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If the clamp is good and clean/tight then connecting to the clamp bolt shouldn't make too much difference in the reading.

The test is only valid if the starter is drawing a full load, e.g. the engine is turning and the spark plugs are installed so there is full compression. It only needs to crank for a few seconds to get a reading.

If the engine doesn't start then no need to disconnect the coil wire, but if you do, make sure it is grounded. You could instead pull the dme relay since the dme fires the coil, advantage is you don't flood the engine with fuel while cranking it either.
Old 11-28-2017, 02:18 PM
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I apologize for the details but you know:

conditions:
car : completely assembled, all ready to go for a drive. battery right off the tender (fully charged).
DVM connected as follows :
-->(1) attach red alligator clip to positive battery clamp
-->(2) touch black alligator clip to negative battery terminal post
set to "20 V" dial setting and ports as described back there ^^^^

DVM readings : "12.56..12.57...12.58"...

turn key to start the car:

DVM readings : "...11.87...11.83...11.82"

return key to null (?) position

... to be continued...
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87 944 NA
Old 11-28-2017, 04:27 PM
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next test:

car : completely assembled, all ready to go for a drive. battery right off the tender (fully charged).
DVM connected as follows :

-->(1) attach red alligator clip to positive battery clamp
-->(2) touch black alligator clip to largest of two posts on the starter

set to "20 V" range

turn key to start car.

voltage readings : "0.00 ...(turn key - "click/thunk"... increases to near 10.93"
UPDATE UPDATE UPDATE UPDATE UPDATE
UPDATE: car is running, so [A] pull center plug off distributor. (did not assure a 'ground')
UPDATE: voltage readings: "0.00 ...(turn key - "normal starting sound"... increases to 0.25 .. 0.18 .. 0.16 .. 0.48 .. 0.15 .. 0.60 (stop) 0.00"
UPDATE: re-attach center ignition cable to distributor
UPDATE: unplug DME (as a test of the conditions)
UPDATE: voltage readings : "0.00 ...(turn key - "normal starting sound" .. increase to about 0.15 volts"
UPDATE: put DME back. start car : normal starting.
UPDATE: red lead on big starter stud ; black on rear jack point
UPDATE: resting voltage : about 12.6
UPDATE: start car (no DME):
UPDATE: 11.28 .. 10.24 .. 11.10 .. 11.07 ..11.54 ..(stop ignition) 12.01
UPDATE: side note: if black is on starter stud, red on rear jack point, voltage reads
UPDATE: about -12.6 (that is "minus twelve point six"). obviously there's a
UPDATE: directionality in a circuit ... could it be a resistor?... anyways, I digress...
END UPDATE END UPDATE END UPDATE END UPDATE

... tried the black lead on the smaller of the two posts on the starter and got a near 12 volt reading, that is, just the battery I guess. the "2000 m" range is too low.

looks like this isn't set up correctly...

OR...

what if there's just too much dielectric grease that worked itself between battery clamp and post?
I also originally, like a year or two ago, had to force the clamp open a bit more to fit on the post. perhaps the fit is slowly going out, with the multiple loosenings and tightenings...
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87 944 NA

Last edited by Bukowski; 02-25-2018 at 03:52 PM.. Reason: updated test results 25 February 2018 19:48
Old 11-29-2017, 02:39 PM
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one thing that will help :

the voltage drop : sometimes it sounds (from the article) that you record a voltage (say, 12) with another voltage (say, 10 ), and the "drop" would be the difference between the two, (say 2).

then sometimes it sounds (from the article) that the reading on the DVM in real-time would be 0.6 volts.

... meanwhile, I'm scurrying around making more measurements ... I've yet to see a clear "0.6" reading on the DVM... could the reading really go as high as 10 V for a really bad battery cable?
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Old 11-29-2017, 03:56 PM
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... ok I think this is making sense :

Following steps A-E on checking starter circuit :

Battery : (+) to (-)
Step A : 12.56
Step C : 11.87

Starter : battery stud to housing
Step C : 12
Step E : zero

... if I follow, that means no voltage is getting to the starter... but then ... why would it read 12?...
Old 11-29-2017, 04:51 PM
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nut and washer are off the ground bolt.

Hello!

I have some good results to report.

PROLOGUE:

it occurred to me, this is a job for impact tools. long story (and it is long) short :

the impact-grade assembly that fits in there:

1. Harbor Freight (HF) 1/2" drive socket set 67899 containing 13 mm (1-1/2" tall)

2. Craftsman 23765 pinless impact swivel (universal joint).

3. HF 9-1.4" long impact extension tool

combination [1+2] gives a working socket depth of 7/8" - that means a 7/8" bolt will extend up inside without too much problem.

the maximum working angle, which will be reached, appears close to 135 degrees.

