Date: Fri, 14 Aug 2009 10:48:07 -0400
Reply-To: Robert Stewart <robertmstewart@MAC.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Stewart <robertmstewart@MAC.COM>
Subject: Re: Update - 1988 Rebuilt Engine Stumbling at various RPM levels
2100-2300, 3400- 4000rpms
In-Reply-To: <B3FD4BD4-2D0C-4D89-8BB8-90B1760B8DAA@mac.com>
Content-type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
Turns out after pushing the engine really hard, off and on 2000 - 4500
rpm highway bursts for about 10 times then with some local country
roads and highway driving with steep hills and some steady high speed
driving for no more than 10 minutes at a time the stumbling seems to
be gone! strange right?
About 1 hr after I did all this driving. I did some errands and in the
process I had to get on the highway. I pull up to the onramp, pushed
the pedal to floor, it steadily climbed to upto 3000 rpms then shot
off like a rocket jumped in the engine performing like it was stick
with amazing performance. Sounds to me like and felt like the
something within the TPS or throttle system was stuck then it just
took off.
Thoughts on that one now?
Robert
NY
On Aug 10, 2009, at 12:14 PM, Robert Stewart wrote:
> Is it all possible that what I am experiencing is due to a faulty Idle
> control unit?
>
> R
>
> On Aug 8, 2009, at 7:08 PM, Scott Daniel - Turbovans wrote:
>
>> 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
|