Date:         Sat, 15 Sep 2018 22:56:18 -0700
Reply-To:     Stuart MacMillan <stuartmacm@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Stuart MacMillan <stuartmacm@GMAIL.COM>
Subject:      Re: [VW gas I4 Conversions] weird engine behavior,
              stops on downhill coasting, diagnostic help?
Comments: To: Don Hanson <dhanson928@GMAIL.COM>
In-Reply-To:  <CAHTkEuKC=znLehJDMzijeTckv4HG1FiZ5GMbtcBO4cD_D3diUg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8

That ICM can mess things up in so many ways it’s amazing, and I’ve experienced most of them. It’s an external computer that was integrated into later year Digifant ECUs for other VW engines. It controls every aspect of closed throttle operation as well as cold starts and warmup rpms.

I hope it’s fixed!

> On Sep 15, 2018, at 8:06 PM, Don Hanson <dhanson928@GMAIL.COM> wrote:
> 
> Thanks everyone.  I think Stuart hit it (fingers crossed) with the idle
> control module.  Swapped in one I found in the box with me spare ECU that I

> have had 'forever '.  Drove a hundred miles with a few long descents
> without any signs of engine dying..
>   I'd never have found my problem with out the List...heck, I didn't even
> know there was such a thing as an idle control module...the one in my
> spares was labeled "ign. Control mod. ". I recall, vaguely, the fellow at
> German auto salvage, in Boring, Ore. asking me if I wanted that part,
> too...and tossing it in for nothing with the 91 jetta ecu that was
> $35...about 5yrs ago.
> 
> On Fri, Sep 14, 2018, 11:12 AM David Beierl <dbeierl@attglobal.net> wrote:

> 
>>> 
>>> The injectors shut off when going downhill and rpms are above 1200. As
>>> soon as rpm drops back down to 1200 rpm, the injectors fire again
>>> 
>> 
>> With Digijet I believe the cutoff is at 1500 rpm and fuel comes back on at
>> 1000 rpm. It's a little more complicated with Digifant. The engine has to

>> have achieved 3,000 rpm before decel mode can be invoked,** and I think it
>> comes back on at 1300 rpm.
>> 
>> **I believe this is since the last time the closed-throttle switch was
>> active.  I did tests on this once but don't remember the exact results I
>> got.
>> 
>> Yrs,
>> d
>>