4AGZE Turbo Spitting/Missfireing at 3lb Boost

[Revolution]

Hey Guys

Im looking for a little help. Im currently running a 4AGZE turbo in a AE93 Secca and a couple of days ago it started spitting/missfireing when I hit 3lb Boost, once i get above 4lb boost the engine runs perfectly through to boost cut off. Its idleing and running fine apart from this. Its wired to a LTX8 Microtech computer.Any ideas on what to look at would be appreciated as Im new to this type of engine and injection system.

Regards

[The Witzl]

Its hard to know what that one is.... has the Microtech been tuned, or is it still being run with the factory "pre-tune"?

I would recommend taking it to a tuner. Plenty around who are good with Microtechs.

[Revolution]

The Microtech has been tuned to the engine.

I will have a look around for a tunner over the next couple of days.

Thanks

[fixeruperer]

any black smoke out the tail pipe when its spluttering ?
or does it pop and back fire ?

[Revolution]

It pops but no backfireing its almost like it doesnt have enough fuel or is down a spark plug but as soon as I get it over 4lb of boost it revs off its nuts. Its got me stuffed.

[abently]

Microtech's are a hit n miss thing. If it was purchased new for that Engine then its possibly just an issue the tuner will be able to pick up.

When did this issue start occuring ? I'm inclined to say, save the Tuned map and send the Unit in for repairs before they stop doing repairs on the LT range...

[oldcorollas]

I'm inclined to say, save the Tuned map and send the Unit in for repairs before they stop doing repairs on the LT range...

don't you think it would be better to identify if it is even a problem with the ECU first, before sending it in for repairs?

MAP or AFM? if MAP, check the output at 3psi boost and see if it has issues.

[Revolution]

Im going to go and get a new set of plugs, leads and fuel filter this arvo just on the incase its something simple.

As for MAP or AFM I have no idea, I didnt build the car so im learnings as I go im more use to rotarys with webbers not fuel injected pocket rocket Toyotas.

[X kyle X]

where your air filter is, does it connect to another device before running to your throttle body?

[abently]

don't you think it would be better to identify if it is even a problem with the ECU first, before sending it in for repairs?

MAP or AFM? if MAP, check the output at 3psi boost and see if it has issues.

Yes I agree, but also knowing Microwrecks as well as I do, I don't hold out much hope for him.



If it was a new unit installed professionally then I'ld say there is an issue with the on board MAP sensor, assuming the fuel and ignition maps are all normal.

[Revolution]

Pod filter into turbo out of turbo through intercooler straight into throtle body.

[YLD-16L]

Post up your injector timing values from 0psi though to 14psi for us and your ignition timing compensation values for the same range just in case it's got some stupid value entered at the 2psi point on the map.


I'm assuming here that if you hold 3psi it stumbles and hesitates the whole time at that point regardless of rpm??

[Revolution]

Post up your injector timing values from 0psi though to 14psi for us and your ignition timing compensation values for the same range just in case it's got some stupid value entered at the 2psi point on the map.


I'm assuming here that if you hold 3psi it stumbles and hesitates the whole time at that point regardless of rpm??

Yes you are corrent in your assumption it doesnt matter what rpm or gear it stumbles and hesitates at 3lb boost.

Can I get the the values you mentioned above from the hand control for the Microtech ?

[YLD-16L]

Yes you are corrent in your assumption it doesnt matter what rpm or gear it stumbles and hesitates at 3lb boost.

Can I get the the values you mentioned above from the hand control for the Microtech ?

Yep, just go into the hand controller, scroll through to LOAD, then scroll through the vac and boost values and note the values.

The do the same in the t_map screens.

Note the values from 10"Hg through to at least 14psi, not from 0psi as I previously noted.

That'll at least let us see if there is an erroneous value in there compared to the values either side of it.

[TERRA Operative]

don't you think it would be better to identify if it is even a problem with the ECU first, before sending it in for repairs?

MAP or AFM? if MAP, check the output at 3psi boost and see if it has issues.

Microtechs have an onboard MAP sensor in the ECU, they don't use the AFM.