Toyota 1ZZ Headaches

[confusis]

Well, this is where my energy and funds have gone. My Toyota Opa, an oddity of a car, has been causing headaches for the past couple of months. From reliable motoring, to stumbling, juddering and just outright loss of power. Intermittently. Like all fun troubleshooting situations -_- Issue occurs across the entire RPM range. (Super rare on "unloaded" idle though - in neutral or park)

Couple months back, I completed a 120km delivery run, and returned to the shop I am based at. Shut it down for 20 mins, and then it struggled to start. From there it ran terribly...intermittently.

It only does this when in "closed loop". No OBD codes present, and Long Term fuel trims look fine. Short terms peg to +20 when it's playing up. I've done a ECU reset (unplug battery overnight) as well.

The parts cannon for this one resembles a GAU-8, and I've replaced;

• Spark plugs (Genuine NGKs)
• Oil change (Sakura filter, Nulon oil)
• Air filter (Sakura brand)
• One ignition coil (broke it when pulling them when replacing the spark plugs) (reputable aftermarket brand)
• Fuel Pump sock (same brand as coil)
• Fuel Pump (same brand as coil)
• Fuel filter (Sakura)
• In-tank fuel regulator (genuine Denso)
• All injectors with used Denso units, and then AliExpress knockoffs
• Cabin air filter (Pretty sure I replaced the original year 2000 filter... this has nothing to do with the engine issue, but check your cabin air filter!!)

Although, a lot of these items were due for service in any case, with the car having travelled 209,000kms. Some items had never been changed, like the fuel pump sock, fuel filter, and some hadn't been done since the car left Japan at 100,000kms, 14 years ago, like the air filter, spark plugs...

Power balance test (unplugging individual coils to see which cylinder isn't contributing) when it's throwing a tantrum has been inconclusive, with the engine stalling out if I disable any cylinder during it's temper fits. Fuel system cleaner has been used a few times, which helped... for a short time each time. Haven't used it since the fuel system filter replacements. The fuel system cleaner semi-working is why I've practically replaced the entire fuel system now..

I use reputable fuel (91 RON) from a local station that is very well frequented (and thus fuel is 'fresh')

Just did a MAF clean, but I'm wondering what to tackle next! At the end of this all, the car will have had allll it's services and it'll be good for another 200,000kms though!

When the car is behaving, it has all that pathetic 1ZZ power, but I can't travel more than 20 mins now without it throwing a wobbly... sometimes... ugh

It's a practical car, and I'm still paying it off - can't afford to replace it.

Anyone have any ideas before I take it to a mechanic? Whilst I could have done that from the start, the cost of the parts replaced thus far have cost around a normal "extended diagnostic fee" and I'm learning along the way.

 

[RAAM]

I have been a DIY mechanic for many decades and your particular issue makes me think of a ground problem which can be easy or very difficult to locate. I would start at the battery then closest chassis and engine grounds first. Next if not found would be grounds for any and all electronics, really weird issues have come about from seemingly unrelated ground problems.

Another check, while engine running, might be best to do this first, wiggle all the grounds, and power leads, then the cables to ensure nothing broken in them.

One more item, ignition switch, give the key a good wiggle, wiring, etc....could be the contacts as well.

I really hope this can help you find it. I have to fix a power steering leak and likely replace on 02 sensor or two on our amazingly fine running 05 V8 AWD 4Runner soon. It only has 309,900 miles (498735.7KM) on it so far and does not use a drop of oil, have any leaks, etc...Last year I did around $8,000 in shop prices maintenance, some not needed but while digging it figured might as well, cost was around $800 in parts. I plan to keep this for a very long time so worth doing all the work on it to make sure it just keeps going strong.

Intermittent problems can be the toughest to track down, 20 years Navy tech, I saw some crazy sheat on very complicated systems. One was a loose wire wrap I could not get to until in port, had to keep the 800lb chassis open and used a broomstick wedged against it, tackle to lock the system in place better than just simple maintenance chassis locks, etc. If not for being one of the most critical systems in the battle group which we could not leave to go to port to fix (had to have a small custom crane assembled in the space) it would of never been hacked like it was but there was nothing else we could do. It came and went so randomly, especially when trying to track it down, it took quite some time to figure it out.

Rick

 

[confusis]

oof, forgot to update this! Thanks for the ideas, @RAAM

Turns out, there was a small mounting clip missing in the shroud beneath the windscreen, which, when raining, would collect all the water from the windscreen, and leak water directly down into the gap in the engine cover next to the oil filler. This would then leak just enough water into the spark plug wells to cause misfiring next time the car ran, but not enough to be detectable by the time I got home to diagnose..

