Running cold

[garethcab]

Hi all,

For the past month or so, my 1995 Cabrio has been starting to run a bit rough, not stalling, but not smooth. I've changed the plugs, leads and Dist cap/arm, no change and i'm about to start the usual suspects of relays/pipes and coil.

I noticed yesterday that it doesn't seem to get up to temperature. I know it's gone colder, but yesterday when I got home after my 30 mins drive with a mixture of motorway and b roads, it was reading about 80*. Today on the way to work, it was lower.

Both my other two vag cars read 90* within a few minutes.

Could this be the thermostat? Anyone else had this and could it cause my rough running? No errors reported by the ECU apart from the 3 I already know about (immobiliser, vehicle speed sensor and abs sensor.)

thanks

[harlemex]

yes it is. 

[Khare]

Yeah it does sound like the thermostat is stuck open.

The vehicle speed sensor *could* be why it's running rough. Mine was dodgy and once in a while when accelerating it would die then get back to life within a second. Changed that and all fine now.

Try cleaning the throttle body, I bet it's black from the years of gunk, that's one of the biggest reasons for rough running, most of the time it's the gunked up throttle body.

[garethcab]

Yeah it does sound like the thermostat is stuck open.

The vehicle speed sensor *could* be why it's running rough. Mine was dodgy and once in a while when accelerating it would die then get back to life within a second. Changed that and all fine now.

Try cleaning the throttle body, I bet it's black from the years of gunk, that's one of the biggest reasons for rough running, most of the time it's the gunked up throttle body.

Hmm, might get a new sensor then, kinda assumed it was just for the speedo :-).

If i remember correctly, changing the thermostat is not easy, but not difficult, just a pain. I seem to remember having to remove the water pump in the distant past on my mk2 gti.

[Khare]

MK3 stat is easy, you need to remove the PAS pump, but that's a 2 minute job. The 2 stat housing screws are then right there. Over all I'd say it's a 20 mine job from start to finish. Vehicle speed sensor is a pain though. Not sure on the 8v, but the 16v it's in a VERY awkward position and the way I did it was by dismantling the complete front end, then it was easy to reach.

[Khare]

Forgot to say, the speed sensor is behind the front engine mount. So I had to remove the engine mount to access the screw holding it on.

[garethcab]

Is it this?

[Khare]

No, that's the speedo sensor.

Vehicle speed sensor is this:

http://www.eurocarparts.com/ecp/c/Volkswagen_Golf_2.0_1997/p/Car-Parts/Engine-Parts/Fuel-and-Engine-Management/Engine-Management-Sensors/?494440200&1&7236e23f4727546bf71a42bb04fc256ffda25846&ESPS


That's the one I bought for my 16v, but as it says on the description, will fit 8v models as well.

[garethcab]

Arr, 1 see.

You said it's a bit of a pain to get to. I'll have a poke under the bonnet in a bit to see if I can see it. Might be the case of thermostat and speed sensor in one go, i.e whilst i'm under the car.

I'll pop up to Europarts tomorrow to see if they have any.

Thanks.

[Khare]

Good luck!