h103

I searched and everyone else's hiccups seem to last a lot longer. I'ld like to chase mine down before it has a chance to become bigger / cause something bigger.

Recently, my LX began having a hiccup above 2500rpm.

95 Civic LX - 1.5L - Automatic transmission

Situation #1:
starting from a dead stop, accelerating up to "county road" or highway speeds -- every time my engine goes over 2500rpm (prior to the trannie up-shifting) -- I hear ONE very quiet "tink" in unison with ONE power hiccup that lasts what feels like less than 1/10th of a second.

This happens about 80% of the time when I am accelerating up to highway speeds.

Situation #2:
on the highway at constant speed -- engine above 2500rpm of course -- depending HOW much over 2500rpm the engine is running, I get the EXACT SAME [1 tink in unison with 1 power hiccup] at intervals ranging from 0.9mi at about 2600 -- 0.6mi at about 2900 -- 1.2mi at about 3200.

This happens during about 50% of total highway trips. Some trips - it does this the entire time I'm on the highway. Some trips - it doesn't do it at all when I'm on the highway. On highway trips when it DOES happen, it is fairly constant the entire time I stay in top gear. If I have to slow down markedly through a construction zone or traffic-backup, there's no way to predict whether the hiccup will resume when I get back up to normal speed - sometimes it does, sometimes it doesn't.

Because I live 0.4mi from [entrance ramps or interchanges] for FOUR expressways / interstates -- 70-90% of every gas-fill is "highway miles" -- even when I drive to the grocery store only 6 miles away.

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The hiccup is ONLY noticeable through the column and pedals. My passengers don't feel any change in the car whatsoever. The "tink" is quiet enough that only some of my passengers hear it.

The other issue -- I've never seen any idiot lights when this is happening.

Whatever the heck this is, I'ld really like to catch and fix it now before it becomes something more serious. I got this car a year ago at 168Kmi, and only have 179Kmi a year later.

If this is something that is going to require lots of Dx time (like MANY intermittent problems) -- I would like to be able to walk into my mechanic's shop armed with as many observations as they could possibly need.

Any ideas on the actual problem, or suggestions on what else I can monitor to help cut-down Dx time?

h103

Does anyone have ANY ideas on this?

The consistency of "Situation #2" is what really concerns me -- the fact that I could drive 5 miles or 150 miles -- on drives when it happens, as long as I stay up in top gear above 2500rpm, it just keeps happening like clockwork, only varying based on how MUCH my rpm is >2500.

g230sport

is your ac on?

sounds like its your ac compressor kicking off, and your feeling the freed up power from that...

h103

I spent some more time testing it over the past two days of driving since I finally didn't have ANY passengers -- more "play" time to drive with and without the AC through all sorts of terrain changes / long stretches on the highway / a little city for good measure / etc.

I don't hear it at all when the AC is off, and only SOMETIMES when the AC is on.

The [dead stop acceleration] tink happens IN UNISON with the shift from 1st into 2nd. I can't really say whether or not there's a power hiccup since of course the feel changes for a split second during shift anyway. The tink SEEMS louder than the tink I hear on the highway, but I'm sure that is merely a matter of general engine noise levels.

If the tink+hiccup happens while I'm driving at highway speeds -- it happens continuously, does NOT come and go DURING any one "highway speed" stretch. If the cruise control is on and the road is relatively even, you can predict every "next" tink+hiccup just by looking at the tripometer.

This is only in the last 1000-1200 miles, so I'm wondering if it's the beginning of a problem that needs to be hunted down, or if I've just turned into a human stethoscope and am noticing something subtle but totally normal

Former User

I agree with g230sport, who cleverly suggested that the tink-hiccup may simply be the A/C compressor clutch engaging and disengaging. The tink may indicate that the clutch mechanism has a little extra free play or the A/C belt needs to be tightened. A hiccup is normal when the A/C clutch engages.

h103

so one hiccup every .6-1.2mi is normal?

thanks for the [maybe belt] info. That will make my first stop a "buddy" mechanic to check my belt tension instead of my [big diagnosis] mechanic. As a "partially disabled" vet, stupid things that I KNOW HOW to do like checking belt tension become real PITA's.

The fact that this is only happening in the last 1-1.2Kmi -- is that perhaps a sign of dropping refrigerant pressure?

Former User

Possibly. You would need to hook up a manifold gauge set to measure refrigerant pressures on the low and high sides to know. The gauge set may be available for free rental from an auto parts store.