volvo 850 running on 4 cylinders

woody1959 · Post by **woody1959** » 13 Mar 2005, 06:02

Following a serious backfire which holed the air intake by the flame trap. My 850 2.0 20v now runs on only 4 cylinders. Checked the spark plugs leads dist cap rotor arm and injectors with no joy any suggestions ? could this be a stuck valve lifter or valve problem she only has 142000 on the clock and upto this point has alway ran as sweet as a nut. Any ideas what can I do to rectify the problem. Please help I`m getting desperate

White850Turbo · Post by **White850Turbo** » 13 Mar 2005, 08:12

woody1959 wrote: Following a serious backfire which holed the air intake by the flame trap. My 850 2.0 20v now runs on only 4 cylinders. Checked the spark plugs leads dist cap rotor arm and injectors with no joy any suggestions ? could this be a stuck valve lifter or valve problem she only has 142000 on the clock and upto this point has alway ran as sweet as a nut. Any ideas what can I do to rectify the problem. Please help I`m getting desperate

Try replacing your plugs and wires. I've had a bad plug wire cause crazy misfiring before. Also, check the compression on the cylinder that's not firing.

sreynolds · Post by **sreynolds** » 13 Mar 2005, 23:39

My 850 did the same thing. I went to Autozone and borrowed one of their cylinder compression testers. Found that 4 cylinders were great compression and one was zero. I was leaking oil pretty bad at the time. I think that, at one point, the level got too low and was not able to lube the valves the way it should, causing one or more valves to sieze. Had to replace the engine cause the mechanics wouldn't do that type of work on an old engine.

My first line of attack was all electrical (distributor, wires, plugs, coil, computer connection, wires), but no luck. One thing that can cause serious backfires is a bad MAF (Mass Air Flow ) sensor. We had one go on us last year and I thought that the engine was going to explode.