tested them by attaching each in turn to a Batt chgr and all glowed
red hot
at the tip within ~12 sec. from the chart in the book that's pretty
good -
of course, they're all only about 4 weeks old.
That sounds good. A plug can still get hot yet draw out-of-spec
current, possibly enough to PO the GP relay. But if all five acted
exactly the same the chances of this are lessened.
Ok, the relay was replaced 4 weeks ago also after it failed to light
up the
GPs one night when my wife wanted to come home. A new replay gets the
GPs
to light but the light goes out within 1 sec (about 1/5 sec) and it
feels
like only 4 GPs are preglowing.
The light is hooked to a temperature-sensitive timer. The GP's are
hooked to a _different_ timer. They have nothing to do with each other,
except that both are started with the key. If all five GP's do not
heat up, and stay heating for something like 90+ seconds before
automatically cutting off, then the GP relay is defective.
With good GP's, if the light does not obey the ambient temperature/time
curve that's in the (some, anyway) manuals, then it is defective.
I don't know what you mean about the 'feel' of 4 GP's.
What do you think? Should I just button things up?
If we have definitively diagnosed the relay, yes. Unless you want
to dive into the relay's guts to try to repair it. Bad for warrantee
issues, and you risk making things worse too. If you still have your
old one, of course...
There was a TSB about cycling a preglow relay that exhibited
foreshortened intervals about 10-12 times in a row (turn on the glow
plugs and allow them to remain on until the relay cut off - and repeat
10-12 times - will likley run the battery down, but MAY revive the
relay
and timing MAY return to normal). This TSB (early/mid '80s as I
recall)
referred to new and used preglow relays that exhibited short timing
intervals after being stored and not used for months or years.
This is SOP for reforming an electrolytic capacitor, since the days
of vacuum tubes. It doesn't always work, of course, but is worth
a try. To save your battery just unplug the GP harness. The timers
should still do their cycling, which should do any possible reformation
during that time.
To _really_ reform a cap, you need to take it out of circuit.
At that point, of course, you'd just replace it.
-- Jim
