82 coupe, ran like crap, fixed

[Huw Powell <human@nh.ultranet.com>]

Symptoms: (happened briefly a few weeks ago but microsoft solution
worked...)

Very rough, low idle.  No power at low revs, hard to rev up.  Runs sort
of ok above 3500, still misses and backfires though.  Managed to get me
home.  Freq valve not buzzing.  Suspect ECU ground at intake mfld.

Measurements:

Nothing at duty cycle tap.  OXS running about .3-.4 volts.  No 12v at
frequency valve! (the ECU regulates it's ground connection, it's
*supposed* to have continuous 12v)

Solution:

Check Bentley wiring diagram, 12v at FV comes directly from "OXS power
relay", a DPST relay Bentley says is by the ecu to the right of the
glovebox.  Guess what?  It is.  This relay also powers the ECU.  Fished
past dash speaker crossover and pulled little relay bracket - jump relay
outputs with car idling (I mean stumbling) - car suddenly purrs like a
kitten and I hear the FV start its merry clicking.  Check 12v to relay,
it's there.  Pull relay - tabs are nice and brown (yuck!), relay's
insides are pretty gunked up too.  Pick the best looking spare relay
from parts department... (easy to say on a Sunday afternoon!), clean
socket contacts and install.  Car all better.

Epilogue:

Solved problem by imagining posting to Qlist (virtual virtual
assistants?) and imagining the likely responses from savvy listers...

-- 
Huw Powell

http://www.thebook.com/human-speakers

82 Audi Coupe; 85 Coupe GT
http://www.nh.ultranet.com/~human