... and this is also my first foray into impact tools, so I got the entry-level HF electric impact wrench.

CHAPTER 1:

put a sock into the hole on bell housing. more importantly, put some thought into this - if something falls on it, how easy will it be to get, etc.

CHAPTER 2:

tools:
bamboo shrimp skewer + paper towel taped on the end
Kano Kroil (yes, this stuff is a tool in my book)

drip the towel end with Kroil until its nice and wet. dab the nut all around as much as can be reached. repeat from the other side of the car (there are essentially two angles of approach to the grounding site).

CHAPTER 3:

immediately (like, within an hour or so) assemble impact tool with attachments as above. give it a whirr. (this was my first time using 1/2" impact tools and first time using impact tools on the car - no testing was posslble, really).

repeat Kroil application. let sit overnight.

CHAPTER 4:

assemble impact tools and give it another whirr. check if the nut comes off.

CHAPTER - oh to hell with this.

next, I found good use of the PREVIOUS tool assembly to back the nut off carefully. Towards the end of this process, I swapped the 1/2"-drive 13mm socket for a Craftsman 3/8"-drive combined 13mm socket/swivel because I wanted the nut way at the end of the ground bolt but not falling off. After, I used magnets and bare fingers to carefully get the nut, and then washer off.

note : I did NOT do anything to the coolant hose - leave it on, it will move/give enough to let the tools work. Worst thing was the hose clamp slipping over the socket rim, which temporarily traps it on the fixture.

... so that's it for now. I have pics but this takes so long. There's rust there though, and in between where you'd think ideally there'd be none.
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Last edited by Bukowski; 12-31-2017 at 11:42 AM..
Old 12-31-2017, 11:40 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #46 (permalink)
 
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I had questions about my main ground cable. It seemed to have a greenish white buildup between the connector and cable. So I replaced the electrical eye connector while I was at it. I soldered the new one on after cutting the old one off.

I wish I had run a voltage drop test before and after.
Old 01-01-2018, 08:37 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #47 (permalink)
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I too am working through getting the ground cleaned up on my 924S (it's affecting how the starter turns over on my car). With patience and the right socket, extension and u-joint, that 13mm nut holding the ground strap onto the motor does come off.

For those following along at home, COVER THE OPENING in the bell housing as Bukowski correctly states in Chapter 1 above.

I have sourced the ground relocation kit from ArrnWorx Specialty Tools and will report back on how that went on my car.
Old 01-04-2018, 09:54 AM
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pics 01

hi

pics




















up next : replacing the battery cable. tips appreciated.

what are those smaller wires that hang off the positive (red) battery cable lug at the battery end?
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Old 01-07-2018, 07:12 AM
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Quote:
Originally Posted by Bukowski View Post
what are those smaller wires that hang off the positive (red) battery cable lug at the battery end?
If you look at a wiring diagram, you will see that those wire provide power to the fuseblock, which then provide power to other components (not the starter).
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Old 01-07-2018, 07:23 AM
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Got the cable out. Iíll put up some pics and notes when I get a chance.

The numbers on the wires 944 Ecology and I were talking about are :

443 971 381

Found it in Pelican ... UPDATE : itís looking like a mistake - itís a harness, but if you search around the internet, it looks like a wire harness for a car seat heater, from Audi ... this is a puzzler...

How does one go about replacing the DME wire, canít find that either... Iím guessing it is inside the large wire loom...

Last edited by Bukowski; 01-23-2018 at 02:54 PM..
Old 01-21-2018, 05:00 PM
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pics of cable removal

pics because pics - I like doing this, I hope this isn't a waste of time - yours or mine :

this wire clamp needs to be loosened. 10 mm wrench. no Kroil, non-impact worked:






old positive battery cable end, with the wires from 443 971 381 removed:



the other battery cable end removed:




the plastic coating was incredibly brittle, and came of as dust for the most part:





... part 2 next - if this doesn't hit a file limit or somesuch:
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Old 01-22-2018, 03:44 PM
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pics 2 of 2

... OK, that seemed to work. carrying on:

engine ground is clear now


cable removal is intuitive. one trick : tighten the positive clamp all the way or remove the bolt (I did both) to get it out of that hole (the one with the OBEN grommet - you know what i mean!)

however, when you get to the part near the oil filler neck, I recommend going back out and around the neck - not up towards the windshield - observe:



... my arm surprisingly fit way down in here - I guess the new diet is working - it helps to push the already-extracted cable back down into this area, and then pull the wire that was in the wire clamp down and around the side of the filler neck:


^^^ that doesn't make much sense as is, but if you try this, you'll see the cable has two relatively easiest paths to take - the first one you think of, up towards the windshield, and then the one I try to illustrate here. Hope that helps.

as incentive to do this project, the new battery cable has a clever nice little new design:


old and new, side by side to check


can you see the new design here?





