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poor performance
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Fri Jan 09, 2015 5:04 pm    Post subject: poor performance Reply with quote

After so many jobs my engine work, though the performance is poor, comes around 140 km / h , then loses power, why ?
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morghen  



Joined: 21 Jan 2005
Posts: 9095
Location: Romania

PostPosted: Fri Jan 09, 2015 5:42 pm    Post subject: Reply with quote

What do you mean looses power at 140? Does it loose a lot of power or it just does not pull that hard anymore? Is it a turbo or a NA?

Check AFR and timing first.
Check compression second.
If it revs at 140 but does not go, check clutch for wear.
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Fri Jan 09, 2015 6:36 pm    Post subject: Reply with quote

It's aspirated 924 of '79 , after about 140 km/h there is no more power, I found a lot of fuel in the motor oil, but I think because I tested injection whit engine off and fuel pump active.
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morghen  



Joined: 21 Jan 2005
Posts: 9095
Location: Romania

PostPosted: Fri Jan 09, 2015 6:45 pm    Post subject: Reply with quote

Then change the oil NOW, otherwise you damage the engine...running with too thin oil.
Check fuel mixture, get a lambda probe and set the mixture using that.
Also get a timing light and check if the ignition timing is set right.
While you do that, check that the engine timing is also right, rotate the crank until the signs match and check if the cam sign is also matched.
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11733
Location: PacNW

PostPosted: Sat Jan 10, 2015 2:41 am    Post subject: Reply with quote

Check fuel pump volume per FSM, check for vacuum leaks.
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  • WeiBe (1987 924S 2.5t) - 931 S3
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Sat Jan 10, 2015 7:36 am    Post subject: Reply with quote

Do you know amount of flow in one minute for each injector ?
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morghen  



Joined: 21 Jan 2005
Posts: 9095
Location: Romania

PostPosted: Sat Jan 10, 2015 7:41 am    Post subject: Reply with quote

Should be in the Haynes manual. What color are the spark plugs?
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Sat Jan 10, 2015 8:10 am    Post subject: Reply with quote

I haven't found in Haynes,
spark are white color
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jason c  



Joined: 13 Jan 2014
Posts: 1018
Location: Nwi

PostPosted: Sat Jan 10, 2015 8:52 am    Post subject: Reply with quote

morghen wrote:
Should be in the Haynes manual.


There is no spec for amount, only that they be even or within a % of each other. The amount varies based on plunger position. Since plunger position varies per car, no spec is given for amount.
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Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11733
Location: PacNW

PostPosted: Sat Jan 10, 2015 3:51 pm    Post subject: Reply with quote

Not so. Fuel pump volume/min is specified in FSM.
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Sat Jan 10, 2015 6:17 pm    Post subject: Reply with quote

what's FSM ?
I'm in Italy, I don't know.
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!tom  



Joined: 28 Aug 2006
Posts: 1941
Location: Victoria, BC Canada

PostPosted: Sat Jan 10, 2015 6:30 pm    Post subject: Reply with quote

chris79 wrote:
what's FSM ?

Factory Service Manual.
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chris79  



Joined: 29 Jan 2014
Posts: 551
Location: milan

PostPosted: Sat Jan 10, 2015 6:35 pm    Post subject: Reply with quote

translated in units of measurement?
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!tom  



Joined: 28 Aug 2006
Posts: 1941
Location: Victoria, BC Canada

PostPosted: Sat Jan 10, 2015 6:48 pm    Post subject: Reply with quote

Fuel pump should supply >= 750 cc in 30 seconds (after fuel filter, before fuel distributor).

Fuel pump current draw should be <= 8.5 amps.
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chris79  



Joined: 29 Jan 2014
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Location: milan

PostPosted: Sat Jan 10, 2015 7:06 pm    Post subject: Reply with quote

ok, but if possible I want to know flow of injectors, because the pump is new and I suppose flow is correct. I want to check if fuel distributor is ok
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