96 850 NA AT Serious Lack ofPower.

waynej · Post by **waynej** » 19 Oct 2011, 14:31

The more I push the pedal the less power I get. With a very light throttle 0 to 40 MPH is 12 seconds. With full throttle 0 to 40 is 37 seconds. In first gear it will not go above 3400 RPM in second gear it's 3000 RPM. On the highway it won't go past 65 and sometimes only 60 and it takes 2+ miles to get up to 60. Will not go up steep hills. No codes. Performance is the same with MAF disconnected. Have replaced air hose between filter housing and throttle body. Fuel pressure is to specs under all conditions. Replaced TPS.

Post by **Choguy03** » 19 Oct 2011, 14:57

Replace the fuel filter.

waynej · Post by **waynej** » 19 Oct 2011, 15:15

Thanks, but I already have. My post says "fuel pressure to specs under all conditions". When it peaks out at 3400 RPM fuel pressure is still holding steady at 43 PSI. at the fuel rail.

Post by **Choguy03** » 19 Oct 2011, 15:17

Is there some sort of rev limiter? Sounds like RPM's being the issue points to something related to that.

waynej · Post by **waynej** » 19 Oct 2011, 15:35

I don't know. I posted here hoping I could get an answer. If there is a rev limiter built into the ECU I would think it would be above 6500 RPM.

Post by **Choguy03** » 19 Oct 2011, 15:55

I agree. You said you have no codes, are you sure your CEL light is working? Haha. I really can't believe you haven't gotten a code thrown. Crazy. I will think some more tonight and see if I can think of something.

Post by **tjts1** » 19 Oct 2011, 15:56

waynej wrote:The more I push the pedal the less power I get. With a very light throttle 0 to 40 MPH is 12 seconds. With full throttle 0 to 40 is 37 seconds. In first gear it will not go above 3400 RPM in second gear it's 3000 RPM. On the highway it won't go past 65 and sometimes only 60 and it takes 2+ miles to get up to 60. Will not go up steep hills. No codes. Performance is the same with MAF disconnected. Have replaced air hose between filter housing and throttle body. Fuel pressure is to specs under all conditions. Replaced TPS.

Theres your problem.

Post by **confused_al** » 19 Oct 2011, 16:07

waynej wrote:The more I push the pedal the less power I get.

If your airbox t-stat failed, it will feel that way since your motor gets very little fresh air...
https://www.matthewsvolvosite.com/forums ... f=1&t=8830

dbeckwith · Post by **dbeckwith** » 19 Oct 2011, 16:14

confused_al wrote:
waynej wrote:The more I push the pedal the less power I get.
If your airbox t-stat failed, it will feel that way since your motor gets very little fresh air...
https://www.matthewsvolvosite.com/forums ... f=1&t=8830

Had this problem with mine. Felt like I was pulling an anchor. Big difference after I fixed the problem.

waynej · Post by **waynej** » 19 Oct 2011, 16:46

My CEL light is burned out but I have the scan tool with me and check for codes everyday until this gets fixed. The code system is working, I get a code when I unplug the MAF. The air box heat has been disabled for a long time. When it is bad it will only produce a 20% reduction in power- I have at least an 80% reduction.

tjts1, I don't understand. I have read many posts on this forum that say the way to check a MAF is to unplug it and see if things get better. I tried unplugging the MAF on my sons 94 850 and only got a modest decrease in performance. I have an extreme loss of performance.

I just did another test. It seems like the car runs better the first minute or two after starting. I parked it outside and let it get cold then started it and revved in park. Went easily to 4000 and could have done more. After running for 2 minutes it will only do 3500.