1998 V-70 T-5 Cranks but no-start after running OK

reluctantmechanic · Post by **reluctantmechanic** » 27 Dec 2021, 15:05

Greetings, this 27th of December, 2021
My car cranks but will not start. I started the car in slightly above freezing conditions (35F+/-) ran it for about a half hour, then home with no problems, shut it off for a few minutes (maybe an hour), returned to it but it would not start. In the past, when I have had a cranking no-start condition it has been when the fuel level was low, the ambient temperature cold and it has been the first start of the day. I assumed that water in the fuel caused the problem, the 3 – 4 times I have had the problem (in 5 years), and after adding drygas and 5 gals of fuel the car would start. So long as I have had ¼ tank, no problem starting the car. I tried this solution today but it has not solved the problem.

I think the problem is a bad fuel pump, but the car has been running rich, possibly because the thermostat is stuck open. When I turn the key to start the car, I can hear the fuel pump click followed by an almost inaudible whirring sound for a second. Usually, I let the car warm up to operating temp, but the day I had the problem, I didn’t have the time to do so. Would the temp sensor on the t-stat cause this problem, and if so, is it possible to bypass this problem so I can get the car started? I’m a little reluctant to change the thermostat right now because I think the torx screws will strip.

Last fall (Sept 15th+/-), I drilled out a frozen caliper bolt on the wheel closest to the fuel pump location. I drove the car to the inspection station 5 miles, shut it off, started it up no problem, drove back to my garage, shut it off and started it up, then home, After an hour, I tried to start it up but no start, a condition similar to that right now. I added dry gas and some fuel and it started right up. To pass inspection, I had cleared a few codes. Today, when I checked, there scan tool showed no codes, though I didn’t clear them.

Thanks for any ideas to solve the problem.

Post by **scot850** » 27 Dec 2021, 17:45

A few possible thoughts on this issue,

1) Does your car come up to temperature relatively quickly once started from cold? If the temp needle shows about half way and the car warms up in say 5 minutes or so, then the thermostat is ok.
2) If the temperature does take a lot longer to get to normal then the thermostat may stick open. Either way, the thermostat is not going to prevent your car starting.
3) The ECT (water/coolant) sensor located close to the thermostat in the same housing, can become an issue with age. If your needle runs regularly lower than half-way, then the ECT could be to blame, or it could be a bad thermostat stuck open. ECT and it's connector on the back of the power steering pump get flaky with age. Check the connector is good.

As you have a turbo, what temperatures are you seeing outside these days? If it is below freezing, then these cars can get intercooler freezing which prevents the engine getting sufficient air to start. Check if the top and bottom intercooler air pipes are collapsing when you are trying to start the car.

Do you have a block heater? If so have you used it and does it help??

Try jumping the fuel pump relay to rule out a failing relay in cold temperatures.

If you are regularly getting cold temperatures below freezing, try parking the car with the hood down wind. Also you can try zip-tying some cardboard behind the hood grille to reduce the chance the intercooler gets too cold which causes internal condensation and then freezing when switching the engine off. Don't run the car with the cardboard in place above freezing.

Neil.

reluctantmechanic · Post by **reluctantmechanic** » 27 Dec 2021, 18:27

Thanks for the response. The temp is just at 32F/0C. Usually, the car fires right up. Will a defective ECT prevent the car from firing up? The car is slow to warm up, and the fan can occasionally stay on for a bit of time after shut down, even in cold weather. If the fuel pump relay is bad, will I still hear clicking from the tank when I turn the key? Also, when the key is in the "run" position during operation, will the fuel pump be operating constantly ( so I should be able to hear it if I turn the key to the run position and put my ear to the tank)? Many thanks, again.

Post by **RickHaleParker** » 27 Dec 2021, 18:54

reluctantmechanic wrote: ↑27 Dec 2021, 18:27 Will a defective ECT prevent the car from firing up?

A defective ECT can prevent a car from starting.

Fuel burns on the surface. Fuel is atomize to rise the surface to volume ratio so that it will burn faster.

When an engine is cold some of the vaporized petrol condenses back into liquid when it touches the cold cylinder walls. You need more fuel to compensate for what phase changes back to a liquid. Without, the Air-Fuel mixture will be too lean to start. Or more precisely the fuel surface to air ratio is to low. As soon as the engine it running the surface of the cylinder walls heat up and the problem goes away.

When the ECT is not working. The ECM does not know it needs to compensate for fuel condensing on the cold cylinder walls and the finial air/fuel ratio after fuel condensing is to low to start.

This is what a choke is for on a carburetor. With fuel injection it is "choked" electronically by injecting extra fuel. The decision to choke or not to choke and how much is based on the ECT data.

