Greg's Mira AvanzatoR4

Figured I’d start a little log here of the '95 Daihatsu Mira TR-XX AvanzatoR4 I’ve just purchased. I knew this car would be a bit of a project, but it looks like it might turn out to be a little more than I initially expected.

About the car: Dohc inline 4 cylinder, 16 valve turbocharged engine with AWD. It has around 144,xxx km or 89,xxx miles.

Modifications: Rear sway bar, bucket seat, steering wheel, two headunits, a big speaker in the trunk, Tein front coilovers, front lip, exhaust LED headlights, boost gauge.

Issues at time of purchase:
Bad rattle from the engine on driver’s side, power seems a bit low, engine sounds kinda unusual, a bit subaru-ish? Bucket seat stuck in position, one headlight doesn’t work, engine occasionally surges at idle, seems to burn some oil. There’s also an absolute rats nest of mystery wires underneath the dash, with several wires just dangling, unconnected to anything.



I’m now trying to address my biggest issue, the ticking engine. I’ve replaced the oil and spark plugs, and removed both belts to check if a seized pulley might be the cause, but no luck so far, the ticking persists. I suspect it may be related to the cam chain, so now have to see if I can find any diagrams that can show me where the camchain tensioner is hiding. I’ll probably also remove the valve cover to ensure timing is ok. But for now, I just need to do some more research. Presumably the jb-jl should be pretty similar to the engine found in the Copen, so hopefully if I can’t find much info on this engine, I can get a rough idea if what needs to be done from Copen forums.

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There are differences but the engines will be pretty similar.

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Great Dai.

The ticking is not something as simple as injector noise? Without hearing it’s hard to say and I’m not sure on your experience. Not trying to be a smart arse but just throwing other ideas out there. Valve adjustment? Have you got a stethoscope?

I know direct injection can be pretty loud, wasn’t sure if that was the case with port injection as well? To me it sounds like the noise is coming from the timing chain area or maaaaaybe the cylinder nearest to it. I’ve removed both belts so it isn’t a pulley going bad.

I don’t have a stethoscope but will be visiting a DIY garage next Saturday which hopefully has one. And if I’ve got time it would be nice to do a compression test, and
perhaps remove the valve cover and check to make sure timing is good and the chain is tight. But honestly I’m not entirely sure how to do that.

I’ve done valve adjustments on a couple motorcycles, but they weren’t as tight of an area as this car is and they had a nice little inspection window where you could line up a Mark on the crank with a Mark on the camshafts. But this car doesn’t seem to have that, just a pulley in the way. I’m also not really sure where the chain tensioner is hiding.

[quote=“gregn8r, post:6, topic:6216”]I know direct injection can be pretty loud, wasn’t sure if that was the case with port injection as well?..[/quote]Hardened injector o-rings are known for causing clicking sounds, given that they are no longer capable of absorbing energy. The best way to determine this would be to remove the metal end of the stethescope and then listen to the suspected area through the stethescope’s hose

Took the Mira to a local-ish DIY garage today for some maintenance. I was able to change out my coolant, trans fluid, transfer case fluid, and diff fluid. They all appeared to be pretty clean except for the trans fluid, which was a a silvery grey. I also changed the oil again after at most two tanks of fuel, there were no metal shavings, but I was a bit surprised at how dirty it had gotten already. Not sure if that really means anything, though.

I also flushed my brakes, which was very necessary because I had to almost bury my foot to the floor to really slow down, and the brake fluid was a pretty nasty brown color. Unfortunately, that has allowed me to discover that the car shudders pretty badly under medium to heavy braking. Hopefully I can get the rotors turned to correct this issue.

For the past few weeks I’ve been occasionally taking the car for short drives, and to work a couple of times, but I think it’s time to park up for a while. This car has too many issues that need to be addressed, I don’t enjoy driving it when all I can think about is how poorly it runs.


  1. Underside of engine bay
  2. Old trans fluid
  3. The floor pan underneath the driver’s seat is dented
  4. This plug boot does not physically fit in the recessed area between cams… You can see where it has bent up to fit.
  5. Plug boot has a slightly different shape and is slightly longer than the other. Kinda doubt this would actually cause any misfires, though.


To do list:
Check compression (tried today but had equipment issues)

Buy/replace throttle position sensor, as I broke it earlier. I suspect it might be a large part of why the car wants to idle at 2k-3k rpm.

Clean idle control valve. I had tried earlier, but the bolts were stuck and I couldn’t get them off. I’ll give it another go in the near future

Pull injectors, check flow, refurbish

Try to replace all old rubber hoses with nice new silicone.

Replace timing chain tensioner?

Refurbish brake rotors.

Check for vacuum leaks.

Replace coils and boots.

