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Heres a good one for a pro, This ones a saga 850 turbo 850

Ok, where should i begin.
Within the past 6 months my 94 850 turbo wagon has been very mysterious. First it began to lose power as it accelerated, cutting out for a moment and then coming back to life. I posted this problem and suspected a clogged cat so i removed it and bashed out the insides of it and put it back on. It didnt change anything. I installed a k, n air filter to ensure good airflow. Still didnt fix. The cars temp sensor began to go up down, all the way to the top then back down to the bottom. I replaced the therm, and the coolant temp sensor, fixed problem. All the while no check engine light. Replaced throttle position sensor, fixed power problem for a short time. Now the car revs in strange patterns with a strange relation to the temp guage, on the highway it will kind of putter off and the temp guage will drop way down then return to halfway then drop down again, never going higher then half way. I replaced the ecu today. Seems like it fixed the acceleration problem as the car shifts and drives well, but still revs at a stop with a direct relation to the temp guage, and still no check engine light even with no cat? And when it does this white smoke puffs out of the exhaust. It also hesitates to start. WHAT IS GOING ON? I cant stress enough that the temp guage is dropping down and directly affecting the rpm of the motor it sounds really wierd but i swear its true. Please hlep me, i am a 22 year old dad full time college student with a job and i almost cannot take this volvo much longer. Please help me keep my sanity intact, help me with my "brick"








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    Heres a good one for a pro, This ones a saga 850 turbo 850

    Okay, this one seems rather odd. The first things you need to check are 1)all of your grounds (I've had a bad ground kick my butt more than once), 2) your charging system (a low charge will whack out the world), 3) check your battery terminal for corrosion and questionable connections on all of those wires going to it (you'd be amazed how many problems are fixed by cleaning a green terminal), and 4) check the connectors to the relays underneath the cowl that sits atop your radiator. One of those relays is your fan (will affect the temp gauge), and the other relay is your main system relay (will affect your fuel trim).

    You can sign on to www.volvoinfo.com, and affordably purchase a three day wiring diagram subscription, which will enable you to access and print all of the wiring diagrams on your car. This way you can trace this, and any other problems you may have pop up, that are electrical gremlin related. I'm not saying that your problem IS electrical in nature, but that a ground or connector problem can cause similar problems.

    Hope this helps,
    Chris








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    Heres a good one for a pro, This ones a saga 850 turbo 850

    Check your auxiliary cooling cooling fan (the one in back of the radiator).

    Mine just went out last week and caused a lot of weird problems.

    If the fan motor breaks and your ac compresssor will lock up due to excessive high side pressure. The ac condensor needs the cooling fan to draw heat away from it.

    Consequently, the engine will overheat from the ac compressor's drag. The engine will surge (not feel right)and the ac will not cool.

    Hey- it's worth a look.







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