Mondeo air con rough running

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Fri 29 Apr 2005 14:45
Mondeo air con rough running - Bigtone
Hi All
I have a 1998 Mondeo TD, When air con is switched on the car runs like a pig (i know air con saps some power but this seems a bit extreme). If i remove the air con belt and switch on there is still a drain on engine maybee ecu should tell the injector pump to run differently when air con is on, but in this case going wrong somewhere! any ideas?
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Fri 29 Apr 2005 19:25
Mondeo air con rough running - Dave N
Does the a/c work?

If it works, then it may be an idle-up issue. If it doesn't, then your compressor is toast.
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Tue 3 May 2005 11:24
Mondeo air con rough running - Bigtone
Yes the a/c works fine, as does the idle up
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Tue 3 May 2005 20:03
Mondeo air con rough running - Dave N
I read your post better this time, so am I right in thinking that even with the belt disconnected, but the a/c on (even though it's doing nothing) it still runs rough?

When you say runs like a pig, what do you mean exactly? I took it to mean it wasn't idling up and bogging down, but you say it is idling up. Not sure how it can idle up, and run rough.
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Thu 5 May 2005 17:56
Mondeo air con rough running - Bigtone
Dave
Yes with the belt disconnected at idle you can still hear a change in engine note, When belt is put back on at idle apart from a slight change in engine note the car idles as normal (idle up working) But when car is in motion it is very sluggish and feels like it has a misfire under accelaration. If air con turned on at 70mph you can feel a distinct change in the car. Also Fuel consuption changes from approx 45-50mpg down to about 25-30mpg
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Wed 4 May 2005 00:34
Mondeo air con rough running - aircool
Just a thought, did the rough running still happen with the belt off, and the ac switched off, because it could be the condenser cooling fan vibrating badly.
regards
Steve
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Thu 5 May 2005 17:57
Mondeo air con rough running - Bigtone
With air con switchd off car drives as normal
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Fri 6 May 2005 01:21
Mondeo air con rough running - aircool
It may have been overcharged,this will overload the compressor, but to clarify, with belt off, ac swiched on, fault is there, with belt off, ac switched off,it is fine?
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Fri 6 May 2005 11:43
Mondeo air con rough running - Bigtone
aircool
Belt off/ a/c off,its fine.
Belt off, a/c on, change in engine note at idle, drives fine.
Belt on, a/c on, change in engine note at idle, drives poor
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Fri 6 May 2005 16:04
Mondeo air con rough running - Dave N
Assuming the compressor isn't about to seize, and the system has the correct charge, it may be you're just experiencing the normal load of the compressor coming on and off. These things can take up to 8/10hp, and can have quite an effect on the driveability.

I had V6 mondeo, and I got a fair jolt when it cycled on and off at 70mph.
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