My '10 Fit Sport is just about to hit 200k miles, but it's doing its best to stop short at 192k.
Maybe 5 weeks ago I was driving down the highway after a particularly bumpy road with many passengers, when my car flipped the CIL and went into limp mode. A quick restart resolved it, and a later scan said P2101, which seems to be related to the throttle valve's commanded position not matching its measured position. Following a service manual, I took out the throttle body and gave it a good clean - the engine-side was blackened but not piling up or anything and the valve had little play. I tried to do an idle re-learn (stay in key position II for a bit, turn off, crank it, rev to 3000 until the fan turns on, allow 5 mins of no-fan operation, drive), but saw no change and got another limp mode and p2101 combo a week later. This time I did a slightly different idle re-learn on a cooler day with the car already warm since I had just limped to a gas station (ON for 2 sec, OFF for 10 sec, 5min idle post-fan, OFF for 30 sec, drive for 20 min). The car felt different after, so I believe I was successful in activating the re-learn that time. About 4 weeks later limp and p2101 struck again, so here I am.
This time, I got a freeze-frame:

• Fuel Sys 1: CL
• Fuel Sys 2: N/A
• Calc Load: 29.0%
• ECT: 185 F
• STFT B1: 8.6%
• LTFT B1: 4.7%
• MAP: 12 inHg
• Eng RPM: 2343
• Veh Speed: 43 mph
• Spark Adv: 55deg
• IAT: 100 F
• MAF: 1.13 lb/min
• TPS: 17.3%
• Run Time: 833 s
• Command EGR: 21.2%
• EGR Error: 11.7%
• Command EVAP: 45.1%

Some other info: the car feels like it is aggressively engine-braking when coasting in I believe 3rd gear, 30-45mph. All of these limps have happened in the 30-50mph range. I had the drivetrain corrosion recall replacement done a few months ago, and a week later had a transmission solenoid replaced. No other major service since 110k-ish for spark plugs and a few others, just fluids and tires. The car rides quite stiff and probably needs its shocks/suspension overhauled. The clearcoat on the roof is deteriorating and the interior used to get soggy next to the curtain airbags in rain before I gooped up the roof. Miles 0-110k were in the US southeast, 110k-190k were in Minnesota including lots of cold, snowy, salty drives. I have gotten a catalytic convertor bank A efficiency CIL in the middle of winter before, and earlier this spring, but not since running a can of cleaner through.
Per this forum it seems I have a few non-OEM options for the throttle valve assembly. My best bet if I go that route is probably a used part.
Since the snapshot showed a large error for the EGR, I'm gonna try popping that valve off and cleaning it out, then relearning idle again. I am suspicious that extreme cold operation has coked up the EGR system enough to finally cause a problem.

Any particular advice? It's not clear to me if this is a simple "replace the throttle body" or if I need to be doing an extensive cleaning of the various air supply systems to make sure I don't have a blockage in particular airflow conditions. Thank you!

 

Haven't gotten to the EGR clean yet, and just got a code quoting EGR malfunction, so I guess I was on to something that the system is coked up - not sure if I should expect this after all the subzero driving or if I should be chasing leaky gaskets now.

 

I'm back, 6 weeks later, as limp mode came back (as did hot/humid weather, doubt that's a coincidence). Long story below. I am watching scrapyards for a ge8 fit to get a decent replacement for the throttle body. Also dealing with AC dying and that catalytic convertor error again, and I did a valve adjustment for the first time so I'm running a little paranoid whereas my engine is running quite well.

The EGR code was user error, I left it unplugged while troubleshooting. 🤦 I cleaned it out and replaced the gasket, dirty but not extreme. No new problems or obvious improvements.

---

About 2 weeks later (mid August) I swapped the coils and plugs and did valve clearance for my first time after being quoted about $1000 at the dealer when they checked/swapped a transmission solenoid for me. Some valves were out of spec and I think I got them back in. Plenty of residue in there, definitely wouldn't call the oil clean but it's not bad. Had a nice jump in mpg, 38+ highway and 34 on my commute from 28 previously. Broke a middle front bolt on the valve cover, though. Little too much faith in the low end of my torque wrench. Gave it a test, no oil leak, so I am still driving while monitoring for leaks. I have replacement parts and tools, I just need a free day to get the plenum off, extract, and replace. I plan to double check the plug tightness while I'm in there. Not hard to do, but that is a ton of cramped disassembly with the cowl, intake, throttle, plenum, and cover, and I had to replace most cowl clips. Took me 4 hours and about $150 in parts with plugs, coils, gaskets, and hondabond.

