Date: Wed, 13 Apr 2011 23:04:39 -0400
Reply-To: Jonathan Poole <jfpoolio@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jonathan Poole <jfpoolio@GMAIL.COM>
Subject: Re: Consistent cutout at 3k rpm
In-Reply-To: <084601cbfa4d$8480cb10$6401a8c0@PROSPERITY>
Content-Type: text/plain; charset=ISO-8859-1
Hey Scott,
Good questions. It has a new coil, a bosch blue that, while not prescribed
by pertronix was reported to work well in some samba discussions that I
read. I did other research on coils (quite a lot of reading at the time)
and it looked like the bosch blue would be as good or better than the
flame-thrower coils. At this point I'm less certain though and feel the
need to test resistance, voltage and other numbers again per the pertronix
specs.
It will cut out without load but I haven't tested it enough to confirm that
it cuts out at the same rpm, with the same consistency as it does under
load.
There is not noticeable side-play in the distributor shaft and the dizzy is
within spec in regards to base, full-advance and vacuum advance timing. I
don't have the specs for testing the centrifugal advance curve but the
engine accelerates smoothly and has plenty of power compared to all other AC
2.0's that I've driven. I also shortened the rotor a bit to accommodate the
magnetic ring, though I don't believe that it is of consequence.
To answer one of your earlier questions, I have adjusted the timing slightly
to give it a few more degrees of overall advance but it didn't seem to have
any effect on the cutout rpm.
I don't believe that there are any intake leaks, post afm, but there
certainly could be due to my taking some things apart to get to electrical
connections for cleaning etc. which is something that I did at the time of
the tune-up (clean/inspect/grease all electrical connections in the engine
compartment).
In the next day or two I plan to do the following to gather more
information:
-run tests with more and less overall advance on the timing to see if that
moves the cutout rpm
-run tests to nail down the cut-out rpm without load to see if it is
different from the cutout under load, or as consistent
-re-test fuel pressure, and fp during the cutout to see if there is any
variance (if I can reliably duplicate the cutout without load)
-inspect for air leaks in the air intake system post afm
-test voltage at the coil
-monitor dwell angle during cut-outs
and relucantly since it is more of a hassle (I have to dig out my spare
parts near the water tank and pull the dizzy again,, oh well):
-try the old coil with the pertronix unit
-reinstall the points and condenser to see if that fixes the problem
Thanks again for the suggestions. Let me know if there are other tests I
can run, like a way to test the injector signal too. Would an inductive
timing light pick up the signal on the injector leads? I'm guessing that it
wouldn't buy will try it.
Jonathan
Oh yeah,, Scott you are busted again on not reading! I mentioned coil
replacement in my original email too,, ha ha.. I know I shouldn't give a
knowledgeable and helpful person such a hard time,, but you seem to also
have a sense of humor so I'm going to.. Of course now I will have to be
extra careful to not make any on-list mistakes myself,,
On Wed, Apr 13, 2011 at 10:41 PM, Scott Daniel - Turbovans <
scottdaniel@turbovans.com> wrote:
> hi.
> lol...it says 83 AIR-COOLED right there in the first line..
> first few words even ! .. my bad.
>
> that's a good thought about the ecu not being able to see the ignition
> pulse from the new electronic ign.
> good thinkin' ....could be possible I supposse.
>
> what coil does it have currently ?
> the old one with 25 years on it ?
> if it's not the correct type coil for your new ign system I'd be
> suspecious of that part ..
> and when they are 'just very old' ..
> I don't trust coils very too much if there are weird issues.
>
> I fixed one points-fired vanagon one time by replacing the coil.
> it was an inline four gas engine ..with points..
> sitting idling it would just 'shut off'.
> coil was really old.
> I put on a new one, or another better used one ....
> that fixed it.
>
> since ignition is 'the thing' you changed..
> naturally that's where your focus would go of course.
>
> is there a lot of shaft side-play in the distributor ?
>
> does it do it no load,
> or just under load ?
>
> is there a crack in the air intake boot and engine torque at 3K rpm is
> pulling it open ?
