[V8] Low idle

Ed Kellock ekellock at adelphia.net
Fri May 14 13:47:13 EDT 2004

I believe 600 rpm is normal correct idle for these cars.
Check the emissions sticker under the hood (?).

My car exhibits about a 1200 rpm idle now among other
things.  I also have some engine cutting out behavior after
starting until everything warms up fully.  It's not a
single cylinder, it's feels like a full ignition lapse for
just a moment.  Anyway, I have suspected those two sensors
ever since I ran a ground wire for my 4-wire OXS.

I found a bolt on the very back and top of the block under
the lower air intake box.  The bolt seems to attach a
bracket for the cc diagphram.  Anyway, I loosened it and
sprayed a lot of carb cleaner followed by brake cleaner
down there to clean any corrosion and used that bolt for my
OXS ground so it was grounded directly to the engine block.

The car ran amazingly better immediately after that and not
just in ways that could be contributed to the OXS.  Cold
starts had been very poor for a while and they were almost
immediately restored to normal.  

My theory is that I cleaned the sensors down there with all
the carb and brake cleaner.  My dist seals are leaking
pretty good and I believe engine oil had fouled the sensors
somewhat.  Further proof of this is that in the 2-3 months
since the "cleaning", the poor running characteristics I
experienced before have slowly and increasingly returned.
I'm going to do another "cleaning" this weekend and I'll
report again later.  

Joel, I think you have solved your idle and rough running
issues and your 600 rpm idle is normal and I believe you
have also shown me that either my reference sensors are
flakey or I should get off my a$$ and replace those dist
seals once and for all.


P.S.  Hi Bill!

From: QuickAudi at aol.com
Date: 2004/05/13 Thu PM 03:16:10 MDT
To: v8 at audifans.com
CC: pavwdoc at hotmail.com
Subject: [V8] Low idle

Ok guys, my idle is really messing with me lately.  143k on the '90 V8q.  At startup before, it was a high idle, around 1200 or so.  Now, it is a low idle, around 600 or so.  I am not sure if it got that way after I had the two engine sensors replaced or at some random point afterwards.  Could the sensors being corroded or loose or put back on the wrong wire make this problem occur?  If not, what else causes a weird idle?  My idle control valve is clean and fine and working, according to VAG-COM.  Oh yeah, no codes, either.  Vacuum leak?  Where would I start checking?  I notice that when I leave it idling that it seems to run rich, or maybe it's just my imagination.  
On the list to replace is the plug wires, distributor cap/rotor, maybe the MAF, might remove the K&N.  Any thoughts?


'90 V8q
'86 5kcstq
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