Car shut off while driving -99 V70 2.5T

[Eliotlm]

Hi! Last week my v70 shut off on my way to work, fortunately it happened just as I had come off the highway. The car refused to start after that so I had to get i towed to the nearest mechanic. I noticed that I couldn't hear the fuel pump priming after I turned over the key and it cranked like normal. I figured that it was the fuel pump but when I tried to start it at the workshop I managed to start the car once but on the second try it didn't work. The thing is that it started just fine when the mechanics tested it a few days later and they couldn't see anything wrong with it. I asked them to order a fuel pump relay as they were quite cheap and I am contemplating replacing the fuel pump myself just to be safe.

I don't know if these things are connected but I have previously replaced the antenna ring which caused a no start condition but I feel like that woulnd't cut the engine when it is already running. I really want to be able to trust the car as it is my only car and I drive it about 45 minutes to work every day. Do you guys have any tips on what to do or what it could be? Thanks in advance!

---UPDATE---
I just got the car back from the mechanic after they replaced the fuel pump relay. As they couldn't replicate the issue I picked up the car this afternoon. The car started and ran like normal but after a while the car stalled at a red light so I had to push it to a parking lot. The car would yet again start after a few minutes but stall after running for a short while. It didn't seem to matter whether the car was idling or driving. I still didn't get any error codes, I have an icarsoft scanner but no codes in any of the systems I could check. I pressed the pressure relase valve on the fuel rail after the car had stalled and fuel came out. Don't really know if that says anything or not though.

Another thing I might thought be relevant is that the car has a problem starting after refueling which might be indicative of a broken evap purge valve (EPV). It can also get a faint smell fuel sometimes outside the car after having driven for a while. Could this cause the car to stall and behave in this manner? The mechanic thought that it might be the fuel pump "overheating" and constricting fuel after running for a while, does this seem plausible?

I am planning on trying to repair the car in the parking lot by myself so any tips are greatly appreciated!

[xanthefin]

IMMO yes doesnt cut engine after its given greenlight start (it sends special message to ECM to cut at cranking if ever).. but you can get (not correct) error message of IMMO not having contact with ECM or vice versa due whel engine cuts there might happen conditions where you still get error of IMMO not getting message from ECM or so but thats in these cases to ignore as even this forum had such case where faulty pump caused those to come.


My 850 did stall on similar place due fuel pump once.

Is there any different signs at cranking.. sounds any different?

Engine is quite basic in the end. Fuel, air and spark. I would as you if it struggles to start or sounds wierd like fighting against starting to check all spark components. Specially start from distributor as no start.

Edit: As its easy on these cars.. was fuel pressure measured? On my 850 before start there is some 1 bar something but when after crank it goes 2-3 bar. I did replace fuel filter recently thinking it was blocked. On Older cars electronical contacts might be crusty.. its not up to maker honestly i seen on all cars similarly happen.
Never touched fuses? pull out and put back.
Does this have ETM? If it connector gets loosy your CAN Bus might crash (unlike on P2.. the P80 CDM aka CEM aka DIM aka instrument panel doesnt give a damn show signs) as CAN Bus end resistors are there if i remember right. So ECM drops connection etc.. Did you see visually any signs anywhere when stalled originally?
Has it been checked that you can contact all ECUs in the car and they dont have any messages left from original stall?

[Eliotlm]

IMMO yes doesnt cut engine after its given greenlight start (it sends special message to ECM to cut at cranking if ever).. but you can get (not correct) error message of IMMO not having contact with ECM or vice versa due whel engine cuts there might happen conditions where you still get error of IMMO not getting message from ECM or so but thats in these cases to ignore as even this forum had such case where faulty pump caused those to come.

My 850 did stall on similar place due fuel pump once.

Is there any different signs at cranking.. sounds any different?

Engine is quite basic in the end. Fuel, air and spark. I would as you if it struggles to start or sounds wierd like fighting against starting to check all spark components. Specially start from distributor as no start.

Edit: As its easy on these cars.. was fuel pressure measured? On my 850 before start there is some 1 bar something but when after crank it goes 2-3 bar. I did replace fuel filter recently thinking it was blocked. On Older cars electronical contacts might be crusty.. its not up to maker honestly i seen on all cars similarly happen.
Never touched fuses? pull out and put back.
Does this have ETM? If it connector gets loosy your CAN Bus might crash (unlike on P2.. the P80 CDM aka CEM aka DIM aka instrument panel doesnt give a damn show signs) as CAN Bus end resistors are there if i remember right. So ECM drops connection etc.. Did you see visually any signs anywhere when stalled originally?
Has it been checked that you can contact all ECUs in the car and they dont have any messages left from original stall?

Thank you for the response. I haven't had a chance to look at the car since it broken down but I will check The connections and fuel pressure asap before i replace a fuel pump. The car sounded like normal while cranking and according to The mechanic it also ran Great.

[scot850]

An antenna ring should not cut the power I believe. It is more likely the electrical portion of the key that is worn that would cause that. I've know this to be an issue where key rings have a lot of additional keys on them when they get worn they can cause the electrical section to move and shut off. Rare though.

The fuel relay is the first thing to check. Be careful of aftermarket ones as most are garbage. Mr. Al did a repair process for the relay using the original and replacing a few components. It has worked well since he did that. I'll see if I can find it and link it here for you to look at.

viewtopic.php?t=101095&hilit=fuel+pump+relay

Good luck!

Neil.

[Eliotlm]

An antenna ring should not cut the power I believe. It is more likely the electrical portion of the key that is worn that would cause that. I've know this to be an issue where key rings have a lot of additional keys on them when they get worn they can cause the electrical section to move and shut off. Rare though.