>
> scott
> turbovans
>
>
>
>
> ----- Original Message -----
> *From:* Jonathan Poole <jfpoolio@gmail.com>
> *To:* Scott Daniel - Turbovans <scottdaniel@turbovans.com>
> *Cc:* vanagon@gerry.vanagon.com
> *Sent:* Wednesday, April 13, 2011 3:50 PM
> *Subject:* Re: Consistent cutout at 3k rpm
>
> Hey Scott,
>
> It's also pretty common for folks to not read what is written,, check again
> and you'll see that my first sentence provides year and engine information
> ;)
>
> Thanks for your suggestion and I agree that it could be the afm. I did pop
> the cover off, lightly clean and even adjust the slider to see if it was
> related to this issue. I have a real-time air fuel ratio guage so can make
> adjustments like this and get the ratio dialed back in although I'm waiting
> for a replacement part on it currently so am set by ear/temp until it comes
> back in. In any case it doesn't appear to be slider wear in the afm. I've
> been wondering if it is the signal coming from the pertonix that is not up
> to keeping the injectors firing at higher rpm. It's like there is still a
> signal at the dizzy but maybe the computer loses it?
>
> Jonathan
>
>
> On Wed, Apr 13, 2011 at 4:49 PM, Scott Daniel - Turbovans <
> scottdaniel@turbovans.com> wrote:
>
>> lol..
>> half the time people don't say what kind of engine they are talking about.
>>
>> since all waterboxers have electronic ignition ( waterboxer starts in 1983
>> ) and 83 diesels don't have points , you must be talking about an air-cooled
>> vanagon.
>>
>> it's really nice to have two distributors ..
>> one to modify, one stock with points as a back up.
>> I think I would look for another good used distributor just to have one
>> anyway.
>>
>> Air flow meter pops into my mind.
>> I have seen them get worn in one spot ..
>> the spot that corresponds to around 3,000 rpm .
>>
>> just a thought of something else to consider..
>> not a real diagnosis.
>>
>> what happens if you just advance the timing more ?
>> just as a test.
>>
>> ----- Original Message ----- From: "Jonathan Poole" <jfpoolio@GMAIL.COM>
>> To: <vanagon@GERRY.VANAGON.COM>
>> Sent: Tuesday, April 12, 2011 9:33 PM
>> Subject: Consistent cutout at 3k rpm
>>
>>
>>
>> Howdy Vanagon List,
>>>
>>> My '83 Air-Cooled Vanagon is consistently cutting out at 3 thousand rpm.
>>> This behavior started recently after I made some changes to the ignition
>>> system. I believe that the problem is related to my changing out the
>>> breaker points for a pertronix electronic ignition module but it may also
>>> be
>>> related to the new plug wires, distributor cap, rotor, coil, plugs or the
>>> thorough cleaning of all accessible electrical connections in the engine
>>> compartment or the adjusted timing.
>>>
>>> A few items of note:
>>> -the timing at idle and high-rpm is good (7.5 deg to 31 deg) so it
>>> doesn't
>>> appear to be an advance issue
>>> -the engine runs great all the way up to 3k rpm with better power/feel
>>> than
>>> before these changes
>>> -fuel pressure was stable when tested it while making these changes.
>>> -engine temps are good (350 cht, < 220 oil) when cruising at 2900 rpm
>>> -I have tried different gaps between the pertonix unit and the magnetic
>>> ring
>>> with little/no change in cutout/performance.
>>> -the tach doesn't drop or jump erratically when the engine cuts out which
>>> may contradict my suspicion of the pertronix unit? The tach is out of a
>>> '91
>>> Vanagon and wired up in typical fashion off of the coil.
>>>
>>> My next tests will be to re-check voltage at the coil at high-rpm and
>>> then
>>> to put the points back in but I wanted to inquire here before the
>>> switch-out
>>> in case there is something easy that I have overlooked that I can test
>>> before pulling the pertronix out.
>>>
>>> Any suggestions, especially of easy tests, are appreciated.
>>>
>>> Thanks,
>>>
>>> Jonathan
>>>
>>
>>
>
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