12 Jan 2018

Copied from the Midlana forum (link above):

So as big things get solved (intercooler ducting, ECU retune, drivability, etc.), issues previously less-important have bubbled to the top of the list.

After installing Engine V2.0, an oil leak was found under the engine, unfortunately traced to one edge of the front cover. I say “unfortunately” because on a Honda K-series engine, the front cover is trapped by the oil pan and cylinder head. Even if I got it out without destroying the head or pan gasket, there’s no way I’d get it back in, and I’m loath to remove the pan and head! Neither gasket in those areas are critical but it would most certainly introduce new oil leaks.

What’s interesting is how the dripping only happens with the engine is not running. Due to running a dry sump oil system, a side perk of it is that it pulls a vacuum in the crankcase which prevents any oil from leaving! The puzzling thing is that just sitting there it drips a fair amount of oil. Over the last six months or so, it’s filled the drip pan on the floor about half way. With the leak along one edge of the front cover, it’s fairly high up on the engine, so where the heck is all the oil coming from? I’d expect that as soon as the engine’s shut down, the hot oil in the head and front cover would quickly find its way back to the pan, and yet there it is on the floor.

So the challenge is how to fix it in-place and what *might* work is to take advantage of the dry sump’s vacuum. That is, apply gasket sealer along the suspect area, then drive for an hour or so. The idea is that the vacuum will draw the sealer into the leak, and the heat will cure it relatively fast. The trick is finding a low viscosity gasket sealer that gets drawn easily into cracks, which seems unlikely, so I’ll probably be stuck with whatever’s available. That said, if it’s too low a viscosity, it’ll get entirely sucked in and not seal anything; water-thin is too far in the other direction. I guess the first thing is to double-check that the leak’s coming from where I think it is.


Thanks to reader Bill who said “maybe it’s time for some UV dye and a UV lamp.” Well, huh, I had no idea such a product existed, and ordered AC Delco 4-In-1 Fluorescent Dye, PN 10-5045, and it’s affordable. During our discussion, it occurred to me that the leak at the front cover might be a red herring, that maybe there’s a second larger leak lower down. The plan is to add the dye, run the engine until warm, then shut it off and watch and wait. The instructions say that the dye can be left in the system without harm, but for peace of mind, the oil will be changed after the leak source is found and fixed.

31 Dec 2017

Happy New Year everyone!

Drove along the beach and saw people laying out in bathing suits – it was 59 degrees. Maybe they’re from somewhere that’s 50 degrees colder so this seems warm?

I decided I didn’t like the rigid mounting of the exhaust pipe. I don’t know how much the engine moves around but even if it’s a little, it’s flexing the weld which will eventually crack. A half-bracket was welded on and safety wire looped around so the pipe can move around when it needs to, while at the same time keeping it from resonating and thrashing about.

With the worst of the tuning hopefully done, I couldn’t help but add something admittedly a little childish. Let me explain: normally when the driver takes his foot off the gas, the ECU shuts off fuel. Trouble is, I found a thread where someone asked on a car forum, “How can I get my car to do that cool crackling and popping on deceleration?” How did I not know about this? Disabling fuel-cut is just a checkbox away, and retarding ignition timing at high vacuum (which happens only when coasting in-gear) is easy. This causes any residual fuel to be ignited so late in the cycle that it’s still burning as the exhaust valves open. Done right, it’s not loud but just as described above, a crackling and popping. If the timing is retarded too much, flames may even come out the exhaust, which is kind of a strange thing to want to do because, A. You can’t see it, and B. The cops can. I guess I’ll have to provide a video because right now, I don’t think I’m emitting flames but haven’t confirmed. 🙂

BTW, burning fuel in the exhaust can be taken to an extreme, at which point it becomes “anti-lag”. This is where fuel is purposely dumped into the exhaust where it burns and keeps the turbocharger spinning, which is all fine, except that it’s both loud as hell, sounding like a machine gun, and  it’s not good for the turbocharger. Not going to happen on my car.

30 Dec 2017

I had this week off but for many it was a partial work week, making otherwise-enjoyable test drives less so, so it was a good time* to deal with the inconsistent throttle issue.

Turns out I had two spare throttle bodies but one was a mirror image of the correct part, probably coming off the original Honda CRV donor engine. Anyway, I removed the one from the engine and stripped it down, leaving only the throttle angle position sensor (TAP) in-place. Playing with it by hand showed no stickiness or inconsistencies, so I was betting one of the removed parts had caused it – I would have lost the bet! The TAP sensor was temporarily reconnected to the ECU and the throttle shaft moved by hand. Sure enough, closing the throttle 10 times resulted in 10 slightly different readings, some differing by more than a full percent. Strange; the throttle plate, shaft, and bearings looked fine and felt fine, no slop, no stickiness, yet it just wasn’t repeatable, and cleaning didn’t help either.

The first thing transferred to the spare throttle body was the K-Tuned Hall Effect TAP sensor, and the readings returned to within 0.1% of zero every single time. Close it slow, close it fast, didn’t matter, it was very repeatable, proving that the TAP sensor was good and that the throttle body wasn’t.

Bolted everything back together and while in there, also cleaned the idle air valve – a known issue with Honda K-series engines when dirty. Next, my tuner buddy, JR, recommended setting the mechanical throttle stop at just under the target 1000 rpm idle, like around 950 rpm. The idea is that regardless what the ECU tries to do, idle cannot drop much bel0w the target. This does not rule out a decelerating engine with “momentum” blowing through this limit as well, but that’s a separate situation.

After much flailing about, I learned out that the Honda idle air valve is partially open at all times when controlling the idle of an OEM engine, no surprise I guess. The way around that was to remove its mounting screws and physically rotate it to close off the valve ports, which lowered idle speed to around 800 rpm, then used the set screw to push idle back up to 950-ish rpm.

After that, the TAP sensor was recalibrated for full open and closed, plus setting the idle air valve’s operating range. I’ve seen several recommended ranges but after again flailing around, settled for “-3%” at target idle.

After all this, went for a few test drives and it’s now close to an OEM-quality idle. There’s still a bit more tweaking to do but it’s refined enough that I can work on it when I want to rather than needing to.

*In the back of my mind was a concern that someday, this “slightly-sticky” throttle body might just decide to stick open at, oh, 50%. Having that much power unexpectedly pushing the car could end very badly. One time at Autoclub Speedway, I got a hint of what that could be like when braking for a turn and catching the edge of the gas pedal on my shoe without realizing it. Nothing bad happened but only because there was no wall or cars ahead of me as I “drove” straight off. It was a lesson I fortunately didn’t have to pay for (kind of like what I learned by overhearing a woman ask another woman “when are you due?”, and hearing her say “I’m not pregnant”). Anyway… a stuck throttle is mildly terrifying, especially in a light car with this engine. The problem was solved by trimming back the gas pedal to move it further from the brake, but still close enough to do heel-and-toe downshifting.