Guest Sullen_Scrota Posted December 12, 2011 Share Posted December 12, 2011 Hi, SWMBO has a 1990 mk4 which misfires when it gets warm. So far I have replaced :- plugs leads coil pack I then compression tested the engine and it was 50psi down on No 2. So I took the engine out and rebuilt it ! Problem is still there... although compression is now good on all four cylinders. So I have now replaced.... EDIS 4 module Crank Position Sensor Air Temp Sensor Water Temp Sensor (in the head under the inlet manifold) Car starts ok and idles fine when cold but as it warms up it wont rev and starts to misifre and finally dies. Any and all suggestions welcome. SWMBO didnt appreciate my suggestion of a gallon of unleaded and a box of matches.... Russell Quote Link to comment Share on other sites More sharing options...
Guest Sullen_Scrota Posted December 12, 2011 Share Posted December 12, 2011 Oh, I have changed the throttle position sensor as well. Quote Link to comment Share on other sites More sharing options...
mickyfin32 Posted December 12, 2011 Share Posted December 12, 2011 i have a efi it use to start back fire and die it turned out to be a dodgy ecu... Quote Link to comment Share on other sites More sharing options...
Guest Sullen_Scrota Posted December 13, 2011 Share Posted December 13, 2011 Where is the ECU located on these cars ? Quote Link to comment Share on other sites More sharing options...
Guest shaun Posted December 13, 2011 Share Posted December 13, 2011 Are you sure you got leads on rightway round (right firing order) ? Quote Link to comment Share on other sites More sharing options...
Guest Sullen_Scrota Posted December 14, 2011 Share Posted December 14, 2011 Are you sure you got leads on rightway round (right firing order) ? Yes, definately the right way round Quote Link to comment Share on other sites More sharing options...
iansoutham Posted February 15, 2012 Share Posted February 15, 2012 The ECU is behind the centre console on the bulkhead under the heater unit and is hidden by a piece of felt-backed plastic covering. I would check the CO potentiometer (in engine bay next to suspension turret). These have a habit of breaking down over the years and can put the mixture excessively out, causing the engine to run lean or rich. To test, remove the potentiometer and, using a multimeter set to ohms, connect the middle and one outer pin and check the reading given. Now, using a small flat-head screwdriver, slowly and gently turn the potentiometer screw one way and see if the value smoothly changes. If it does, check the middle and the other outer pins and do the same. If it does not (which I suspect), then you need a new CO potentiometer (about £25 from Ford) and, once fitted, you will need to get the CO reset using a gas analyser (MOT station should do this for a drink). Quote Link to comment Share on other sites More sharing options...
jinks Posted September 3, 2015 Share Posted September 3, 2015 did you fix the prob I have same prob Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 4, 2015 Share Posted September 4, 2015 There is an air inlet temperature sensor on the inlet manifold as well near the plug for the engine wireing. Quote Link to comment Share on other sites More sharing options...
jinks Posted September 4, 2015 Share Posted September 4, 2015 (edited) the white one I got three and change them when I unplug it it runs bit better think my seconded hand tps is ka put awaiting on price also put new water sensor on the one under the manifold Edited September 4, 2015 by jinks Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 4, 2015 Share Posted September 4, 2015 Yeh I think its white, take it out the manifold when the engine is stone cold and warm up the sensor with a hot air gun and put it back in. If it dies then I'd say that was the problem. Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 4, 2015 Share Posted September 4, 2015 There's a few 1afa ecu's on eBay starting from about £20 if it turns out that is the problem Quote Link to comment Share on other sites More sharing options...
jinks Posted September 4, 2015 Share Posted September 4, 2015 so what your saying when I warm it up then put it back in and engine dies my ecu duff . if you remember I had this a bit lol Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 6, 2015 Share Posted September 6, 2015 Nah just the air sensor lol. Quote Link to comment Share on other sites More sharing options...
jinks Posted September 6, 2015 Share Posted September 6, 2015 few thanks . il just order one see what happens like I said I got three seconded hand one I have obtained in the shed unlucky if all three gone lol Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 7, 2015 Share Posted September 7, 2015 Have you tried the 3pin diagnostic thing on it? Quote Link to comment Share on other sites More sharing options...
jinks Posted September 7, 2015 Share Posted September 7, 2015 yes I did comes up air sensor but some said it always comes up with that fault so I I unplug it when I do the test who do you believe lol just started xrx44 got lots of welding Quote Link to comment Share on other sites More sharing options...
Stephen Bearded Minky Hill Posted September 7, 2015 Share Posted September 7, 2015 Hmm lol strange Quote Link to comment Share on other sites More sharing options...
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