1997 Volvo 850 GLT Wagon Intermittent starting issues

[clearyakh]

Good evening. I have a 1997 Volvo 850 GLT Wagon, 152,222 miles. Replaced fuel pump in December, new Bosch starter in January. Ran fine for about one month. Started to notice if I drive the car either 10 miles, 30 miles, 45 minutes, park it in the garage for 3 hours and then try to start the car to go out, the engine make a sound like "dut*dut*dut*dut* really fast as if it was trying to start. I give it a rest, the next attempt to start it results in a successful ignition and off we go.
Engine does not run rough, doesn't sputter and the car doesn't shake. This starting problem is in the cold, hot weather, damp or dry. The issue has become more frequent so I left it with the dealer for 2 weeks. They could not recreate the problem, of course, so the mechanic put in a new ignition coil and relay. Drove the car home Friday, about 20 plus miles, parked it in the garage, two hours later, the issue returned.

After the new starter was installed, the car started like it was brand new, no hesitation. The dealership doesn't know what else to do and I find with a 29 year old car, not too many people want to work on it.

Someone did ask me if I was starting the car correctly, my response was, is there a special way to insert the key and turn the ignition ???

Any thoughts or suggestions ? I am concerned that one of these times, most likely if I'm out and about, it won't start.

Thank you.

[jreed]

It sounds like you already replaced the fuel pump relay (based on "so the mechanic put in a new ignition coil and relay"), which is one of the more frequent causes of crank/no-start issues, so that's good.
I would also inspect the camshaft position sensor (CMP), connector and wiring, and replace it with a new one. A failing crankshaft position sensor could also cause an intermittent no-start.

[abscate]

Ignition is most common no start failure.

When were cap rotor plugs last changed?

[jreed]

Does the problem also occur after overnight cool-down/first start of the day?

[erikv11]

Many of the aftermarket fuel pumps for the 850 are super low quality, especially Delphi brand. Since the fuel pump was replaced a couple months ago, and because the symptoms fit with a fuel pump check valve gone bad or failing, I'd start there. You may have already used up the lifespan of the aftermarket part.

Try this the next time the symptom appears:

1. Turn the key on to position 2, without cranking the starter
2. wait four seconds
3. turn the key off then quickly back to position 2
4. go back to step 2

Cycle the key on an and off like this about 5 times. After waiting four seconds the last time, crank the engine.

If it fires right up, you've solved the problem: the check valve in the fuel pump is bad and the fuel pressure is dropping to zero after the engine shuts off. The fuel pump relay pulses the fuel for a few seconds each time you turn the key, so it takes several cycles to get the pressure back up and get fuel to the engine. You can also check the fuel pressure after the car sits overnight, it should not drop at all from the 45 psi it reads right after you shut off the engine.

An overall failing fuel pump could give the same symptoms. Checking fuel pressure when the problem shows up will help diagnose that, too.

[aeg]

Did it sound like this?

[clearyakh]

The starting issue occurs after the car has cooled down for 2-4 hours, in the garage and outside in a parking area. I don't recall it happening after an overnight cool down. Thank you for the Robert video, unfortunately, none of those sounds match what I am hearing.
I will try the "turn the key to position 2, wait four seconds, turn off quickly and repeat and see what that does.
And call the dealer and ask about the fuel pump check valve and did they check the starter installed in January.
I'm not going to give up on my car - thank you all for the suggestions. I'll let you know what I find out.

[Vova585]

Great good tips above.
I would suggest to first try to narrow it down to the particular system that is at fault and go from there. You know it is not compression, timming issue since car starts great at times and works excellent. Now you need to see if it is a fuel delivery issue vs ignition. I would get myself a fuel pressure test gauge and connect it to the rail(some people might not be comfortable with drywing a car with gauge attached, so you can drive it for a good time to get it to "hot", come home, put on a fuel pressure gauge, start the car to normalize pressure in the rail and let it work for a couple minutes. Can rev engine a couple times to assure you got rid of all possible air pockets. Turn off abd leave for 3-4 hours as usual. Now come back and look at pressure. Should be around 0.7-1bar. If it is staying stable-you can prime the system as suggested by Erikv11 and see if the pressure jumps up immediately to around 3 bars. If yes, pump is doing a good job and holds the "rest" pressure. You might need to recreate this test a couple times to be 100% since your issue is not reproducible every time.
Get yourself a noid light kit(also harbor freight has a decent one) and install in place of one of the injectors. Remove the center wire from distributor cap and put close to ground so you can test spark. With the help of the helper "ignition start position" and monitor if noid light blinking(ecu control) and if you have spark from coil to the distributor. If both checks great- take advice of abscate and look into replacing distributor cap, rotor and wires. It is decently cheap option. One of recent threads ended up having an issue with condensation inside of the distributor cap from likely faulty pcv system blowing the camshaft seal and "blowing" into the distributor cap. Good luck and keep us posted.