Hi everybody go easy on me, I don't know that much about cars, but I know I love my Volvo.
Suggestions for things to check on. My 1985 740T manual shift station wagon, with 306,000 miles put on by me since new, (I'm only and original owner) is now balking at climbing the hill (road) to my house. The turbo surges but nothing happens, and I can make it in 2nd gear, with effort. On the flat the car races like a champ!
She's been in to the shop, where they discovered a lot of broken off debris in both mufflers as well as in cat converter. Recommended I replace all. The mufflers were done back in early 2000s so, around 20 yrs ago. The cat converter is original.
During the pandemic the car was barely driven: maybe I put on 2-3000 miles in 28 months. I usually drive the car about 10,000 miles a year, as it's a second car now, but most beloved and more comfortable.
The mechanic (who I've been going to since 1992 after leaving the Volvo mechanics when the Volvo dealership left my county) diagnosed a leak in the turbo gasket, but said the turbo itself looked and operated fine, and he replaced the offending gasket. Yep that meant removing the turbo. He did not recommend replacing the turbo (which I've done at least two times since 1985) which he said looked good.
The mechanic found all the clunky chunks in exhaust system and replaced as well as recommended catalytic converter be replaced, and it was.
The mechanic checked fuel pump, fuel system, spark plugs and charging, the turbo itself, as well as MAS air flow. ALL GOOD or normal.

ANYONE HAVE any other suggestions?
Thank you!
I'm at my wits end with this. I also have a 1994 850T which is not as comfortable as this car.

 

Not sure what your tech did to test/check stuff. I'd say start with the basics - spark, fuel, compression. My sense is the added load of going up hill is literally blowing out the spark or there's not enough fuel delivery to create the extra HP being demanded.

Start with a compression test - you can rent/borrow a guage from Autozone etc and there are vids on youtube on how to check. Just do it on a warm engine. A turbo should be in the 150 PSI range. While the plugs are out, check for color, oiling etc.

Next, when was the last time the car had a tune up? given the car has been sitting, its more prone for corrosion so I'd suggest a "stage 0" tune up to baseline the car - cap, rotor, wires, plugs and check the connections to the coil. There should be date codes on the wires - anything over 5 years is too old.

Finally did the tech measure fuel pressure after the regulator? Not sure of the exact spec for the 740Ts - its about 40 PSI for the 850T and even higher for newer models. You can also measure the pump's pressure. You may also want to try jumpering the fuel pump relay to see if that changes anything.

Plenty of other posts on how to check out the fuel system I assume your tech also checked for issues like a clogged exhaust system (say due to a pinched pipe) or a clogged intake air filter etc?

 

The tech could be correct. I have seen pictures of catalytic convertors that had their innards reduced to a ball that acts as a plug reducing horsepower under load so it may be correct. Also, there was a post on this forum a while back where the air intake hose pre-intercooler that gets soft and can collapse under heavy load thus robbing horsepower. I believe the post was by Pierce - who no longer frequents this forum.

 

Think about this: when you're going uphill gravity would pull any 'chunks' in the catalytic converter to the back of the converter and pile up enough to plug it. When the car's level they settle flatly enough for the exhaust to exit.

 

The OP noted the cat was replaced... PS one trick I've heard of to test for a clogged cat is to remove the O2 sensor and go for a test drive (lol easier said than done on a 30 year old car... ). Good news is many states don't do emissions on pre-2000 cars any more so you could always remove the cat, shake out the bits and reinstall . There's really not much in there other than a metallic grid...

 

Understood, but could there be previous "chunks" that lodged in any curves in the whole exhaust system? And continue to back up when going uphill and level off when going flat? Sounds like 'gravity' is the culprit here. If he can remove the O2 sensor how about pumping some compressed air thru the opening and see how much comes out at the exhaust tip.

 

Can 't believe I didn't think of this earlier but here goes: Sounds like fuel starvation. When the car is tilted going uphill, all the gas settles in the back of the tank and doesn't supply enough to the in-tank pump. Or the pump is shot and tilting doesn't gravity feed enough to the mid-way pump. Sounds possible? Have you tried going uphill with a full tank?