Re: AFC fuel injection 1977 Beetle

On Nov 19, 3:45 pm, Speedy Jim <volks_cl...@xxxxxxxxxxxxx> wrote:
eastwardbound2...@xxxxxxxxx wrote:
On Nov 19, 4:46 am, "dave AKA vwdoc1" <vwdoc1nos...@xxxxxxxxxxxxxxxxx>
wrote:

These almost sound like your situation and Speedy's responses!  lolhttp://en.allexperts.com/q/Volkswagen-801/1979-Super-Beetle.htmhttp:/...
OR is it you!!!  8^)

try contactinghttp://www.bba-reman.com/
It "should" be a breeze for them if they want to touch it!  ;-)

Now how do you "know" that is not normal for that circuit?
I would think that circuirt would inherently have some resistance using a
low impedence DIGITAL VOM coming from the ECM.
On some vehicles I am able to check wiring, sensors and other components
from the ECM's harness plug.
So did you read that circuit with the cyl head temp sensor at the ECM plug?
--
later,
(One out of many daves)

"Speedy Jim" <volks_cl...@xxxxxxxxxxxxx> wrote in message

news:iaMUk.7503$c45.5700@xxxxxxxxxxxxxxxxxxxxxxx

eastwardbound2...@xxxxxxxxx wrote:

On Nov 15, 11:45 am, "eastwardbound2...@xxxxxxxxx"
<eastwardbound2...@xxxxxxxxx> wrote:

I checked the OHMS of the number 2 temp sensor as specified by the
maintenance manual.  Bentley Manual.  It was reading around 7,000 OHMS
when it should of been around 2,500 OHMS.  So I ordered a new sensor

from Aircooled.net  I installed it last night and as I suspected the

car ran rough so I had to re-adjust the air/fuel ratio by the
adjustment screw under the air box.  I adjusted it to full rich I
believe and it still was not enough.  The box had been opened before
so I suspect the whole air flow meter needs to be opened again and re-
adjusted.  I just don't know how exactly.

My other question is this.  When I took the old sensor off.  It had
this adapter on the end of it that goes between the sensor and the
engine head.  It plugs in right between just like an electrical
adapter but the ends of it are the same as the sensor and the port
that it goes into.  It looks like the end of a chisel without the
wedge part as it's long but it just plugs in between the two.  Do I
need that part on there?  I couldn't separate them so I put the new
one on without it and it fits fine.  The old part had a lot of rust on
it which could of been the reason why there was more resistance than
usual.  What does this part do?  Why is it there?

I just wanted to update everyone on what happened to this car.  I
troubleshooted the problem with the number 2 temperature sensor with
my trusty multi-meter.  I then found out that the problem was not the
sensor but was something with the wiring harness giving out 3,000 OHMS
resistance on its own.  I further traced the problem using a 10 foot
long 22 gauge wire going from the lead for the temp. sensor in the
engine compartment and all the way back towards where the wiring
harness plugs into the computer for the fuel injection.  I was trying
to find out if there was a cold spot in the wiring harness causing
this 3,000 OHM resistance.  To my surprise the wiring harness only had
a 1 OHM resistance and there was actually nothing wrong at all with
the engine wiring harness.  The whole time I had a faulty computer/
brain/power-train control module (PCM) whatever you want to call it.

Unfortunately I can not find anyone who sells a new or re-manufactured
computer for this car.  Not mid-america motorworks, not JC Whitney or
anybody else what have you.  This is quite disconcerting for me.  And
I can't just put in a brand new 1600cc dual port w/solex carb because
it all has to be CA smog legal.  What a rotten day on the west coast,
especially with all this smoke and ash from the wild fires!

Do a search on:
http://www.thesamba.com/
for "ECU"

I'm a little confused though where the 3000 Ohm error was.
And how you know for sure the ECU is bad.
?
Speedy Jim
http://www.nls.net/mp/volks/

Yes, what I did was check the circuit at the ECU's plug using a wire
running from the back seat to the engine compartment.  Essentially the
currently only passed through the wire on the engine harness just for
temp. sensor #2 including the 10 feet of wire I bought from radio
shack.  The two lengths of wires together had 1.2 OHMs.  But If I
check the OHMs with the ECU attached and from the engine compartment,
it has an extra 3,000 OHMs tacked on to it.  Troubleshooting does take
time but at least now I can eliminate the sensor and the wiring
harness as the culprit which can only mean that the problem is the
ECU.  The car still runs, but gets terrible gas mileage and has poor
performance.

East-

I know  I'll sound like I'm beating a dead horse or badgering,
but I'm not convinced that the ECU is at fault.  And, if it were
my car, I'd want to know for sure before forking over a chunk
of change for another box.

You said:
"check the OHMs with the ECU attached and from the engine compartment,
it has an extra 3,000 OHMs tacked on to it. "

Does this mean that the temp sensor was disconnected and your
multimeter was connected from chassis to the harness wire (the one
that went to the sensor)?   And the meter read some resistance
that was 3,000 Ohms more than you expected?

If the above is what happened, then the reading may be perfectly
normal.   The resistance looking *into* the ECU has no meaning and
has nothing to do with the temp sensor resistance.

------------------

Want to do an experiment?
Go back to Radio Snack and get some kind of variable resistance
(like a volume control), if they have any.  An ideal one would
be something like 10,000 Ohms.   Ground the center terminal
to chassis and connect one of the outer terminals to the
harness wire that normally connects to the temp sensor
(we won't be using the sensor).

(Alternate:  Get a handful of 1/2watt resistors, like:
100, 330, 470, 1K, 2.2K, 3.3K.   One at a time, connect
one of them from chassis to the harness wire.)

Get the engine running and turn the control thru its range.
Does it affect the running?  It may go all the way from
purring smoothly to belching black soot.

If the control has any effect at all, the ECU is very likely
working just the way it should.

Speedy Jimhttp://www.nls.net/mp/volks/

Jim, if what you are saying is true. Then that would mean that I
tested the sensor the wrong way. I placed the multi-meter in "series"
between the sensor and the engine wiring harness where it normally
attaches. I did this according to the diagram in the Bentley manual
where it displays the meter placed just like what I described with the
sensor mounted on the engine block. One end of the meter attaches to
the sensor and the other attaches to a symbol that looks like an "I"
with a circle on top which to me would mean an electrical connector.
If the meter was supposed to be grounded to the engine block it would
show an electrical schematic symbol for "ground". So please bare with
me here. What is the correct way to test the temp. sensor if I am
doing it the wrong way?

If I attach the meter between the sensor and the other side of the
meter grounded to the engine. It displays a healthy 2,500 OHMs.
.

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