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Old 03-23-2013, 08:32 AM
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JimN JimN is offline
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Originally Posted by Mark rsa2au View Post
Now I am stumped!!!

Motor still running very rich, black smoke from exhausts and black sooty plugs from an hour on the water. Also backfiring over 4000rpm!! Dream boat not so much fun anymore

This is what we have done so far:
IAC broken unit replaced with new one - working perfectly.
Injectors reconditioned, all good. Also tested with New injectors - no change. New injectors had same flow rate as old injectors ( I wonder if old injectors were swaped for bigger flow units at some time)
Fuel pressure tested with dodgy fitting onto guage. Read 25psi before leaking so I think 30psi would be a safe bet.
ECT tested as above post, all good. Reading a little high but at least telling ECM it is HOT.
TPS tested as above post, all good. Replacement part no change.
Map sensor tested as above, all good. Replacement part makes no difference.
Plugs changed & gaped at 1.3 (from factory) will adjust down to 1.1 tomorrow but should not change issue above.
Distributer cleaned.
Timing checked as per manual and 10degree BTDC @1000rpm. ( floats a little on the timing light - not rock steady but easily visible).

What the hell else is these to check - service - replace to stop it running so rich and stop the backfiring?
Have you checked the compression?

ECT- you mean the temperature gauge on the dash? That has nothing to do with what the ECM sees. The ECT you need to check has two wires and you need to check its resistance. If the resistance is high when the engine has been warmed up, it's bad.

The timing mark should be rock steady if the engine has been put in diagnostic mode. If it moves, it's either not in diagnostic mode or the shaft bushing may be worn.

How old are the cap, rotor and plug wires?
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