Repaint the car? That’ll be in the very far future


Today I was loading some stuff into the passenger seat so I could take the car to a local DIY motorcycle garage, and the car’s blinkers started intermittently switching n on and off. This lil mystery box seems to be the culprit. So I’ll have to add"clean up the wiring harness" to the list

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Compression tested today, and verified all plugs had good spark (not that I had any reason to doubt). I did accidentally shock myself once, that was kinda fun.

Each cylinder showed around 185psi dry, and around 210-225 PSI wet (dumped a little oil in the cylinder)

Good enough for me, and one less thing to worry about.

Next up, yank my injectors out and take them to a local injector cleaner.


The past couple of days I’ve really been tearing this car apart. I’ve pulled off my fuel rail and sent the injectors to be cleaned.

Idle has been 2-3k the past couple times I’ve driven it. I was fairly certain that was due to me breaking the throttle position sensor. Sure enough…

I’ll have to order this from abroad, unless an older Toyota or Daihatsu used a similar part

I cleaned up the idle control valve, although it was probably functioning fine

And lastly, I pulled out my timing chain tensioner. This part was providing spring tension as I removed it, and it seems to slide freely, so I’m not sure if it was the cause of the noise I’d attributed to “loose chain slap” . I’m also not 100% certain on how to reinstall it as it ratchets, so I’d need to install it in it’s compressed state and then free it.

There’s a little hook on the side that holds the plunger in, I’m thinking I may need to pull the valve cover off to release the hook from inside

The idle air control valve can be omitted. It is primarily a cold start thing. Idle is then set at the butterfly.

You’re saying that if I had issues with it and it was stuck open or something I could block it off with a flat plate of metal or gasket material, and manually adjust with the throttle stop screw?

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Note that normally water flows through. It is designed to increase the idle and keep it running when cold. It uses a bimetalic section that moves with temp and will give more or less air. I’ve always blocked the water lines and made a plate up that lets one delete these idle control valves. All it does is leak air into the engine. Just do that via the butterfly.

A new ICV is buttons from aliexpress - I have two, one fitted to my car and another on one of my spare throttle bodies. They were about £15 delivered IIRC.

Guide here: K3-VE & K3-VE2 ICV repair/replacement

And part number is: 22270-97401

Blankable, yes, but if the part is this cheap, do you want to be spending hours fiddling around blanking it off and manually adjusting it all?

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I omitted mine for reasons other than it being broken and not wanting to replace it (it was working). Rather I am in a hot climate and wanted to omit the engine coolant passing through the throttle body/manifold. If you look through my build you’ll see I even laser cut Teflon inlet manifold gaskets and Teflon washers. Pre and post testing found the manifold ran cooler by one or two degrees. That was while running and with at least idling air flow. Surprisingly my heat sink pre and post tests found almost no temp difference. For example, with the bonnet closed, 10min after shutting down the manifold was same temp either way. The omission of this item does make for a tidier engine bay and anything not necessary for performance is just in the way of my big hands when performing maintenance. My engineering brain says the bypass is a complex solution to a problem that can be done more simply and would take less time than ordering, walking to the post box, unwrapping and installing. 45min job max. But hey I get some people like to keep things factory and that is good too.


I will keep the idle block off in mind, and might give it a go if I can’t get the car to idle correctly in the future (it doesn’t idle correctly right now, but that could be due to a bunch of issues.) Unfortunately while I do plan on using this car as a fun fair weather toy, I live in an area that may see snow from October thru April, so I’d prefer to keep it just in case

Small update: today I temporarily fixed my broken throttle position sensor. I ordered a TPS from some old 80’s Toyota, I think it was an mr2? Not 100% sure. It had the same D-shaped throttle shaft and had a three-wire connector, so I ordered it on a whim because two-day shipping beats weaks of waiting on a part from Japan. Unfortunately, the part was similar but didn’t really fit. I had to remove the little red plastic piece and remove some material with a Dremel before sticking it in my old TPS. It will work for now, but needs to be replaced eventually

Reinstalled my freshly cleaned fuel injectors, but I haven’t tried to run the car yet, so I can’t say if it helped anything.

I also attempted to re-install my timing chain tensioner. I had removed it in hopes that it would be faulty and the cause of my engine’s chain-slap sounds. It seemed functional, so I compressed it and put it back into place. However, the manual I’d found for the JB-DET engine didn’t mention how to release the tensioner plunger… I was hoping that perhaps when it was pressed against the chain guide it would compress enough for it’s retaining hook to fall off and release it, but no luck. The only way to ensure it released was to pull the valve cover…

And that’s were I’ve left off. I don’t see any obvious signs of damage, and it would be hard to tell how tight the chain is. I’m thinking I’ll have to get the car jacked up and try turning over the engine by hand to see if I can find anything. I don’t actually own a jack and jack stand though, might have to go shopping :shopping_cart:

It probably wouldn’t hurt to check valve clearances while I’m here, I may have to look into that as well. I’ve done it in my motorcycles before, but they all had easily removable plates near the crankshaft with timing marks on them. I don’t think this car has that.