ecu trouble

[justin parker]

hi guys this is my first post on the forum so please bare with me. 

So i brought my 1998 r34 gtt a few months back now and i’ve had nothing but problems i’ve been having a misfire since the second day of me owning the car i’ve gone through the normal things like changing spark plugs and the coils but nothing has worked i have taken the car to a mechanic in perth and they couldn’t tell me for sure what was wrong but the have told me to try changing the ecu because the car isn’t sparking properly but that has ended up being very difficult because i own a auto r34 was just wondering if i have any other options or even if someone has a ecu that would work in my car. any gel is appreciated the part number for my ecu is 23740 AA511

thanks guys 

[robbo_rb180]

Before getting another ecu.
Has a comp test or leak down test been done?
Is it using coolant?
Have you connected consult and looked for any error codes or weird trigger readings?

Shouldn't be too hard finding an ECU, look around on facenovel or scumtree sales pages

[GTSBoy]

Auto ECUs are as easy to find as manual.

But, I wouldn't believe it's the ECU any more than I would believe the misfire is caused by the LH rear tyre. Far more likely that you have shitty connection in the coil loom. Also possible to be dirty injector (although less likely).

And....what sort of misfire? Idle only? Only in the middle rev/load region (ie, near peak torque)? Only at high revs? Severe, or mild?

[justin parker]

On 18/8/2022 at 2:52 PM, robbo_rb180 said:

Before getting another ecu.
Has a comp test or leak down test been done?
Is it using coolant?
Have you connected consult and looked for any error codes or weird trigger readings?

Shouldn't be too hard finding an ECU, look around on facenovel or scumtree sales pages

from what i’ve been told from the mechanic the compression is fine and the fuel pressure is fine and they told me that the car hasn’t been showing any error codes so i’m just very confused 

[justin parker]

On 18/8/2022 at 2:53 PM, GTSBoy said:

Auto ECUs are as easy to find as manual.

But, I wouldn't believe it's the ECU any more than I would believe the misfire is caused by the LH rear tyre. Far more likely that you have shitty connection in the coil loom. Also possible to be dirty injector (although less likely).

And....what sort of misfire? Idle only? Only in the middle rev/load region (ie, near peak torque)? Only at high revs? Severe, or mild?

so the misfire starts in cylinder three at low revs and then it goes to cylinder one when you raise the revs

i got this video off the mechanic

[robbo_rb180]

Does it happen once the car warms up?

Check that there is a ground strap from the block to chassis and the condition of the coil loom is good with no resistance issues. 
If can get ecu try that but will be something else.

 

[justin parker]

On 18/8/2022 at 7:07 PM, robbo_rb180 said:

Does it happen once the car warms up?

Check that there is a ground strap from the block to chassis and the condition of the coil loom is good with no resistance issues. 
If can get ecu try that but will be something else.

 

it use to happen when the car would warm up but lately it’s just been consistent as soon as i start the car. 

mill check the ground from the block tomorrow morning and i’ll check the whole coil loom thanks heaps for your help man. 

i’ll let you know how it goes