Question about 1991 Volvo 740

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If I speed up slowly I can go to 70-80 but if I push too much gas it will drop off to idle and I must turn off the key and turn on again and it is good to go

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Check your crank sensor. The symptoms you describe indicate a timing error. When you push hard the ECU tries to advance the ignition according to the signals it receives from the the crank position sensor CPS. These signals are either being interrupted or corrupted. Make sure the cps connection is dry, free of dirt and corrosion and that there is continuity in the wires with no obvious breaks or insulation removed. Remove the CPS and check that it is clean and free of body cracks. If problems persist swap the crank sensor out for a new one. These sensors are prone to heat and age.

Posted on Oct 16, 2010


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So I am going to assume it...
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Always set the SPEED with the idle screw first... Then adjust the FUEL with the idle screw...

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