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EFII Ghia owner
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355 Posts
Discussion Starter #1
Hey all,
i have an EF i6 and whenever I put the air con on the engine runs rough, and engine becomes sluggy with a very noticeable power drop, whenever the air con cycles off there is a big power boost, what and why is this happening?
without the air con on the engine is very smooth, you can barely notice the engine is running
thanks
 

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Shaken Not Stirred
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328 Posts
I have EXACTLY the same problem in my EF Fairmont Ghia!

Have no idea whats wrong but its a major pain in the ass!
 

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30 Posts
from the start air conditioning always has and always will effect horsepower. on a hot day u will have your air conditioning on full blast, which can use up to 10% of your horse power. u may have other problems with your car if its that noticeable, but keep this in mind.
cheers.
 

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EFII Ghia owner
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355 Posts
Discussion Starter #5
not ford said:
your IAC valve might be stuffed or full of carbon.
but it only happens when the Air conditioner is on
 

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We all know that A/C takes power from your engine, Our alternators should overcome this, But if your alternator is old and the bushes are on the way out, Your alt.. can't cope with the Power usage... Try checking the wires in the back of your Alternator or get it checked out...
 

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Old Ford Fan
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340 Posts
MakoZH said:
We all know that A/C takes power from your engine, Our alternators should overcome this, But if your alternator is old and the bushes are on the way out, Your alt.. can't cope with the Power usage... Try checking the wires in the back of your Alternator or get it checked out...

Ac takes mechanical power from engine- blower takes electrical power from alternator, then alternator takes a bit more mechanical power... I think 10% power mentioned farther up might be misleading- at highway speeds maybe, but at the couple HP being produced at idle, it might even be more- maybe over a third.
My camaro was running really rough at idle- A/C belt was loose, belt flapping, compressor rpm uneven, tightening belt smoothed out a lot.
There should be a vacuum switch to disengage A/C clutch- perhaps a higher vacuum tripout point would help acceleration if you can find one.
Ive never heard of underdrive A/C pulley, but ask around- it might be an option. I'd been told that if A/C clutch looks 'greasy' it might indicate bearing/seal going bad- would imagine this could add a bit of drag too.
Good luck : )
 

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Old Ford Fan
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not ford said:
your IAC valve might be stuffed or full of carbon.
I agree- even though he replied "only with air on" -

when A/C is on, ECM compensates for the load by richening mixture- by adjusting idle control flow and injector firing. these things do get gunked up easy
never messed with one on a ford, but my camaro's has needed cleaned out several times in the last 19years...had to think for a minute, cant believe that car is that old already.
 

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EFII Ghia owner
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355 Posts
Discussion Starter #9
thanks for your replys,
also when the air con is on the compressor makes a ticking sound, could this be a stuffed pully making all this drama?
 

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Air conditioning compressors draw upto 4 horsepower if running on a 1 to 1 pulley size at maxium load, the smaller the drive pulley (crank pulley in this case) the lower the load.
Alternators draw around 2 to 2.5 horsepower for your avarage 100 amp output.

All airconditioning systems and chargine systems are designed around the vehicle travelling at 60 to 80 Kph and doing 1800 to 3000 rpm.
 

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Oh and another thing the ticking sound could be from the spring loaded belt adjuster moving around as the belt slackens off.

On the ideling problem check you load componsator to see if is working, try turning your steering wheel full lock to see if the revs drop alot and if the do it may be this causing the problem.
 

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EFII Ghia owner
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Discussion Starter #12
olcoolone said:
Oh and another thing the ticking sound could be from the spring loaded belt adjuster moving around as the belt slackens off.

On the ideling problem check you load componsator to see if is working, try turning your steering wheel full lock to see if the revs drop alot and if the do it may be this causing the problem.
Yep when on full lock, the revs do drop. what does this mean? and where is the load compensator and what does it look like?
 

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EF_Dave said:
Yep when on full lock, the revs do drop. what does this mean? and where is the load compensator and what does it look like?

This is exactly what is happening with my car as well. Can anyone elaborate on this? Do I need a new tensioner, just a new belt, or something else?

Thanks a ton for any help!
 

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fordmech
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315 Posts
EF_Dave said:
Hey all,
i have an EF i6 and whenever I put the air con on the engine runs rough, and engine becomes sluggy with a very noticeable power drop, whenever the air con cycles off there is a big power boost, what and why is this happening?
without the air con on the engine is very smooth, you can barely notice the engine is running
thanks
Hi guys
Here's a couple of suggestions to help you pinpoint the problem. First of all check the compressor bearings. If they become seized (and I read somewhere in this thread that you could hear a noise coming from it, which could be a bearing noise) when you engage it it will have more drag on the engine than it should. Remove the belt and make sure that both the pulley it runs on AND the shaft attached to the clutch can be turned freely by hand. If this is good check your IAC for carbon deposits. It sits on top of the throttle body and it blocks up really easy, specially if you're using low octane fuel.This is what someone referred to as a load compensator. After that check that the throttle stop screw hasn't been screwed in/out, if so, you need to reset it.
Now here's the hard part. EFs were known for having an internal PCM problem that wouldn't let them control idle speed. To overcome this, most chunky owners/mechanics out there play with the settings of the throttle stop screw and wind it in so that your car idles again, but it looses the ability to compensate when loads are added at idle (a/c, power steering and so on). The only way to know if your PCM has this fault is to scan it, if you get a code that means something along the lines of "cannot control high/low idle" then you need another PCM which you can pick up at the wreckers for $40-60.Hope this helps and remember, start with the easy things before blaming the PCM. cheers
marc
:hy:
 
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