Driver to drive?

On Feb 13, 8:37 pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:

I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to switch
the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough, that
fixes the problem within a few seconds.

Sounds like an intermittent connection, doesn't it?

The engine fires up and runs fine
for a few days. Otherwise, its crank, wiggle wires, poke around with a
voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor. New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

I'm pretty sure its the solid state module that's got to go*. It's the only
old part left. But I'd like to understand the cause behind the failure
while I fix it. And this is an interesting puzzle. BTW, the module is
potted, so I'm can only guess about its innards.

Any thoughts?

I fixed a friend's Isuzu a ways back. The dealer wanted to sell him a
new ignition "computer" for more than a poor dental student could
afford. I traced it out and tested it--it wasn't much more than a big
darlington, firing off an inductive pickup.

The Darlington was fine, the problem was the pickup gap. Tweaked
that, and t'was better than new.

Good luck!

--
Cheers,
James Arthur

 

[Paul Hovnanian P.E.]

dagmargoodboat@yahoo.com wrote:

On Feb 13, 8:37 pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough,
that fixes the problem within a few seconds.

Sounds like an intermittent connection, doesn't it?

Thought of that. But pulling the coil lead off, wiggling it around and
plugging it back in (same physical manipulation as connecting the timing
light) has no curative effect. I've been through the rest of the circuit
with continuity tester, wiggling connections. And tugging on them with the
engine running. No effect. Unless its inside the potted module, of course.
But then, explain the timing light.

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
The race for quality has no finish line ...
so technically, it's more like a death march.

 

[Paul Hovnanian P.E.]

Jim Thompson wrote:

On Mon, 13 Feb 2012 17:37:35 -0800, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:

[snip]

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With a few test points brought out as well. I've found a few DIY projects
on line (including one with the obligatory uC).

The basics of a very good method, which uses a standard ignition
coil...

http://www.analog-innovations.com/SED/Self-Inverting-CD-Ignition.pdf

The control system is around somewhere... on paper... pre-CAD ;-) It
measured the current in the emitter and the base and calculated IC (HV
transistor beta was ~4 at 5A

This was circa 1972. Modern circuits elements will make it easier now
than then.

Shown previously while arguing with El Dorko... the 5mH, 5 AMP, yes
AMPERES, inductor for my CDI ignition...

http://www.analog-innovations.com/SED/CDI_Inductor.jpg

...Jim Thompson

Thanks. I'll add this to my collection of notes as I ponder a DIY solution.

When I get my module built and running, I'll try to un-pot the OEM module
and see if I can find the fault. The puzzle is more interesting that fixing
this.

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Klein bottle for rent -- inquire within

 

[Paul Hovnanian P.E.]

Joerg wrote:

Paul Hovnanian P.E. wrote:
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough,
that fixes the problem within a few seconds. The engine fires up and runs
fine for a few days. Otherwise, its crank, wiggle wires, poke around with
a voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor. New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

I'm pretty sure its the solid state module that's got to go*. It's the
only old part left. But I'd like to understand the cause behind the
failure while I fix it. And this is an interesting puzzle. BTW, the
module is potted, so I'm can only guess about its innards.

Any thoughts?


If it's the old grounded collector kind with a high voltage PNP
Ge-transistor in there it could be that the capacitor in the module has
come loose. It's usually the same kind that used to sit across the
points before they went to transistor ignition. If that's the case you
could try hanging such a cap from coil minus to ground, in parallel.

Also, check the points. See whether there is dirt or gunk in there.
AFAIR with old transistor ignitions the voltage flies up with the coil
minus voltage.

No points. It uses a reluctance pickup. That's probably why its been running
for 33 years without maintenance.

The cap idea is good. If the one inside the module is going bad, this should
be an easy test. But keep in mind that this fault is intermittent. I can
drive for a few days and it runs perfectly.

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With a few test points brought out as well. I've found a few DIY projects
on line (including one with the obligatory uC).


It could be done sans uC although that doesn't have the right coolness
factor these days. And don't forget that big blue flashing LED

The FJ40 is a nice 4WD. A friend has modified his and put a Chevy engine
in it, he now calls it a "Chevy-ota".

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Software Engineering is like looking for a black cat in a dark room.
Systems Engineering is like looking for a black cat in a dark room
in which there is no cat.
Knowledge Engineering is like looking for a black cat in a dark room
in which there is no cat and somebody yells, "I got it!"

 

[Paul Hovnanian P.E.]

