I have a 93 850 I use as my daily driver. Love the car and I really don’t want to get rid of it, but it has recently been a pain in my ***. I'll drive the car, have my foot steady on the pedal and when I hit the gas pedal to accelerate, the car won’t increase the speed it should be going and instead decelerates. I’ll step harder on the pedal, but the pedal moves and not the speedometer. Once the speedometer decelerates to 0 the entire car pretty much breaks down and all the lights on my dash will pop up.I'll turn off the car but then my car won’t start at all for about 5 minutes. I’ve taken it to 2 shops and they couldn’t really fix the problem. I had a friend look at it andI think he saidit could be a possible computer problem in the transmission but he's not quite sure what the problem might be. Any ideas?

 

I would first retrieve fault codes stored in the ECU. On 93 models you can do this by yourself without a tester. See attached for procedures.

Also, can you inspect the exhaust? If the exhaust system has a blocked section then back pressure could build up, preventing acceleration.

Wait for others’ replies; we have great members with wealth of knowledge & skills.


JPN

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The OBD-I/ECU fault code access terminal location.


JPN

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In addition to checking the codes in the computer, when was the last time it was tuned up, especially the air and fuel filters changed?

 

+1 on the tune up and filters... And has the MAF been cleaned?

I would also suggest that this may be the beginning of the dreaded fuel pump relay issue, which you may want to explore after you've addressed the tuneup issue. Here's a link that may help if you want to explore repairing the fuel pump relay.
http://www.matthewsvolvosite.com/for...ic.php?t=16766

 

So, I will check the codes soon and see what they say. We did a semi tuneup before but it definitely needs more. It's going to get a basic tuneup very soon so i'm not gonna worry about that right now. I think it may have more to do with the fuel filter as it may be the orig. and after 140k should be changed. Where is the fuel pump relay... is it hard/expensive to replace?

We want to have the timing belt and gaskets all replaced and one place told us it is very difficult to do on these cars and will not be cheap AT ALL. What is a rough estimate for new belts and gaskets etc... a real good tuneup so this car runs good again.

 

See my 1st & 2nd replies at:

https://volvoforums.com/m_48928/tm.htm

Stick to OEM parts as much as possible. The extra $ is well worth it.

http://www.fcpgroton.com/product-exe...ategory_id/172


JPN

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I did a timing belt and serpentine belt change on ours with all new pulleys, water pump and tensioners about 2 yrs ago and it cost about $350 for parts, and it took me about 5 hours to do it all. It was NOT that hard and thereare plenty of instructions on this site and others on how to do it.

 

And when you are done, make sure to turn the crankshaft by hand at least 3 times. This way, if the valves & pistons are not timed correctly you would feel them. If this step is skipped, the valves will be bent, pistons may get scored, you would be destroyed by your wife...[:@].


JPN