My 1995 Volvo 850 turbo will not start in the cold or damp weather. I dont know if it might be sensors or the computer or something. The ignition will crank but it does not start. Eventually after about 15 minutes of trying the car will start. Please give me some advice on what to do with this problem. I am replacing the cap and rotor tommorow so that might help.

 

Try that first and see if that fixes it. Also with the car running in a pretty dark area see if the coil is arking bad.

 

Follow Tech’s advice first.

If it doesn’t work, no-start conditions on the 850s are usually due to:

- Faulty CPS (Cam Position Sensor): Check for spark/trouble code.
- Faulty fuel pump relay
- Faulty fuel pump
- Faulty MAF (Mass Air Flow) sensor
- Faulty neighbor playing some trick on you.....[8D]. Have him/her diagnosed by a doctor.

Pulling trouble codes is a good place to start. See attached. I believe the ’95 models came with both OBD-I & OBD-II. You can use OBD-I with no testers/tools, or you could also visit a local auto parts shop that provides free diagnostic services (AutoZone, etc..).


JPN

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And these cars REALLY require TLC.

FYR: https://volvoforums.com/m_48928/tm.htm

Good luck & let us know how it goes.


JPN

 

I agree, the cap and rotor are most likely the culprit. I once had a Chevy with a small crack in the coil. Started and ran fine except when it was damp or really hot outside. You should have seen the light show from the arcing one night when it wouldn't start.

BTW... Good to see you back JPN!

 

Thanks Glenn, I too am glad to see you all!

I hope jpm2346’s 850 comes back to life soon.


JPN

 

My 1995 850 has stared the firing but not staying running for about 20-25 tries in the cold. I tried for 15 minutes this morning (it was 29 degrees) and it always fired but never caught.
I recently had a complete tune up and it has been running well with the exception of struggling to start in the cold.

Any ideas of what I can do?

 

a few things to check
1) engine coolant temp sensor (located under the thermostat - follow the upper radiator hose. You can measure impedance with a VOM. cold it should measure high resistance (say 3K ohms or more) warm it should measure low (say 300 ohms or less).

2) fuel pump relay, fuel injector relay

3) spark plug gap/temp range are wrong. check plugs for color and regap to .028 - note plug model # and verify as correct.

You didn't say how long it cranks when its a bit warmer - if your car's normal cranking is say 10 seconds or more, then you may have a fuel pump or fuel pressure regulator issue.

 

In warm weather it cranks immediately, like a second or two for sure not 10.

I do not understand this: You can measure impedance with a VOM. cold it should measure high resistance (say 3K ohms or more) warm it should measure low (say 300 ohms or less).

What is a VOM and where would I find one? What are ohms and where do they occur?

 

VOM is short for Volt Ohm Meter, standard equipment for testing electrics. Damn, where's that Radio Shack when you need one? Ohms are the measurement units for electrical resistance (ie the ratio of voltage to current). Most "volt meters" also have a setting where you can also measure resistance. Any hardware store, big box autoparts store, Sears etc would have them - even the $20 kind are good enough. So back to your concern - the engine coolant temp sensor is a common failure item - they run about $50 but you may need to drain some of the coolant and then remove the thermostat cover to access, so most people throw in a new thermostat while doing the job. The question about crack time is a casual test for fuel pressure. Cars with weak fuel pumps or leaking fuel pressure regulators need a bit of extra time to build the right about of fuel pressure for the injectors, thus the longer cranking time. The proper test would be for your mechanic to put a fuel pressure gauge on the schrader valve on the end of the fuel rail to measure before starting the engine and then see where it goes to during cranking and idle. Has the car ever randomly stalled recently but then restarts ok?

 

No problems with the car randomly stalling and then starting. I will get with my mechanic after the holidays. I print out your advice and take it to him.

 

You may also simply need a tune up - wires/distributor cap/ rotor/ plugs as well. most wire sets actually have a date code imprinted on the wires so you can see roughly how old. If they show being manufactured more than 5 years ago, its time... My thinking is you may need a standard tune up or you may need a new engine coolant temp sensor.

 

Had a complete tune up, new spark plugs and wires etc about 3 months ago. so maybe the sensor
.