Alright... I've noticed that my car (JDM H22A w/bolt ons + P28 tune) bogs out like its about to stall when the coolant fans engage.... While their running, it also runs shitty and sluggish at low throttle like when you do a light take off from a stop 1,800-2,200rpm...


Is this normal or what? If not, what can be done?

 

Well, the fans engaging shouldn't do anything more than cause an additional drain on the alternator which could very well drop the idle, but it shouldn't be that bad. Mine will go down a bit when my fan engages....that's how I know the fan is on

Have you checked your alternator output or anything?

 

Thats what I was thinking, but someone local told it was normal..... I'm like, riiiiight... the car feels like its about to stall when the fans come on. Its famous for doing it in traffic or in drive throughs....

 

Have any idea what your idle is before an after the fans come on?

 

Yeah, maybe your base idles is a touch low. You could raise base idle to say 850 and when fans kick on it should only normally drop around 50 to 100 (atleast in my car's case)

Excessive drop would indicate that the A) fan circuit is drawing too much current do to an electrical issue causing excessive lag on the alternator/electrical system or B) the charging system is inadiqate which would indicate your alternator or battery is going. I doubt B) would be the problem given that the only issue is when fans ingage.

How much of an Idle drop are we talking anyway?

Any other issues that you might have missed out?

 

Either take your car to AutoZone for free alternator testing or just monitor the car's voltage when the fans kick on. Might as well check the battery while your there.