1.3MPi 1998 Felicia with idling problems - Today it was taking itself up to 2000rpm and staying there or staying at ~2000rpm for a while then falling slowly to ~800-1000rpm. Other times it'd be fine. Sometimes it could be felt 'pulling' the car along when it should be over-running.

I checked various things and then it seemed to be idling too slowly! Around 700-800rpm but it didn't stall. Temp sensor and thermostat housing have been changed (because of a problem with bogging down), MAP sensor was oily but has now been cleaned, it has a new fan switch, the throttle body has been cleaned and the lambda sensor has been tested and is working properly.

The only other thing I haven't tried is re-setting the tappets and putting in a new inlet manifold gasket but I just wanted to ask about the 4-wire water temp sensor: if it is unplugged, at any temperature, all that changes is that the temp gauge inside the car stops working, as you'd expect. Should I notice any difference in the running of the engine if the temp sensor is unplugged?

Thanks,

Si

not sure if the 1.3 is the same, but on the 1.6 the breather pipes make a big difference to the tickover running, look for the pipes that feed back out of the engine into the air intake...they often get gunked up and the rubber goes soft and gets perished. - just something else to check and change.

not sure if the 1.3 is the same, but on the 1.6 the breather pipes make a big difference to the tickover running, look for the pipes that feed back out of the engine into the air intake...they often get gunked up and the rubber goes soft and gets perished. - just something else to check and change.

Thanks, but the breather pipe is clear. The oil on the MAP sensor was a bit of a concern but it hasn't returned yet.

Normal idle is about 800-900 rpm i think?!

If you've got a fast idle you could maybe try re-setting the throttle body... disconnect the battery negative lead and leave it off for about 10 mins or so... then re-connect and turn the ignition on and leave for about 30 secs... this will re-set the throttle body... its worked for me a couple of times with this problem.

Phil

Normal idle is about 800-900 rpm i think?!

If you've got a fast idle you could maybe try re-setting the throttle body... disconnect the battery negative lead and leave it off for about 10 mins or so... then re-connect and turn the ignition on and leave for about 30 secs... this will re-set the throttle body... its worked for me a couple of times with this problem.

Phil

Thanks, Phil. When it's idling slow it seems as though it's just not stalling, iyswim, but it never does so I suppose it's ok. I'll definitely try disconnecting the battery to reset the tb.

Just read the bit about the temperature sensor... yes you should notice a difference with it unplugged.

This sensor is quite important in this engine as it tells the ECU how warm the engine is and if broken can cause poor running of the engine.

If i dis-connect the sensor on my engine the revs drop and the idle becomes rough!

Give the reset a try and if its still not good look at your temperature gague... if it not reading properly then the sensor is most likely broken.

Just read the bit about the temperature sensor... yes you should notice a difference with it unplugged.

This sensor is quite important in this engine as it tells the ECU how warm the engine is and if broken can cause poor running of the engine.

If i dis-connect the sensor on my engine the revs drop and the idle becomes rough!

Give the reset a try and if its still not good look at your temperature gague... if it not reading properly then the sensor is most likely broken.

Ok, thanks. It's a new sensor so I'm wondering if it's the wiring. I looks ok and disappears into the loom after only a short distance but I'll have to check it somehow.

Si

Ah right... what happens if you unplug the sensor... nothing? or does the idle get even worse?

phil

Ah right... what happens if you unplug the sensor... nothing? or does the idle get even worse?

phil

All that happens is that the temperature gauge falls to zero. Absolutely no difference in the engine note or speed whatsoever. This can't be good.

Si

But the temperature guage is working properly then? So if thats the case then it can't be the sensor or wiring to it.

Would hazard a guess at either throttle body related or maybe something to do with distributor, spark plugs or air filter related?

Phil

Hmm i would consider making sure that the MAP sensor terminals are also ok and not rusted (green). If so give them a clean with electrical connector cleaner and cotton bud stick.

Other than this i would point towards the inlet manifold gasket as the original isnt up to the job to be honest and the replacements is much better.

An outside bet would be the crankshaft sensor but this tends to just affect starting.