94 850 Turbo no start after sitting dormant for 6 months.

Hiwatt Scott · Post by **Hiwatt Scott** » 16 Jan 2023, 09:34

Hi, folks. Last summer my 94 850 turbo wagon burnt a valve. I parked the car and took it about 6 months for me to get the head off, rebuilt, and reinstalled. During this time the battery was out of the car. Once I got it back together, the car turns over but has no spark, even from the coil. Oddly enough, once you attempt to start it once, the cooling fan comes on and won't turn off without disconnecting the battery.
Barring the obvious such as a broken wire somewhere or something I forgot to connect, is there anything (possibly Volvo specific) related to an 850 sitting dormant with no battery for an extended period that would cause this condition? The only electrical things I disturbed were the pieces directly related to head removal (distributor, cam sensor, etc.)

Thanks for any input!

Hiwatt Scott · Post by **Hiwatt Scott** » 16 Jan 2023, 14:24

Update: turns out the car probably kinda needs the crank sensor plugged in. Found it lying under the bottom radiator hose. Turns out these connectors aren't as unique as I thought. Still working on getting the other connectors where they need to be.

Post by **volvolugnut** » 16 Jan 2023, 15:37

Battery fully charged?
Cranking is not always proof of proper voltage for Volvos.
volvolugnut

Hiwatt Scott · Post by **Hiwatt Scott** » 16 Jan 2023, 15:58

Update 2: Got it running. Fan still stays on, though. I won't worry about that today. I'll worry about that tomorrow.

Post by **scot850** » 16 Jan 2023, 18:45

The fan relay on top of the radiator may be corroded at it's contact wires or just gone bad with sitting. Carefully remove it and check the connections and wires.

Neil.

Post by **Chuck W** » 16 Jan 2023, 19:53

Hiwatt Scott wrote: ↑16 Jan 2023, 15:58 Update 2: Got it running. Fan still stays on, though. I won't worry about that today. I'll worry about that tomorrow.

There enough coolant in it?

The fan running constantly is also a potential sign that the ECT sensor is bad. Perhaps a lack of coolant is causing a bad(dry) read.

Hiwatt Scott · Post by **Hiwatt Scott** » 17 Jan 2023, 09:26

Update #3: After getting it started, I discovered that it wouldn't restart after warming up. Had a hunch that it would restart after cooling down, so I let it sit overnight. Sure enough, it started this morning no problem, but wouldn't restart after getting warm just like yesterday. While it was running, I connected my OBDII dongle to it, and found out the coolant was registering -40 degrees Fahrenheit! Ran the codes and got a P0117 code, denoting a coolant sensor issue. I should note that I discovered yesterday that I hadn't reconnected the temp sensor on the bottom of the thermostat housing. I reconnected it, but I'm not positive it's a good connection (connector is showing it's age). Fan was running randomly today while it was running. So all this points to the car thinking it's at a different temp than it actually is. Will continue to troubleshoot and report back. Thanks to those who have responded!

Post by **scot850** » 17 Jan 2023, 10:01

There are a set of resistance values you can use to check the ECT to see if it is operating as it should v's ambient temperature. Test when engine is cold. Connector at the back of the power steering pump is a known issue with age for failing wires and connector.

We only recommend the OE Volvo part for that. As you know that also controls when the fan comes on and off along with the relay above the radiator.

Neil.

Post by **Chuck W** » 17 Jan 2023, 16:30

The connector itself can be a cause of errors, even if the sensor itself is still "good". I've swapped the stock connector out on both of our cars for a WeatherPak type connector. It means I have to convert any new sensor to that connection, but I no longer have to deal with a rotten stock plug.

Hiwatt Scott · Post by **Hiwatt Scott** » 19 Jan 2023, 04:25

Update #4 (hopefully final for this issue). Went in and made sure I was getting positive connection on the connector. Car began behaving correctly and reading a correct temp via my OBDII dongle. Chuck W, you are quite correct about the connector being lousy. I'll endeavor to get it replaced in the future, but for now I need to attend to getting the car back roadworthy after 6 months. Thanks to everyone who responded! I appreciate the help!