95' 854 GLT - Low Power and stalling

fredt2 · Post by **fredt2** » 21 Apr 2023, 16:13

Hello everyone,

120k miles on my 95 glt, one week ago the car starting to run weirdly, with symptoms as follows:
Rough idling and very low power, the car used to live up pretty easily, with nice mid low torque, now it feels like I truck, having to push the pedal all the way down for it to rev some.
This morning it stalled 4 times in my 5mi commute to work, 3 of those while reversing out of my garage.
Here's what I've already tested and dismissed as cause:
-Already run the car with MAF unplugged, didn't change anything.
-Fixed the stuck flap on the airbox
-Checked the fuel line for leaks and cramps
-Spare fuel pump relay didn't help it

The engine revs freely when parked, only hesitates when driving.
Have yet to try to start the car with the o2 sensor unplugged, is this a good way to test if it's malfunctioning?
Also, as the car is running rough and stalling parked, I really doubt it's the tranny slipping.
I have a decent amount of time spent in this car, but never had anything like that, any help will be appreciated!

fredt2 · Post by **fredt2** » 21 Apr 2023, 16:59

Update: took the o2 sensor out and still the same.
Officially out of clues

Post by **matthew1** » 21 Apr 2023, 17:21

Check fuel pressure (42 psi), airbox and filter, spark plugs and spark plug gap (.028 inch).

fredt2 · Post by **fredt2** » 21 Apr 2023, 17:41

Fuel pressure is nominal and pump seems to be working fine.
I think it could be the battery, these issues started just when the temp here went from 25°c to about 10°c in the morning(77°F to 50)
Voltmeter reads about 11,5v with the car off and lights on

Post by **Sveedy** » 21 Apr 2023, 18:17

I was thinking a vacuum leak, but when you mentioned the temperature being a factor, coolant temp sensor is what I'm leaning toward.

Post by **abscate** » 22 Apr 2023, 01:10

fredt2 wrote: ↑21 Apr 2023, 17:41 Fuel pressure is nominal and pump seems to be working fine.
I think it could be the battery, these issues started just when the temp here went from 25°c to about 10°c in the morning(77°F to 50)
Voltmeter reads about 11,5v with the car off and lights on

That’s a dead battery!

fredt2 · Post by **fredt2** » 22 Apr 2023, 03:49

Well, thanks for the advice, i'll try to start the car with the temp unpplugged, see if It makes any difference, if not, then it's prob the battery.

Post by **scot850** » 22 Apr 2023, 12:07

As you mention, check the coolant temp sensor (ECT) by the thermostat. Also check it's connector by the power steering pump. Replacement we only recommend Volvo OE or Vernet ? (OE supplier) but that is not available in North America. The connector and the wiring there are known issues for corrosion. There are readings for testing the ECT on the website using resistance values and ambient temperature.

Neil.

fredt2 · Post by **fredt2** » 22 Apr 2023, 15:08

Checked the thermostat, unpplugged it and the car ran the same way, so I doubt it's the problem. Also the connector seems fine, both ends are in good shape, sprayed some contact cleaner on it too.

Post by **scot850** » 22 Apr 2023, 16:41

That does not prove it is good. The ECU needs a signal to set parameters. You need to measure the resistance in the unit at ambient temperature (engine cold) to see if it is good. It is a pain to remove to check it over a range of temperatures as you need to remove it to do that.

When was the fuel filter last changed? Have you checked the fuel pressure as suggested?

Even though it is a non-turbo, you need to check all the vacuum lines are good.

When was the distributor cap last changed along with the rotor, plug leads and spark plugs? Have the plugs been gapped to 0.028"?

Neil.