Car Jerking when Ac on..

[niccm0314]

hi all,
i'm owning a saga lmst with 4g13p,done top head overhaul,change spark plug,air filter and extra...
problem is jerking. When my rpm without on AC is 1000 every thing is ok without jerk,when AC on the rpm drop to 750 to 800 car so jerk..i checked the vacuum connected from intake magnaflow is ok without fault.After that i tried to adjust the AC idle with AC on to 1000rpm, it was no jerk but in the same time i off the AC rpm went to 1300 to 1400, it was too high so i decided to adjust it back to 1000rpm when AC on rpm became 750 to 800 -engine jerk like originally setting, when compressor cut down the engine is non jerk but when compressor on with the "click" sound engine jerk again, i already adjusted all the idle include AC, fuel pedal and extra... for information i also adjust the distributor to b advance but problem still same... isn't compressor is starting to have problem? but my AC is cool...don know whats problem..
i had went to see AC repair man at shop, they also adjusted the idle to b higher n higher that i mention,problem can't fix because b4 this my engine with 900rpm with AC off n 750 to 800 rpm with AC on without jerk, but rightnow it is jerking... make me annoy... Please advice thank u..

 

[xtremeleo]

the adjustment of a/c and idle shud be made differently.. switch the a/c off and set the idle speed, switch the a/c off and set the a/c idle speed via its vaccum/cable assembly

 

[niccm0314]

that mean i need to set the AC idle n the speed idle to b equal?

 

[xtremeleo]

set the a/c idle a tad higher

 

[niccm0314]

tomorrow will have a try,but if the problem seem same isn't compressor nearly death?

 

[xtremeleo]

maybe, but it showed to me its the idle issue jer when u mentioned it was all good when the revv is left a tad higher

 

[nyantong]

This isn't likely caused by the a/c compressor. Its most likely the idle air switch thats dirty or spoilt. At the same time, check to see if there's a lot of dirt and oil inside the throttle body. Both dirty idle air switch and throttle body are the main culprits in causing unstable idling when a/c is on.

 

[xtremeleo]

d engine is carburetted

 

[babe.cube]

my car is carburetor, isn't carburetor dirty? i tried already but the problem still there..

 

[xtremeleo]

what did u tried babe.cube?

any update niccm?

 

[babe.cube]

tried to set the ac idle when ac off n adjusted again in 1000rpm,when on ac drop to 750rpm engine jerk... engine problem? did top head overhaul already.. carburetor dirty?

 

[xtremeleo]

babe, maybe problem with vacuum hose/connection, carb dirty can be a contributor to this problem but for ur case id look at the vacuum connection first

 

[babe.cube]

check the air cond vacuum host from the intake magnaflow? the aircond vacuum is good in condition, host is ok.