97 Tracker bogs down, low acceleration with AC on

[holemania]

Hello,

I have a 97 Tracker 4WD, 1.6cyl 16v. USA model.

I've read alot of the maintenance tips here...thanks!

Today, I cleaned the EGR, throttle body and that entire tubing and loop. I also changed the plugs, plug wires, fuel filter, distributor cap and rotor.

The engine seems to be running great!

....except, when I turn on the Air conditioning, the tracker has very, very slow acceleration....just bogging down.

The AC works fine and blows cold air, but it really affects my acceleration.

As soon as I turn off the AC, it runs fine again.

I'm sure this has to do with the AC compressor loading down the system or something, but I'm not sure how to check it or isolate the problem.

CEL = off
have the problem with hot or cold engine.

Can anyone give me some tips on how to inspect the compressor?

Or could it be a sensor or something like that? Or a connection?

Thanks for any feedback!

Dave

[shackwrrr]

have you tried spinning the compressor by hand? It could be on its way to freezing up. also has it been recharged lately if so it could be over full

[holemania]

shack,

thanks for your reply.

No, haven't tried spinning compressor by hand...you mean taking serpentine off first?

No, it hasn't been charged lately.

AC seems to work fine....I almost suspect the engine should be running stronger overall to handle the extra load when the AC is turned on.

I thought it was running pretty good with AC off, but maybe it should even be running better. It is a remarkable perfomance difference when I accelerate with no AC as opposed to accelerating with AC on.

Dave

[shackwrrr]

with the engine off you should be able to reach down and spin the front of the compressor

[jtgh]

bogs down 10% , is normal.

ac draws like 2.5Kw.
2500 watts, 3.35 HP. ( can be way more if you factor in all the inefficiencies of pump, and speed)

so at idle , when you switch on AC the ECU , raises the idle speed.
just enough to compensate for increased load.
The same waste happens in the goofy automatic transmission. 2.5kw , parasitic load. too. doubling the effect.

when you select Drive postion. the ECU again. adjusts idle (ISC) for this newer load. Fans, Defrost, 1000 watt audio, etc.

this all robs power form the engine. ( it has little and no free lunch it gets 30+mpg but is low powered. what more to say..... )

keep in mind the pulleys on the AC ar fixed. not variable.
so the faster you spin the motor the worse the loss.
a simple but wasteful design. ( it cost you $3000 to buy AC , imagine $5000 for one)

so it gets worse at high rpms, this power loss for no net gain in AC performance.
it does cycle , in and out. but when cycled IN, you will see the loss of power on all 1.6Lmotors made (non turbo on boost)


the real issue is, have you tried another 1.6L car with AC, to see if it works the same.?

just curious.

[holemania]

shack,

i cannot turn the ac compressor pulley at all with engine off....are you sure it should spin, cause it is attached to the main crankshaft via belts???

jtgh,

thanks for the ac power info.

when i turn on the ac, the idle does increase...probably to 1200.

seems like last summer it used to accelerate better with ac on...now with ac on, it is very slow acceleration indeed...afraid to pull out in intersection.

i have not tried another 1.6 cyl with ac to see how it works.

just doesn't seem like normal operation to have this little power with AC on and beginning to accelerate when it seems to accelerate fine without AC on.

could there be any other items to inspect (like a connection, sensor, etc.)?? Or should I assume the compressor is just giving the engine more resistance as it ages?

thanks again for any feedback!

Dave

[jtgh]

ok , now i have your perfect perception , cant pull out, ouch, sorry that is bad.

drop the belt off AC and drive. (i do not remember what else is connected to this belt.)

but keep Water pump and alternator intact.


the pulley will spin free, key off. on compressor.
the front of pulley is a plate, this is connected direclty to the compressor.

put a wrench on the nut of said plate and turn CW.
feel the friction , should fell like stick in thick butter.

best, is fell a good car, any and then feel yours. see? KEY OFF.


dropping the belt solves the who is bad issue.

cheers.

my 96 fsm shows AC having own belt.

not sure which years went to 100% serpentine belts. or it it picks up A?C..

but a 1 min. look answers that.



your engine might be sick and AC breaks the camels back?
belt off answers that.

is CEL lamp glowing while driving.

[holemania]

Originally Posted by shackwrrr

have you tried spinning the compressor by hand? It could be on its way to freezing up. also has it been recharged lately if so it could be over full

shack,

my apologies....

i looked again and I can spin the front part of the AC compressor by hand pretty easily!!

Dave

[holemania]

jtgh,

thanks for info....I can spin the front plate of the AC compressor by hand...no wrench needed.

Not sure if I can disconnect the belt from the AC compressor as it is attached not only to the AC compressor and main crankshaft but to a 3rd pulley all on the same belt....maybe power steering (please see image at

Picasa Web Albums - holemania - Geo Tracker

...there is a small black, sorta rusty cylinder on the right hand side...this cylinder has tubes going down to an assembly which has the 3rd pulley on it).

Also, there is no CEL light.

[jtgh]

that extra pulley my be the power steering.
see hose going from the pump to the steering gear box, bingo.
id not hesitate driving car with no power steering.
its your call on that.
this will prove if motor has issues.

be a shame to condem a good A/C to motor issues.
makes sure the clutch is unlocked at AC compresser.

you can feel the pulley on compressor with belt off and rotate the pulley
and you shoud only feel a easy to spin bearing. free a bird, it will be.

i do know some of these cars, have AC and PS together, because mine had 2 belts offered (sale) for PS , (one for AC with and one belt for without AC) .

i think that is the best path, , besure motor is ok before condeming AC.

then flogs its booty up a tall hill and see how she does.

cheers.

PS:
ive run many motors with not belts at all , (very fast test , 1 min max)
for finding noise. but a stethoscope is far better .
just to give an idea of extreme ideas.
the PS ,is missing on my 2door and I dont miss it at all.

you never said door count so dont know if yours is 500 lbs heavier car.
i guess a 4dr is ok with no PS.
it sure will not hurt the PS. only high steering effort.

a flash back to 1960. ( enjoy)