Well, last june I began having some issues with my 94 volvo 850 turbo. You may remember my post about loss of power and finding the long term fuel trim and knock sensor codes.

Here's an update as to what is happening:

Since about last june my volvo has had loss of power going up steep hills but otherwise seems to run great and I don't really notice anything and I avoid the hills that I know it has problems on. I just drive it a few times a week around my town and it runs real smooth.

Well the knock sensor code has been there a long time and was present before the loss of power issue started. But the code 232, long term fuel trim was new. So I got some feedback from the forum here in June with the suggestion it could be the fuel relay. I finally decided to get one and installed it the other day.

I took it for a drive and decided to head up the steep hill that, in the past would make the car loose power and would make the check engine light come on and throw the code 232-long term fuel trim.

Well to my suprise, the car made it up the hill, no check enging light and no code! I was all excited! So I went home told my husband and he was shocked and wanted to test it out for himself. I told him I went up the hill casually and he wanted to really push it to see, well we drove up the hill rather fast and hard and it made it but my husband said the power is still lacking, better but not right. I was saddened I thought I fixed it. So I dropped him off and went and tried another steep hill, known to throw the code. Sure enough I lost some power and it through the code again. Probably blew the brand new fuel relay! I cleared the code again and went to the HWY where are pushed it a bit harder than normal, nothing much though and it threw the code again. ARG!

Next I went and put in a bottle of Thecron(sp?) fuel cleaner. Drove 15 miles went up a couple hills where it had lost power in the past(not the big one) and it made it just fine. I tried pushing it hard and it has power but I can tell it's not perfect. But now after putting in that fuel cleaner and pushing it, a bit on the HWY it won't throw the code. Even though I can tell its power is not 100%. It's like the cleaner might have done something to make the car not through the 232 code??

So Now I'm stumped. So basically, the new fuel relay helped for a few hills then bam, back to the same old same old.

Something is causing the code 232, and it's not the relay. It doesn't seem to be the fuel filter as it wouldn't have made it up the hill with the new relay when I test drove it?? not sure? and the fuel cleaner I put in last night seemed to do something as it seemed to have a bit more power and now won't throw the code. Not sure if it's related to the cleaner or just a fluke. All I can say is that, it never made it up this one hill without throwing the code and loss of power except just after installing the new fuel relay. Then after a couple more hills it did it again and now after adding the fuel cleaner I can't get it to throw the code but it still isn't 100%

Any ideas would be greatly appreciated. I like to work on my car myself and will do so until I just can't do any more.

What all can throw a 232, long term fuel trim code and cause severe loss of power on inclines but seem just fine when driving around town??

Thanks in advance,

Volvogal

 

It could be a clogged fuel filter or possibly a weak fuel pump. One way to figure it out would be to install a fuel pressure gauge and watch it while you are under high load/high boost conditions. The gauge might show adequate pressure at idle and at light load but if the filter is clogged or the pump is weak it might drop off once the demand for fuel volume increases.

Otherwise it could be the mass airflow sensor or maybe an injector or who knows what else.

good luck!

 

so I just cleared the codes again and took it for another ride. I pushed it a bit up a hill and now it just through the knock sensor code only, not with the fuel trim code, 232, which is what it has been throwing since this started. The knock sensor code has been there long before this problem of loss of power started.

Now I'm wondering if the knock sensor code 143, that I ignored for years is actually the start of the problem and has just got worse over time causing the 232, long term fuel trim code and the loss of power??

Any ideas now???

Thanks to the person who left some advice!