Volvo 850 stalls when engine gets warm

Annema1 · Post by **Annema1** » 04 Jan 2017, 13:36

Hello,

My 1995 Volvo 850 (pre-OBDII) has been in a garage for a year now, but this problem started about 3 months into this year. The problem is that when I start the car all is well and it actually starts incredibly fast even with sub 0 temperatures, but when it gets warm about 10 minutes later it will run with what sounds like some sort of misfire. When I give it some gas it will run more smoothly but when I hit the gas too quickly it will sputter and stall if I don't release it. Eventually it will stall and when it does it WON'T start anymore, no matter what I try.

What have I tried so far:
-Checking fuel pressure before and after the stall by pushing the little pin(it squirted out so I think this is good).
-I closed the hot air valve going to the airfilter becasue the airfilter got very hot and this did make my problem occur later, because the engine takes slightly longer to warm up.
-I checked the vacuum lines bij blowing in the vacuum tree with a sigarette and no smoke escaped anywhere.

It is probably good to know that my 850 is equipped with an MAP and temp sensor combination instead of the regular MAF.

I hope anyone has any idea what this might be?

Thanks in advance,
Sergej

Post by **bmdubya1198** » 04 Jan 2017, 14:05

Have you checked for codes? I would suggest the MAF sensor, but that can't be the problem if you don't have one.

Annema1 · Post by **Annema1** » 04 Jan 2017, 14:14

I have the codes right here:
A3: 122, 141, 412, 413, 414, 421, 422, 444.
A7: 113, 122.

The only one of interest to me seems the temperature sensor code, but the temperature on the dashboard gets up to 3 o'clock.

Post by **bmdubya1198** » 05 Jan 2017, 18:00

Well for one you have an issue with your ABS... seems the module isn't getting power. Anyway, that's unrelated.
You might want to look further into the temp sensor, these cars do weird things when those go bad. I bet that is related to this problem.

Annema1 · Post by **Annema1** » 05 Jan 2017, 20:06

Thank you for the tip. Should I just replace it, since it isn't so expensive. If so, should I go for a specific brand or anything?

Sergej

Post by **bmdubya1198** » 06 Jan 2017, 14:50

I'd give it a shot and replace it. Check out this thread as far as brands go: https://www.matthewsvolvosite.com/forums ... hp?t=75308

TheCynicalCanuck · Post by **TheCynicalCanuck** » 06 Jan 2017, 16:01

This sounds pretty similar to my problem with my 95 T-5's engine coolant temperature sensor. I know theres a way you can test your ECT if you have a multimeter and you can find what Ohm's the ECT is supposed to operate at. If you do replace the ECT don't be like me, buy a OEM or Genuine ECT or you'll just end up having the same problem two weeks later.

Annema1 · Post by **Annema1** » 06 Jan 2017, 16:25

Thank you both. I will check the Ohm value's of the ECT and replace it if it's bad. I will report back as soon as possible wether or not it was the ECT. I will go for the Valeo sensor along with the Wahler stat if I end up replacing them.

Sergej

Annema1 · Post by **Annema1** » 07 Jan 2017, 14:49

I checked the ECT and it seems to check out. What I found particularly interresting is that there is a ringing sound coming from the thermostat when I squeeze the thermostat-radiator hose quickly as well as the fact that there seems to move coolant thru the thermostat when the engine is cold. Does this mean it is most likely broken? I would take it apart and see for myself but it is pretty tight on there and I don't have the proper tools right now.

Sergej

Post by **bmdubya1198** » 08 Jan 2017, 08:17

If you have coolant flowing through the engine while it's cold, the thermostat is definitely broken. That is something that needs to be replaced.