KeelesKustome
15+ Year Contributor
- 882
- 15
- Dec 29, 2007
-
Waverly,
Tennessee
Hey i need help
My ECU is not receiving any power to pin 12 or 25, thus causing my car to not wana try to crank and the fuel pump not coming on.
The relay in the dash behind the radio has been changed 3 times and it never makes any clicking noises. This relay also does not have a constant 12v going to it like I think it should even when the key is off.
What's weird is when I probe the fuel pump wire at the ECU with my test light while having the key on acc, the pump will run until I let the probe off.
I have messed with the neutral safety switch with no luck.
On my ECU pinout it says the wire should be black, this is not the case, it is black with a red stripe.
I would like to try and bypass the N switch at the transmission, as it is an automatic 2g, but I can not figure out the wiring schematics on how to do so, and I am unsure if this would allow power to enter my ECU even if I did.
I checked and bypassed the 20amp, 30 amp, and the 100amp fuses under the hood one at a time to make sure this was not my problem, it did not help.
Every now and then I'll hear some clicking coming from where the neutral safety switch is located.
I also changed the ignition switch with no luck.
I also locked and unlocked the car with the key to make sure it wasn't some safety feature,
I also ran a wire from the fuse panel with a constant 12v to the MFI relay where it says 30 amps, as this is suppose to stay charged and it doesn't, with my hard wire it does but has not fixed the problem and the relay still does not click or allow power to the ECU.
I am considering the neutral safety switch, how do you get rid of this on an automatic that is staying automatic?
~~~~~~~~~~~~~~~~~~~~~~~~~~
I connected the neutral safety wires, red with black stripe big, to the black big wire, nothing changed.
I tried grounding the last mentioned wire, it already had ground and i added one, nothing changed.
I ran from the 30 amp fuse power to the #12 and 25 pin the ECU starts up and shows the CEL light for 5 secs, so that's a sign the ECU is good I do believe. Problem being the relay still isn't triggering the starter and the fuel pump, why?
Also side note, now when the ECU is working, so does my keychain to lock and unlock the doors, I checked to make sure it wasn't the security system again and it is not.
Please shoot me some more ideas to do, as I have swapped every other MFI plug in the car where this one is and it isn't changing a thing, and i know they are good because I have tested them in other spots. The MFI plug seems to not be making it's ground properly, where should i look for this at?
~~~~~~~~~~~~~~~~~~~~
Okay so here's what I have done, the MFI relay: I added a ground to the side that wasn't getting it for some reason, this allows the starter to now crank over.
Although the CEL light isn't coming on because it's still not getting power, so i add the 30 amp fuse direct path power wire to one of the terminals, i think 25, now the fuel pump kicks on and it turns over and the CEL light comes on for 5 seconds.
I am here by myself so checking for spark is hard, i manage, and i have none.
I can only assume that the relay is messing that up too. I think what the heck is going on with this?
I have swapped this relay numerous times and still nothing, and how come i am not getting fire even bypassing it?
some info I might try that I found.
My ECU is not receiving any power to pin 12 or 25, thus causing my car to not wana try to crank and the fuel pump not coming on.
The relay in the dash behind the radio has been changed 3 times and it never makes any clicking noises. This relay also does not have a constant 12v going to it like I think it should even when the key is off.
What's weird is when I probe the fuel pump wire at the ECU with my test light while having the key on acc, the pump will run until I let the probe off.
I have messed with the neutral safety switch with no luck.
On my ECU pinout it says the wire should be black, this is not the case, it is black with a red stripe.
I would like to try and bypass the N switch at the transmission, as it is an automatic 2g, but I can not figure out the wiring schematics on how to do so, and I am unsure if this would allow power to enter my ECU even if I did.
I checked and bypassed the 20amp, 30 amp, and the 100amp fuses under the hood one at a time to make sure this was not my problem, it did not help.
Every now and then I'll hear some clicking coming from where the neutral safety switch is located.
I also changed the ignition switch with no luck.
I also locked and unlocked the car with the key to make sure it wasn't some safety feature,
I also ran a wire from the fuse panel with a constant 12v to the MFI relay where it says 30 amps, as this is suppose to stay charged and it doesn't, with my hard wire it does but has not fixed the problem and the relay still does not click or allow power to the ECU.
I am considering the neutral safety switch, how do you get rid of this on an automatic that is staying automatic?
~~~~~~~~~~~~~~~~~~~~~~~~~~
I connected the neutral safety wires, red with black stripe big, to the black big wire, nothing changed.
I tried grounding the last mentioned wire, it already had ground and i added one, nothing changed.
I ran from the 30 amp fuse power to the #12 and 25 pin the ECU starts up and shows the CEL light for 5 secs, so that's a sign the ECU is good I do believe. Problem being the relay still isn't triggering the starter and the fuel pump, why?
Also side note, now when the ECU is working, so does my keychain to lock and unlock the doors, I checked to make sure it wasn't the security system again and it is not.
Please shoot me some more ideas to do, as I have swapped every other MFI plug in the car where this one is and it isn't changing a thing, and i know they are good because I have tested them in other spots. The MFI plug seems to not be making it's ground properly, where should i look for this at?
~~~~~~~~~~~~~~~~~~~~
Okay so here's what I have done, the MFI relay: I added a ground to the side that wasn't getting it for some reason, this allows the starter to now crank over.
Although the CEL light isn't coming on because it's still not getting power, so i add the 30 amp fuse direct path power wire to one of the terminals, i think 25, now the fuel pump kicks on and it turns over and the CEL light comes on for 5 seconds.
I am here by myself so checking for spark is hard, i manage, and i have none.
I can only assume that the relay is messing that up too. I think what the heck is going on with this?
I have swapped this relay numerous times and still nothing, and how come i am not getting fire even bypassing it?
some info I might try that I found.
Here is the short version of what it says to check for the relay.
Section 4-3, Fuel Injection Control Relay Check. (just the relay)
This tests the MPI side of the MPI relay
step 32 - Remove EFI relay
step 33 - Connect battery positive (+) to terminal 10 and battery negative (-) to terminal 8
This should activate the one side of the relay causing it to connect pin 10 to pin 4 and 5
step 34 - Connect voltmeter negative probe to the battery negative terminal, Connect voltmeter positive probe to terminal 4 and then to terminal 5, There should be 12volts at each terminal.
if you do this before step 22 you'll see pin 4 and 5 don't have 12v before hand and do after
This tests the fuel pump side of the MPI relay
step 35 - Connect battery positive (+) to terminal 9 and battery negative (-) to terminal 6
step 36 - Check for continuity between terminals 2 and 3, there should be continuity, next remove the ground lead from terminal 6 and check again, there should be no continuity.
step 37 - Connect battery positive (+) to terminal 3 and battery negative (-) to terminal 7
step 38 - Check for voltage between terminal 2 and the battery ground, there should be 12v
step 39 - If the test results are incorrect, replace relay with new part.
According to this my relay passed, but maybe not.
What this doesn't test is that MPI relay is functioning in the car. For that you need to check that you have 12v at the connector for pin 10 all the time, turn on the ignition switch and verify you have 12v at pins 4 and 5 when the ignition switch is in the run or start position.
If the the relay checked out but you done see 12v at 4 and 5 then you need to look at the ECU and the signals going to it. )
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