i have another problems for you guys

here was a previous problem i had and was fixed

https://volvoforums.com/forum/volvo-...roblems-58127/

but now its doing something new.

it starts up fine and will accelerate if i am light on the pedal, however once i punch the gas a little it will loose power and decelerate. the rpm's still increase but i notice the turbo gauge go down rather than up. i know that the turbo takes air from the exhaust and my muffler is rather rusty and has multiple holes where air is escaping so may that be a problem? otherwise maybe some sort of bad sensor or fuel intake problems? I'm not really sure so if you guys have any advice it would be appreciated.

 

Well, to be more accurate, the turbo doesn't really "take" exhaust flow. All of the cars exhaust flows through the turbo and then out the down pipe to the exhaust. If the car is running smoothly (no misfires) but acceleration is pathetic and boost falls, most likely there is a restriction/leak in the charged air from the turbo. The first thing to check is the large S hose from the air box to the turbo. With age, it gets weak and will actually collapse, effectively cutting off air flow when under boost. To check it, you need to have someone power brake the car into boost while you examine the hose. If it shows any sign of sucking inwards, replace it. I've heard of people covering the hose with caterpillar clamps to reinforce it...but I'd just replace it. You could also have a leak in the intercooler. The stock one is 99.9% plastic and over the years, can crack or become holed. My 84 had a hole on the very bottom. It wasn't visible until it was pulled.

 

I did not see any inward sucking on the "S" hose you mentioned and after examining the plastic hose i did not see any flaws.

however after testing the car more i am noticing sporadic misfires coming from what seems like the engine. as noted in my other post we just changed all the spark plugs, wires, distributor cap and rotor so that shouldn't be a problem as it did drive fine for about month after they were replaced.

so the main problems would be the lack of power while accelerating and these misfires. any help or ideas are appreciated

 

i also notice the turbo gauge go down while the RPM's still increase when giving while accelerating. the turbo gauge will go up if i accelerate slowly but if i give it gas it will drop down.

 

check all the hoses to/from the intercooler.... I found the "s" hose that swift was talking about, and the "L" pipe the attaches to the throttle body were deteriorated and sucking in un-measured air.... this might be why you have no boost under acceleration in gear- the engine is under load, where just revving it up isn't. hope this helps.

 

well i finally had the time to fix the problem. turns out the mass air sensor was clogged up with pieces of foam that broke off from the padding in the air filter compartment. simple fix.

 

 

its airbox -> turbo -> intercooler -> AMM -> throttle body -> intake manifold.

yeah, I imagine disintegrating foam could easy clog up the turbo, and maybe the intercooler too. I'd probably disconnect all the big air hoses, and use a compressor to blow out everything backwards.

 

If I pull it apart, might as well upgrade to all aluminum and toss the old hoses.

I was thinking of going with a quart of trans fluid in the oil for 20 miles and then change oil/filter before giving it a good drive.

But I am wondering if its too aggressive and I am risking other damage.

Thanks in advance for your time and assistance.

 

ummmm. an ATF colon cleanse in your engine oil is not going to do anything for foam in the intake path.

 

double post deleted

 

Fair enough, the ATF will only clean the turbo oil lines, etc.

Just wondering if I go the lazy route whether I am risking damage or if the system will blow itself clean soon enough.

My guess is anything that made it past the 2 AMM screens was very fine dust.

I've only driven it about 1 mile since cleaning the AMM, its running well all things considered so wondering if the idle will sort itself out.

Thanks in advance for your time.

 

the air path past the turbo tends to be rather oily, so that foam dust would stick to everything and gum it up.

rough/uneven idle, I wonder if the throttle body is gummed up so the idle switch isn't clicking?