JW wrote:

On Mon, 13 Feb 2012 17:37:35 -0800 "Paul Hovnanian P.E."
paul@hovnanian.com> wrote in Message id:
doCdnSgw_clnJ6TSnZ2dnUVZ_tSdnZ2d@posted.isomediainc>:

I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch the coil in place of the old points.

[...]

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With a few test points brought out as well. I've found a few DIY projects
on line (including one with the obligatory uC).

That's a pretty old vehicle, but have you tried the local junkyard?

Yes, sort of. FJ40 parts (non wear) are difficult to come by. But there's a
chance that there's a cross reference* Nipondenso part for some other
model.

*I found a Volkswagen parts dealer that had all the Porsche part numbers
(Bosch parts) crossed to VW parts. For 1/3 the price. I'm not to proud to
be driving a 928 with VW relays. ;-)

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Have gnu, will travel.

 

[Paul Hovnanian P.E.]

Winston wrote:

Martin Riddle wrote:
"Paul Hovnanian P.E."<paul@hovnanian.com> wrote in message
news:doCdnSgw_clnJ6TSnZ2dnUVZ_tSdnZ2d@posted.isomediainc...
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch

(...)

Bad ground? Distributor to block, block to battery.

Plus ignition module to distributor and all those
nifty connectors.

--Winston

I've pulled all the ignition parts, cleaned and re-tightened the connections
in the process of replacing most of them. battery cables are (relatively)
new. But there may be a block ground I've overlooked. Distributor would be
a non-issue, as this doesn't use points (the mag pickup is floating and
shielded).

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Diplomacy is the art of saying "nice doggy" while looking for a rock.

 

[Joerg]

Paul Hovnanian P.E. wrote:

Joerg wrote:

Paul Hovnanian P.E. wrote:
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough,
that fixes the problem within a few seconds. The engine fires up and runs
fine for a few days. Otherwise, its crank, wiggle wires, poke around with
a voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor. New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

I'm pretty sure its the solid state module that's got to go*. It's the
only old part left. But I'd like to understand the cause behind the
failure while I fix it. And this is an interesting puzzle. BTW, the
module is potted, so I'm can only guess about its innards.

Any thoughts?

If it's the old grounded collector kind with a high voltage PNP
Ge-transistor in there it could be that the capacitor in the module has
come loose. It's usually the same kind that used to sit across the
points before they went to transistor ignition. If that's the case you
could try hanging such a cap from coil minus to ground, in parallel.

Also, check the points. See whether there is dirt or gunk in there.
AFAIR with old transistor ignitions the voltage flies up with the coil
minus voltage.

No points. It uses a reluctance pickup. That's probably why its been running
for 33 years without maintenance.

The cap idea is good. If the one inside the module is going bad, this should
be an easy test. But keep in mind that this fault is intermittent. I can
drive for a few days and it runs perfectly.

Yes, but those caps are large and potting isn't perfect. You could have
fatigue cracking in the solder joints.

I've had that in my Citroen (classic ignition with points). Drove on an
autobahn ... pop ... POOF ... **BAM* ... pop ... what the hell ...?
Stopped, took spark plugs out, were ok, took big fan off the crankshaft,
looked at the points and the cap, looked ok. Dang. Figured I'd limp
home, somehow. Put it all back in, one (!) throw with the crank ...
VROOOM ... huh? Drove home without it missing a single cycle. On Sunday
I wanted to get back to my university town. Crank, crank, crank ...
<sweat> ... crank .. *KABLAM* .. phutah ... pop. Didn't start, no matter
what I did. Took the cap out. Turns out one crimp connection in the cap
leads was loose and you could twirl the cap around in it. Soldered it,
no problem with the ignition ever again.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Paul Hovnanian P.E.]

Dennis wrote:

"spamtrap1888" <spamtrap1888@gmail.com> wrote in message
news:383625d0-1de9-4ecf-8abd-6e86fbc05dee@vd8g2000pbc.googlegroups.com...
On Feb 13, 5:37 pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch
the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough,
that
fixes the problem within a few seconds. The engine fires up and runs fine
for a few days. Otherwise, its crank, wiggle wires, poke around with a
voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor. New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

Are the plugs gapped right? You might just want to clamp a neon lamp
across the coil, to simulate the timing light.


I'm pretty sure its the solid state module that's got to go*. It's the
only
old part left. But I'd like to understand the cause behind the failure
while I fix it. And this is an interesting puzzle. BTW, the module is
potted, so I'm can only guess about its innards.

