1998 S70 Stalls when hot outside

Cherries22 · Post by **Cherries22** » 18 Jun 2015, 17:57

I have been using this site for years to get advice and I have finally found a problem that I have yet to solve. For the last month my car has been stalling out every time the temperature gets above 85° outside. I have been chasing this for some time and will try to include everything that has occurred. (sorry for the length)

First stall - Was on a road trip going up a steep grade, car was hesitating so roughly that it was more like bucking. Car eventually lost all engine power and would not restart for several minutes. When I got it restarted it was idling very rough and would not move forward. Temp outside was 92°. Towed car to the closest open shop. Once we arrived there it had cooled down to 80° and the car started right up with no issues. I had the shop run a diagnostic test on the car, since it did not throw any codes. They diagnosed a faulty MAF. I did the repair myself and was able to continue my trip and make it home with no issues. The temperature outside was in the high 70s for the rest of the trip.

Second Stall - Two weeks later I was running errands and midday and 90°, the car bucked and stalled out again. The only MAF i could buy the first time was refurbished and I figured I got a bad one. I unplugged it and the car would idle fine, but would not drive. Still no codes. I ended up walking home and decided to give the car some time before I started it again. I went back at dusk and she started right up and drove home with no issues. I swapped out the MAF for another refurb hoping that would resolve the issue.

Third Stall - Two days later I was doing okay with the second MAF and drove to work with no issues. It was 95° when I got off work and I got about two miles from work before it stalled out again. This time it did not buck, but still hesitated and then I was able to coast to a stop. Again I came back at night and the car started back up and made it home. I tried and tried to get the issue to repeat at night and the car just runs perfectly.

At this point I was done with refurbs and bought an OEM MAF that was used, but known to be good. I read on one of the forums here that it helps to disconnect the battery when replacing the MAF, so I gave that a try. When I hooked the battery back up I finally got my first code. It pointed to the front temperature sensor (the blue one on the passenger side) and I replaced that the same day. After I replaced the sensor the light went off.

Fourth Stall - The next day it stalled out again when test driving in during the heat of the day. Again, I waited until night and it drove straight home. I was letting it idle at home in the heat to see what would happen and got my second code. This time it was a misfire and I checked the plug indicated and it looked burnt out, so I just replaced everything. No plugs were covered in oil or anything and I was hoping that if it was the coil or fuel injectors or something else on that path that the light would still be on. No luck. After the plugs were replaced the code went away, but I wasn't confident that I had solved the problem. I took out the fuel pump relay to test if that was the culprit. I hooked it up to 12 volts and could not hear a click from it turning on. I took it to work where there are a few EEs and they were 100% confident that it was faulty. I replaced the relay.

Fifth Stall - When testing again during the heat of the day after the relay was replaced it stalled again. This time it did not buck or hesitate, it just lost power to the engine and would not move again until night. After this I took out the throttle body and cleaned it. It didn't seem that dirty, but at this point I was grasping at straws.

Sixth Stall - I ended up taking it to my Volvo mechanic yesterday and explained all the issues to him and asked him to drive it around when it was hot outside and test the cam position sensor the o2 sensors and to look for vacuum leaks. He could not get the problem to repeat and on my way home from the shop it died again. It was 85° outside and again after dark I had no issues.

Where do I go from here? I feel like I am just stabbing in the dark with no codes. The next places I am looking at chasing are the ignition coil, the fuel pump (I am not sure on this one, but this is what the mechanic suggested) and the computer. The Volvo dealer will reset the computer for $130, which isn't that bad, but I would prefer to know with some level of certainty before I sink any more money into this problem.

Any suggestions are welcome

Post by **abscate** » 19 Jun 2015, 04:19

You can diagnose the fuel pump by monitoring the fuel pressure on the rail next time it gets hot. It should be 50 psi, not 30 psi or less with a good fuel pump.

I would try replacing the coil with a new one. They can fail when iffy and be temperamental.

Other candidates are crank and cam sensor. Use PnP parts for these.

How old and what brand are cap rotor and wires?

Not sure what a computer reset is. The ECU resets each time the battery is disconnected, I only charge 90 to do that, plus travel...

It's definitely one of these....you are so close, due to a good troubleshooting protocol, well done

Post by **Ozark Lee** » 19 Jun 2015, 07:55

Tell us a bit more about the car.

Is this a turbo or a N/A? Which engine do you have 2.3T, 2.4T, or 2.4 NA?

How is the temperature gauge behaving? Does the gauge go to the 3:00 position and stay pegged there?

Do you happen to have a list of the codes that you have retrieved, the code numbers specifically? If you do have the code numbers please tell us at what point n this process they popped up. I'm sure that you set a MAF code after you started the car with the MAF unplugged so it is useful to know things like that.

Lastly, any other observations like the cooling fan running on and whether or not the A/C is on when these things occur can be helpful.

