Date: Mon, 15 Feb 2016 10:29:22 -0500
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: 1988 Vanagon GL tintop
In-Reply-To: <CA+az7_7tT+w7GYqu8X0poQgeBJcGn=p1FAfJc3Bvk5hqYXDesw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
John,
Again I would now approach this in steps. Having the O2 sensor increase idle RPM with the ISV disconnected is a sign that either the basic settings are off or the O2 sensor is weak and the ECU is enriching the mixture. The sensor and system can be tested with a voltmeter. With the sensor disconnected and after a re-start the idle mixture should be set for sensor reading of .4 to .7 volt. For those with 1.9L engines you want to be near the lower end of this range to help prevent that idle hunt cycling. Also, be sure that the ignition timing is set to spec, not over advanced as some due thinking it makes it run better. After that you can then begin to work on the idle control system. Keep in mind that the idle controller is connected to that power steering switch, AC compressor clutch, temp 2 sensor, and the tach. So when that harness failed it is possible the ICU was fried. Also to troubleshoot the system you need to be able to measure the duty cycle for the idle valve and the current. I have seen more than once that both can be bad. If you connect a replacement ICU to a valve with a bad coil you will have another bad ICU. BTDT.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of John Rodgers
Sent: Sunday, February 14, 2016 9:27 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: 1988 Vanagon GL tintop
I was there in the shop and directed the troubleshooting. Of course the well experienced mechanic concurred with me. All I ask him to do was turn the engine iff. Disconnect the O2 sensor, and the ISV, then start it again.
After doing that, it idled nicely at 850 rpm. Shut down. Re-connected the
O2 sensor. Started it, and the rpm was up 100 rpm. Didn't tinker with the ISV it was so late and the shop was closing. Will try that Monday morning.
Will also check that hunting action on the rpm as well. When it was warm it ran real nice after a bit with that ISV disconnected.
On another subject - I've got a really squeaky front end, especially when I go over railroad tracks or tne likes. Front end bushings? Van is approaching 300,000 miles and the have never been changed. Mechanic checked them and said they were OK as far as he could tell. One upper control arm bearing had a torn boot. Beyond that, nothing. I'm suspicious of the squeaks!
John
On Feb 14, 2016 20:07, "Dennis Haynes" <d23haynes57@hotmail.com> wrote:
> Did you ask that shop to diagnose it for you or are you trying to do
> this yourself, even after the harness and ECU replacement? There are
> lots of connections including to the idle stabilizer. Don’t assume
> that if the valve is buzzing that it is good. I have seen them get bad
> coils so that they would open too fast and the controller can’t
> "modulate" them and I have also seen the insides get messed up with
> excess crankcase fumes or cleaning solvents. I have seen where both
> the valve and control unit needed to be replaced to get it all to work
> properly. There can also be another problem outside of the idle control system.
>
> When troubleshooting by the part elimination process you want to make
> only one change at a time. In this cae yo also want to work in some sequence.
> Without the idle stabilizer get it to run and idle 700-900 rpm.
> Connect the O2 sensor and test it for proper operation.
> Then connect the idle stabilizer. Restart engine after each change.
> See what you have.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On
> Behalf Of John Rodgers
> Sent: Saturday, February 13, 2016 1:33 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: 1988 Vanagon GL tintop
>
> Today the new (to me) ECU with Shoebox Monitor pigtail, arrived.
> Took,it to the shop and the mechanic there installed it. The new 7.5
> fuse was in place and the new 2003 TDI starter turned the engine
> easily. With the replacement ECU in place, the engine fired right up.
> However, there were two immediate problems.
>
> The engine hunted up and down rapidly over a significat range of rpm.
> As the engine warmed this tended to disappear.
>
> The other problem was that the engine idled way to high, about 1800 rpm.
> Shut it down, pulled the O2 connector, and the ISV connector, and
> started again. Engine idled nicely at 850 rpm!
>
> What to do with this situation I don't know at this point. The ISV was
> working just fine, Could hear it buzzing beautifully. Left the isv
> unplugged but hooked up the O2 connection and 5he rpm jumped to 1400 rpm.
> Don't know what to make of it.
>
> Reseated the front wheel bearings and retorqued the spindle lock nuts
> and peened them down. Greased the C/V'S.
>
> MONDAY I pick up my magic carpet!!!
>
> Comments and opinions appreciated.
>
> John
>
