Fried ecu - RB25det into 1987 200sx NEED HELP.

[S12_hybrid]

Alright now I know this is not the standard swap, but lets be honest: The wiring of these things isnt THAT complicated as long as you get your grounds and power from ignition right.

Apparently though, its too hard for me..

Engine is an R33 Rb25det Series 2.

Hooked everything up as best I could, this included:

-Ignition switch went directly to a junction of power wires on the harness-Start switch was left connected to the old lower harness, I just swapped it onto the new starter.Off the fuseblock I ran:-ECU power to pin #45 (If I remember correctly) this was a 10 amp fuse-Continuous ECU power taken from the clock un-interupted power

The grounds which are located in the harness (By the injector clip) were grounded to the manifold.

The Relay is engaged by ground activation via the ecu. The ECU itself received switched 12v power from the ecu fuse (off the fuseblock, as I mentioned).

When I spun the key to "ON" my ECCS relay engaged, and all seemed well..

Then a few seconds past - the relay did not disengage - and smoke started billowing from the box.

It appears that i melted the area around pin #47 to #50 and #59 & #60. Just as a reminder, these are the main switched 12v power lines..

So, I check all my connections, make sure i've got continuity on grounds, and no 12v where there shouldnt be 12v..

I ended up finding that there was 12v on pins #26 & #27 - these are maf sensor lines - I do not know the internal workings of the MAF in depth so DO these lines need 12v??

There didnt appear to be any shorting on the MAF lines, but I dont know..

Also, do these ECUs need to have their case grounded? Are there grounds that I could have missed?

I will get pictures asap!

Oh and just for ****s and giggles, here are the specs on the car.

1987 Nissan 200sx coupe-Stance coilovers (GR+)-S13 rear subframe with J30 LSD and axles-walbro 255-Z32 TT rear brakes & parking drum-180sx front brake conversion-All around 5 bolt conversion (Ichiba in front, 300zx in rear)-Bings Tension rods-Bings Adjustable tie rods-30x12x3 FMIC with mandrel bent intake piping-Greddy intake manifold-Q45 TB-AE86 seats-1 piece driveshaft (steel)-Wilwood biasing valve-Homemade CO2 intercooler sprayer-S13 coupe digital gauge cluster-Prosport gauges (Oil pre, fuel pres, Boost)-Will soon have a full 3" custom exhaust (DP to tip)-Headlight conversion (eliminated pop ups)-17" RTX rims (Whatever I could find cheap with decent rubber)

[S12_hybrid]

Also, I am not using an ignition relay - just my ECCS relay..

As far as I could tell, the only thing the 'ignition' relay does is power the AC relay and the FICD relay.. Neither of which are needed... (?)

-Dan

[Joe]

the MAF is 12 volts

series 2 rb's dont have ignition relays.

[S12_hybrid]

Thanks for your response!

I have but one question:

If I am getting 12volts on both pin 26 and pin 27, is that right? Shouldnt there just be one 12v line?

-Dan

[duece.four.oh.sx]

do you have any pics of your car im interested in your project .....Danny

[S12_hybrid]

No one has any idea what could be wrong?

[S12_hybrid]

So lets get this right here..

Pin #21 Color:L/W AF37 AAC, Boost Valve, Variable Timing Control

This wire needs a switched 12v source, correct? What function did the corresponding S13 wire do? I dont need wire colors or numbers, I need to know how much current demand there is, and what its function was (ON condition).

Pin#24 Color: W/B AF29 ECCS Relay Power

This wire requires constant 12v? The ECCS relay in series 2 is the same as series 1, correct (Minus the ignition relay)? Both positive terminals go to a junction, the junction branches into two. One of these wires gives constant 12v to the ecu, the other RECEIVES constant 12v from the M63 connector.

Pin #12 Color: B/R AF36 Ignition Switch

Provided by the actual igntion switch. When there is continuity to the ignition wire (In start and run) 12v is provided to this wire. This allows the ecu enough current to 'power up' so that it can GROUND pin #16 and activate the ECCS relay? Is this the right train of thought?

Pin#8Colo: B CDE1 ECCS Ground

This grounds STRAIGHT to the chassis? What did the corresponding S13 match do?

Pin#40 Color: B AE08 Grounded & ECCS Ground

Another chassis ground? I just dont know about this one.

Also, can the ignition switch flow enough power to supply the injectors (gray wire)?

Thanks!

[S12_hybrid]

Whats up with this? Does no one here actually know how their wiring works? Is EVERYONE on this forum just a 'guide follower'..

over 70 views, and 1 somewhat useful response.. Come on guys... We've all been in a dreary spot at some point. Help a brother out.

-Dan

[Vkoslak]

Try these guys:

http://www.club-s12.org/

I love the s12. I wish I still had one.

[S12_hybrid]

I am a member there. In fact I have a build thread for this very car going on in those forums. Thanks for the advice though.. This is an RB issue, not a chassis issue (At least I do believe so)..

Yeah they are definetly fun little cars..

-Dan

[Reaper]

sorry, i paid a shop to do my wiring so i wouldn't have to worry about things like that

[Vkoslak]

Pin #40 is a ground, just run to car chassis.

If this was series 1 or an rb20det, it would be much easier.