I've done 5,000km since the last time it played up, after I replaced the clip (and siliconed it in for good measure).

 

[RAAM]

Do you have access to an OBDII scanner or whatever is used where you are? If not maybe you can borrow or rent one.

I recall a partially plugged fuel line issue a very long time ago, symptoms would come and go and since the fuel system cleaner seemed to work for a short time it might be that, A good shot of highly compressed air could help, not sure ever saw one small enough but a snake through the line could be in order.

When working on the fuel pump did you take a good look inside the tank for anything built up in it?

 

[confusis]

I've got a scanner, no code present. Only useful data I saw was short term fuel trims going suuuuuper positive when the engine was throwing a wobbly, but not much of a change on the o2 readings (I have a spare o2 sensor ready if that happens to be an issue) . As I mentioned, after sorting the water ingress issue, I've had no problems. Although now that I've said that, I've got 200kms of a delivery run drive tomorrow for work, so it'll probably play up now

Tank was super clean, thankfully!

 

[RAAM]

Yeah! Very glad it was something simple and especially free to fix! I have had or seen some funky issues but this one goes up high on the list!

It was good that I did see and post as it helped clear out of few more cobwebs, always better to keep exercising that lump between the ears.

I just realized the date you first posted this, I need to pay more attention it seems

Rick

 

[RAAM]

Never had a 1ZZ but had a boosted 2zz blown on the dyno by a guy with bigger ego than talent for tuning, I replaced it and went somewhere else. Had a 2.5 in a Scion tC blown by another tuner but it lasted at least 2.5 days, put 5 holes in the block at 100MPH and went off track backwards on fire, exciting times indeed. 1.6 Echoboost in my 400HP Fiesta blew head gasket and warped the head because F'in Ford was too cheap to install a real temp sensor and were selling a known faulty cylinder head on it for a few years that tended to crack and leak oil onto the manifold and catch fire. I was installing a newer version and bent valves in two cylinders because I did not know they did not key the crankshaft pulley but I take the blame for that, a bit at least, it was in the manual but not the area I was dealing with at the time so never saw it until to late. That is it for broken engines in over 50 years of messing around with them.

 

[confusis]

Even with the broken engines, it seems like you've had a load of fun!

Mods are out of the budget for now, but one of these days I want to buy a 1ZZ engine, rebuild and port it, and teach my son & daughter some mechanical things! Not sure how available an aftermarket ECU for a Toyota Opa would be though

 

[steelfractal]

Even with the broken engines, it seems like you've had a load of fun!

Mods are out of the budget for now, but one of these days I want to buy a 1ZZ engine, rebuild and port it, and teach my son & daughter some mechanical things! Not sure how available an aftermarket ECU for a Toyota Opa would be though

Products - Haltech

www.haltech.com

 

[confusis]

Products - Haltech

www.haltech.com

Sorry, should have said a direct plug in aftermarket ECU

 

[RAAM]

Except for the computer I built, was nearly all used, now a bit of new stuff in it, all my time and budget goes to our RV total remodel(really only keeping the main structure, all else significantly redone at a very high level but very low budget) My car mod days are pretty much done but I do want to tweak up my old 4runner a bit more. A light bar I have had for a few years for it, clean up and texture the fender flares, bumpers, etc, redo the drivers seat upholstery, upgrade the audio a bit...

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I always built my cars to handle, stop, stay cool, safe and reliable first then added power up to where it needed to be well balanced, etc..I have beaten more cars than I will ever remember with big budgets, to much power, not enough anything else....The ST was the highest power to weight ratio car I ever built up and only did so for when Porsche Turbos, etc, would out drag race me on the straights and get in the way on corners so I gave it the same P/W ratio and beat up a few cars with my lap times, quite a few and some decent full race cars as well before I even added the 175 HP I got out of the stock turbo at 225. At 400 HP it would of been quite a handful to drive but sure fun on track but I never took it out again.

Though I have met some cool high dollar car owners and some that could even drive the majority were only driven by ego and very easy to out drive. (I consider myself very competent but have met those that are mind blowing fast)

Over the decades I always had the most fun driving a slow car fast, as the saying goes, instead of a fast car slow. I have had 6 or 7 Miata cars and most pretty stock and loved everyone of them. At the most I would not want more than 200 HP in one, simply not what the car is about.

Building an engine with your children would be wonderful for them and you

Rick