99 7.3 won't start in cold weather

[Johnpec]

I have a 99 7.3 that when the weather gets down to about 30 it's starts hard and below that temp it sometimes won't start at all. It will if I plug it in though but it should start at 30 without being plugged in. I recent put injectors and glow plugs and relays thinking that would solve everything and it didn't. Trust me it does run great after that but the cold start it still an issue. My mechanic mentioned to me about a stuck ring but never checked it or did a compression test. Would that even be an issue? I'm stumped! If there is anything else I can check advice would be greatly appreciated. It starts and runs perfect in the summer. I know the batteries are getting a little weak too but I had new ones in there before and it still did it cuz I heard that your batteries have to be good to run the glow plugs. I heard so much stuff but was wondering if someone out there has had the same issues

[OKANE1]

Do a compression test on engine when you experience the weather conditions.Your mechanic is probally right.Cold retracts metal, heat expands.How many miles and how long have you owned the vehicle etc..

[suzanv]

A faulty ECT can be the problem. If you disconnect it it should start with extra fuel.

[scadamso]

well, if your glowplugs and relay have been done, and they have been tested to ensure they are still good, I would say next step is the check your valve cover gasket and check your electrical plugs on them. I would be willing to bet that you may have a GP or two that are not working.

[Brian Wynn]

I have the exact same problem you are describing. I have a 2000 E450 7.3. Did you ever figure your's out? If so what was the problem?