I have an 87 745 turbo I bought recently. It had a broken timing belt when I got it - and was running great up to the belt breaking (tensioner was froze solid). I had it towed back to my place. I changed the belt, tensioner, all drive belts and water pump. Runs absolutely great, however when in gear (its an auto btw) it has ZERO power. Idle power only. I noticed that when revving it in park, the boost guage never exceeds 12 o'clock. My 89 744T goes around to 3-4 o'clock. I checked the turbo - very little shaft play and it spins very free. The AMM is next, however, it idles wonderfully, just nothing in gear. Tranny is ok as well. To sum up how it acts: it acts just like the pedal isn't hooked up. No acceleration AT ALL, but the throttle does move when you step on the pedal.

Does it sound like something is plugged or stuck (CBV, etc.) - just wondered what would cause it to idle so nice, yet have NO power whatsoever? I can hear the fuel pumps running fine also. Like I said, it idles like a champ, just ZERO acceleration.

Thanks in advance.

My vacum/boost guage was doing the same thing and I found that the wastegate actuator rod had fallen off of the WG. The WG was always open and I never had boost. I reconnected it and the guage regularly runs to the 2 o'clock position and of course the car runs much stronger.
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Erwin in Memphis, '88 745t 183,000 miles, '95 855t For Sale

Thanks very much....those suggestions are all in the area I was suspecting. I did completely unhook the AMM from the airbox, in the event the filter, etc., was a culprit. I had a 91 940SE several years back that acted this way although it wouldn't run at all. I would be driving and it felt as if someone "unplugged it" and it just coasted to a stop. Turned out to be all that rediculous foam Volvo glues to the inside lid of the airbox was coming off in small parts and blocking off the AMM. I did check the AMM on this 87, by covering it with my hand (it stalls) and just unplugging it (it stalls) so I 'assume' it is working. I have a friend who also has an 87 740T that runs great, so I can try out his AMM as a Plan B if it points back to that.

Is there a sure-fire way to check the CBV for failure? Or perhaps a given vaccuum line to remove to see if something is/isn't working? What perplexes me is that the car runs so solid at idle, but nothing beyond that (and I mean absolutley NOTHING beyond that).

My other fear is that its something transmission related. Car does have 190k on the clock. I have a low mileage 93 complete drivetrain waiting in the wings, as I was aware the 87s have a weak bottom end anyways, but didn't want to climb that mountain....YET.

Thanks again very much to everyone in advance :)

Yes. Use a vacumn gauge on intake manifold and you can easily check for proper exhaust performance. Since you just got this car the exhaust system can easily be clogged with who knows what.

on that model there is a vacuum hose on that runs from the intake manifold to the turbo. that, I believe, is the blow-off valve. it opens when you let off the pedal, dumps the excess turbo pressure. If that were stuck open or had a hole in the valve plate then maybe, but I would think it still would accelerate although poorly. turbo problems shouldn't enter in until you hit boost.

I wonder if it isn't a blocked hose or air filter. I've heard horror stories of chipmunks and squirrels hiding nuts in the airbox and causing running problems too.