I have intermitant engine starting problems. Turnover but engine does not catch. Happens mainly on hot days. Let it sit for 15 minutes and starts right up and I will go for a week or so before it may happen again. Per this board, people have said this is the "classic fuel pump relay" and talk about it costing $39 and located near the fusebox. The dealer says the FUEL SYSTEM RELAY costs $39 but is located near the driver headlight. He says there is also a FUEL PUMP RELAY(also called FUEL INJECTOR RELAY)near the relay panel for about $83. He seems to have replaced the FUEL SYSTEM RELAY a lot, but no so much the other one. Which relay are we talking about? Don't mind replacing the cheap one even for proventive maintence but do not want to replace both if unnecessary. Also is this something that can be done easlier by a novice. Where could I get info on replacing one or both of these relays. Anyone out there that understands this world of fuel relays.

Keith,
I have the same car, same problem. I have a recent thread on it. Change the fuel system relay. It's easy to get to and doesn't cost much. You can change it in 5 minutes. It is on top of the fan shroud near the fan relay. Spray the contacts in the plug with wd-40 then use a little grease in there for longevity of the contacts. Do this and I'll bet it fixes the problem. Think about how hot this stupid thing gets. It's right above the radiator! Not a wise location decision on Volvo's part but hey, their dealers love it. They pick up $200 bucks for 5 minutes work every three years or so. If the problem persists, then change the other relay. Much more difficult than the one depicted here. But I'll bet you don't have to mess with it.

Thanks for the help. I bought the fuel system rely and replaced it myself. Very easy and I don't know Jack about cars. Still don't know yet if this was the problem, but have my fingers crossed. If not I'll try the other fuel pump or injection relay, but this looks harder to get at and may choose to do it by an inde when I have something else done. Hopefully though I won't need to replace this part. You are right, the fuel system relay is right where it could really overheat, especially in hot weather. I could see how these things might need to be replaced every 3-5 years. But there's nothing in the maintaince schedule about this per my inde Volvo mechanic. Thanks again. I may have saved myself a hundred bucks or so.

A true story by Ronjon:
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Classic fuel pump relay symptom:

Keith drives his beautiful 850.

One day, while driving, suddenly, he loses power, pressing the gas paddle has no response.

He barely parks the car on the roadside without power breaks. In the mean time all the error/indication lights on the dashboard are lit.

He turns the car totally off, waits few seconds and cranks it. It starts with no problem.

Few days later it happens again.


The fix story:

The dealer has no clue what is wrong and charges him labor ($65).

He takes it to an indy shop, upon hearing the story, says “When we replace the fuel pump relay the problem goes away.”

The mechanic orders the wrong part, the system relay ($35, located on the fan shroud, next to the cooling fan relay) and replaces it.

The problem is nowhere to be found. Keith is happy.

He goes back to the dealer for a refund ($65) and gets a free transmission service!

Later he finds out that the mechanic replaced the system relay not the fuel pump relay. The mechanic is confused. Have you seen this happen during surgery??

Two year later the problem appears again.

This time Keith makes sure the mechanic orders the fuel pump relay ($55).
With the help of Brick board brothers Keith replaces it (located near the fuse box).

Currently he waits to see if this took care of the problem.