I own a 1987 760 turbo wagon. I have owned it for 20 years and have done tons of work on it and solved lots of strange problems. I thought I knew it pretty well, but this is a new one for me. This has happened three times in a row, so I can't imagine it's a coincidence. This is what happens....Car is running beautifully, always starts on a dime. I pull in to fill up with gas, fill it up and the car wont start ! It cranks and cranks, I can hear the fuel pumps running, the tach gauge is jumping but it wont start. Wait 5 minutes and it starts right up and runs perfectly again until the next fill up. The last time I took the gas cap off and didn't fill it up because the gas price was so high that I changed my mind, get in and no start for 5 minutes ? Has anyone ever heard of anything like this ? I'm stumped, I don't know what would cause something like this ?

Thanks, Mark

I believe it must be a fuel related problem. The check valve suggestion makes alot of sense. I don't know why filling the tank would cause the check valve to malfunction, but it is a place to start. Thanks for the suggestion. I am going to make up some kind of fuel pressure gauge and install it in the line. i will let you know what happens. thanks !

Mark

"I don't know why filling the tank would cause the check valve to malfunction,"

My check valve thought was not based on the act of filling up, but on the assumption that the engine being off (while filling up) was long enough to allow "heat soak" from a warm/hot (?) motor to boil the fuel in the injector fuel line, causing fuel bubbles to form a "vapor lock" which blocked the fuel flow.

A working check valve would prevent the vapor lock bubble from forming by maintaining in some residual fuel pressure while the motor was off during the fill up time.

In your case, I'm guessing that the "5 minutes" of cranking you mention was long enough for the vapor lock to dissipate, restoring normal operation. I would try a fuel pressure test to monitor both running and residual pressure under the conditions you've described.

An inline gauge tee'd in at the fuel rail inlet could be left in place for a quick check at the next fill up.
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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Here's a shot in the dark. What if you leave the gas cap off or loose after filling up. Does it still do it? I'm thinking when the tank is full there is less air space and the tank will develop negative pressure if the venting isn't working correctly.
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1992 745 approaching 500k km

If you still think it's a fuel issue, how old is fuel filter? Might be clogged...?

or is your gas cap fully sealing? there might be a air leak in in gas fill pipe from cap to tank, I recall reading a problem that involved such a leak which affects fuel pressure.
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I own a Volvo or Does Volvo Own Me? Try the easy to search Expanded Style FAQ Index http://40mph.com/Brickboard_700-900_FAQ_Expanded_Index_Version/

...which could well be caused by a failing Check Valve at the fuel pump outlet.

The Check Valve's purpose is to aid warm/hot starts by holding some fuel pressure in the lines to prevent vapor lock (fuel boiling due to heat-soak from hot engine). It's not meant to hold pressure "overnight". The spec for this "residual pressure" is measured in minutes (min 14.5psi after 20 minutes).

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Bruce Young, '93 940-NA (current), 240s (one V8), 140s, 122s, since '63.

Only one way to know for sure. Measure fuel pressure while crank and no start condition occurs. Make or obtain a fuel pressure gauge. Perhaps one like this:
http://www.brickboard.com/RWD/volvo/1470160/940/960/980/V90/S90/fuel_pressure_test.html

What happens when you drive it around up to normal temperature, then shut it off? Then try to start it. (no fill up) Been on this board years and have never heard of this happening. Can't think of anything that is related to stopping for gas except for "hot start issues".
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Post Back. That's whats makes this forum work.

I drive it around all week and it runs perfectly. It always starts right up...always. I filled up yesterday and the same thing happened. I have been working on volvo's and this car for years and have no idea what would be causing this. It makes no sense to me ! Very frustrating !

Well, I do not see any problem with the fuel pressure regulator. Car is running perfect right now, but I am going to need to fill up again soon ! Any suggestions would be appreciated.

mmm... I'm not sure. Have tried any searches here on BB?

Check out this re-worked index of the FAQ pages: http://40mph.com/Brickboard_700-900_FAQ_Expanded_Index_Version/index.html See under Engine section "Engine Tune and Performance"

I don't think it's fuel related, many here are quick to start with fuel pump, but they are fairly durable and reliable. Could just as well be a spark/ignition issue.
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I own a Volvo or Does Volvo Own Me? Try the easy to search Expanded Style FAQ Index http://40mph.com/Brickboard_700-900_FAQ_Expanded_Index_Version/

Mine did that. But it's a 91. I don't think you have the CPS. Have you looked into the Fuel pressure regulator? I don't know how yours is set up. Is their fuel in the vacuum line?

I have not checked the fuel pressure regulator, but it was replaced with a new one about 6 months ago. I will look tomorrow at the vacuum line to check for the presence of gas. Thanks for the input.

Mark