Help.... auto to manual ecu.....!!!!

[Bodbod]

Hey peeps.... i have a manual converted legnum. I just recently purchased a manual ecu and installed it and now it wont start. Winds over but seems like no fuel pump. Just wondering if the pins are different from manual to auto ecu and if so which ones do i need to switch? Regards jamie

 

[Gt_Galant]

What numbers/part numbers are on the manual ecu box ?
And just outta curiosity what numbers are on the auto engine ecu box ? (Not transmission ecu)

 

[Bodbod]

No numbers on the manual ecu.... its a havok tuned one. Auto ecu MR578136

 

[BCX]

There is no real difference between an auto and manual ecu. The software is the same, table values are a little different (idle values, etc). Nothing that would stop it running and no need to replace as part of conversion.

Do you have something you can log with?

What wiring changes have you done as part of the conversion?

 

[Bodbod]

I followed the guide thats posted on here. Been driving it for two years with the manual conversion. But when it first starts cold in the morning it revs pretty high, always had even with the auto so i thought putting a manual ecu might eliminate such a high cold start. And i thought while im at it ill get a tuned ecu with some pops and bangs and launch added. From what i can see there are 2 wires different which i have joined to trick the ecu that its in park so it will start!

 

[Bodbod]

But as soon as i cut those wires the car wont wind over. On the ecu pinout it says for auto ecu both thise wires are the inhibitor switch.. but on the manual ecu 1 of those wires is ignition +12v and the other is ground.

 

[BCX]

So to be clear on the symptoms, the starter motor wont crank or the car wont start?

The starter signal comes directly from the old inhibitor switch. Ecu technically doesn't need this to start (think push start in manual) but helps as the injectors batch fire while cranking I believe then switches to sequential.

The other signal, neutral/park, in manual is tied to 12v/gnd (cant remember which) so the ecu thinks its always in neutral. Cant tell you if not having that wire will prevent the ecu from firing injectors or coils but this wire definately changes which maps to use for idle in gear/neutral for automatic for example.

If you have a high idle, can be fixed by reflash.

I personally wouldn't use another tune/ecu unless you know that the tune suits the condition of your engine, injectors, coils, spark plugs, etc. If its quite an aggressive tune, it could be mis-fuelled for your setup. Do you have a wideband to confirm?

When I'm in front of my pc, i can post up a wiring diagram of auto vs manual from a Magna. The wiring is the same between them, just the colours of the wires different. Manual magna have almost same pinout as vr4. I use a magna ecu to run vr4 code for my bench setup.

 

[Bodbod]

Yeah so it winds over but wont start!!!! I hard wired the fuel pump relay which allows it to start but runs on like 2-3 cylinders and extremely rich!!!. The inhibitor wires are wired together. Black with yellow stripe and black with red stripe. Ive tried cutting those wires which in turn results in no winding over. So since people have sucessfully put manual ecu into autos im lost as to why its not starting. As all iv'e really done is bypassed the park switch to allow the starter to engage.

 

[Bodbod]

So do you think that maybe i have to put black/red wire to 12v ignition and black/yellow to ground? As that what it shows on the ecu pinout?

 

[Bodbod]

So..... i sent the ecu back to n.z to havok.... i finally recieved another manual ecu. Same problem. Winds over but wont start. So i decided to find out whats goin on. So i tested fuel pump voltage and thats all good. Next tested injector pulse... again all good. So that left me with ignition. So i found its losing the signal from the ecu while cranking. So im at a loss as to why its doing this.... manual converted legnum. Runs fine with auto ecu... wont run with manual!!! Maybe @TME_Steve knows why???

 

[naughtika]

as dumb as this may sound. Can you confirm if you have fuel?

 

[Bodbod]

Its all good im pretty sure the ecu ignition outputs are toast..! He said he sent me another ecu but used the same case but im pretty positive he just sent me back the same ecu.

 

[BCX]

Can you please post a photo of the PCB of the ECU?

Did Havok mention it's specifically a VR4 ECU?

 

[Gt_Galant]

No numbers on the manual ecu.... its a havok tuned one. Auto ecu MR578136

I have a feeling the “manual” ecu could be different or probably not for the vr4 since there’s no number plus exactly what “BCX” said pictures would have helped of the inside since there’s no numbers on the outside ecu.

 

[BCX]

Indeed, there are slight differences in the hardware between ECU PCBs.

For example:
4cyl ecus only have 4 injector drivers
Magna ECU with VR4 rom does not run as there appears (from my brief testing) missing the drivers for the ignition coils as Magna uses a dizzy.
This is the same as using a Magna ECU in my MK Triton. Both are 6g74, but ignition systems are different (coil packs vs dizzy)

 

[jungle]

So why don't you use the auto ECU if that runs fine? Then get a tune if you want some more power?