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1994 ls400 with huge power loss...sometimes

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Old 12-12-12, 07:56 PM   #16
stephen18
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should i touch up the traces? they look pretty solid IMO but the soldering job looks bad..
anyway the repair was done by a previous owner. im going to order the correct type cap and replace them
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Old 12-12-12, 08:14 PM   #17
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you do not need to mess with any traces that are not eaten in two (severed from corrosion)
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Old 12-14-12, 11:34 AM   #18
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ordered new caps
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Old 12-14-12, 01:23 PM   #19
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you definitely want to take a loupe (magnifying glass) and inspect all of the traces on this board carefully once the old caps are desoldered and removed, and again once you have finished the new cap installation.
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Old 12-15-12, 12:05 PM   #20
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I hope this solves the power loss issue. its weird how it is only sometimes,
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Old 12-18-12, 06:34 PM   #21
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well i replaced all the caps with new low ESR caps and it still runs the same.
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Old 12-18-12, 07:24 PM   #22
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I would try a different ECU from ebay - in case those traces have gone bad from the leaking damage, that ECU looks pretty rough from previous leakages/repairs

what are the ODB-I codes stored? - does the check engine light come on when it goes into low power mode?
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Old 12-19-12, 04:15 AM   #23
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I knew it!
Have your car diagnosed by a shop!
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Old 12-19-12, 01:30 PM   #24
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Quote:
Have your car diagnosed by a shop!
good luck on finding a competent diagnosis of a pre-OBDII 90's car these days!

Quote:
well i replaced all the caps with new low ESR caps and it still runs the same.
did you order the particular caps specified by yamae and myself in the CURRENTLY RECOMENDED CAPACITORS section?

How did you determine what the original correct values were for each cap in your ECU? (the ones you had in there, had several incorrect values)

Last edited by LScowboyLS; 12-19-12 at 01:49 PM..
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Old 12-20-12, 06:19 PM   #25
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Quote:
Originally Posted by LScowboyLS View Post
good luck on finding a competent diagnosis of a pre-OBDII 90's car these days!



did you order the particular caps specified by yamae and myself in the CURRENTLY RECOMENDED CAPACITORS section?

How did you determine what the original correct values were for each cap in your ECU? (the ones you had in there, had several incorrect values)
i looked on your thread and found a guy who posted each Cxxx and i went by that. yes i ordered exactly each cap that was mentioned in your thread.

guess i will need to find another ecu.. its weird how the afrs are normal but it can vary greatly in power.. like its pulling timing or something
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Old 12-21-12, 03:21 AM   #26
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How many miles do you have? Has the timing belt been replaced? Also there are two coolant sensors for this car. One is sender for the gauge and the other is for the ecu. check the ecu one. It has two wires goin to it. If its faulty it might contribute to your issue.
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Old 12-21-12, 10:08 AM   #27
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Quote:
there are two coolant sensors for this car. One is sender for the gauge and the other is for the ecu. check the ecu one. It has two wires goin to it. If its faulty it might contribute to your issue.
very true!

PS - the sensors he is speaking of are on the front, top of the engine, passenger side, beneath the little carrier that holds the four plug wires that go across the front of the engine (behind the coil)
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Old 12-22-12, 06:25 AM   #28
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Originally Posted by LScowboyLS View Post
very true!

PS - the sensors he is speaking of are on the front, top of the engine, passenger side, beneath the little carrier that holds the four plug wires that go across the front of the engine (behind the coil)
i have replaced the ecu coolant temp sensor and the timing belt soon after i bought the car in june. i just checked the valve timing as well and its spot on still.

i ordered a "used rebuilt" ecu from abay. it should be here after christmas. This is seriously puzzling me. i have never had such a hard time diagnosing a car.... but then it might be i hardly have much time since the wife and newborn get a little jealous.
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Old 12-25-12, 08:33 PM   #29
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replaced the ecu.. still seems a little short on power. still felt it "click" and get all its power back. so not sure where to go from here. maybe a new tps?
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Old 12-25-12, 08:44 PM   #30
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the ECU was likely not rebuilt correctly, most rebuilders don't understand the importance of using the correct type and brand of capacitors, this is fully technically explained in my guide to replacing your ECU capacitors which now has had 11,000 people look at it!
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Old 12-25-12, 08:44 PM
 
 
 
 
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1994, 400, 91, ecu, fix, intermittant, lack, lexus, loss, ls, ls400, power, power loss, video, youtube

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