Any thoughts?

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With
a few test points brought out as well. I've found a few DIY projects on
line (including one with the obligatory uC).

No junkyard parts available? That would be my first choice.


=======================================================================

Bosch made a range of "universal" ignition modules. I'm sure hunting
around you would find one for much less than $350. They were black about
75mm x 25mm 8mm thick with 5 or 6 terminals along the front edge.

They looked like these:
http://www.mrm-racing.se/shop/img/p/57-133-large.jpg
http://www.ignition.com.tw/Product-20081028142259.jpg

I'm considering aftermarket. I'd like to not have to throw out or mod the
distributor pickup (it seems to work OK).

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Q: Why do mountain climbers rope themselves together?
A: To prevent the sensible ones from going home.

 

[Paul Hovnanian P.E.]

Jim Thompson wrote:

Shown previously while arguing with El Dorko... the 5mH, 5 AMP, yes
AMPERES, inductor for my CDI ignition...

http://www.analog-innovations.com/SED/CDI_Inductor.jpg

Meh. This is the kind of inductor us power guys like playing with:

http://www.jcmiras.net/jcm2/p106.htm

Of course, I've never actually wound one myself. ;-)

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
The world is coming to an end ... SAVE YOUR BUFFERS!!!

 

[Winston]

Paul Hovnanian P.E. wrote:

Winston wrote:

Martin Riddle wrote:

(...)

Bad ground? Distributor to block, block to battery.

Plus ignition module to distributor and all those
nifty connectors.

--Winston

I've pulled all the ignition parts, cleaned and re-tightened the connections
in the process of replacing most of them. battery cables are (relatively)
new. But there may be a block ground I've overlooked.

Yayesss, could be.

Distributor would be a non-issue, as this doesn't use points (the mag
pickup is floating and shielded).

The pass transistor in the ignition module still needs
a solid ground, to work properly, yes?

--Winston

 

[Oppie]

Most common problem I've seen with these is intermittent opens in the
trigger coil, Excessive reluctor to pickup gap or damaged bias magnet.

 

[Oppie]

The newer MSD (Multiple Strike Discharge) units will get you a bit better
combustion. Instead of one spark per cycle, this throws a burst. Just for
sake of discussion:
http://www.streetbeatcustoms.com/Toyota/Ignition-Systems/

"Oppie" <Oppie@127.0.0.1> wrote in message
news:ENz_q.20612$4K5.5785@newsfe16.iad...

Most common problem I've seen with these is intermittent opens in the
trigger coil, Excessive reluctor to pickup gap or damaged bias magnet.

 

[Jim Thompson]

On Tue, 14 Feb 2012 10:30:12 -0800, "Paul Hovnanian P.E."
<paul@hovnanian.com> wrote:

Jim Thompson wrote:

On Mon, 13 Feb 2012 17:37:35 -0800, "Paul Hovnanian P.E."
paul@hovnanian.com> wrote:

[snip]

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With a few test points brought out as well. I've found a few DIY projects
on line (including one with the obligatory uC).

The basics of a very good method, which uses a standard ignition
coil...

http://www.analog-innovations.com/SED/Self-Inverting-CD-Ignition.pdf

The control system is around somewhere... on paper... pre-CAD ;-) It
measured the current in the emitter and the base and calculated IC (HV
transistor beta was ~4 at 5A

This was circa 1972. Modern circuits elements will make it easier now
than then.

Shown previously while arguing with El Dorko... the 5mH, 5 AMP, yes
AMPERES, inductor for my CDI ignition...

http://www.analog-innovations.com/SED/CDI_Inductor.jpg

...Jim Thompson

Thanks. I'll add this to my collection of notes as I ponder a DIY solution.

When I get my module built and running, I'll try to un-pot the OEM module
and see if I can find the fault. The puzzle is more interesting that fixing
this.

