1G no power to pin 103 on ecu

[MM's Talon]

I have tried everthing and anything.. ohm'd all wires and bought all new fuses and relays.. checked my whole harness.. i've read everything i can.. went on alldata and did all the test's.. tried 3 different ecu's.. new injector wiring.. ohm'd the injectors.. and still not getting power to any of my injectors..
Put the noid light on and nothing.. i want to say the cause it with pin 103... i have no power there and its a backup (12v) and i dont understand how or why.. i keep asking everyone for help but its like noone can either point me in a direction or just wont help.. its bull..

I have tried 3 different ignitors..
3 different CAS's
3 different injector resistors on the fire wall.. everything...
checked the voltage to the relay and it has power but nothing.
Ive read that pin 103 gets power through fuse "19" and i replaced it and still nothing..
I still dont understand whats going on..? I did a complete rebuild.. all stock with a new turbo and nothing has chnaged other than the new engine..

Put a new knock sensor in.. i dont know what else to do..

 

[pos4g63]

I had a similar problem and it turned out to be the cas. The old wire covers were cooked and the covers fell off shorting out my cas. So I took it apart cut 4 inches off and soldered it all back together.

 

[russell3123]

Did you check the mpi relay?

 

[yokotabrat]

The wiring diagram only shows that pin 103 goes through fuse 19 and then through subfusible link #6 which is a 40A fusible link. Check the fusible link (measure with an ohm meter) and if that's okay, you'll need to ohm out the wiring from there to the fusible link and then to the battery.

 

[MM's Talon]

I had a similar problem and it turned out to be the cas. The old wire covers were cooked and the covers fell off shorting out my cas. So I took it apart cut 4 inches off and soldered it all back together.

Wired a new one in already

Did you check the mpi relay?

Tried 3 of them.

The wiring diagram only shows that pin 103 goes through fuse 19 and then through subfusible link #6 which is a 40A fusible link. Check the fusible link (measure with an ohm meter) and if that's okay, you'll need to ohm out the wiring from there to the fusible link and then to the battery.

What do you mean link 6? sorry for being a little confused but can i get more details.. thanks man most appreciated

I replaced link 6 it was 80a on my car.. and still nothing.. i ohm'd the wring to my cas and everything comes out right. checked voltage to my injectors and they are good.. still nothing

 

[steve]

How is the ECU turning on without power to pin 103? It doesn't for me when I test it.
The 80A alternator fuse is sub fusible link 1. Sub fusible link 6 is green 40A fuse and powers several other fuses besides multipurpose fuse 19.

 

[MM's Talon]

How is the ECU turning on without power to pin 103? It doesn't for me when I test it.
The 80A alternator fuse is sub fusible link 1. Sub fusible link 6 is green 40A fuse and powers several other fuses besides multipurpose fuse 19.

i have a check engine light.. put fuse 19 in and i have power to pin 103.. but still no pulse from injector.

 

[steve]

i have a check engine light.. put fuse 19 in and i have power to pin 103.. but still no pulse from injector.

Does the CEL turn off after 5 seconds?

When did you fix the problem with pin 103? Was it just the fuse?
Were all the other parts swapped before you fixed the problem with 103?

I'm not sure how you got the MPI relay to turn on while power was missing on 103 since the ECU shouldn't have activated it. Without the MPI relay activating you wouldn't get power to the injectors which you said you measured in your PM.

So the timeline is throwing me off here.

 

[MM's Talon]

Does the CEL turn off after 5 seconds?

When did you fix the problem with pin 103? Was it just the fuse?
Were all the other parts swapped before you fixed the problem with 103?

I'm not sure how you got the MPI relay to turn on while power was missing on 103 since the ECU shouldn't have activated it. Without the MPI relay activating you wouldn't get power to the injectors which you said you measured in your PM.

So the timeline is throwing me off here.

ok so i have never had fuse 19 in since ive had the car.. which is the dome lights/pin 103 backup 12v and than after i started having problems with no pulse from injectors, i swapped the ecu, cas, mpi relay and no progress was made.
I have power to and from the ecu after running multiple tests from the ecu to the relay and from relay to resistor on firewall and ohm'd everything from ecu to the relay and to the injectors, and ohm'd all my wires leading to the CAS.. I've read several things about common issues with this problem i have on my hands.. i've worked on a lot of dsm's and never ran into this problem.. i swapped ecu with 5 ecu (known working ones) and 3 different CAS and 3 different mpi relays.. i have ran through my whole harness and nothing obvious was wrong.. i have replaced all of my fuses,relays, wiring to the injectors since mine were dryrotted. anything and everything.. and about the check engine light i do believe it does go away after 5 seconds. what does that mean?

after putting fuse 19 in i did have power showing up on pin 103..

i cranked the car and checked for power at the injector resistor and after and everything was good. and i checked power at the CAS and it was good.

was else is there? i think the chances of all those relays and CAS and ecu's are all bad

thanks for helping me steve

 

[steve]

I'm still confused as to how the ECU ever powered up missing backup power on pin 103. The ECU shouldn't have been able to activate the MPI relay without the backup power.
I'm assuming your saying that the car ran before the rebuild and you never had backup power on pin 103.

The normal behavior on power up is for the ECU to turn on the CEL for 5 seconds and then turn it off. If it doesn't turn on then the ECU is working and if it stays on there is a problem with the ECU or it found a problem with the sensors connected to it.

The first step is always verifying that the ECU is working since nothing interesting happens if it isn't.

If you have a logger you can check to see if the ECU is seeing CAS pulses by looking at the RPM during cranking. You can also remove the CAS and turn it by hand and watch the voltages at the ECU to see if then pulse. The plugs should spark and the injectors pulse while turning it as well.

The logger is also useful to see if the rest of the sensors give reasonable values.

 

[honduraneclipse]

I had a short to ground inside my fuel pump assembly causing the ecu not ground the injectors, i believe mpi relay was involved in picking up the high resistance and the ecu recognizing not to ground the injectors. look for shorts in the mpi system.

 

[MM's Talon]

I'm still confused as to how the ECU ever powered up missing backup power on pin 103. The ECU shouldn't have been able to activate the MPI relay without the backup power.
I'm assuming your saying that the car ran before the rebuild and you never had backup power on pin 103.

The normal behavior on power up is for the ECU to turn on the CEL for 5 seconds and then turn it off. If it doesn't turn on then the ECU is working and if it stays on there is a problem with the ECU or it found a problem with the sensors connected to it.

The first step is always verifying that the ECU is working since nothing interesting happens if it isn't.

If you have a logger you can check to see if the ECU is seeing CAS pulses by looking at the RPM during cranking. You can also remove the CAS and turn it by hand and watch the voltages at the ECU to see if then pulse. The plugs should spark and the injectors pulse while turning it as well.

The logger is also useful to see if the rest of the sensors give reasonable values.

yeah the car never ran with fuse 19 in so i have no clue how that worked.. the fuel pump turns on.. so i dont have a short anywhere.. i have replaced the ground wire the pump itself.. and still no luck. i have everything i need hooked up.. i was reading today that timing might have something to do with it? i know my timing is right on the money. what else could it be?

I had a short to ground inside my fuel pump assembly causing the ecu not ground the injectors, i believe mpi relay was involved in picking up the high resistance and the ecu recognizing not to ground the injectors. look for shorts in the mpi system.

i have checked for shorts.. looks pretty good to me.. i have ohm'd everything and no Resistance