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Sc400 loss of power, runs rich, loud

Old 05-15-18, 08:21 PM
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Braaap1uz
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Default Sc400 loss of power, runs rich, loud


I recently bought a 92 sc400 and it ran perfect for about 2 weeks before randomly messing up one morning when I tried to start it.
Issues:
Before any major issues, the car randomly stalled at stop lights every once in a while.
Barely wanted to start, cranked and cranked until just barely starting up.
Next, I tried driving down my street and it bogs down when I floor it, but will get up to speed when I slowly accelerate. Drove it around fine, up to 50 mph but like a slug. In first gear it drives pretty nicely, but as soon as I put it in second gear it wonít go above 1k rpm.

So far Iíve tried replacing:
Fuel pump ecu
spark plugs
ignition coils
sent ECU to get fixed.

Right now Iím investigating the camshaft/ crankshaft position sensors. The info Iíve found on symptoms of bad ones matches pretty closely to what issues I have. But Iím not sure whether my issue is cam or crank position sensor.
Iíve also checked the throttle body, itís pretty clean and snaps perfect, opens all the way when floored in accessory mode. After sitting in my garage a few weeks,and turned on a few times it also started misfiring pretty bad when revved up. Sounds like 2 step.
Any help with this would be greatly appreciated

Last edited by Braaap1uz; 08-16-18 at 05:13 PM.
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Old 08-16-18, 05:07 PM
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Bump?
bump?
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Old 08-16-18, 07:12 PM
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Another user recently posted about a similar issue and found his o2 sensors were bad, it might be worth a shot to check them out.
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Old 08-17-18, 07:06 AM
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Any engine codes?
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Old 08-18-18, 04:28 PM
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I recently posted this, my o2 sensors were black. still haven't replaced them
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Old 08-20-18, 10:04 PM
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Originally Posted by Braaap1uz View Post

I recently bought a 92 sc400 and it ran perfect for about 2 weeks before randomly messing up one morning when I tried to start it.
Issues:
Before any major issues, the car randomly stalled at stop lights every once in a while.
Barely wanted to start, cranked and cranked until just barely starting up.
Next, I tried driving down my street and it bogs down when I floor it, but will get up to speed when I slowly accelerate. Drove it around fine, up to 50 mph but like a slug. In first gear it drives pretty nicely, but as soon as I put it in second gear it wonít go above 1k rpm.

So far Iíve tried replacing:
Fuel pump ecu
spark plugs
ignition coils
sent ECU to get fixed.

Right now Iím investigating the camshaft/ crankshaft position sensors. The info Iíve found on symptoms of bad ones matches pretty closely to what issues I have. But Iím not sure whether my issue is cam or crank position sensor.
Iíve also checked the throttle body, itís pretty clean and snaps perfect, opens all the way when floored in accessory mode. After sitting in my garage a few weeks,and turned on a few times it also started misfiring pretty bad when revved up. Sounds like 2 step.
Any help with this would be greatly appreciated
Wait for ecm.. then run the car and pull codes..
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Old 08-22-18, 09:23 AM
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Mine was disintegrated distributor rotor and cap.
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Old 08-26-18, 11:02 AM
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Wouldn't that cause it to not start at all?
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Old 08-26-18, 11:38 AM
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Mine missed, ran but only on 4 cylinders. Way do in on power. Two distributors,two coils.
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Old 08-26-18, 11:39 AM
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Yeah not the same problem as mine than, occasionally it runs fine and it's not misfiring.
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Old 08-26-18, 01:42 PM
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I'm new to them 2. Frustrating. Try pulling codes. Obd1 though, oriely may be able to help. Let me know, curious
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Old 08-26-18, 01:45 PM
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No codes. Never threw any.
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