I lost one of those on my '77 LTD. It was a wirebond inside the
potted module :-(

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Tue, 14 Feb 2012 10:58:24 -0800, "Paul Hovnanian P.E."
<paul@hovnanian.com> wrote:

Jim Thompson wrote:

Shown previously while arguing with El Dorko... the 5mH, 5 AMP, yes
AMPERES, inductor for my CDI ignition...

http://www.analog-innovations.com/SED/CDI_Inductor.jpg

Meh. This is the kind of inductor us power guys like playing with:

http://www.jcmiras.net/jcm2/p106.htm

Of course, I've never actually wound one myself. ;-)

I actually did wind (and re-wind and re-stack) the original until I
got it the way I wanted (it is gapped). Then a company in Arizona
City made the pre-production units. But Ford balked... it cost ~$1
more than a conventional approach with a tranny just doing points
duty. But it outperforms a conventional ignition hands-down... it'll
blow oil out of the plug gap ;-) I even demo'd a version that would
multi-fire at low RPM's to up burn efficiency.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Jim Thompson]

On Tue, 14 Feb 2012 15:55:17 -0500, "Oppie" <Oppie@127.0.0.1> wrote:

The newer MSD (Multiple Strike Discharge) units will get you a bit better
combustion. Instead of one spark per cycle, this throws a burst. Just for
sake of discussion:
http://www.streetbeatcustoms.com/Toyota/Ignition-Systems/

I had that ~1972, but Ford wouldn't spend the extra $1 :-(

"Oppie" <Oppie@127.0.0.1> wrote in message
news:ENz_q.20612$4K5.5785@newsfe16.iad...
Most common problem I've seen with these is intermittent opens in the
trigger coil, Excessive reluctor to pickup gap or damaged bias magnet.

Ford's never had a reluctance issue, just open pick-up coils.

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Artemus]

"Paul Hovnanian P.E." <paul@hovnanian.com> wrote in message
newsMCdne4RPMUTNqfSnZ2dnUVZ_hCdnZ2d@posted.isomediainc...

I've pulled all the ignition parts, cleaned and re-tightened the connections
in the process of replacing most of them. battery cables are (relatively)
new. But there may be a block ground I've overlooked. Distributor would be
a non-issue, as this doesn't use points (the mag pickup is floating and
shielded).
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------

My old Toy truck had a similar problem with the ignition. It would go
from running fine to running like crap and back again. Long story short -
a new set of HV plug wires had it humming happily and 2 more mpg to
boot.
Art

 

[ehsjr]

Paul Hovnanian P.E. wrote:

<snip>

When I get my module built and running, I'll try to un-pot the OEM module
and see if I can find the fault. The puzzle is more interesting that fixing
this.

John Larkin used a "witches brew" of acetone & paint thinner for
unpotting, AIRC. Check with him for the proportions/brands/etc.

Ed

 

On Mon, 13 Feb 2012 17:37:35 -0800, "Paul Hovnanian P.E."
<paul@hovnanian.com> wrote:

I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to switch
the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough, that
fixes the problem within a few seconds. The engine fires up and runs fine
for a few days. Otherwise, its crank, wiggle wires, poke around with a
voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor. New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

I'm pretty sure its the solid state module that's got to go*. It's the only
old part left. But I'd like to understand the cause behind the failure
while I fix it. And this is an interesting puzzle. BTW, the module is
potted, so I'm can only guess about its innards.

Any thoughts?

*A replacement is $350. I'm pondering building a DIY unit from scratch. With
a few test points brought out as well. I've found a few DIY projects on
line (including one with the obligatory uC).
Greetings Paul,

I've had two cars with this type of ignition that were failing
intermittently. The first was Pontiac with the HEI ignition. The
module sat in the distributer. It turned out to be heat related. For
some reason the module would get hot and fail and it wasn't just
engine heat. I would mess with wires and such and the thing would cool
down and the car would start. So it seemed like something I was doling
was working when it was just a failing module. I replaced the module
and that fixed the problem. The second car also had the reluctance
wheel type ignition and it would just die. Any time, without any kind
of pattern. When I replaced the wires, rotor, cap, and plugs it worked
fine for a couple weeks and then started crapping out again. One day
it died while I was on the freeway and in desperation I tried turning
the distributer in the hope that maybe it was timing. The car started
up. And ran sorta OK but the timing wasreally advanced. Setting the
timing properly would make the car die whenever it felt like but with
the timing advanced it would always start and run. Thinking about why
this would be it occurred to me that with the ignition advanced less
energy was required to make the spark jump the spark plug gap than
when the timing was closer to TDC. So I thought maybe the spark was
going to ground somewhere. Looking at the distributer shaft with the
new rotor off and using a magnifier I could see a little spot where
maybe sparking was happening. To confirm my theory I put the timing
light on spark plug wire #1 and with the timing set properly the
timing light wouldn't trigger. But with the timing light on the coil
wire it would trigger no matter where the timing was set. Putting in
yet another rotor, this time a different brand, fixed the problem.
As far as building your own electronic points replacement, there used
to be available kits to convert points igntion cars to electronic
igntion. I bet there still are, and I bet could be used to replace
your setup for less than $350.00. This outfit:
http://www.hot-spark.com sells kits for points replacement for all
sorts of cars. Maybe you distributer will be close enough to the old
points style that one of these kits will just be a bolt on fix for
about $60.00. I just googled points replacement so I don't know
anything about the company that makes the Hot-Spark system.
Eric

 

[Paul Hovnanian P.E.]

