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Subject:Re: '88 lurching at 2500-3000 rpm
From:Shawn Wright, SMUS Network Analyst
Date:Mon, 11 Mar 1996 19:57:19 PDT

> for some reason, i was thinking they bent it outward, not inward. might want
> to ask the list and get the opinions of them what has done it. but i think
> that the cleaning would be a good thing. i think you can get some "cleaner"
> in a can from Radio Shack or any good electronic wholesale place.
> 
> >How do you adjust the idle? Mine is at about 1100rpm & surges from
> >1000-1250 or so regardless of temperature. I'm thinking this may be
> >another cause for the surging - is this likely?
> 
> hmmm. that sort of surging is usually associated with the coolant temp
> sensor ... the blue sender gizmo on the thermostat. it's a $12 part (don't
> forget to get a NEW o-ring with it ... another $2!!!). it's telling the
> engine that the coolant isn't warm yet. maybe.
removed the connector & idle went up right away (engine hot). When 
given any throttle, engine sounded like it was choked (running rich) 
& almost stalled. Back to normal when plugged back in. I guess this 
means the sender is OK??

> another possible surge cause could be the adjustment of the throttle switch.
> if the engine seems to idle ok with the throttle cracked just a tiny bit,
> this might be the cause. it's the little gizmo located on the air intake
> plenum (the silver "spider" just to the left of the air flow meter) and
> down kind low, near the throttle cable connection. it has a small adjusting
> screw (and it is EASILY damaged!! be careful) which should be set at the
> factory and blobbed with wax to keep people like me and you out of it!! :)
Didn't seem to matter if throttle was touched a bit, although there's 
a vey fine line between idle & 2000rpm... Wait a minute - you said 
switch... hmmmm. I looked everywhere, but there is NO switch anywhere 
connected to the throttle linkage - just a standard set-screw type of 
thing. My Jetta has these switches for idle & full throttle, but I 
can't see any here - it loooks pretty much like my old CIS injected 
Scirocco... Is it possible this switch has been removed???

> another surger cause could be the idle mixture air valve ... on the rubber
> boot that goes from the air flow meter to this silver spider, there is a
> smaller rubber hose that runs off toward the back of the bus. it eventually
> goes to the crankcase breater thing in the middle of the back of the engine
> (back is back). somewhere along that hose is a thing with an electrical
> connection. it looks like a metal cylinder stuck off at an angle to the hose.
> this thing works like a PCV. sort of. when the engine is cold, it's supposed
> to allow more air to recirculate, and raise the idle. you might try removing
> it and cleaning it with spray cleaner (or brake cleaner) to remove any
> gunk and stuff inside. several folks have reported smoother idle after doing
> that.
> 
> and lastly (that i can think of), check all the electrical connections on the
> engine. especially the ground strap over by the ignition coil ... make sure
> it's connected tightly on both ends. and over in front of the right rear
> taillight (we got "front taillights?? :) there is a bunch of relays and such.
I checked all the plugs I could find, but no relays aside from two 
inside a box over the coil... Are they in a different place on an 
'88? With those under the dash maybe?

> the big one is THE idle stabilizer what controls your idle. you might pull it
> out (it's a bear to get it off that plugboard) and clean the contacts and
> put it back. one fellow said that cured his idle problems.
> 
I'll pull all those under the dash & clean just in case..

Thanksfor all the info so far...!

Shawn.

 good luck.
> joel
> 
*--------------------------------*
| Shawn Wright, Network Manager  |
| St. Michaels University School |
| 3400 Richmond Rd, Victoria, BC |
| Canada                 V8P 4P5 |
| (604) 592-2411 Fax: 592-2812   |
| swright@smus.bc.ca             |
*--------------------------------*
I haven't lost my mind;  I'm sure it's backed up on tape somewhere!