Last week, on a cooler day, I got the catalytic efficiency warning again, so I bought a can of cleaner for my next fill-up, bringing us to now.

The heat and humidity are back. Yesterday, during the drive running cat cleaner, after a few weak AC cycles the AC shut down and hasn't returned.

This morning while paranoidly listening to my engine, I fixated a different lower pitch tick/knock coming from the engine, sounds like it's from the valve area but hard to tell, didn't grab my stethoscope. Seems to be at 1/4 engine rpm. Might be an old noise from the lifters, might be new, while looking for problems everything sounds new and expensive. Looking at other people's videos it sounds just like Pyts' first video in the following thread, so it's probably fine. Got everything for an early oil change just in case. https://www.fitfreak.net/forums/2nd-...djustment.html

Stopped by a dealer on my commute for a paranoid noise check and a Honda dealer mechanic said nothing sounded catastrophic. Reassuring words. Five minutes later I got limp mode on the highway. Probably cursed by the shop. Haven't checked the code yet, but I assume it's throttle position again. Will correct after a code read.

For the AC, it is not the AC relays, I swapped the clutch/compressor/fan relays around as that got me before, all could run the fan so something else is getting me. Probably low refrigerant, especially with the weak cycles, unless the compressor or clutch are dead. Just learned they use refrigerant for lubrication in the compressor so maybe it's both. My mysterious ticking noise does not correlate with compressor engagement/request.

Maybe I do need a new throttle body after all. This one seems to just dislike hot, humid air. That's relatable. Of course it could be a sensor that doesn't like the air. Waiting on a ge8 to show up in my local scrapyard to get a better part cheap, so far just gen 1 and 3 coming through. Hopefully one shows up before mine. I'm sure some parts work across gens but I don't have a lookup table. Hopefully being cheap doesn't end up expensive.

I'll do a throttle relearn as I commute home from AutoZone, and if I make it home I'll do a refrigerant recharge and oil change and see if things get better.

Nearby shops are asking $150+ refrigerant or $250 flat for a recovery and recharge. Is that insane or am I out of touch? Like the sparks/coils/valve service, is $200 per hour it would take me to do it what I should expect from mechanics?

 

For those prices, you can get the tools (manifold gauge set, hoses, service connectors, vacuum pump, can tap) to do pretty much any A/C work yourself. R134a is the same stuff they put in canned air dusters - it's not hard to get and aside from being a potent greenhouse gas, is not especially damaging to the environment. It makes sense to have professionals use a relatively expensive machine recover refrigerant (they can reuse it), but the one-in-a-thousand DIYer dumping an automotive A/C system or two to atmosphere for service is nothing compared to the office workers and IT folks using it to blow out keyboards and CPUs.

 

Thanks for replying! Yeah, I went ahead and bought a vacuum and manifold for about $120 last night. Also grabbed a holding tank and refrigerant pump for $325 (ouch). All that to save 450g of R134a. Hoping I'll be able to service my various window ACs with it as well but if not there's always reselling. Considering just a recovery and recharge are around $200, I'm sure any diagnostic and repairs would run in the thousands. Given I can put together a full rebuild minus hoses on rockauto for about $500, I'd say I have a pretty big tool budget.

I read through the AC section of the service manual. I need to check if the clutch is actually spinning the compressor or if the armature plate sheared and is no longer driving the compressor shaft. Ironically, a clutch plate wouldn't need any of the tools I just bought... But I would replace the compressor, too. Might even do the condenser since it's so beat up and not much more cost. Maybe I'll know more once my tools arrive and I can run through the troubleshooting on page 21-50 onwards. Lots to learn.

And for the weird noise after AC dying, it seems to be louder with a fresh fill of 5W-20. It goes away after a very long warmup. Listening to other's videos, it isn't consistent with loose sparkplugs or valves, but may be consistent with piston lash or a failed AC clutch pulley. Given the sudden appearance I am pretty sure it's the clutch, but the sparkplugs and valves are a very recent service, and it sure sounds liquid/airy and goes away after warmup. Hoping for AC clutch, then valves, then lash, then plugs. At some point I forgot how to read my torque wrench and started going 10lbft over on everything during the valves/plugs/coils service. I think I did the plugs right but that's how I sheared a bolt in the valve cover...

