A/C causing engine to hesitate??

[FLYLOW]

Anybody else driving with a 1.6L 4 cyl notice that when the A/C clutch engages every 20 sec or so the engine momentarily hesitates and then returns to normal??

[tk1138]

when the load on the engine changes, the RPMs change in an aproximatly inverse realationship. When you turn your lights on, brake enough to brake lights on, turn, turn your stereo up loud...It's more noticable when you're at idle, but it happens at any RPM. <P>It just takes a second or to for the ecu to adjust the idle. There's not a lot you can do about the A.C., but a better battery/cappacitor can help a little with the electric loads. <BR>Also some people have noticed that sludge builds up in their intake manifolds, causing their cars to stall when coming to a stop after high speed travel. If you have it getting this removed will help.

[voltaire]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by tk1138:<BR><STRONG>when the load on the engine changes, the RPMs change in an aproximatly inverse realationship. When you turn your lights on, brake enough to brake lights on, turn, turn your stereo up loud...It's more noticable when you're at idle, but it happens at any RPM. <P>It just takes a second or to for the ecu to adjust the idle. There's not a lot you can do about the A.C., but a better battery/cappacitor can help a little with the electric loads. <BR>Also some people have noticed that sludge builds up in their intake manifolds, causing their cars to stall when coming to a stop after high speed travel. If you have it getting this removed will help.</STRONG><HR></BLOCKQUOTE><P>Man, if turning up your stereo or turning on your lights change your idle, your car (alternator) has some serious problems.<P>Turning on the A/C changes the idle due to the extra load of the compressor, but your alternator is always gonna turn regardless of how much electricity you're using. It's not like you're alternator goes faster when you turn more things on...

[Paragon]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by voltaire:<BR><STRONG><P>Man, if turning up your stereo or turning on your lights change your idle, your car (alternator) has some serious problems.<BR></STRONG><HR></BLOCKQUOTE><P>hehe, i was sitting with my car started and turned my stereo all the way up, and my engine shut off...is that bad? 153.4 dB, btw...

[tk1138]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by voltaire:<BR><STRONG><P>Man, if turning up your stereo or turning on your lights change your idle, your car (alternator) has some serious problems.<P>Turning on the A/C changes the idle due to the extra load of the compressor, but your alternator is always gonna turn regardless of how much electricity you're using. It's not like you're alternator goes faster when you turn more things on...</STRONG><HR></BLOCKQUOTE><P>How bad it is for your idle to change depends on how big the change is. If your car shuts off, that's REALLY BAD(not so much physically damaging, just indicates system problems). You probably need a bigger alternator and/or bigger/better battery and/or Cap. There's some relavent posts in the general and stereo forums, good luck. Nice numbers too!<P>As for the second part: I can see how that would appear to be the case, but: Consider all the belt driven accessories, they turn all the time as well. The A/C has a magnetic clutch, so that it compresses fluid only when the clutch is engaged. The power steering turns constantly as well, again set up so that it (pretty much) only does work when it's needed.... The accessories RPM is proportional to the engine RPM, but the tourqe required to turn them changes as their loads change.<BR>Look at tourqe curves for engines for instance, especially ones that have different runs under the same conditions- the lines are not the same (similar, but not the same). What would a tourque curve would look like if you didn't have WOT?... Tourqe can be different for the same RPM. The tourqes of the accessories & attatchments add together and are equal in magnitude to the tourqe of the engine. When the load changes, the engine is still putting out a relativly fixed amount of power, and the RPMs change in an inversely proportional manner, untill the ECU & feedback systems can correct.<P>Mmmm physics, oops I mean engineering.

[TedLeeper]

does taking out the ac improve preformance much?

[tk1138]

Taking the mass of the AC components off your car will probably improve preformance more than removing the drag caused by the pulley.<BR>If you don't EVER use your A/C and you're not going to sell the car EVER, then it might be worthwhile. I think this is a pretty common thing to do IFyou're putting on forced induction systems, so you might check out that forum.

[TedLeeper]

will a under drive pully do any good if i removed the ac system?

[Majin Vegeta]

i purchased the underdrive pulley for my car, and i've noticed less A/C "problems" than i did before the mod. perhaps you should look into getting one... it weighs significantly less than the stock pulley, and since there is less weight to start spinning, i believe those issues might disapear. also, it feels like the A/C works better as well!<P>just my two cents.

[bronzeboy]

I've been battling this problem for 3 years now. I have a 94 RS and every time the A/C compressor kicks on, the belt squeaks for a second and the car lurches. I have spent over $1500.00 and 10 trips to various garages, including the Mazda dealer, and nothing helps. I've had the belts replaced 6 times, all the pullys replaced, the waterpump replaced, etc, etc. Only thing I haven't done is replace the A/C compressor. Not sure it is worth it now.