) tell me if I can solve the problem

It had been sitting idle for about 8 weeks prior to the purchase

Many many thanks for any help

 

[grober]

There are 2 types of throttle control on these cars. A straight cable system and a electronic "cable-less" type. First thing to establish is which you have got. If its the cable type it may be best to replace the cable if its sticky. If its electronic it could be the sender unit attached to the throttle pedal or the actuator on the throttle body. The other thing that often happens is that the throttle plate orifice gets dirty causing the throttle plate to be "sticky" a removal of the cross engine air inlet pipe and a careful clean with carb cleaner or similar solvent if often all that's required.

 

[andymerc]

As grober said clean thottle housing,also check the two springs on the thottle housing as it is a common fault for the return spring to break.

 

[jayo70]

Thanks guys never even thought of that was panicking with visions of wasted money.

used to driving ancient old big diesels that you can fix with a bash of a spanner so things like spark plugs and carburettors and the like terrify me.

Thanks again