No CEL or oil light and wont start???

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Unstock240
Posts: 181
Joined: Wed Jul 09, 2008 3:46 am
Car: 89 240sx se

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Okay I found a way to get ecu power. I jumped the 3 and 5 normally open cantacts on the egi relay. When I do this I have power. I got a code 55 no problems. On the relay i think pins 1&2 have only 12v when they close the relay, but why am i getting no power to the other side of the relay? Still wont start because my battery is low, so who knows.

I have ignition power all the time. I also tested the ignition and egi relays and they are working fine.

Modified by Unstock240 at 11:48 AM 3/2/2010

Modified by Unstock240 at 11:54 AM 3/2/2010
Modified by Unstock240 at 11:56 AM 3/2/2010


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sx moneypit
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Joined: Wed Aug 26, 2009 2:54 am
Car: 2010 Nissan 370Z
1986 Toyota MR2
Location: Memphis,Tn.

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I am going to pull my car in the shop later on and check some things and i will get back with you.

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Unstock240
Posts: 181
Joined: Wed Jul 09, 2008 3:46 am
Car: 89 240sx se

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I forgot to mention the cel turned on first try today until I charged the battery without doing anything, then it lost power again. I have tested the wires to the relay and they have low resistance. Whatever it may be i think its intermittent or one component that is bad but god only knows where.

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sx moneypit
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Joined: Wed Aug 26, 2009 2:54 am
Car: 2010 Nissan 370Z
1986 Toyota MR2
Location: Memphis,Tn.

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Check pin 34 you should have battery voltage while cranking the engine.Check pin 36 to see if you have battery voltage with the key on.I will check back in the morning.

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Unstock240
Posts: 181
Joined: Wed Jul 09, 2008 3:46 am
Car: 89 240sx se

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FINALLY some good news anyway. with that jumper wire in place it started and ran, sounds like a staging dragster with no maf plugged in . I plugged in the maf and it melted that wire in 2, thats why i used only like 2 strands of wire. I need a new maf no doubt, now I can get that.

I need to find the short anywhere from maf to the egi relay. They both have b/w wire to them, so I guess I rip my harness apart now. Worst case I could put a 10A fuse in place of the jumper wire until I completely solve this thing. Thanks moneypit for all the suggestions! Now I have some idea of where to look at least.
Modified by Unstock240 at 11:54 AM 3/3/2010

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sx moneypit
Posts: 8911
Joined: Wed Aug 26, 2009 2:54 am
Car: 2010 Nissan 370Z
1986 Toyota MR2
Location: Memphis,Tn.

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Glad you got it running!I am still curious about this wiring issue though. When you dig into the harness you will probably find the problem and i am sure it will be something stupid.Glad i could help you out.Good luck and keep me posted on what you find.

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Unstock240
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Joined: Wed Jul 09, 2008 3:46 am
Car: 89 240sx se

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Well countless hours later, still haven't solved the problem? I have replaced the engine harness, and complete relay harness to the junction block inside the car. I dont really know what else to look into. anyone have suggestions on things than can fail and stop main ecu power?

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Unstock240
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Car: 89 240sx se

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SUCCESS AT LAST WOOHOO!I decided to look inside my ecu for a final time, and pin 36 ignition trace was burned in two. I pulled apart my test computer and it as well was burned in the exact spot. I put a jump wire in place of the burned spot and it started on its own for once.

I think somewhere in my harness was shorted and I possibly eliminated the problem. Now I get another ecu or solder the trace lol.

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sx moneypit
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Joined: Wed Aug 26, 2009 2:54 am
Car: 2010 Nissan 370Z
1986 Toyota MR2
Location: Memphis,Tn.

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Good news brother!


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