The fuel relay is the first thing to check. Be careful of aftermarket ones as most are garbage. Mr. Al did a repair process for the relay using the original and replacing a few components. It has worked well since he did that. I'll see if I can find it and link it here for you to look at.

viewtopic.php?t=101095&hilit=fuel+pump+relay

Good luck!

Neil.

Thank you, I believe The mechanic ordered oem but i am not completely sure. I have two keys, one doesnt want unlock The car despite new batteriets and no visible damage and The other works. Is it hard to get new keys?

[scot850]

Keys can be bought, but remember programming is needed as they have a chip. Good used fobs are also hard to find.

I just had an issue with my aftermarket system when one fob stopped working. They are rechargeable fobs, and as we don't use the car over winter we forget to check the charge on them. One had gone so flat that when recharged it would not work. Fortunately it could be re-sync'd to the system easily. No idea if this this can happen to the OE one. It is worth checking the contacts are clean and making sure the contacts are making good contact with the battery. Carefully bend the contact upwards to ensure it is doing it's job.

Neil.

[Eliotlm]

Keys can be bought, but remember programming is needed as they have a chip. Good used fobs are also hard to find.

I just had an issue with my aftermarket system when one fob stopped working. They are rechargeable fobs, and as we don't use the car over winter we forget to check the charge on them. One had gone so flat that when recharged it would not work. Fortunately it could be re-sync'd to the system easily. No idea if this this can happen to the OE one. It is worth checking the contacts are clean and making sure the contacts are making good contact with the battery. Carefully bend the contact upwards to ensure it is doing it's job.

Neil.

Thank you! I just updated the post with some more info. Does that give you any more insight to what it could be or do you still think it could be the same thing?

[scot850]

I would suggest if you are getting a smell of fuel you need to get under the car and follow the fuel pipes and see if you can see any signs of fuel leaking around. I'd focus on the fuel tank area. It takes a bit of work, but you may want to remove the access panel for the fuel pump behind the rear seat. You might have to remove the panel on the floor behind the rear seat to get to it. I can't recall if you have to on a FWD car. You do on an AWD. Have a good look in there and see if you can see any signs of fuel leaking around the visible part of the top of the tank. I would however, suggest the symptoms sound like it may be a failing fuel pump. As it warms up the pump starts to fail. Did the repair shop not check the fuel pressure at the fuel rail after fitting the relay? On your car it should be around 55 psi but around 50 psi is ok

Earlier cars were around 43 psi.

I'm giving both values as being a European market car, I'm not sure if a 99 is actually a 99 or like here a August 98- car is a 99. For us the fuel pressure changed in the 99 model year.

How full is your fuel tank when:

a) you get the failing pump? - If you have >1/4 tank your fuel pump should be submerged and the fuel will help cool the pump. Less than that it can expose the pump causing it to run hotter.

b) you are getting the fuel smell? If it is all the time then you have a leak somewhere. Now if that is part of this issue or a separate one we will have to find out.

One final question for now. When you fill the tank, to you just fill until the pump cuts off and stop, or do you try to add more?

The 2nd option can cause issues with the carbon filter and flood it. That can cause issues with fueling, but also fuel getting pushed out the vent on the top of the fuel pipe at the filler.

Neil.

[jmartin919]

This is what ChapGPT says:

Based on your description, it seems like the stalling issue could be related to the fuel delivery system or a component affecting engine management. Here are some potential areas to check, based on my experience with Volvos:

1. Fuel Pump or Fuel Pump Relay:
Symptoms: Intermittent stalling, especially when the engine has been running for a while, is often caused by a failing fuel pump or fuel pump relay. The fuel pump may not be delivering enough fuel pressure under load, even though fuel is present in the rail.
Diagnosis: The fuel pump relay can intermittently fail as it heats up, leading to the stall. A quick test is to bypass the relay (if you're comfortable) or to swap it with another known good relay from a similar circuit.
Check fuel pressure: A fuel pressure test at the rail while the engine is running can confirm whether the pump is providing consistent pressure.
2. Evaporative Emission (EVAP) System Issue:
Symptoms: Difficulty starting after refueling can often be linked to the EVAP system. A malfunction in the purge valve or other components can cause a vacuum lock or improper venting, affecting fuel flow.
Fuel smell: If there's a fuel smell after driving, it could be a sign of a fuel vapor leak, which may also be related to the EVAP system.
Check: Inspect the EVAP purge valve and hoses for blockages or leaks.
3. Mass Air Flow (MAF) Sensor:
Symptoms: If the MAF sensor is malfunctioning, it can cause erratic air-fuel mixture readings, leading to stalling and hard starting. While not always triggering an error code, an aging MAF sensor can produce intermittent issues.
Diagnosis: You can try unplugging the MAF sensor to see if the car runs better without it temporarily. If it does, the MAF may be faulty.
4. Crankshaft Position Sensor:
Symptoms: A failing crankshaft position sensor often causes stalling when the engine heats up. It can lead to intermittent issues without setting off codes, as the sensor's signal can degrade over time.
Diagnosis: If you have access to live data on your scanner, check if the RPMs drop to zero just before the stall. This could indicate a crank sensor failure.
5. Fuel Tank Venting Issue (Check Valve or Charcoal Canister):
Symptoms: Difficulty starting after refueling and occasional fuel smells may indicate a venting issue in the fuel system. If the fuel tank is not venting properly, it could cause vapor lock or pressure issues.
Diagnosis: Check the fuel tank vent and the charcoal canister for blockages.
Suggested Next Steps:
Check fuel pressure while the car is running to rule out the pump.
Inspect the EVAP system for blockages or leaks.
Test the crankshaft position sensor and MAF sensor.
Inspect fuel system components (fuel lines, charcoal canister, etc.) for leaks that could explain the fuel smell.

[coop]

Have you checked the battery and cables. The last time I had issues like that i needed to replace the battery.