ZT Caldina 1AZ-FSE problem

[ZTSAM]

Hi Guys

I'm having an on going issue with my ZT Caldina with the 1AZ-FSE engine. The problem starts when the car reaches its operating temperature which causes the car to idle rough and has a mean stutter or hiccup not sure how else to explain it when travelling with little use of the accelerator (ECO mode) and goes away when revving higher or putting the gas on. I have had the car looked at by several mechanics which have replaced coil, battery, checked the computer, fuel etc and no one seems to have any idea on whats causing the issue and how to fix it. Can anyone shed some light on this for me?

Cheers[/b]

[strx7]

it needs to be run on the highest octane petrol you can find. the injectors dont like NZ's poo fuel, they are on the whole a horrible engine.

try this thread viewtopic.php?t=85511&highlight=1azfse

[ZTSAM]

Thanks for the feedback, the original engine was using oil so the workshop replaced the engine because it was faster to do that than rebuild my old engine. The previous engine ran great on 91 and had no issues apart from using oil. There is defineitly something a miss other than needing higher octane fuel.

[strx7]

the reason it used oil was cause the injectors crapped out from being run on 91 to the point that at certain psi they wouldn't atomise and would just pour the fuel in causing it to bore wash and then USE OIL............

They are a WEIRD motor and they do WEIRD things, from memory they are designed for 102 octane.

[Grrrrrrr!]

So reading between the lines about the 91 octane being a problem I'm figuring it goes something like this..

Owner fills tank with 91, car has detonation issues, detonation damages end of injectors (direct injection) so injectors no longer atomise properly, resulting in fuel not burning properly and O2 sensor reading lean. ECU bumps up fuel delivery to get O2 reading back in spec, but this just results in more unatomised fuel running down bore washing the oil away and killing the rings..

That sound reasonable? Do these cars suffer from shit fuel economy when they have this issue?

[ZTSAM]

When my original engine was using oil i was getting 700kms from 60L of 91 pretty good economy fuel wise. Well.... maybe engine conversion is needed.

[Grrrrrrr!]

700kms in what sort of driving? Open road, city traffic or urban commute?

[Lloyd]

We have had a couple of these that were constant problems and every component tested as fine even when faulting. Coils, injectors, ECUs etc all were fine. Multiple workshops including the local experts and dealer couldn't get to the bottom of it.

I have a feeling it was getting to operating temperature and trying to get into its lean mode but always ended up going too lean and misfiring. There was no fix for it at all.

End result was actually to cap the signal from the water temp sensor so it thought it was always just below operating temperature and it ran much better.

[ZTSAM]

Thanks Lloyd that sounds like what the are going to do to my car, it seems strange having to do that though when most of the components and computer are from the original engine but hey if it fixes the issue i'll be stoked!

[strx7]

if left to bore wash for a while the petrol thins out the oil and the motor will throw a big end and put a rod through the block. which is what started the whole thing of how I began to learn about the issues these motors have.

[Bling]

And you'll start springing for some good fuel, yeah?

[Crucible]

We had one of these in a month or so ago, same problem. I scanned it and it had no fault codes logged but the fuel trim numbers were around 25% at idle which is a huge compensation for a lean condition.

I thought maybe it had something to do with it being a lean burn engine, ie richer off cruize because with high numbers in any other car it would normally set a lean code. The customer didnt want to go further and just wanted the usual plugs, coils checked so never got to the bottom of it.

[ZTSAM]

Thanks for the feedback guys. I was reading the Dog and Lemon and they mentioned the safety fuel cut off solenoid can be dodgy is there one on the 1AZ-FSE or are they talking about the diesel Avensis? And if so could this cause the issue?

[Rob]

Take the hint pal...Put the best fuel you can find in any Jap car, especially one with direct injection like yours. They clog up with carbon and run like crap after a while.

I say this from experience swapping hundreds of engines for people who were too tight to fill up with descent gas.

Good luck with that

[ZTSAM]

Ok car fixed was the EGR system if anyone was still interested.

[puketaha]

Hi ZTSAM, what exactly did you do to the EGR system to fix it?

Mine is doing the same now, swapped the EGR valve for another but no difference.

Cheers,

[ZTSAM]

Hey Puketaha, the mechanics had to block it off, it was the only way round the problem. Engine light is on all the time now which is bit of a nuisance but better than having ya car feel like its going to blow up! And also on the motorway using BP 98 I'm getting 100km out of 7.25L!!

[puketaha]

Thanks for that!! do you know if they blocked of the main hole through or the small tube?

Thanks mate!!

[ZTSAM]

Hey Puketaha, sorry man not sure how they blocked it off but the guys that did the work were efitech in albany.

[puketaha]

Thanks for that! I actually just tried unplugging the EGR valve plug (took all of 15 seconds to do) and it seems to have solved the stuttering. Engine light is now on permanently as yours is.