My 1992 245 has been great and reliable. It starts every time, except when the temperature is below 40F. Last year when it got below 40F I jumpered voltage to fuse #4 and it started instantly. I would like to fix this properly so I don't have to jumper it.

I bought a new fuel pump relay last year and that didn't fix it.

Seems I remember something about a bad solder joint on the ECU effecting this? I haven't been able to find the post.

Any ideas are greatly appreciated as we'll be getting some colder mornings in the next few months. Thanks!

"Seems I remember something about a bad solder joint on the ECU effecting this?"

Does not sound familiar. The hybrid chip issues are all or nothing.

So need a lot more details:

LH 2.4 or 3.1 (if you have an automatic, no need to check...it is 2.4)
You jumpered Voltage to fuse 4 on from?...to which side of the fuse holder?
Any codes?
Have you cleaned the Throttle body lately and adjusted the throttle position switch?And when you say "does not start" it cranks but does not fire at all, correct?
Have done a full fusebox service?

I ask all these questions because Volvos start in the cold...period. In the warm, not as often. This has to be something telling the car you are not at idle, coincidental to the cold or a standard no-start issues that needs the same four things checked.

Yes, it cranks over normally but doesn't fire up until I apply 12v to fuse #4.

It's a LH 2.4.

I jumpered 12v to the left side of fuse #4.

The fuse box connections have been cleaned, and all new fuses installed.

There have been no error codes.

Cleaned the throttle body, but have not adjusted the throttle position switch.

Last year I remember testing several times and if it was 41F and above it would start normally, but 40F and below it never would until I jumpered it.

I have no way of testing it now since it won't be cold for awhile, but would like to fix it before then. Thanks

You sure you aren't affecting the lousy connection by your jumpering technique? Like Onkel said, the hybrid failures have been permanent, not temp affected, and beside that, occurred in ECUs for cars before '92. And, they wouldn't keep it running when you pulled off the jumper. Just for grins, which ECU are you running?
--
Art Benstein near Baltimore

Duct tape is like 'The Force'. It has a light side and a dark side, and it holds the universe together.

Yeah, I am voting poor tension on fuse 6 or 4. It is almost always those fuses, or the alternator ground wire, when folks say they have checked it (or the infamous 25 amp fuse). Not sure why it seems to always be those things except that they are so finicky and easy to mis-diagnose when you are used to "normal" cars.

It's possible I still have a bad connection. I'll try cleaning the connections again.

I don't understand why it only does it below 40F. Just a weird phenomena with a bad connection?

I just connect the jumper for a second or two and it fires. I then remove the jumper and it runs normally.


I'll check to see which ECU I have tomorrow.

Thanks for the info.