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11-22-2021, 06:32 PM
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#1 | ||
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Board Member
Join Date: Aug 2003
Location: Ocean Springs, MS
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93 940 N/A (Rex/Regina) Very Rich at Idle
Help me....I'm running out of ideas.
This is a N/A Rex/Regina, so we are looing at an air intake temp sensor and MAP sensor. No MAF Sensor. At idle its sickly rich. If I idle for 5+ minutes it starts to load up like a carbed car dumping fuel. It starts to stumble and I have to put it in neutral and rev to clear it out. The gas smell from the exhaust has every one hating me. Here is what has been done. New O2 Sensor New MAP Sensor New Intake Air Temp sensor New ECU Temp sensor New Injectors (reconditioned) New Fuel Pressure Regulator I've verified correct vacuum at idle to make sure exhaust is not clogged (will mess up a map sensor reading) I adjusted Throttle Position sensor (but have not replaced it) My MPG is 20-22 in town, so it seems to predominantly be at idle. Idle does bounce around slightly as if a small vac leak is present, but I have yet to find it (could also be a result of inconsistent fuel). Usually a vac leak in the MAP will cause them to run lean unless the leak is on the MAP circuit...it is not. I'm throwing no check engine codes either. Not sure if this one has a cold start injector. But that is what I'm checking next. Perhaps the injector is leaking a bit. Anyone got any other ideas? I'm really running out of them myself.
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1983 242 v8 (aka Berserker) 1985 740 Jurbo 1990 740 Turbo (daily driver) 1993 945 n/a slow as caca. Berserker 242 Build Thread Quote:
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Last edited by noz-e8tr; 11-22-2021 at 07:04 PM.. |
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11-23-2021, 01:31 PM
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#2 | |
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Board Member
Join Date: Feb 2011
Location: connecticut
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Quote:
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11-23-2021, 01:59 PM
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#3 |
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Old and boxy but good.
Join Date: Jun 2002
Location: S NJ, a suburb of Phila.
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I would double check that the O2 sensor is the correct Rex/Regina type. Also measure the coolant temp sensor at cold, warm, and hot temps to make sure it's working properly. I once encountered a coolant temp sensor that went open circuit when the engine warmed up caused super rich running. Didn't set any codes.
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Dave, 1982 242 turbo. 338k miles. MVP coilovers and 3" exhaust. Flowed 405 with a V15. Cossie turbine housing with upgraded compressor housing. 90+, IPD remote oil filter. Some other goodness, too. Been lots of fun over 25 years. Restored in 2k. Now ready for a 2nd restoration. 1993 245 Classic, 435k miles, enem V15. IPD bars and chassis braces. Simons sport exhaust from Scandix. sbabbs ezk chip. Been a good road warrior. Genuine Volvo rebuilt leaky M47. 
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11-23-2021, 07:36 PM
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#4 |
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Board Member
 
Join Date: Dec 2006
Location: Rushing Lane, Scappoose, OR
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Weak link is usually the fuel pump. Only one on those and it is in the tank...
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1988 245 White slicktop M47 Wagon! 93 b230f. LH 2.4 STS flat flywheel. 1990 745 B230FT Getrag JohnV flywheel 240mm clutch 13c A-cam 3.54 G80 548K 1991 740SE B230FT NPR Strut braces IPD bar A cam 550cc EV14's. 3.73 G80 M90 to put in. 1995 940 White racing wagoon. 13c m90 to put in 
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11-23-2021, 08:42 PM
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#5 |
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Making Volvo Parts Fit
Join Date: May 2008
Location: Rockland County, NY
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If none of the new parts made any difference, were they all OEM supplier parts?
Doesn't seem likely the fuel pump would cause a rich at idle symptom, though. Leaking CS valve could load it up at idle. |
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11-23-2021, 08:43 PM
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#6 |
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Board Member
Join Date: Aug 2014
Location: Boulder CO
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Have you checked the plug wires and plugs? Do the plugs look equally awful?
You can still find the TP31903/1 Regina greenbook (partial copy) via the Internet Wayback Machine (e.g. link) Some of the sensor measurements, especially if measured from the Regina connector, would help rule out bad sensors/wiring. |
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