Ecu issues

[Ryan95]

Hi guys 190kw manual motor idle is Abit rough, seems to run okay but have a feeling it is underperforming its running pretty rich only getting about 450km on a tank around town. Diagnosed an injector but have since replaced and engine light no longer appears. Mechanics said it is likely to be the ecu. Has anyone else had this issue before or have any knowledge on it? Cheers

 

[Fu Manchu]

Loads.
The ECU can be a bitch on VZ.

They are repairable. Quite a few places can do it.
Injectronics is one.

 

[gungazza]

see how it goes I would have changed all injectors

 

[keybored68]

I'm no ECU expert, but since the engine is running, that means the ECU is reading the cam shaft position, its telling the injectors to inject, it's telling the spark plugs to spark, etc, so doesn't sound to me like the ECU has 'failed'. Need to plug in with an ODBD scanner and see if there are any fault codes.

 

[Fu Manchu]

They can operate incorrectly without generating codes. Eg. Stuck injector being told to remain open, or not at all.
Coil #x not receiving anything to tell it to spark and not generate a code to indicate this condition.

The VZ ECU is by far the shittest ECU ever put in a car, & that ECU is used in many other GM vehicles.

@wannaeatyourbrains found moving the ECU off the motor got its temp down enough for it operate more reliably.

Over the years many have had issues when the ECU is hot and not when it’s cold.

Anyway, getting that far into fault finding straight away is a stretch isn’t it.

Above post nailed it and it’s going to need someone experienced to interpret high end scan tools data as they can access independent sensor data and even test sensors etc without the engine running in many cases.

 

[Big Red VF-SII Go-kart]

I am not convinced all and any VZs had a problem with the ECUs.
Not once during my ownership of the VZ before my present VF did I have any reason to suspect any of the electronics, including the ECU the subject of these posts, was at serious enough fault to warrant an argument or investigation. But it is known as a fact that cars (VZs, among) prepared for the Services may have legacy foibles as a result of tapping into the BCM, particularly bypassing the immobiliser, as the Services had specific requirements for onboard communications, lights, sirens (printers and mini-fridges too!) and supplementary tricks such as the one-button "kill all" switch hidden under the centre console.

The greatest risk of faults arising comes the moment modifications are attempted that tap into the electronics without realising the real and potential sequalae that result.

 

[Fu Manchu]

The weakness in the VZ ECU are the really fine wires around the outside from what Jason at Envyous Customs has found and this guy points out the connections can be loose

Inside the VZ ECU (flick through to 5:20)

But again, this conclusion should be coming way down the track from the more basic checks and diagnostics.

 

[Moritussum]

Hello All, first, thank you for all your helpful posts - I have read so many.
I now have the dreaded "ECU mystery fault", have read several threads about this, but my symptoms do not all match the previous posts.
My dashboard lights up like a christmas tree, it sings me a happy little song in beeps, and the engine runs like a dog, power steering goes half heavy. Lights; engine, ABS, Trac off, airbag, brakes (!), oil. Its like a disco party.
It started a few weeks ago, and after reading 2007 posts I pulled the ABS fuse out several times when it happened, let it cool down.
The problem stopped immediately, engine performance got far better (easy 10% over mormal, crazy), steering returned to normal. I kept driving (after driving, fuse back in).
After about 4 times I just left the fuse out, happy car, kept driving, several weeks.
Now the problem is happening again, with the ABS fuse permanently out.
VX, LS1 mid year 2000, all original electronics no extras, engine refreshed, all rubber hoses & air seals replaced, dyno at 315HP/6krpm. Its a smooth daily ride, engine is perfect.
No error codes found, about 3 months before it started.
I bought it off my broter-in-law, he bought/drove it off the showroom floor.
With ABS fuse permanently out, can anyone think what else might be causing this?
I dont mind buying a new ecu, as long as its a gauranteed fix.
Thanks, M.

 

[Fu Manchu]

Best to start a new thread.

 

[lout]

unplug the electrical connector to the abs module