Homer Posted September 28, 2009 Share Posted September 28, 2009 At low RPM under anything more than 10% throttle the engine stutters, almost like a misfire, but not quite. It's worse at lower rpm, but tends to go away once the revs get above 3500-4000rpm. Once at above that rpm the stuttering goes away and it accelerates as normal. It seems to be load related as it gets worse the high the gear. Also fuel economy seems to be dropping. I've changed the plugs even though the originals looked new, but this didn't make any difference. There's no sign of smoke from the exhaust and no other indication of problems other than it not being serviced in a year or two. Any idea's as to the cause? Air flow meter? Coil packs? Is there any easy way to read error codes? Ford are hopeless, they refuse to do anything until they have hooked it up to their computer, which costs £80. That's without then doing anything else... It's a 1998 Mondeo 5spd 2.5 V6 (Duratec engine) Quote Link to comment Share on other sites More sharing options...
nevins Posted September 28, 2009 Share Posted September 28, 2009 common thing to go is the tps, from past experience Quote Link to comment Share on other sites More sharing options...
den1 Posted September 28, 2009 Share Posted September 28, 2009 Guy at work has a 1.8 mondeo (Same Symptons) and the problem with that was the Throttle Position Sensor Quote Link to comment Share on other sites More sharing options...
Homer Posted September 28, 2009 Author Share Posted September 28, 2009 That's what I like, two quick replies saying the same thing Thanks guys I'll go have a look into tps issues, I was getting a bit confused with this before as the Duratec uses a fly-by-wire throttle system, which seems to not be used on the other models. Guess if it's the tps it doesn't matter though? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted September 28, 2009 Share Posted September 28, 2009 I was all set to say timing, but if its drive by wire that must be taken care of in the ECU, think you were right with the flowmeter Quote Link to comment Share on other sites More sharing options...
andyou Posted September 28, 2009 Share Posted September 28, 2009 check all the hoses mate had the same prob with me st200 Quote Link to comment Share on other sites More sharing options...
Steve Posted September 28, 2009 Share Posted September 28, 2009 Any help? http://www.fordfuelinjection.com/?p=30 Quote Link to comment Share on other sites More sharing options...
nevins Posted September 28, 2009 Share Posted September 28, 2009 When ever these symptoms have come up its been the tps 99.9% of the time. Hope this helps you out mate Quote Link to comment Share on other sites More sharing options...
Homer Posted September 28, 2009 Author Share Posted September 28, 2009 check all the hoses mate had the same prob with me st200 Had a good look around but there are very few of them and couldn't see any signs of cracks. The engine is very low mileage and everything seems to be in great condition. Any tips as to where to look as the ST200 seems to share then same base engine? Any help? http://www.fordfuelinjection.com/?p=30 Thanks Steve, very helpful! Will take a look at that tomorrow When ever these symptoms have come up its been the tps 99.9% of the time. Hope this helps you out mate Cool, not sure how to check the tps on these engines, but have a feeling a new one is going to cost a pretty penny! Thanks all for your replies Quote Link to comment Share on other sites More sharing options...
Ian R Posted September 28, 2009 Share Posted September 28, 2009 It could be because it has a Ford badge on it Sorry couldn't resist Quote Link to comment Share on other sites More sharing options...
nevins Posted September 28, 2009 Share Posted September 28, 2009 The way that i check them was by using auto diagnos, basically reading the live data while operating the throttle by hand. By doing this it would show the signal drop out or jump out of range. If you do swap it ideally you will want to set it up watching live data also, to set it up properly. Quote Link to comment Share on other sites More sharing options...
Homer Posted September 28, 2009 Author Share Posted September 28, 2009 It could be because it has a Ford badge on it Sorry couldn't resist For sure, they are bloody terrible cars, will never buy another Ford (unless it's got a jumping horse on the tailgate ). Quote Link to comment Share on other sites More sharing options...
Homer Posted September 28, 2009 Author Share Posted September 28, 2009 The way that i check them was by using auto diagnos, basically reading the live data while operating the throttle by hand. By doing this it would show the signal drop out or jump out of range. If you do swap it ideally you will want to set it up watching live data also, to set it up properly. How should I go about doing that? I don't have an oscilloscope, just a multimeter. Quote Link to comment Share on other sites More sharing options...
nevins Posted September 28, 2009 Share Posted September 28, 2009 a quick non technical way of doing it is find a donar car with the same set up, then while still in place mark the sensor in a place where you can line it up identical onto your TB. This should be ok for testing, and most of the time is a suitable way of doing it. Quote Link to comment Share on other sites More sharing options...
tooley Posted October 1, 2009 Share Posted October 1, 2009 i had an st200 and its common fault....theres a fix for it jump on the st200 forums its fixed with a piece of pipe and a small hole in the pipe Quote Link to comment Share on other sites More sharing options...
Homer Posted November 21, 2009 Author Share Posted November 21, 2009 Ran out of patience with this so booked it into a local (decent) garage. Two really simple faults in the end: 1) One of the new plugs I'd bought had a crack in the top insulator 2) One of the clips to the plug (on another cylinder) had a poor connection, it was crimped up as a quick fix This was resulting in the spark on one cylinder running down the outside of the plug (the plug had a burn line down the outside of the insulator) and was essentially running on 5 cylinders when under load. Seems to be good now, but still has a occasionally has a little hesitation at low rpm. but nothing at all like before. The garage said the timing report showed some erratic behavour results still, they said the coil packs, TPS and airflow meter were all tested and showed no problem, but though the leads is the most likely cause and recommended replacing those. Thanks for the advice all Quote Link to comment Share on other sites More sharing options...
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