... that's the positive end, the one where, if you touch your wrench to the windshield cowl, ZAP! now, it's angled up at 45 degrees! how cool is that!... we shall see.

... um - is it impossible to replace the 443 971 381 cable, where it goes into the fuse box?
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Old 01-22-2018, 03:53 PM
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hasty update notes

installation notes

1. putting the cable clamp back on: easiest route:
left arm
push down between air box/engine
reach over to clamp

2.putting battery cable in:
not sure about kink/history in cable - had to go back/forth under/above car to ensure no kinking/twisting. mine seems to have gone clear around and then under the reference sensor wires.

3. assembling grounding stud components:

battery cable lug ->DME cable lug (? copper) ->washer->nut

4. turning the nut onto the stud: easiest path is NOT the removal path:
A. attach M8 nut evenly on circular magnet picker-upper
B. work/rotate nut onto stud by rotating clockwise, sliding circular magnet down off and re-centering. this is difficult to describe, but I think least-effort and least-damage path.
C. use deep-well 13mm socket (1/4" was used) to tighten nut rest of the way.
* I tried using paper to secure nut in 13mm (3/8") socket, but the angle was so much I feared it would strip the stud.

... you think this'll fix the problem?....
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Old 02-24-2018, 09:27 AM
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INITIAL RESULTS:

important tech detail : the negative battery cable clamp is CONICAL inside, that means about 18mm on the widest end, 16.5 mm on the narrowest end, and this will CUT INTO THE BATTERY POST if you put it on backwards!

additional work:
* tighten alternator belt til it feels tight by hand and deflects about 2 mm (not measured).
* tighten all THREE bolts on the air compressor: both turnbuckle bolts AND the bolt it pivots on (this one was loose before I think.
* tighten steering belt
* both turnbuckles get a good coat of aluminum anti-sieze (this is another post).
* attach alternator cooling vent pipe (that one that nobody has on their car).

assembled. ready.

plug in the Innovus or whatever voltmeter into the lighter socket.

results:

ignition : good (like nothing bad happened)

voltmeter - 12.5-ish

drive it around 20 minutes, running blower, blinkers, lights, etc. (but not the cooling fans).
plug-in voltmeter never goes below 13 volts, on-board voltmeter good.

use trusty Harbor Fright alternator/battery tester:
13.5v (normal) green alternator result.
battery best results (not sure of label).

... djnolan, I'll have to get measurements of the voltage drop tests with the multimeter later. UPDATE: see previous post for new measurements!

also : forgot to remove the sock! it survived the trip, and seems ok...

BTW

key "on", but not started: on-board voltmeter needle at about 12
car running, the on-board voltmeter reads ... mmmm... 13.5
so, closer to 14 than 13. but nicely up there.

and - I might be just seeing things, but it seems the interior lights are brighter now...
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87 944 NA

Last edited by Bukowski; 02-25-2018 at 03:55 PM..
Old 02-24-2018, 12:45 PM
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FLAPS test - with the big hand-held computer - ALL (starter, alternator, battery) GOOD!

I forgot a tiny tech tip:

get yourself a pack of metal pipe/tube brushes from Harbor Fright

take one of the short-metal-fiber ones, then wrap it around a ~M8 sized cylinder (i.e.bolt) - you need good gloves for this.

coil it up - now you can stick it down on the stud and clean it a bit more.

cleaning the stud and environs with metal brushes is very limited, but works - you have to go in from as many approach angles as possible, and cannot expect too much of the stud surface to be cleaned from each angle. Different brushes/tools to do this helps.
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Last edited by Bukowski; 03-17-2018 at 05:53 AM..
Old 03-17-2018, 05:48 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #56 (permalink)
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Great project, nice write ups!

I bought the ground relocation kit from ArnnWorx Engineering for $12.82 for my 924S. If you have patience and the intake off, this is an easy upgrade from the stupid stud on top of the motor. Much more secure ground and it helped my grounding issue.
Old 03-17-2018, 06:38 AM
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