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Running Rich? OR Rebuild?

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Old Feb 8, 2016 | 05:29 AM
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noobienz's Avatar
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Running Rich? OR Rebuild?

This evening i bought a 1998 FD RX7 (double turbo factory set up)
The car was said to have had a rebuild and then placed into storage for a few years.
The car starts up warn and cold fine and has good power. Very minor puff of smoke on start up and then immediately settles and goes away.

Theres no smoke on boost or on acceleration, however after acceleration when you deaccelerate the car puffs out black smoke.
Would you think its from carbon build up and also running rich?
It does smell quite heavily of petrol.
Or could it be a sign of turbo seals or the car just simply sitting for so long?


Im not good with rotary engines so would appreciate your thoughts.


Thank you
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Old Feb 8, 2016 | 05:09 PM
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Michael Mansour's Avatar
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Originally Posted by noobienz
This evening i bought a 1998 FD RX7 (double turbo factory set up)
The car was said to have had a rebuild and then placed into storage for a few years.
The car starts up warn and cold fine and has good power. Very minor puff of smoke on start up and then immediately settles and goes away.

Theres no smoke on boost or on acceleration, however after acceleration when you deaccelerate the car puffs out black smoke.
Would you think its from carbon build up and also running rich?
It does smell quite heavily of petrol.
Or could it be a sign of turbo seals or the car just simply sitting for so long?


Im not good with rotary engines so would appreciate your thoughts.


Thank you
The smoke is most likely because rotary engines inject small amounts of oil into the combustion chamber, to keep things lubricated. The smoke is the oil burning, nothing to worry about.
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Old Feb 8, 2016 | 07:06 PM
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roTAR needz fundZ
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Other question is how old is the gas?
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Old Feb 8, 2016 | 11:11 PM
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From: Phoenix
Black smoke is excess fuel. White is coolant and grayish blue is oil.
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Old Feb 9, 2016 | 12:41 AM
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Originally Posted by Michael Mansour
The smoke is most likely because rotary engines inject small amounts of oil into the combustion chamber, to keep things lubricated. The smoke is the oil burning, nothing to worry about.
yes rotarys inject small amounts of oil but when running correctly they don't puff smoke like that so it is something to have a look at. and as said above oil smoke is blueish grey.

how many k's on the rebuild when you got it?
did the previous owner run it in, maybe its still on the rich run in tune?

if your going to keep the car id get rid of the twin turbos when you get a chance and put a single on.
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Old Feb 9, 2016 | 03:53 AM
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Thanks heaps for your response. The rebuild seems to be done 30000ks ago. It's got plenty of power and starts perfect both hot and cold.
When it's reving past 5rpm it puffs a very large amount of smoke. It'd sounding alot like turbo seals?

Originally Posted by sandy_RE
yes rotarys inject small amounts of oil but when running correctly they don't puff smoke like that so it is something to have a look at. and as said above oil smoke is blueish grey.

how many k's on the rebuild when you got it?
did the previous owner run it in, maybe its still on the rich run in tune?

if your going to keep the car id get rid of the twin turbos when you get a chance and put a single on.
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Old Feb 9, 2016 | 09:55 AM
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Depends on the color of the smoke if it puffs black past 5k then it probably has a pretty rich tune on the top end. If it's grayish blue then it's possibly oil which could have many sources.
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Old Feb 9, 2016 | 06:38 PM
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Originally Posted by noobienz
Thanks heaps for your response. The rebuild seems to be done 30000ks ago. It's got plenty of power and starts perfect both hot and cold.
When it's reving past 5rpm it puffs a very large amount of smoke. It'd sounding alot like turbo seals?
have you got it tuned since youv had it? if it not losing crazy amounts of oil it should be a easy fix.

yea might be the turbo seals. that's why I said to put a single on, one less thing to break/replace.
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