Like the title says.....I'm sure I have read about this before but I can't find it using the search.

Issue: Son's 1995 Volvo 850 Turbo suddenly won't start. It cranks fine and fires, but won't start. Smells like it is flooded. I tell him let it sit for about a half hour and then I will try it. In the meantime I try to pull the codes. No codes, no check engine light.

I try to start it. It fires but won't catch. I hold the pedal to the floor and keep cranking. After about 20 seconds it sputters a couple times and finally starts. I let my foot off the gas, it instantly dies. Crank the hell out of it for about 45 seconds and it fires and runs with a lot of black smoke (unburned gas) out the tailpipe. I hold my foot on the gas and keep it at about 2500 RPM for a minute then let off. It idles smooth as silk. Revs fine and drops back to idle smoothly.

I let it idle for 10 minutes with no issues so I take it for a spin. It runs absolutely great. Flor it, and it runs like a scalded dog. Then I notice the temperature gauge. It hasn't moved a tick off the cold peg. Try the heater and it is putting out a ton of heat. Check the upper and lower radiator hoses. They are nice and hot too.

I'm thinking one of the sensors is bad, along with possibly the thermostat. I replaced the one sensor that goes under the thermostat about 18 months ago, but it caused different problems then I am seeing now.

Please point me in the right direction

Glenn

 

sounds like a bad ECT sensor.

wait for the experts

 

Sounds like a combo. Bad ECT and maybe collapsed lifters.

 

Can collapsed lifters come on suddenly? The car ran fine yesterday and each day before. It has only sat overnight (12 hours or so)

One thing I do know, the boy put synthetic 20W50 oil in last oil change (about 1500 miles ago) I think it is too thick. Could that cause any issues?? The only difference I noticed once I got it started was the temperature gauge staying on cool.

Lastly, it looks like the back torx bolt on the thermostat housing is pretty buggered up. Any tips on how to get that sucker out if I have issues with it!

Thanks,

Glenn

 

One last question. Would a bad ECT sensor NOT cause a code/check engine light? Last time I had one go bad, it threw a 123 code and check engine light

 

It will not always throw a code.
Try the screw carefully.
I have seen lifters collapse overnight. Then when you try to crank there is no compression and then it floods the motor with gas.

 

I'll try the car again in the morning. I guess I will be ordering an ECT sensor, Thermostat, and other stuff for it. Thanks Tech

Glenn

 

Ok, so I couldn't wait until morning <grin>

I waited until the car was cold and tried to start it. It started pretty hard, but it started and ran kind of rough. I shut it off right away so it wouldn't get hot and then disconnected the ECT connector. Tried starting it up again, and it started right away and ran smoothly. Of course the check engine light came on and the cooling fan started running. Again I shut it off right away before it got warm. I re-connected the ECT sensor, and once again it started hard and ran rough (no cooling fan). Disconnected it again, and it started easy and ran smooth.

Looks like the sensor went over the hill, Don't you think.

 

I'm not one of the experts that you were suggested to wait for... but your test certainly points a finger at the ECT in my opinion. Let us know how it turns out with a new sensor, if that's the route you go.

- Goat

 

agreed...

 

Agreed bad ECT.

 

Parts are on order. I went ahead and ordered a new thermostat as well. Figured "as long as I am in there".....

 

Good plan!

 

Yeah. Why tempt fate. The way my luck runs from time to time, I could just see the thermostat going out 6 weeks after I replace the ECT sensor!

 

Very true!!

 

Replaced the ECT and the thermostat today. Seems to work a lot better. TIme will tell. Temp gauge is at 3 o'clock when warm, just like it should be.

 

Glad it is good now.