Engine Is Losing Mid-rpm Power, but doesn't stall or anythin

Mr_LV · Post by **Mr_LV** » 11 Jan 2011, 23:59

I have a 1993 850 GLT

This problem has been going on for a few months now. I thought it would go away with higher grade gas, but that's not the case anymore. I'll try to explain the best I can. I might make a video of it tomorrow if I remember.

Last summer the car started losing power when I floored it. It would go fine if I drove normally, but if it went past 4000 rpm it would feel like i took my foot completely off the pedal and the engine would slow down to idle speed. That was fixed by replacing the flexible neck/tube that fed air to the air filter box. It had a hole in it, so when the engine required a lot of air the tube would collapse and choke the engine.

It seems like the problem has come back, but slightly different and worse. I checked the tube and it was fine, but replaced it again anyway, that didn't work. Now if I floor it the engine takes a lot longer to rev up. 1000 - 2000 is still normal, but 2000 - 5000 there is nothing. It feels like the middle of the power band is somewhat dead. Even if I am on the freeway and it kicks down so I can pass someone, the same thing happens in every gear. It takes a considerably longer time to get to 5000 rpm. But by that time it's about to shift so it's back to square one again.

Any help would be deeply appreciated as this problem has really taken some fun out of this car. It makes me not want to race between the lights and that's no fun. The problem is worse when the car is full of people. It's painfully slow then.

Let me know If you guys need a video so record one.

Post by **jblackburn** » 12 Jan 2011, 05:44

Take your hand/foot/something and smack the bottom of the catalytic converter. Do you get a sound like it's full of gravel?

Post by **vjaneczko** » 12 Jan 2011, 12:55

jablackburn wrote:Take your hand/foot/something and smack the bottom of the catalytic converter. Do you get a sound like it's full of gravel?

+1

Also, have you done any Stage 0 stuff?

Mr_LV · Post by **Mr_LV** » 13 Jan 2011, 02:59

I did a regular tune up a little over a year ago: plugs, wires, cap, rotor, air filter, fuel filter. Other things I did around that same time: camshaft position sensor, ignition coil, fuel pressure regulator, rpm sensor. Everything was good until about 3 months ago. I also changed the fuel pump relay a few weeks ago, didn't help with power, but did fix the random stalling though

valvster · Post by **valvster** » 14 Jan 2011, 04:32

Also checkout your airbox thermostat, I jammed mine with a piece of dowel so it only gets cold air and there was a noticeable increase in power and fuel economy.
https://www.matthewsvolvosite.com/2009/0 ... t-failure/

Valvster

Tsquared · Post by **Tsquared** » 14 Jan 2011, 12:46

I would try another fuel filter. Yours may be clogged.

Mr_LV · Post by **Mr_LV** » 14 Jan 2011, 20:42

Tsquared wrote:I would try another fuel filter. Yours may be clogged.

Replace the fuel filter? It's only about a year old. And I got it from FCP Groton.

Post by **jblackburn** » 14 Jan 2011, 21:34

Try the test above to see if the converter is clogged. The car is old, it may very well be.

Tsquared · Post by **Tsquared** » 15 Jan 2011, 08:32

Mr_LV wrote:
Tsquared wrote:I would try another fuel filter. Yours may be clogged.
Replace the fuel filter? It's only about a year old. And I got it from FCP Groton.

Age is not the issue. If it is clogged there will be no-flow but it can have a diminished flow.

The cat test mentioned by others - how did that go?

The problem you have described is a result on one or more of the following: not enough fuel, not enough air, or a restriction on the exhaust.

It would also be good to know what your fuel pressure is running. The "random stalling" fixed by replacing the relay for your fuel pump leads me to believe you have a fuel related problem. Has you fuel pump ever been replaced?

Post by **jimmy57** » 15 Jan 2011, 17:33

The 1993 850's have the variable intake system. If the dampers don't open in the intake runners then it will not breathe too well.
This is assuming no blockage in catalyst as well as some other items already listed to verify.