Date: Sat, 8 Aug 2009 16:08:25 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: 1988 Rebuilt Engine Stumbling at various RPM levels
2100-2300, 3400- 4000rpms
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
reply-type=response
I believe there are few resistance checks in the Bentley book for the AFM.
Can't remember the last time I measured any though.
it's common for the sweeper in the AFM to not make contact where it's been
rubbing for 'ever.'
there are tricks and tweaks to do there, and 'some progress' is possible...
but a new or AFM is the right way to go if that's the
source, of one of the reason it stumbles, or runs unevenly.
'mostly' AFM's make it run unevenly.
I've seen them 'loose power' for a instant ......then recover, that was worn
contacts in the AFM.
I've seen a van that seemed to subtly 'miss' at 3,100 to 3,200 rpm .....but
it wasn't missing per se, it was a bad AFM.
on that particular syncro, you were always right at about the rpm, in normal
driving, like 80 % of the , seems you were right at that rpm.
new AFM fixed that perfectly.
it's usually worthwhile to do the checks and tests that are in the Bentley
book , that you can do.
Where they say plug in some special VW tool or instrument, you can't do
that, but many of the checks are just continuity and resistance.
Just start at the beginning in the fuel injection and ignition section etc,
and do all those checks.
It IS ..for sure, a 'blockage or leakage, of fluids and electrons" , and
don't forget that 'fluids' include gases, not just liquids.....
gases like vacuum, air, and exhaust .
on page 28.42 they do mention checking timing with a timing light ...and
say it should be on the notch.
which is well known I'm sure.
shoot me the link to those timing instruction you mentioned, if you can
please,
thanks,
Scott
it's not the timing, unless it's way off, or there's more to it than is
obvious at first.
Try not to be oblivious to the obvious of course !
----- Original Message -----
From: "Robert Stewart" <robertmstewart@MAC.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Saturday, August 08, 2009 2:10 PM
Subject: Re: 1988 Rebuilt Engine Stumbling at various RPM levels 2100-2300,
3400- 4000rpms
>I had the mechanic set the timing according to Chris AKA
> TentCentLife's (Samba user) process.
>
> What do I look for the AFM?
> How do I take the proper reading?
> What should the numbers be?
>
> Is there anything else I should be looking for?
>
> R
>
>
> On Aug 8, 2009, at 4:39 PM, Scott Daniel - Turbovans wrote:
>
>> air flow meter is a good candidate.
>> timing should at least be in the ball park of correct. Too advanced
>> initially isn't good.
>>
>> but the old sensors back in !
>> Scott
>>
>>
>> ----- Original Message -----
>> From: "Robert Stewart" <robertmstewart@MAC.COM>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Saturday, August 08, 2009 11:39 AM
>> Subject: 1988 Rebuilt Engine Stumbling at various RPM levels
>> 2100-2300,
>> 3400- 4000rpms
>>
>>
>>> I just got my Rebuilt Engine back in my automatic 88 wolfsburg. It's
>>> been Stumbling at various RPM levels between 2100-2300rpm & 3400-
>>> 4000
>>> rpm's.
>>>
>>> It has good power through the band but if you are not pushing the
>>> accelerator down and staying steady at any of the RPM ranges stated
>>> above it will stumble once in a while, not continuously.
>>>
>>> The engine only has 100 miles on it so far. Mostly country road
>>> driving with very little highway driving.
>>>
>>> It has a brand new bosch O2 sensor, all other sensors on the van are
>>> new.
>>>
>>> New Fuel Lines, Injectors are 2 yrs old. New fuel in the tank, all
>>> old
>>> fuel in the tank was removed. All new fuel lines on the tank as well.
>>> New Oil filter and Fuel Filter. Air Cleaner just cleaned.
>>>
>>> Any ideas of what I should be looking for?
>>>
>>> Could it be the advance timing on the engine?
>>> Maybe it was set incorrectly?
>>>
>>> AFM problem?
>>>
>>> Thanks,
>>> Robert
>>> NY
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