Club 80-90 Forums

My 2.1 DJ digijet van has an occasional stalling prob at low revs, junctions and parking etc, usually before it has got up to temp, but sometimes when warm as well, wondered if the temp sender in the 'stat housing could be to blame, the engine seems to run a bit rich and smells a bit like there's unburnt fuel in the exhaust gasses, timing is spot on, all ign parts are fairly recent, plugs pretty new, new fuel filter, injectors were ultrasonically cleaned and tested about 18 mnths ago, the idle speed stabiliser unit was replaced about a year ago, going to clean and check the little throttle position switch under the throttle flap housing and set it, but just wondered if the temp sender could be acting up, and would these symptoms indicate a faulty one? any advice would be great!

I suppose the most sensible reply to this question is try to get hold of a Bentley workshop manual as this has various sections on how to check the wiring and associated components.

It also gives you a list of expected values at various temperatures when bench testing water temp senders.


Regards

Fritz,,,,,,,

PS, I doubt such detailed information is covered in the Haynes manual.

That makes sense, Ta, Fritz.

I would replace the ecu temp sender as a matter of course, if it is giving the incorrect temp to the ecu, then the ecu will provide the wrong mixture via the duration of the injectors.

Another thing to have a look at is the copper tracks on your air flow meter. Lever off the plastic box on top, and visually check the condition of the tracks, also check the air temp sensor that is part of the air flow meter.

Another cause of poor idling is a worn throttle body, check for play and wear in the shaft when you take it off to clean the throttle position switch.

Also check that the idle stabilisation is actually working, if you have power steering and a big alternator the unit should lift the revs accordingly to take the load. The unit should buzz audibly when ignition on, but not running. Also check and clean the hole in the oil crankcase breather where the wire plugs in by the rubber bellows after the afm.

Lastly go through all the wiring connectors and look for corrosion, a good squirt of WD-40 every now and then keeps corrosion at bay, and as all the sensors work on resistance, any corrosion will upset the ECU.

This is the innards of the AFM.



I an gonna have a go at tunning it on the rolling road, or with an exhaust gas lambda probe that I wish to install, so as I can see what is going on whilst driving.

Many thanks for that info, Simon,
I have looked at the innards of an airflow meter before, but i'm reluctant to fiddle with this one, as it's a re-calibrated, recon one from ATP electronic developments in staffs, and i'd void the warranty by taking the top off! they fit a new air temp sensor in them too. (my original suffered damage from a big backfire when running on LPG with various air leaks, and badly out of tune)
will check for play in the throttle spindle, and look at getting a new genuine temp sender i reckon,
the air bypass valve (if thats the correct term for it) near the fuel press. reg. does buzz away when ign is on, and i took it off and cleaned it out with brake cleaner just to be sure it wasn't gunked up,
be very interesting to know what results you get from fine tuning the AFM when on a rolling road