I searched the forums and found no pics so I thought I would ask for some help.
My 2008 Honda Fit Sport is having an issue where if I am stopped, at idle and with AC on the idle will drop to the point where it feels like it will simply stall but kicks back up every time.
It's usually when the compressor kicks on and happens every 15-20secs depending on how hot the ambient temp is. With AC off, the idle never does this...

I searched and it seems that initial shade tree wrenching states cleaning the TB and IAC should help. I got the plumbing all pulled off and thoroughly cleaned the TB and the stall is still there so now I go to clan the IAC and I can't find what the images are showing for my car? It makes no sense, seems like it would have to be attached the the TB but I can't fin this part.
Anybody got a pic of where there's is located to help me out? If and when I find, pull and clean this part and it still does this I will pull the alternator and have it tested.

Thanks in advance.
Dean

 

Fit has no IAC valve (it's "drive by wire")
such problems can be caused by bad spark plugs/coils, (if it jerks/labors then recovers) leaking EGR if idle slowly sinking down, then recovers, out of adjustment valves.
Rent or borrow the OBD2 scanner that can show live date and look for MAP reading (idle in park, idle in gear, a/c on in park, a/c on in gear) and post your reading in here

 

 

Your readings are normal (reading in kPa):
Ac off

Park 27-26

D 33-34

A/C on park 38

A/C on in drive 48
Compared to mine
A/C OFF

MAP readings with ECT at 91 C (a/c off)

Idle in park 26kPa

Idle in drive 33kPa

(STFT 1.6 LTFT 0.8)

A/C on:

MAP reading (with ECT at 82 degrees C):

Idle: 38 kPa

D+brake 49 to 50 kPa (blower at 2nd speed)

STFT -.8 LTFT-1.6

Try idle re-learn procedure and see if it helps.

 

 

Anywhere from mid-11v area to mid 14v area, it all depends on what the PCM decides it wants to run the charging system at. Research Hondas ELD controlled charging system for more info.

 

IIRC, the with A/C or lights on the voltage should be above 13.5; without electrical load it can be 12 v in drive

 

So as an update... I am still experiencing this and only because the Defrost turns the A/C on automatically.
Does anybody have a clue what may be causing this Idle drop during stops at lights? It never throws a code, voltage seems normal.
Car is completely stock. ~135k miles on the odometer, all maintenance up to date and no other issues.
It's not every time I stop either? It's just one of those things where I fear the car will eventually die sitting at a stop light and I would rather not have to push it to the side.
The only good thing would be I would finally have something to sort out.

 

It bogs down only when the compressor cycles on? Maybe the AC is overcharged.
Exactly how low does it drop-- according to your scanner data?

 

Interesting thing.
Few times over past 3 years, I've noticed that car idles at speeds lower than typical (at 550 to 600 rpms). It typically happens in stop and go traffic with engine warm and random. If I momentary cycle the headligts (on and off) the idle gets where it suppose to be (700 rpms in D); the idle is stable around 800 rpms with lights on. During the "abnormal behavior" the scanner indicates higher STFT + 6 to + 8% than typical (as opposed to +1.6...2.3%%) Otherwise it looks to me like a "gear backlash" in throttle body drive, but I am sure I wrong on this one. Or can it be biased A/F sensor (reads lean when mixture is actually normal) so an extra fuel causes RPMs to drop ?? . (On 97 Camry (A/F sensor and MAP type EFI) there were no noticeable idle change, however the car failed smog for CO and set P0171 code.

 

Interesting thing.
Few times over past 3 years, I've noticed that car idles at speeds lower than typical (at 550 to 600 rpms). It typically happens in stop and go traffic with engine warm and random. If I momentary cycle the headligts (on and off) the idle gets where it suppose to be (700 rpms in D); the idle is stable around 800 rpms with lights on. During the "abnormal behavior" the scanner indicates higher STFT + 6 to + 8% than typical (as opposed to +1.6...2.3%%) Otherwise it looks to me like a "gear backlash" in throttle body drive, but I am sure I wrong on this one. Or can it be biased A/F sensor (reads lean when mixture is actually normal) so an extra fuel causes RPMs to drop ?? . (On 97 Camry (A/F sensor and MAP type EFI) there were no noticeable idle change, however the car failed smog for CO and set P0171 code.

 

Turn the lights on and see if it helps

 

Defrost automatically turns the AC on if AC is otherwise turned off? I haven't noticed this, I don't think that happens with my 08. just curious. Best of Luck on the issue.

 

the first step is to find out
a) if idle speed control is reacting fast enough to the engine operation condition changes (throttle angle correction)
b) what causes such changes
The European Jazz users reporting broken wire in the bundle for throttle control circuit (but it sets a code)