gavinmosher

Alright i have been studying the FSM trying to figure out what to do to find my voltages on my ecu..... but when looking at the FSM it shows 3 different plugs going to the ECU.... i only have one single plug going to my ecu? so how do i know which pins are which to check the voltages?

that one guy300

are you sure that this is the ecu under the passenger side floor under the feet of the passenger?

gavinmosher

am i sure about the FSM or my Car? the FSM it was under EMissions and i went to Control Unit... on my car its up above my feet

HAILERS

Where the soles of the passengers feet are if the carpet was not there , nor the metal protective cover over the ECU was not there.

gavinmosher

O damn... my bad hailers your a life saver.... so i check the voltages on that under the carpet.... are they the same for a N/A car and a Turbo car?

gavinmosher

alright guys backprobed the 1a pin which should be power.... got nothing there and only .20vdc at the main relay so i have confirmed my ecu isnt getting any power.... any reccomendations on how to fix that?

HAILERS

1A and 1B on the series five turbo or non turbo should have batt pwr.

1A does not pass thru the Main Relay. Its fed by errrrrr....ahhhhh.....I think right now, by the Room fuse and the Room fuse is fed by the BTN fuse in the engine bay.

1B is fed by the Main Relay and that pwr comes from the EGI fuse in the engine bay. The Main Relay in turn is pulled in by the ENGINE FUSE in the interior who gets it's power from the ingnitoin switch when the ignition switch is put to ON or better.

Your series five have power on 1B????? or not? Series four will run without their equiv of pin 1A. Seems it's a memory function of some sort. I know not if a seires five will run without it....but I'd bet a few bucks it will run without it.

gavinmosher

No power on 1a and only .2vdc on 1b


which pin should feed the whole ecu? isnt it 1a?

HAILERS

You should have both, but NEED 1B. Didn't I write somewhere above that my car runs just fine without the power from the ROOM fuse (pin 1A)?

Your MAIN RELAY is not pulling in...............or your EGI fuse is bad ..............or the EGI fuse is not being fed by the battery...........or your harness has been severly screwed up somehow.,

Works like this. Key to ON, power goes from the BLACK igniton lead.........thru the ingition switch to the BLACK/WHItE igniton lead............which in turn feeds the ENGINE fuse in the interior (and all fuses on the IG1 row of fuses).........from the ENGINE fuse to the positve side of the MAIN RELAYs coil (neg side of that coil has a gnd 24/7)...........MAIN RELAY pulls in and the internal contats *make* and send power from the EGI fuse to the ECU pin 1B plUs at the same time feeding the lead and trail coils and the fuel injectors.

You need to put your hand on the MAIN RELAY and have someone put the key to ON. You should feel the relay pull in. If it does not, then check the ENGINE fuse for being good or bad.

If the coils have pwr when the key is ON, then the ECU should also have pwr.

YOu sure your coils have pwr when the key is ON?????????????????

Pin 1B MUST have power for the ECU to work and pulse fuel injectors and on/off signals to the lead and trail coils.

My 86/87's will run fine without the power from the ROOM fuse (equiv of your 1A). The 1A is a memory thing.

Will_s

iTrader: (7)

just a little more info 1A is merely a backup for when the car is off. You don't need it connected for the ecu to work.

MattsFc3s

Sorry to bring this to life, anyone find the solution to the problem I have the same issue for my 1B. I also notice if I take off the ecu ground I get 9v to 1B