86 XT hard starting at certain temperatures

[zooeyhall]

I have an 86 XT 1.8 non-turbon MPFI that is giving me fits. I
overhauled the engine 2 years ago, and everything has been working
fine, until lately when I have been having trouble getting it started
in the mornings. I have to crank and crank and finally one cylinder
will kick in and then gradually the engine comes up. Once it is up and
running it runs ok, no driveability problems, and I can restart with no
problems. It seems like the issue is related to the outside
temperature, and it seems to have a pattern where if the weather is
very warm (+90) it starts ok, but around 70 or so (like in the morning)
I have the problem.

The ECS light doesn't come on, and it doesn't flash a code. I ran
through the ECS diagnostic program that is described in my Subaru
factory repair manual, but it says everything is ok.

Checked the compression on each cylinder and it seems ok.

I checked if it was getting a spark when it wouldn't start, and it was
so the ignition seems to be ok.

Can someone give some advice on how to troubleshoot this problem?
Thanks so much in advance for any help!

 

[jb]

Can someone give some advice on how to troubleshoot this problem?

Thanks so much in advance for any help!

NFI, but try running a tank or three of premium petrol with an octane
booster / cleaner additive through the system. Should clear out some carbon
deposits and help with the cold starts as the fuel is more volatile.

-mark