civic ignitor question

anyone know the ecu switching voltage for the ignitor?

i want to test one out of the car. i've read this:
http://www.gcw.org.uk/rover/ign.zip from graham woods excellent rover
200 web page. the only info it doesn't give is what signal voltage the
ecu gives the ignitor - and that would allow me to rig up a dry test.
i'm guessing it's 5v as the ecu is old skool electronics, but anyone
know for sure?

any help much appreciated!

 

Not sure exactly what you're up to. Are you just trying to see if this ignitor
has failed or not?

For ignitor electrical tests, see pages 16-50 (fuel injected) and 16-51 (carb'd)
of
http://www.honda.co.uk/owner/ConcertoManual/62SH200/16-48.pdf .

www.autozone.com 's free repair guides describe the same or similar tests under
Engine Performance and Tune-Up Procedures, PGM-Ig (sic) ignition system,
diagnosis and testing.

If you have access to a working ECU in a Civic:
The pin number in the ECU which provides output to the ignitor (white wire)
could be any of several, depending on the particular model of car. Electrical
diagrams at both of the above sites do list pin numbers. E.g. For the 1988-1991
Civic LX, ECU pins C8, B8 and B9 are white wired and go to the distributor. At
the autozone site under chassis electrical, wiring diagrams, see Figure 20.

Also maybe worth skimming for more detail on the ECU pins is:

http://www.hondaswap.com/forums/index.php?showtopic=45852

http://honda-tech.com/zerothread?id=478377&page=2 (note especially turbogixxer's
post here about 5/8ths of the way down on the site)

For very detailed electrical information, the guys at the above two sites say
get the Helm manual for the specific vehicle and go to the electrical section.

I'm still thinking this may be on the net somewhere. Will post back if I find
the voltage.

 

Not sure exactly what you're up to. Are you just trying to see if this ignitor
has failed or not?

For ignitor electrical tests, see pages 16-50 (fuel injected) and 16-51 (carb'd)
of
http://www.honda.co.uk/owner/ConcertoManual/62SH200/16-48.pdf .

www.autozone.com 's free repair guides describe the same or similar tests under
Engine Performance and Tune-Up Procedures, PGM-Ig (sic) ignition system,
diagnosis and testing.

If you have access to a working ECU in a Civic:
The pin number in the ECU which provides output to the ignitor (white wire)
could be any of several, depending on the particular model of car. Electrical
diagrams at both of the above sites do list pin numbers. E.g. For the 1988-1991
Civic LX, ECU pins C8, B8 and B9 are white wired and go to the distributor. At
the autozone site under chassis electrical, wiring diagrams, see Figure 20.

Also maybe worth skimming for more detail on the ECU pins is:

http://www.hondaswap.com/forums/index.php?showtopic=45852

http://honda-tech.com/zerothread?id=478377&page=2 (note especially turbogixxer's
post here about 5/8ths of the way down on the site)

For very detailed electrical information, the guys at the above two sites say
get the Helm manual for the specific vehicle and go to the electrical section.

I'm still thinking this may be on the net somewhere. Will post back if I find
the voltage.

 

It's me!

Make up the LED test device as described in the zip file and
use that and the text instructions and the f/finding diagram.

Voltage signals are the wrong concept since the devices work
by current like 74 series TTL does. If you uncouple the signal]
wire to measure it on voltage alone, the lack of current may lead
you astray!

If the ECU can 'suck' a milliamp or two through the LED, making
it flash, then things are working.

HTH

 

It's me!

Make up the LED test device as described in the zip file and
use that and the text instructions and the f/finding diagram.

Voltage signals are the wrong concept since the devices work
by current like 74 series TTL does. If you uncouple the signal]
wire to measure it on voltage alone, the lack of current may lead
you astray!

If the ECU can 'suck' a milliamp or two through the LED, making
it flash, then things are working.

HTH

 

excellent! great to hear from you graham!

yes, i'm familiar with the old 74 series ttl - long time back, but
hopefully not all the neurons have decayed.

regarding the test, what i have is a working honda, and either a
non-working coil or a non-working igniter. i replaced both coil and
igniter after getting stranded one time. now i want to chuck out
whatever doesn't work. i've tested the old coil & it seems ok, but i'm
not confident that's an absolute result in service, hence now i want to
dry test the igniter. and i want to try this without stripping the
working car back down again because i have a broken finger which makes
for a little bit of a dexterity problem!

any thoughts?

 

excellent! great to hear from you graham!

yes, i'm familiar with the old 74 series ttl - long time back, but
hopefully not all the neurons have decayed.

regarding the test, what i have is a working honda, and either a
non-working coil or a non-working igniter. i replaced both coil and
igniter after getting stranded one time. now i want to chuck out
whatever doesn't work. i've tested the old coil & it seems ok, but i'm
not confident that's an absolute result in service, hence now i want to
dry test the igniter. and i want to try this without stripping the
working car back down again because i have a broken finger which makes
for a little bit of a dexterity problem!

any thoughts?

 

wow, thanks caroline. huge amount of info. i'll wade through it.

 

jim beam wrote:

74 series TTL came with totem-pole output and open collector output.
7400 is an example of the former, 7401 of the latter. I gather you mean
the ECU output is open collector.

I would hook it up as follows (terminal numbers pr.
http://www.gcw.org.uk/rover/igncloseup1.jpg):

0V: = 0V (ground)
T1: = leave open
T2: = 1 k ohm resistor to +12V
T3: = +12V
T4: = Leave open for now.

Then measure the voltage at T4. If the ECU is open collector (or likely
open drain) the ignitor would need to have a pull-up device. You should
see either about 12V or about 5V with T4 left open. If you have a
function generator, set it to a square wave, 25 Hz, negative peak to 0V,
positive peak to whatever you measured at T4 when it was left floating.
Hook the function generator to T4. This simulates the engine running at
750 RPM.

Now you should see square waves at both T1 and T2. You can also hook up
the coil (short the secondary to avoid painful surprises!) and measure
if you still get a square wave at T2 with the actual coil in the system
instead of the 1 k resistor. The resistor is a much lighter load than
the coil.

 

perfect - can measure t4 open & use that. thank you!