1997 Volvo 850 starting problems

dcunited122 · Post by **dcunited122** » 13 May 2009, 12:59

When I start my NA 850 after about a day, it starts very weakly and then turns off. Then the second time I start it, it fires right up. I just replaced spark plugs and wires about a month ago and the car has 112,000 miles. What could be the issue with this?

Thank you in advance

Post by **FlyingVolvo** » 13 May 2009, 13:15

I'm no expert, but by looking at other cases like this, I'd say it could be related to fuel delivery. Failing fuel pump?

Are there any error codes?

dcunited122 · Post by **dcunited122** » 13 May 2009, 13:59

Well yes, I've had a fuel mixture is too rich code for years, but no one has ever been able to diognose the problem after different tests and oxygen sensor replacements.

I can see why you would say a failing fuel pump because it starts and then acts as if its not getting any fuel to burn. But then the second time it starts pefectly fine. Maybe because it has fuel then?

tommy33 · Post by **tommy33** » 13 May 2009, 16:18

After this group convinced me to keep my 94 850 (135000 miles) I went about trying to solve the problem I had of a very very hard to start engine. Engine would crank and crank. Someone reccomended that I turn the key off and on several times to build up fuel pressure before trying to start. That seemed to work.

Changed plugs, wires, rotor, cap, all vacuum lines under the hood and fuel filter and fuel pump relay.

Still had to turn the key off and on 4 or 5 times before it would get fuel and start.

Finally ordered a new fuel pump and installed it this past weekend in about 30 minutes. Easiest job especially with the posts on how to do it on this site.

Now I turn the key on and tap the accelerator once and it fires right up.

dcunited122 · Post by **dcunited122** » 13 May 2009, 19:37

Maybe I'll try turning the key several times and see if it makes a difference. I'm guessing that could indicate if I have a bad fuel pump.

dcunited122 · Post by **dcunited122** » 13 May 2009, 20:07

I tried turning the key, but still it would not start on the first try. Any other ideas?

Post by **Ozark Lee** » 14 May 2009, 02:31

It could be the check valve in your fuel pump. If defective, a bad check valve causes the same problems. Get a fuel pressure gauge on the end of the fuel rail, start the car, and then observe the pressure again after 20 minutes. It should hold 30 psi or so. If it rapidly drops to zero the check valve is bad.

Unfortunately the check valve is built into the fuel pump housing and the entire assembly will need to be changed or an after market check valve will need to be added to the fuel line.

...Lee