97 850 GLT crank no start after very cold temps

Post by **mkc1** » 06 Feb 2023, 17:10

Hi,
We had a very cold snap a few days ago with temps around -33C (around -27F). Since then my 850 cranks but refuses to start. I thought the fuel pump relay might've gone or there might be some frozen water in the fuel, but there's fuel pressure at the schrader valve on the fuel rail, so I think it's getting fuel. I've read of intercoolers freezing and starving the engine of air, but there's no indication of the hose from the intercooler to the throttle collapsing when cranking, so I don't think it's that. Next I thought of spark. Removing the coil wire from the distributor cap and holding it next to a nut on the strut tower whilst cranking produces a somewhat weak and orange spark, but there is spark. Any suggestions of what might be likely to have been damaged due to the cold? ECT sensor? Camshaft position sensor? Coil damaged even though it's still producing a spark? I pulled codes and got P0455 (Evap large leak) which was there before, and P0133 (O2 sensor circuit slow response bank 1 sensor 1) which I'm thinking is more of an effect than the cause of the crank-no-start. Ideas welcome.
Thanks!

Post by **scot850** » 06 Feb 2023, 18:46

Do you have anywhere you can get the car under cover and heated or out of direct blowing cold?

Does your car have a block heater and if so have you used it?

Neil.

Post by **BEJinFbk** » 06 Feb 2023, 18:53

How fast is it turning over?
What's your resting battery voltage?
What's your cranking battery voltage?
Have you got a block heater?
Any codes?

WhatAmIDoing · Post by **WhatAmIDoing** » 06 Feb 2023, 19:03

What's you battery voltage at? Check for corrosion on the battery connections and engine grounds. The cold will increase resistance of poor connections. Test the ECT sensor. Possibly cam position sensor, but it should throw a code. Mine went bad last winter in the cold. Would still be suspicious of the fuel pump relay. Jump it out just to rule out the easy fix.

Post by **jreed** » 07 Feb 2023, 05:11

Moved down to NC a while ago in part to escape the cold, but when I lived in CT we once had a super cold (for me at least) spell of about a week at around 0F (about -20C) and after that my car would crank but not start for a couple of days. I heated up the fuel filter with a hair dryer -- enough heat to get it warm to the touch -- and that got the car to start. I later added IPA drygas to the tank to absorb the water and also replaced the fuel filter in case the icing and thawing had damaged it.

Post by **mkc1** » 07 Feb 2023, 07:25

Thanks for the suggestions/questions. The car is under a carport, but I'm not able to get it anywhere heated. No block heater. Resting battery voltage is around 13V. Seems to crank pretty normally for a while but then starts sounding weak after a few attempts, so I put the trickle charger back on it and leave it for a while and/or use a jump pack that is kept charged inside. Not sure what the cranking voltage is...will try later today when it's warmer, but I'm thinking the use of the jump pack probably mostly eliminates battery problems? Codes were stated in the original post -- P0455 which was pre-existing and P0133, which I think I've seen before in crank-no-start conditions so I'm thinking it's more of a result than the cause of the crank-no-start.

How do you suggest testing the ECT sensor? Put it in hot water and observe the change in resistance? The behaviour is somewhat like it was when the sensor was bad a few years ago...but then it's also not unlike when it was lawnmowered or when the ignition coil was bad.

Thanks for the idea of heating the fuel filter with a hair dryer. I've thought of applying heat somewhere but wasn't sure if near the engine or further back made more sense. I was thinking that getting fuel under pressure from the schrader valve on the fuel rail kind of eliminated fuel problems, but I haven't measured the pressure. It does build back up again after I've drained it and then turned the key on though, so it seems good as best I can tell without actually measuring. I might try the hairdryer trick and/or jump the fuel relay when it's a bit warmer out. It's supposed to get a few degrees above freezing today so maybe that'll help.

I might try swapping the camshaft position sensor over from the parts car, but parts from it haven't been terribly reliable (the coil died not long after I installed it) so if it doesn't work, that still doesn't rule out the CPS. Guess I could try measuring the resistance at the pins.

Thanks again!

Post by **abscate** » 07 Feb 2023, 16:40

Weak orange spark is no good. Has to be bright white or blue. These are high compression engines and need a flame

Your battery is probably tired. If it’s over three years old, in -27F , it probably wint cut it. Take out and charge fir 24 hours on a 6 amp charger in warmth

Post by **scot850** » 07 Feb 2023, 16:59

At those temperatures, when you are running probably every electrical option, (heated seats, heater fan on full, headlights, radio and possibly heated mirrors and rear windshield heater) if you don't run a good distance, then you are possibly running the battery down faster than it is charging. Once it gets cold the battery can freeze and charge deplete even faster.

That is when you really need a block heater or oil pan heater, possibly a battery blanket (these can be heated). All these help get the engine up to temperature quicker and less load/drain on the battery. As Abscate's daughter found out short runs to work drained even a healthy charging system and battery. She now uses a battery tender at least once a week to top the battery back up.

I recently bought a 1200A jump pack for those times we might go out and can't plug in the block heater. Fits in the glove box. If you can borrow a jump pack for those really cold days, may be worth seeing if the car then starts well.

Neil.

Post by **mkc1** » 08 Feb 2023, 12:06

As mentioned I am using a jump pack. It's above freezing here today so I made a few more efforts. Replaced the fuel injection relay and cam position sensor from the parts car. I had high hopes for the cam position sensor since the plug on the old one was melted into the socket. Hasn't made a lot of difference though. Here's a video of a spark plug firing after the changes. Thoughts?

WhatAmIDoing · Post by **WhatAmIDoing** » 08 Feb 2023, 18:08

mkc1 wrote: ↑08 Feb 2023, 12:06 As mentioned I am using a jump pack. It's above freezing here today so I made a few more efforts. Replaced the fuel injection relay and cam position sensor from the parts car. I had high hopes for the cam position sensor since the plug on the old one was melted into the socket. Hasn't made a lot of difference though. Here's a video of a spark plug firing after the changes. Thoughts?

Definitely weak spark. That plug looks really fouled. Do you have a clean / new plug to test? How old are the plugs, wires, cap, and rotor? Bad grounds / corroded B+ cable can't be ruled out either.