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Need help, maybe ecu related

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Old 05-21-13, 12:46 PM   #1
Bender25
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Default Need help, maybe ecu related

I have a 93 sc300 with an auto tranny, and I have been having issues with the fuel mixture. I have black smoke coming out the exhaust and it smells of gasoline and it idles very rough with no power while it drives. The CEL is on but when I go to pull the codes it just stays solid.

The o2 sensors, cap, rotor, grounds, plugs and wires have all been changed. The iacv, maf and tps have all been inspected with a multimeter and check out fine. The ecu has been inspected and there are no leaky caps.

The car runs great after the car has sat for awhile with the battery unplugged. The ecu even reads codes properly and the Cel and od light flash properly while the diagnostic ports are jumped. But after 20-25 miles of perfect driving these symptoms return. And I get the rough running, with the Cel staying on. When I go to pull the codes while it's in this state the Cel stays solid and the od light doesn't blink either.

Any help is appreciated
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Old 05-21-13, 01:09 PM   #2
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sounds like the ecu may be going bad but its hard to confirm in the early stages.
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Old 05-21-13, 02:42 PM   #3
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Do the fuel pump ECU 12v mod?
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Old 05-21-13, 03:39 PM   #4
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No 12volt mod. I jumped the fuel pump ecu from under the hood and there was no change in the idle or how it ran.
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Old 05-22-13, 10:59 AM   #5
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Any other thoughts or suggestions? I'm pulling the ecu now to inspect it
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Old 05-23-13, 05:50 AM   #6
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Quote:
Originally Posted by SC400slide View Post
Do the fuel pump ECU 12v mod?
Please stop giving advice, it's never on par with the actual problem ANY time you answer.

Ecu's can go back and forth like this. My gf's car would do this, and as soon as she decides to bring it to me it would run normal, CEL act right, everything. Until one day I was driving it and it quit for good. I'd get a spare, everyone that dailies one of these things should have a spare ecu just in case. These things tend to get exposed when summer rolls in. I did a couple gte ecus and an sc400 ecu a couple summers ago right after our first real heat streak, within 2 weeks.
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Old 05-23-13, 08:22 AM   #7
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Quote:
Originally Posted by Vrank View Post
Please stop giving advice, it's never on par with the actual problem ANY time you answer.
I will keep giving advice because that is why i'm here. This here is my second family, nobody is gonna tell me to leave and expect me to leave, cause I'm not gonna.. This was a mistake. That's what happens when you're up too late I guess...
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Old 05-23-13, 08:31 AM   #8
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refer to this thread
http://www.clublexus.com/forums/perf...-bad-caps.html
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Old 05-23-13, 08:31 AM
 
 
 
 
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