On them really cold days when you got to hold the throttle open to keep it running. That is the super cold cylinder walls taking longer then normal to heat up.

reluctantmechanic · Post by **reluctantmechanic** » 27 Dec 2021, 19:09

Thanks for the response. Should I be able to hear the fuel pump run when the key is in the run position (i.e., in the position it would be in after the key is turned to the cranking position)? It isn't colder here than it was the day the car stopped running. I never have to hold the throttle open to keep the car running. Today, while I was trying to start it, I did keep the throttle to the floor while cranking but it made no difference - no start. Thanks again.

Post by **RickHaleParker** » 27 Dec 2021, 19:32

Fuel pump will run only when the fuel pressure needs to be brought back up. It will not run when there is enough pressure in the fuel rail.

Go outside and try to start it. If it does not start disconnect the ETC. If it fires up with the ETC disconnected, it is the ETC reporting a higher temperature then what is true. If it does not start up with the ETC disconnected the test is inconclusive, it still maybe the ECT.

Try a shot of start fluid. If it starts on starter fluid. The Air/fuel mixture is to low for the engine temperature. Starter fluid is chemically choking the engine ... same thing as a fuel injection electronic choke.

To manually engage electronic choke on a fuel injection engine you got to push the pedal all the way to the stop .. hard. If there is carpet or a weather mat blocking the pedal at all it will not engage.

reluctantmechanic · Post by **reluctantmechanic** » 28 Dec 2021, 11:27

I cranked the car and then checked the fuel rail schraeder for pressure; only a dribble (mebbe 1ml) came out. I also jumpered over the fuel pump relay contacts and tried to start the car; once again, it cranked but no start. I think it is the fuel pump, so I'm gonna change it out, tomorrow.
What had me confused into thinking that the fuel pump was OK, is that when I turned the key to start the car, I could hear clicking from the rear of the car at the area near the fuel pump followed by a whirring sound, for a second. I interpreted the sound to be pressure building. When I jumpered over the relay, I heard no sound; my understanding is that the pump would have been audible continuously running, under this scenario. What do you all think? Reasonable diagnosis?
Once again, Thanks for your help!

Post by **misha** » 28 Dec 2021, 14:57

RickHaleParker wrote: ↑27 Dec 2021, 19:32 Fuel pump will run only when the fuel pressure needs to be brought back up. It will not run when there is enough pressure in the fuel rail.

Maybe on Me7 and later cars...on 850,s,v,c,xc70(pre Me7) fuel pump will prime everytime for one second when key is in pos.II.

Post by **misha** » 28 Dec 2021, 15:04

reluctantmechanic wrote: ↑28 Dec 2021, 11:27
What had me confused into thinking that the fuel pump was OK, is that when I turned the key to start the car, I could hear clicking from the rear of the car at the area near the fuel pump followed by a whirring sound, for a second. I interpreted the sound to be pressure building. When I jumpered over the relay, I heard no sound; my understanding is that the pump would have been audible continuously running, under this scenario. What do you all think? Reasonable diagnosis?
Once again, Thanks for your help!

There should be no clicking sound from fuel pump...just whirring sound for one second..everytime you turn the key to pos.II.

Yes...when fuel pump relay is jumpered...fuel pump will run continuously when key is in pos.II.

reluctantmechanic · Post by **reluctantmechanic** » 12 Jan 2022, 14:17

Hi again,
Since my first post describing the problem, I put in a new fuel pump; I could hear it run in the same manner as the pump I replaced. The car did not start, and there was little or pressure at the schraeder valve. I guessed that the fuel filter (infront of the right rear passenger wheel) was clogged. Anyway, because I don't have a lift, cannot keep the car in the roadway during the winter, I had it towed to a garage that my family uses. I thought the guy fixed the problem, since the car worked for about a week. He told me that the crank no-start condition was caused because of a combination of problems, the filter in bad condition and spilled oil in the valley of the head (under the plastic cover) deteriorating the plug wires. Well, two days ago, the temp was about 26F, I let the car warm up to operating temp, and I drove about 5 miles to a store; When I came back to the car, about 30 minutes later, it would crank, but no start, again! I checked the fuel rail with a pen cap and there was only a dribble coming out of it. I can hear the fuel tank pump pressure up when the key is turned.
I think there is still some crap in the fuel line; does that make sense? I believe there is a secondary, hi-pressure fuel pump, could this have failed? The key switch sometimes has to be turned backwards a bit to get the front lights to come on; could this cause the no-start condition, and is there a way to jumper out contacts to test this ?

The mechanic working on the car now is pretty good, and fair pricewise, but I'm afraid he's gonna get sick of the car (and me), then I'll be stuck