Car Won't Start, No Check Engine Light

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    SupraForums Member SSupraMan94's Avatar
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    Car Won't Start, No Check Engine Light

    I HAVE A 1994 SUPRA it has been not wanting to start alot lately, now it wont start at all..... we have checked out all the usuall stuff like fuses, fuel,some relays... one thing we noticed is that the check engine light doesnt come on when you turn the key on, also figured out that pin # 31 from the ecu is not hot like it should be,the is the wire that safc2 and greddy bcc is powered by. and those are not coming on. we did add power to that wire and then the check engine light comes on and the car willl start,but as soon as we take the power away the car dies. what would cause that wire not to be hot? any help would be gratly appreciated

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    you need to check the basic first,see if you are getting fuel,sparks and power to your starter solenoid..

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    SupraForums Member 87toysupratt's Avatar
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    pin 31 is from your efi main relay, you said its not getting power and when you power it up the car starts. I would check the relay and wires to/from it.

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    The way he is describing it, there is no fuel/spark problem. Seems to be more of an electrical problem. obviously it had to do with the install of the safc/bcc. I would check all connections and grounds to see if you have power. Or, I would completely uninstall the safc/bcc and go from there. goodluck.

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    Homesick Texan btm7687's Avatar
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    How does the car act when you turn the key? All the lights come on, no dimming or hesitation? If you had tried it multiple times it would eventually turn over? When my car wouldn't start everything was fine, the battery was charged, everything was getting power, however, my starter contacts were bad. It would take a few tries to start the car, until eventually, I tried for 2 or 3 minutes straight to get it started, I had to take my dad's car instead, the next day, he fought with it to get it turned on and drove it over to Toyota to have the starter contacts replaced.

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    SupraForums Member SSupraMan94's Avatar
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    the car turns over fine ,lots of battery power. it wont actually start though , spins over just fine.all the lights come on as usual but the check engine light does not. and i have already took out the safc2 and the bcc.

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    SupraForums Member 87toysupratt's Avatar
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    Quote Originally Posted by cord4530
    On my car (94 TT) the fuel pump is powered by the EFI main relay. Power for that relay comes from a 30 Amp fuse labled "EFI No 1." Being that size, I'm guessing it's in the engine bay though. A number of things run off that same relay (O2 sensor heaters, VSV's, IAC motor, and power for the ECU.

    EFI No1 is located in the engine bay fuse box. It's in the #2 spot. The EFI relay is in the same box in the "G" location. Make sure you have power across the fuse, and make sure the relay is clicking on when the key is on. May not hurt to check the relay, or switch it with one of the others nearby (Fog light and A/C clutch seems to be the same). Actually, you could swap it with the starter relay (A) and see if the engine still cranks over. That will tell you if the relay is good or not.

    If all those come up good, then we'll think of a few other tests to perform.
    which I got off this thread:

    http://www.supraforums.com/forum/sho...ighlight=relay
    Last edited by 87toysupratt; 07-07-2006 at 12:38 AM.

  8. #8
    Toyota Powertrain Guru JZ1's Avatar
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    On any Toyota, no MIL bulb check is either a lack of power into the ECM from the EFI relay (includes 30A EFI fuse) or a shorted VC (5v sensor reference wire). Post #3 was going in the right direction. Swap the relay with another one and also check the fuse/female contacts while you are at it. If it still does not work, how it all happens is the key switch sends 12v out to the ECM on the IGSW wire. The ECM then sends out 12v on the MREL wire to trigger the main relay. When power from the EFI Main Relay comes into the ECM on B+, the ECM full "wakes up" and the bulb check occurs. Sounds like a relay is getting dirty. Less than 9.8v into the ECM and it won't function.

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    SupraForums Member SSupraMan94's Avatar
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    Quote Originally Posted by JZ19
    On any Toyota, no MIL bulb check is either a lack of power into the ECM from the EFI relay (includes 30A EFI fuse) or a shorted VC (5v sensor reference wire). Post #3 was going in the right direction. Swap the relay with another one and also check the fuse/female contacts while you are at it. If it still does not work, how it all happens is the key switch sends 12v out to the ECM on the IGSW wire. The ECM then sends out 12v on the MREL wire to trigger the main relay. When power from the EFI Main Relay comes into the ECM on B+, the ECM full "wakes up" and the bulb check occurs. Sounds like a relay is getting dirty. Less than 9.8v into the ECM and it won't function.
    thanks for the info guys , we are gonna mess with it some more friday.. ill keep posting as we go...

  10. #10
    Toyota Powertrain Guru JZ1's Avatar
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    happy to help

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    SupraForums Member SSupraMan94's Avatar
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    well we just checked the pins on the harness at the computer , they all seem to be ok, none pushed back . we also double checked the efi main relays , 1&2 under the hood they are working and getting good connection, so we are still stuck and are not getting power to that wire , if we power it up manually the cel comes on and the car starts.

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    SupraForums Member SSupraMan94's Avatar
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    we fixed it, it runs again!!! all because a freeking plug on the bottom of the box that has the efi main relays, the damn plug was loose and had fallen off .... so add that to your things to look for when these problems occur. thanks for all your help and coolness. im off to the carwash .... latas

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