Could my Factory ECU be faulty

[BZR4AGE]

Hi guys
I have a issue that I've never seem to be able to solve.

My car (BZR) have random flatspots or misfiring. It only occurs at the same rev range (between 1000-3000). The car will rev, but it won't go. This issue happens when ever it feels like, and under different driving conditions. The problem goes away after I reset the ECU (disconnecting the battery for 15mins).

But it will re-occur after a few hundred k. (usually happens once or twice per tank of petrol - just to give you guys a rough idea).

I've check the leads, sparkplug, dizzy cap, recently changed ignitor.

I can only remember this started occuring after I installed a oil catch can. The can is hooked from PCV valve to can, and side of head to can, and it is vented. The PCV valve has been drilled through by the installer, so it is only functioning like link instead of opening when it is suppose to. COULD THIS BE MY PROBLEM??

Remember i have a e-manage ultimate piggyback ECU. My tuner couldn't figure out why it happens too.

I am suspecting is something to do with the Factory ECU, since the problem alway go away after i've reset it.

What do you guys think?

Cheers! and thanks in advance.

[xsspeed]

These could help?


Blacktop hesitation problems...several pages to trawl through
http://forums.toyspeed.org.nz/viewtopic.php?t=46052

20V ECU links, the second link in the thread is for the b/top ecu
http://forums.toyspeed.org.nz/viewtopic.php?p=601032#601032

[BZR4AGE]

thanks alot xsspeed! Will read them after work!

[Dell'Orto]

With your motor, I'd be inclined to ditch the factory ECU anyway, I'm impressed it makes good power.

[BZR4AGE]

Dell'orto: I will rip out the factory ECU during the weekend and check the internal according to the guide. If that dosen't fix things, maybe is a good excuse to get a standalone LINK!

[Crampy]

If that dosen't fix things, maybe is a good excuse to get a standalone LINK!

I like the way you think.
A link will probably be the best thing for your engine at the moment anyway.

[BigDon]

Maybe faulty oxygen sensor and/or knock sensor.

Had similar problems on my BT, changed those and it was sorted.

[Jonno2002]

i 2nd the faulty oxy sensor, my honda was doing wierd things like that till i changed to a heated sensor, reason being is that the sensor was moved back down the exhaust after extractors went on and a single wire (unheated) sensor didnt work properly so far away from the heat in the manifold, but yea i had a bad idle and often hesitated at wierd times but now doesnt do it at all...

[xsspeed]

I recommend checking out the FAQ on the blacktop ecu, apparently they go quite often. I will be ripping open mine before installing the blacktop to my corolla. Gunna do it early so if it looks fried I will start saving for a link or something while I'm doing the install.

[RedMist]

I'd like to third the O2 sensor. People don't realize they are a consumable item, they go on a regular basis. I've had similar hesitation issues on a number of my cars and replacement of the O2 sensor corrected them.
In addition I wouldnt be looking at your ECU as you state that a reset causes the fault to go away. The ECU will "learn" an additional fueling table based on the faulty O2 sensor and will eventually create a table based on false readings. As such it'll run like poooose, with hesitation and generally a very rich mix.

[MAGN1T]

Have you checked for fault codes?

Steve

[BZR4AGE]

Thanks for the heads up! so i guess the first thing i will check is oxy sensor!

Yes i've checked for fault codes, nothing comes up!