I have an '89 JD 1070. It was in the low 50's the other morning when I went to start my tractor. I wasn't sure if one needs to use the glow plugs at that temp but I figured it wouldn't hurt. When I went to start it, it just rolled over but didn't fire. Now, this tractor ALWAYS starts so I was confused. I let it sit a few minutes and then she started right up. Was I wrong to use the glow plugs or was there possibly another issue?