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Showing results for tags 'fuel economy'.
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Hi all, my 1.4 8v polo (AEX) is having some odd issues, they’re not much of a problem at the moment but want to nip anything in the bud. 90% of the time it idles fine but occasionally it’ll idle at a noticeable higher speed for 10-20 seconds and then drop down to a near stall before stabilising again. Recently I’ve also noticed that sometimes if I stall the car it’ll be very sluggish to start again, struggling at about 500rpm until I give it some throttle, it’ll run fine again after that. I’m wondering if this has anything to do with the temp sensor? It seems to heat up fine and show on the gauge but the gauge has never, ever moved past about 90, even on 5+ hour motorway trips. my other thought was the PCV valve? I often get a very oily petrol smell when stationary with the blowers on, and there’s a fair coating of oil in the air box.(level has never noticeably dropped while I’ve owned the car however) Any idea what I can do to test all these, should I even be worried? Cheers
zob posted a topic in Engine, Transmission and ExhaustNew to the Polo scene after buying a '93 Mk2F Bready reacently. Its got 145k on the clock and has its problems but mechanically seemed sound enough (for the price) when I bought it. First drive after getting the keys was Southampton back to Birmingham and it behaved fine so I was happy enough. However I've noticed a few problems and they all seem to be inter-related. I'm trying to work through them using fixes I've picked up from these forums, however no one thing I've tried yet has done the job. Problems: 1) Temp gauge never got higher than ~75 on a long run, although the fan did kick in when parallel parking (lots of revs to get up a curb!) after a long journey. 2) Starts ok but idle is lumpy and until its vaguely warm any light use of the throttle almost kills the engine. Have to keep revs high to change gear when cold 3) Loads of white smoke and the smell of unburnt fuel, especially when cold. Tried solutions: 1) Coolant and temp gauge sensors relatively new (replaced by previous owner). Checked the blue coolant sensor when cold and has a high(ish) resistance - ~5kohms. Gauge sensor is similar (but a correct colour - black) 2) Tried warming up the engine and then blipping the throttle a few times past 3000revs (or what i believed to be - no revcounter on this car) with the blue sensor plug off, replaced it after. Supposedly to clear any error codes associated with the sensor after it was replaced. 3) New fuel filter put on recently by previous owner Possible solutions (yet to try this weekend): 1) New thermostat housing put in a year ago (according to records) but no thermostat on the service bill - seems mad to replace the housing but not the 'stat but you never know. When heating the car up I tried to see if I could feel warm water entering the radiator earlier than it should but it was inconclusive. My feeling is the 'stat, if faulty is opening early rather than just being stuck open. 2) New plugs and leads - only pulled one plug so far (have to remove air filter housing off the top to get to the rest) and was pretty carboned-up. HT lead plug had some green corrosion around the nipple seat. Could it be simply time for new plugs and leads? 3) Throttle body clean - looks clean enough to me but worth a squirt. I found a link (unfortunately now old and dead) to supposedly a guide to adjust the Bosch monotronic SPI - anyone know if this is a thing? Something about throttle idle stop screws (I'm new to fuel injection here!) 4) Lambda sensor? No revcounter to test how it holds revs when warm but might be able to hear any fluctuations by ear. My feeling is this wouldn't have much to do with it running bad when cold The car had its MOT last month and failed first time on emissions (v badly!) and I can see why now. Its definitely running too rich when cold and may well be all the time. Air filter was changed again recently too so its not that. Could most of these problems be down to poor plugs+leads and an engine that isn't getting to temp often because of a slightly dodgy thermostat? Could it just be that the ECU isn't switching to a closed loop mode because the engine isn't getting to temp / it doesn't think its getting to temp?