...Lee

Cherries22 · Post by **Cherries22** » 19 Jun 2015, 16:49

Temperature gauge rides right at about where it always rides, cooling fan kicks on as needed. It is the 2.4T. P0302 and P0112. I am absolutely positive that the P0302 was solved when I replaced the spark plugs. The gap on the plug from cylinder 2 was nearly .85! Well over twice the gap, the electrode was nearly burnt to the porcelain. In regards to the P0112, we found that the temperature sensor had been torn off. It was the passenger side one, not sure how it happened honestly. We found one at a Pull and Save and replaced it.

Neither code trips, and when the car dies nothing trips.

Cherries22 · Post by **Cherries22** » 19 Jun 2015, 16:57

I'll check the fuel rail and I'll take a gander at the coil and let you know what's in it exactly. Our mechanic ran a diagnostic on the cam and crank sensors, both checked out.

I misspoke about resetting the computer. I meant reprogramming it. Volvo said that they've had periodic programming changes. Those are considered periodic maintenance rather than issues on their end and provided free of service.

Post by **abscate** » 20 Jun 2015, 06:26

Cherries22 wrote:Temperature gauge rides right at about where it always rides, cooling fan kicks on as needed. It is the 2.4T. P0302 and P0112. I am absolutely positive that the P0302 was solved when I replaced the spark plugs. The gap on the plug from cylinder 2 was nearly .85! Well over twice the gap, the electrode was nearly burnt to the porcelain. In regards to the P0112, we found that the temperature sensor had been torn off. It was the passenger side one, not sure how it happened honestly. We found one at a Pull and Save and replaced it.

Neither code trips, and when the car dies nothing trips.

h

Still wondering about cap rotor and spark plug wires. It sounds like those plugs had mega miles on them to have an 085 gap!!

Cherries22 · Post by **Cherries22** » 21 Jun 2015, 11:46

Cap rotor is Bosch. Spark plug wires say 'Volvo Bougicord Class C-1'. About 5 years ago, the distributor cap was replaced. Don't remember if the wires were changed at the same time.

When I had my mechanic look at it, he pointed something really odd out. There was a secondary inline fuel pump put in the system... It had to have been there since I bought the car, I never got close enough to it to realize it was a pump, I was always under the impression that someone thought a second filter was needed. Really weird. He suggested that we restore the fuel system back to original. Had my mechanic order me a replacement in-tank fuel pump. Professional Parts Sweden fuel pump. We replaced the original fuel pump and pulled the secondary one out, it was between the filter and evaporator. The fuel pump inside the tank must've been shot.

To test the car, it was driven for about 35 miles. While at a grocery store, it was left idling and the AC was on. To check what the clicking was that I was hearing(AC pump relay opening and closing) I turned it off. The car threw 2 codes exactly at the same time as I shut it off. P0455 and P0410. Are they something that I need to worry about?

Post by **Ozark Lee** » 21 Jun 2015, 12:46

Stuff like that is what makes our jobs (amateur guessers) so tough. It never dawned on me to ask about the additional inline fuel pump. I'm pretty shocked that the inline pump worked at all, electric fuel pumps are good at pushing fuel but they are terrible at trying to suck it. The kink in the fuel line on the in-tank pump wasn't helping things either.

The P0455 is an evap code, it doesn't hurt performance in any way and it is a nuisance. It could be that the gasket on the fuel pump nut isn't sealing tight so pay attention at your first fill up to make sure that fuel isn't leaking out of the top of the tank.

The P0410 is a SAS code. If this is the first time you have had it just clear it and see if it comes back. If it does we have a trick in the repair database that tricks the system into thinking the SAS is working fine and you can just get rid of it.

...Lee

Cherries22 · Post by **Cherries22** » 21 Jun 2015, 14:11

Both pumps were operating in tandem. Whoever put the in-line pump in ran off of the positive and negative leads going to the in-tank pump. So, one was pushing to the other, the other was both pulling and pushing at the same time. It is extremely odd that anyone wouldn't have fixed it right from the start. I cannot fathom why someone decided to do it.

Ozark Lee wrote:Stuff like that is what makes our jobs (amateur guessers) so tough. It never dawned on me to ask about the additional inline fuel pump. I'm pretty socked that the inline pump worked at all, electric fuel pumps are good at pushing fuel but they are terrible at trying to suck it. The kink in the fuel line on the in-tank pump wasn't helping things either.

The P0455 is an evap code, it doesn't hurt performance in any way and it is a nuisance. It could be that the gasket on the fuel pump nut isn't sealing tight so pay attention at your first fill up to make sure that fuel isn't leaking out of the top of the tank.

The P0410 is a SAS code. If this is the first time you have had it just clear it and see if it comes back. If it does we have a trick in the repair database that tricks the system into thinking the SAS is working fine and you can just get rid of it.

...Lee

Post by **abscate** » 22 Jun 2015, 04:13

Those splices were sitting bathed in fuel in the in-tank pump?

Yikes !

Buy a lottery ticket this morning...

Fixes like that do make diagnosis tough. They also speak to a certain lack of awareness on PO or mechanics part.

I don't recall ignition parts life for your model but I think it is about 30000 miles for standard parts.