ezone

No, I don't think so..... This started when you said this:

Somehow you went way beyond this over the next several posts.

kinakoes2

....

kinakoes2

*sigh*

Another 22-mi run today upcountry to my quiet caf%u00E9 lunch... am now over 100 miles on this first quarter tank... climbing to 5000 ft and back, with the A/C on. Can't wait to see what the mileage is like on the 45-mi drive Sunday.

Shifting: still excellent... balk in 1st since the ECT issue must've been a fluke. Not sure I'll have time to swap the trans fluid as planned either... busy Mother's Day weekend. It'll be soon though.

Steering: slightly better feel since the ECT issue, as is high-speed handling.

Brakes: slightly less grabby since the ECT issue.

Clutch: level not fluctuating wildly as before. Juddering hasn't happened anywhere near as bad since the ECT issue. Car does need a bit more time to feel 'happy' after starting cold now... I'll take it.

Accel: another Civic, really. Esp rolling on in third to merge, I'm car lengths ahead compared to before ECT issue. Much less strained at high speed, and while the tiniest bit buzzier, it has reserve in the pedal climbing 15% grades now in fourth that would've demanded third before.

[Oil consumption]: thing of the past. Despite all the climbing lately... level hasn't dropped one bit. Guess that half-quart of Rotella-T did its job before... kept it in as a maintenance dose, as it wasn't the 5W-40 added visc of the oil that was dropping mileage; it was the ECT issue.

Have to say... if the bore is still capable of this kind of sealing after close to 150K... I'm impressed. At 150K my '92 Paseo was still very much in spec compression and leakdown-wise... but it's an undersquare mill (barely) that didn't oval its bore very much... lost quite a bit of seal vs. 45K when I bought it though. This Civic is very undersquare... so as in moto engines at 50K (very oversquare), I'd expected 150K here to bring the first signs of consistent blowby esp cold. Not the case, so far.

kinakoes2

So I think that's it for what works and what doesn't on my '04 EX manual's driveability problems thus far:

-- Use of a half-quart Rotella-T6 5W40 synth diesel oil with the rest a Mobil 1 HM 5W20, is a harmless way to address oil ring sticking/oil consumption in the D17, without tagging mpg much if any (right now @ 216 mi on a half tank, or 36 mpg... with A/C and climbing to 5000 ft and back three times this week).

-- Clutch reservoir level with a worn clutch is very sensitive to being overfilled. Better to be slightly underfilled than any amount overfilled,, doubly so if you suspect your slave cylinder seals of leaking, like mine (holding fluid fine right now though).

-- If you're seeing a sudden drop in driveability, such as a juddering clutch, strange handling at high speed and poor mpg + lack of power esp off the line (stalling), esp if they're happening together... check your sensor connections to make sure there aren't any intermittent opens through a loose connector.

Though the D17 PCM will throw a code only if the open exists for 2 secs or more, if 1.99 sec it still apparently affects driveability, as fixing it on mine brought unexpectedly large changes in powertrain refinement. Be warned to check *all* sensor and switch connections disturbed, like the EGR sensor with the ECT when changing a valve cover gasket.

I don't know how the D17 PCM will react when it has an intermittent open on any of the major sensors, and no one here seems to know why the car behaved how it did either (for the geekier wrenches: no one knows what strategy the PCM used in that scenario or why). The difference was as small as seated-and-not-clicked, vs. seated-and-clicked, on the ECT connector. The temp gauge was working perfectly the whole time as well, so there was contact happening. 1mm to clicked, and it gained almost 3 mpg... so not a trivial problem.

-- The stock D17 air filter area is small but adequate enough to get pretty high mpg -- when clean. When dirty, the small area can quickly erode your mileage. Using a K&N drop-in filter is fine for the D17, as it has a speed-density FI system that doesn't use an airflow meter like the K motors (filter oil droplets foul the meter), but K&Ns increase flow by letting through more dirt with the air. Had good luck with the K&N drop-in in my Paseo however for more than four years.

-- Plugs & sensors: for '04-'05s, remember that your upstream exhaust sensor is an LAF, or wideband A/F sensor, not an O2 sensor like previous 7th-gen years... and if it's old, a new one will perk up throttle response, increase mpg and maybe even give a bit of power. Denso's pt# is 234-9017, ~$145 on Amazon. The Honda cross-ref pt# is 36531-PLR-003. The Denso double-plat plugs worked for me much, much better than the OEM-spec NGKs in this car -- look for Denso pt# PKJ20CR-M11 (Honda 12290-PGE-A01).

That's it for now... if I find any other new info about driveability problems and how to solve them, I'll post them here.

ezone

A dirty air filter does not affect gas mileage on a modern fuel injected engine.
It will restrict performance.


It only took the EPA 30+ years to admit this.

http://www.fueleconomy.gov/feg/maintain.jsp

kinakoes2

Not in my experience, which is all that matters (all except one vehicle, with speed-density FI, including the D17A2).

kinakoes2

Here we go... again.

So, some of the driveability problems are back... and I can't blame them on the clutch issues, since it's worked flawlessly, untouched, for a couple of weeks now... just topped off the clutch res this AM, back to okay. No this I think may be related to a sensor issue.

What's known, to date:

-- stalling and juddery clutch engagement, esp when cold and esp when it's raining;

-- after the ECT connector issue was fixed, the car gained an amazing 3 mpg... with two climbs to a drizzly 5000 ft in five miles, on the part of the half-tank left after the fix (I fill every half-tank to minimize rust in the tank with the humid salt air here). The following half-tank was better, giving a solid 36.2 (0.3 mpg better) without the two climbs... all with A/C on constantly, except when accelerating hard;

-- the car maintained this performance (not weak-kneed, either... which was surprising) until the last bit of the previous half-tank, when first a major rise in consumption in the first quarter-tank (86 vs 109 mi) was followed the following AM with the same damned juddering and stalling issues as ever.

Now, the PCM takes (according the FSM) about a full tank of fuel to adapt idle settings when a reset occurs... the gauge issue from before was the ECT disconnecting, so that may've reset the PCM to idle learn from scratch. I did not do the idle learn proc at the moment I found the click in the connector, but did idle cold for a full 5 mins the next time I got behind the wheel... so the idle learn not being done IINM isn't the source of the stalling.

It does make sense, however, that the length of time this problem took to come back (~2 half-tanks = ~1 full-tank), and the length of time the PCM stops adapting what idle settings to use, are the same. Now, if a sensor were slowly going bad, and finally went bad during this time... that would explain the sudden drop in driveability and mpg, which occurred together. A bad ECT reporting cooler temps than actual for example, would richen fueling way too much (Hondas are already super-rich), and a bad or failing MAP (which could be either electrical, or a vacuum line with a crack or other leak) would also explain the whys behind how the engine got such great mpg while climbing with the A/C on -- richness likes load and cooler temps together, and hates low pressure and hotter temps.

ECT, MAP, and IAT are all pretty cheap, so may just replace them all while I can afford them. Again, no codes when read with my reader and Torque.