Date: Thu, 26 Aug 1999 05:40:59 GMT
Reply-To: jeff_gilbert@PEOPLESOFT.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jeff Gilbert <jeff_gilbert@PEOPLESOFT.COM>
Subject: Pressure Regulator/FI problems
Content-type: text/plain; charset=us-ascii
Thanks for the reply Joel...
I double checked my Bently manual and it says:
2.0 (29) connected
2.5 (36) disconnected
for both digifant and digjet (mines digifant).
I disconnected the hose both with the engine running and after waiting 10
minutes after shutting the engine off. When running, it jumped to 36 as
expected...when not running, the psi stayed the same (as suspected).
I clamped the injectors while the engine was off (after waiting 10
minutes), and while the pressure was still in normal range (29 psi).
Pressure jumped sharply to around 36psi when clamping either injector hose.
Upon removing clamps, pressure dropped significantly...down to around
20psi.
Yes, the van has been cruddy for a long time. I t hink its always been a
little rich as my MPG (15 max) has never been as high as other list
members' vans (87 syncro camper). Symptoms get worse then improve with a
new part or just by chance. Its finally gotten out of hand and the van is
basically undrivable. Main symptoms are:
1. Billowing black smoke.
2. Severe loss of power at freeway speeds (max speed 50ish).
3. Van will run fine, then 1 mile later lose power, then 5 miles later
just kick back in.
4. Cant pass smog (duh).
5. Always starts fine, but sometimes jerky at lower speeds.
6. Symptoms far worse on hills.
7. Disconnecting O2 sensor definitely helps overall power (and is only way
I can drive it now).
What I've done/checked:
1. Replaced AFM at mechanics request.
2. Replaced O2 sensor twice (over last two years).
3. Replaced Cat Conv twice (over last two years).
4. New engine installed in February (had leaky heads and a bad crank
shaft).
5. Mechanic tested O2 sensor, said it was ok.
6. Mechanic tested Temp sensor II, said it was ok.
7. Mechanic said it was electrical and that he wasnt qualified to diagnose
further.
7. Took it a VW specialist who proceded to swap in a new ECU, a new Idle
stablizer and even a new O2 sensor.
8. New mechanic tried all the new parts in different combos with my parts
and still couldnt solve the problem.
9. New mechanic said Co2 is off the charts with any (new or old) O2 sensor
conencted.
9. New mechanic said with O2 sensor off, Co2 still over legal limit, but
much better and decent power/MPG returns.
10. New mechanic baffled and told me to drive the van with O2 sensor off
for a week or two and see if symptoms return.
11. Van drove pretty good for about a week, then slowly started to get
worse (two lack of power sessions every 50 freeway miles).
12. Soon van was constantly lagging again (even with O2 off).
Since then on my own I have confirmed:
1. Battery ok
2. Pressure Regulator ok.
3. Idle stabalizer working.
4. Done pin checks on ECU connector harness per bently except:
#3 - tests wire from starter and adapter to idle stablizer.
#5 - injectors
#8b - second test for intake air sensor potentiometer (kinda want to
assume AFM works fine because its pretty damn new).
5. My throttle valve switch isnt getting the required 5 volts, so there
may be a wire break or ECU is faulty, but if the latter, why then didnt the
new ECU that the
mechanic swap out not work?
6. AFM passed tests on Bently 24.57.
7. Hall unit is ok.
8. Checked o2 sensor with engine at 2000 rpms...volts hovered around .05 -
.07 and varied by .001 to .005 every couple of seconds (these readings seem
low).
9. Disconnected O2 sensor and grounded green wire from ECU, creating
same rich situation Ive had all along.
10. Connected 1.5 volt battery (positive side) to O2 connector from ECU
and grounded negative side of batter, created a lean mixture to almost
stalling. In both 9 and 10 disconnecting the ground/battery stopped the
problem and the ECU returned the mixture to normal idle in a couple of
seconds. This seemed to tell me the wiring between O2 and ECU
was ok, at least at that moment.
11. Ive visually checked for vaccuum leaks and tonight hope to test with
vaccuum gauge.
12. I dont know what else to do except finish the last few pin checks and
test the injectors and fuel pump relay. Ill also try adjusting the AFM
spring tension as a last resort.
any insight is greatly appreciated,
jeff
"Joel Walker" <jwalker@uronramp.net> on 08/25/99 07:19:48 PM
To: <jeff_gilbert@PEOPLESOFT.COM>
cc:
Subject: Re: Checking Pressure Regulator
> wasnt sure if I should disconnect the vaccuum hose while checking the
> residual pressure. Im pretty sure I wasnt supposed to, but Bently showed
> the pressure should be between 29 and 36psi, the latter being the value
for
> when the hose is disconnected.
my diagnosis book says that the pressures are:
bar (psi) vacuum hose on pressure regulator:
2.2 (33) connected
2.5 (36) disconnected
it does NOT makes it clear when the vacuum hose is to BE disconnected ...
before, during, or after the test (during the residual pressure check).
but
since the engine is supposed to be running to provide vacuum, i'd bet on
the
hose being CONnected during the residual test. i think the disconnection is
just to test if the pressure regulator can sense the removal of the engine
vacuum.
> I disconnected the vaccuum hose anyway and saw no change in pressure.
For
engine running or not?
> laughs I clamped the return line to the fuel tank and nothing changed. I
> then clamped both hoses leading to the injectors and the pressure jumped
up
> to about 34/35. When I disconnected the clamps, the pressure dropped
down
> to about 20psi.
mine says:
- stop engine. wait 10 minutes.
pressure should be 2.0 - 2.5 bar (29 - 36 psi). if NOT, there are three
possibilities:
* fuel pump check valve - test by clamping off line from fuel pump.
* fuel pressure regulator - test by clamping off return line to tank.
* fuel injector(s) - test by clamping off lines from injectors to
pressure regulator.
if necessary, test individual injectors for leaks and spray
patterns.
- observe pressure gauge while clamping off each of these individual lines.
if pressure drop ceases or slows dramatically, problem is in the
indicated
component. use care not to damage lines with clamping device.
so that makes me wonder ...
- if you clamped off the injector lines while the engine was OFF, sounds
like you've got a leaking injector somewhere in there.
- if you clamped off the injector lines while the engine was running,
sounds
ok to me.
is it running badly? or doing anything to suspect that anything is wrong??
hope it helps. good luck!
joel
> Im assuming everything checked out ok, but could some reassurance.
>
> Thanks,
>
> Jeff
>
> 87 syncro westie
>
