I have a Volvo 850, non turbo. Ever since I purchased it a year ago on occassion it wouldn't start. Rolls over but acts like it's flooding itself. So I figured out that if you pump the crap out of it, and hold the gas to the floor after like 4 minutes of cranking it will finally start up and run. It starts extremely hard, but it starts. Well this problem was very intermittent, couldn't figure out anything that was affecting it. That is until today. I changed a headlight yesterday, and this morning it wouldn't start. My wife brought to my attention that everytime I change something electrical it won't start the next day. I couldn't believe it, but she's right. Each time that the starting problem has occured I had worked on something electrical the day before. Do any of you techs have any clue what's causing this? Thank you.

 

I think it is just Ironic.
How long does it usually sit for when it won't start? Like just overnight or for a couple of days?

 

It could be caused by several things. Is the check engine light on? If so, you need to pull the codes and it will point you to what is wrong.A bad coolant temperature sensor could cause this issue as well. When was the last full tune up done?

 

Or every time you change something electrical, your wife is watching you and when you are out of sight, she drains the battery by doing whatever takes and creating an opportunity to talk to you.....

.....[8D].

No, it is just a coincidence.

As Psaboic has already asked, when was the last tune-up? Hard starting may be caused by one or more of following:

- Faulty ECT (Engine Coolant Temp) sensor
- Faulty MAF (Mass Air Flow) sensor
- Faulty CPS (Cam Position Sensor)
- Faulty fuel pump or pump relay
- Neglect, of course
- Etc...

See attached for additional possibilities. Also, see my 1st & 2nd replies at:
https://volvoforums.com/m_48928/tm.htm


I hope our suggestions get you to the right direction.


JPN

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Thanks for the advice fellas. Car was tuned up recently. Only code it throws is "Bad Knock Sensor", which was replaced. Still throws the same code. Fuel pump and relay were also replaced within the last 6 months. This problem is extremely intermittent, happens maybe once every 5 or 6 weeks. The car only ever sits overnight. It's a woman's car, not being on the go is not in their nature.

 

A knock sensor (the ECU, to be accurate) retards the ignition timing and should not cause difficulty in starting in general.

Maybe one of the electrical connections for a sensor(s) is dirty/loose. I assume it could be the CPS starting to go.

When in doubt, go with Tech.


JPN

 

If the knock sensor code is stuck in there and comes back every time after you clear it the ECU might be bad.
I have seen a few ECU's go bad and keep setting the knock sensor code.

But if the car sits for a couple of days before it doesn't start the lifters might be bleeding down.