Hired a guy to put a rear main seal in my 1994 940 Turbo wagon. Drove in fine. After the seal job was done, car starts, runs real rough and wont rev at all. Almost seems like mass air flow but tried two different ones with no change. Unhooked crank sensor, wont start at all. Car has always run fine but leaked oil out the rear main seal. Wanted it fix. Well it doesn't leak anymore but now I cant even back it out of the shop...

 

Have him repair the crank sensor wiring that he broke. It's no doubt an intermittent break, it may or may not show on the insulation. Before he does, pull the codes on the OBD. Guarantee it will show intermittent rpm signal a/k/a crank sensor. When he pulled the transmission and flywheel/flexplate to get to the seal, he was right there.

 

More likely he put the flywheel back on wrong, in which case the tranny has to come out again, as the wheel goes on only ONE correct way. Experienced mechanics unfamiliar with Volvos will often do that...

 

You're absolutely right! That's such a given I neglected it...

 

Thanks for the responses. I'm in the process of testing the crank sensor. I'm inclined to think the flywheel sounds more plausible at this point. If the flywheel is in the wrong place, how does one know where the right place is. I noticed there is only one spot on the "squirrel cage" that is solid. Where should that one spot be in relation to the timing marks on the crank? Crank timing at zero with the spot at the sensor hole? Mitchel Repair mentions nothing on this...

 

Your sensor is fine, what you describe is right on flywheel being off... Sorry but tranny has to come out again. Try this:
http://www.brickboard.com/FAQ/700-90...Reinstallation

 

That was it. He marked the flywheel with one bolt in the bottom but still managed to be off by one step... I do most of my work myself but some things I hire out. It cost me $150, which is what I prearranged and I supplied both the rear main and the input shaft seals. I was a little freaked out for a while but I've learned older Volvo's can do that to you... Thanks to this forum, it all worked out... Thanks everyone... Now it's off to grounding my dash and idiot lights....