Winston wrote:

Paul Hovnanian P.E. wrote:
Winston wrote:

Martin Riddle wrote:

(...)

Bad ground? Distributor to block, block to battery.

Plus ignition module to distributor and all those
nifty connectors.

--Winston

I've pulled all the ignition parts, cleaned and re-tightened the
connections in the process of replacing most of them. battery cables are
(relatively) new. But there may be a block ground I've overlooked.

Yayesss, could be.

Distributor would be a non-issue, as this doesn't use points (the mag
pickup is floating and shielded).

The pass transistor in the ignition module still needs
a solid ground, to work properly, yes?

--Winston

Right. But how is my cheap Sears timing light fixing that (only a connection
to coil secondary needed).

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
What if no one ever asked a hypothetical question?

 

[Dennis]

"Paul Hovnanian P.E." <paul@hovnanian.com> wrote in message
news:RYCdnSbxOZSZMKfSnZ2dnUVZ_tadnZ2d@posted.isomediainc...

Dennis wrote:


"spamtrap1888" <spamtrap1888@gmail.com> wrote in message
news:383625d0-1de9-4ecf-8abd-6e86fbc05dee@vd8g2000pbc.googlegroups.com...
On Feb 13, 5:37 pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:
I have an old Toyota FJ40 (1979) with 'transistorized' ignition. A
reluctance pickup wheel in the distributor and solid state module to
switch
the coil in place of the old points.

Its starting to get a bit flakey. From time to time (and more frequently
now) the ignition just cuts out. Just like turning the key off. But it
still has +12V to the coil. After starting the replace parts until its
fixed method, I'm down to the solid state module now.

But, and here's the puzzle, one of my diagnostics for spark/no spark has
been to throw an old timing light on to the coil output. Oddly enough,
that
fixes the problem within a few seconds. The engine fires up and runs
fine
for a few days. Otherwise, its crank, wiggle wires, poke around with a
voltmeter to no effect.

At first, I figured that too large spark plug gaps were causing the coil
secondary (and primary) currents to decay too slowly and that this was
screwing up the module's operation (bad flyback diode perhaps?). The
addition of the timing light was like putting a gas discharge surge
arrester in the circuit, clamping the primary voltage quickly. But this
failure continues after having changed plugs, cables, cap, and rotor.
New
coil too. So everything should be within spec. And when it runs, it runs
beautifully.

Are the plugs gapped right? You might just want to clamp a neon lamp
across the coil, to simulate the timing light.


I'm pretty sure its the solid state module that's got to go*. It's the
only
old part left. But I'd like to understand the cause behind the failure
while I fix it. And this is an interesting puzzle. BTW, the module is
potted, so I'm can only guess about its innards.

Any thoughts?

*A replacement is $350. I'm pondering building a DIY unit from scratch.
With
a few test points brought out as well. I've found a few DIY projects on
line (including one with the obligatory uC).

No junkyard parts available? That would be my first choice.


=======================================================================

Bosch made a range of "universal" ignition modules. I'm sure hunting
around you would find one for much less than $350. They were black about
75mm x 25mm 8mm thick with 5 or 6 terminals along the front edge.

They looked like these:
http://www.mrm-racing.se/shop/img/p/57-133-large.jpg
http://www.ignition.com.tw/Product-20081028142259.jpg

I'm considering aftermarket. I'd like to not have to throw out or mod the
distributor pickup (it seems to work OK).

--
Paul Hovnanian mailtoaul@Hovnanian.com
------------------------------------------------------------------
Q: Why do mountain climbers rope themselves together?
A: To prevent the sensible ones from going home.

I'd bet there'd be a Bosch unit that would couple directly to your reluctor
dissy.

There are some pocket books (like a little bible, thin paper etc) mad by
Bosch that had ALL the info on Bosch stuff. "Bosch Automotive Electronics
Handbook" or similar name. One of those books would help you a great deal
if you could find one (or download??).

good luck.