1 Stupid quick question, and a slightly harder one about 5000tq...

[Bernard Littau]

Hi Cody,

Is it Cody, or is it John?  Color me confused :-)  That's close to my
natural state, being confused, so I'll roll with it...

> After just cruising arround for the first few runs after I fixed
> my ignition problem I decided to see just how quick my car is
> today. The cars quick, but it now isn't opening the wastegate I
> think. Having never dealt with a car with overboost protectin
> before, my simple and stupid question is : When I'm hard on the
> throttle in any gear except first the car arround 1.6bar on the
> factory boost gauge the car trys to throw me through the
> windshield with the motor shutting down for a second or two.
> Would that be the fuel pump cutout on overboost?

Yay!  Always nice when they run.

The stock ECU will cut out the fuel above 1.5 bar, so your supposition about
fuel pump cutout is correct.

The wastegate has two chambers, the top and the bottom.  Manifold pressure
goes to the bottom fairly directly.  The top chamber also gets manifold
pressure, but it is routed through some solenoids and is under the control
of the ECU.

A stock wastegate spring will allow no more then 1.3 bar of boost before it
regulates.

A possibility is that you have a non stock wastegate spring with a stock
ECU.  Also a possibility is that the wastegate is not functioning: it is
either stuck, or the diaphragm is torn.

There are two other possible reasons you are seeing more than 1.3 bar boost:
1) The lower chamber is not getting manifold pressure when it should, or 2)
The upper chamber is getting pressure when it should not.

Scott's site has something to say on this topic of overboost.  See:
http://www.sjmautotechnik.com/boost.html#chklist
then:
http://www.sjmautotechnik.com/10vwaste.html

(Have you noticed yet that all I ever do is refer people to Scott's site :-)

#1) Inspect the hoses to the lower wastegate chamber.  If these are not
intact, the wastegate will not regulate boost correctly.  For instance, if
the lower hose is disconnected and plugged, this would cause the behavior
you are experiencing.

#2) pull a vacuum on the upper wastegate nipple.  Break the vacuum suddenly,
and you should hear a clunk as the wastegate closes.  No clunk means you
likely have a torn diaphragm.  Again, a torn diaphragm will cause the
behavior you are experiencing.

#3) assuming the results of #1 and #2 are good, remove and plug the upper
wastegate hose and run the car again, see if it still cuts out.  This is
testing the "signal" from the upper wastegate hose.  Sometimes the hoses to
the solenoid get hooked up wrong.  If the car gets 1.3 bar with the upper
hose off, and does the >1.5 bar thing with the hose on, you likely have
incorrect routing of the hoses.

> And for the slightly hard question: I'm getting a huge (~11.5
> amp) draw on the battery now with everything shut off. I did have
> an interior light in the front passengers footwell sticking on so
> I removed the bulb, but today I came outside to find a very dead
> battery, and upon recharging an ~11.5 amp draw. I had a friend
> sit in the back seat with a multimeter while I pulled fuses, but
> not a single fuse stopped the draw. Any hints on where to start tomorrow?

11.5 amps is indeed a huge draw.  It should make some serious heat
somewhere.  That is 140 watts -- imagine a 100 watt light bulb somewhere
heating up stuff.  Feel around for some heat on the alternator and the
starter motor.  Also check your headlamp switch and your ignition switch.
That much draw would melt the switches, so I am guessing your alternator has
some bad diodes.  I would disconnect the big red and small blue wires from
the alternator (with the battery disconnected), and then test to see if the
draw is gone.

Best,

Bernard Littau
Woodinville, WA
'88 5ktq