As for the problems I posted this thread for, I did an idle relearn and I haven't had issues yet. I should boot up my service machine to confirm I did a relearn/command one. Sorry for doing 3 problems in 1 thread and writing so long, bad habit, but cars are complicated.

Edit: Investigating the clutch since I noticed it wasn't engaging (could have sworn it was on Sunday). I am getting a high impedance reading on the coil, hopefully not just struggling to get a ground connection. The armature plate of the AC clutch is bent, evident from the clearance varying and the wear pattern. I could just grab a new coil. The bearing isn't wobbling at all and I had fine compression on Saturday. I just worry that the coil is dead because of some other flaw in the clutch/compressor.

 

AC: I ended up replacing the compressor and condenser, and all making all associated vacuums and gases. AC works very well.
Throttle body: just had the problem on the exact same stretch of highway at the same speed today. Theres's a '10 fit at a junkyard 40 minutes away, think I'll go grab what's left.
Cat convertor: continued intermittent code. Doesn't happen if I let the engine warm up. I should do a drive with my computer hooked up to see if the O2 sensors are giving clear data.
I still wonder if the cat and throttle are linked, since the sensors that say they're working have a lot of overlap. I replaced my PCV after noticing my oil topoff blows air if I open it. Still does, and the old one had fine motion. Wonder if there's a clog in that line.
I can't wait til I get an electric car... Working on ICE for lawnmowers and motorcycles is a ton of fun but car problems where 90% of what's happening is in a digital black box aren't fun. Just make the whole thing run on code already, let mechanics work remotely lol.

 

Some air movement is normal, but you shouldn't run the engine with the cap off. Put your oil fill cap back on. Disconnect the breather tube (rubber hose to 4-way metal tube contraption) at the valve cover. Hold a plastic bag over the valve cover port as if you were going to fill the bag from the port. If the bag fills up, you're getting excessive compression blow-by (an issue with piston ring sealing or cylinder wall damage). If the bag slowly shrinks, the PCV system is working fine.

 

Thanks, that is a way better test! Someone online had recommended holding a piece of paper over the oil cap to check for blowback. Definitely not something I do regularly or for extended time. Beyond being an abnormal condition turbulent sucking/blowing of unfiltered air is sure to pull debris into the crankcase. And making the (hopefully) one-way, 2-port ventilation system of breather hose and pcv into a 3-port system where the fill cap allows positive and negative flow really shouldn't tell me much about the ventilation. A pressure gauge oil cap would be pretty cool.
For PCV valve function the service manual suggests pinching the vacuum line from the PCV valve to the intake manifold and listening for the valve clicking in response, which I suppose relies on my pinch making positive pressure in the vacuum line, slamming the PCV valve shut. And I suppose barring leaks and turbulence the intake should always be sucking air, since one cylinder should always be in suction, unless I messed up my valve adjustment.
Is that all that causes residue on the manifold side of the throttle plate, turbulent backflow from crankcase ventilation and EGR? The computer wouldn't allow backflow from the port injection unless something seriously unexpected happened, I hope.

 

Yes but probably not in the way you're thinking, and no. The PCV valve never fully shuts - it has a open and restricted positions. There's a plunger inside the valve which is held in the open position by a weak spring. When there's a strong pressure difference across the valve (atmospheric pressure on the crankcase side, low-engine-load manifold vacuum on the other), the force on the plunger pushes it over to the restricted position. When the pressure on either side of the valve is close to equal (high engine load or obstructed hose), the spring pushes the plunger back to the open position. The click you hear is the plunger changing positions. Depending on which side of the valve your pinched hose is on, you could be causing both sides of the valve to see atmospheric pressure (vacuum hose pinched) or engine vacuum (crankcase hose pinched), but the valve will react the same way as it reacts to a pressure difference.

Residue on both sides of the plate can come from especially bad compression blow-by, but just on the manifold side is probably PCV.
EGR is usually carefully metered to each cylinder, near or in (when the EGR manifold is cast into the cylinder head) the intake port. I don't think EGR would make it back up the intake runner without a significant valve sealing issue like you said.