99 forester no start

[aa8jzdial]

1999 forester manual

Went out to start a couple of days ago and only cranks. Good and strong.

The long and short of it is no spark from the back 2 terminals coming off the coil pack. cyclinders 3 and 4.

Front 2 jump 1/2" or more to ground.

I don't have a code reader nor a full blown schematic.

 

The coil pack has a 4 terminal connector.
Using an oscilloscope I found the front most terminal on the coil pack jumps from zero volts to 12 volts in time with the cranking.

I assume this drives the functioning half of the coil pack. I found no other terminal doing this.

If I knew which pins from the ECU fed the coil halfs I could at least cut my troubleshooting in half.

 

I read somewhere about an intermediate ignition driver module but not sure my 99 has such a thing. If it does, I did not locate it.

 

Can anyone recommend a good source for an official full blown shop manual?.

I used to have this info but my old laptop died and darned if I can now locate a source.

If worse comes to worse, can I order an internet copy somewhere?

 

thanks

rick

cold and snowed in west michigan

 

[ocei77]

Here is link for Legacy 2.5 etc. IIRC the engine specs are the same.

Don't have a Forester dedicated link, though you could join the Subaru Forester Owners Group and perhaps find it there.

www.main.experiencetherave.com/subaru_manual_scans/

 

O.

[lmdew]

If you have spark on 2 it should be firing at least.  

 

I have several coil packs if you need one.

 

Larry

[Gloyale]

Transitor unit which ups the signal and passes on the ECU's spark pulse to the coil is mounted to the firewall, just about center.

 

These coils are paired units.....2 seperately powered and triggered parallel circuits.  I believe there should be 2 wires with 12v in, and 2 more with 12v out leading to the 2 halves of the coil.  As well as 1~2 more signal in, (- pulse) and 2 signal out to coil.

 

Check for 12v out of in and out of this transistor , and a pulse set on both circuits.

[aa8jzdial]

humm.

Looked long and hard for the mysterious transistor unit.

Tommorow when I get the garage thawed out, I will look again.

I can't imagine a module with a couple of transistors being large.

This definately is not incorporated with the ignition module itself??

I need to wade through the schematics more to locate it.

Thanks for the help.

rick

[aa8jzdial]

I looked high and low for the ignitor.

I have not found it.

This leaves me to believe my 99 has the ignitor intergrated with the ignition coil.

Also stumbled across this very interesting site:

 

http://www.northursalia.com/techdocs/pdf/electrical/ignition.pdf

 

Not all vehicles have an ignitor seperate from the ignition coil (coil pack).

 

I think if the ignition coil has 4 terminal connector it is ignitor and igniton coil combined.

If the ignition coil has 3 terminal connector it is used in conjunction with external ignitor.

From my understanding the ignitor is an amplifier that bumps up the pulses to the ignition coil.

 

Since I am getting a pulse only to 1 coil this leads me to either the ECM is shot or an open circuit from the ECM to the coild pack wiring.

 

According to the above link note that both secondary windings (high voltage) are completely floating from ground. Therefore measuring the hv output of the coil pack with an ohmeter to ground will show infinity. The ground is artificially obtained by the opposite, nonfiring spark plug, soft firing, simulating a ground.

Neat, Huhh?

 

Or am I missing something?

 

My attempts at getting an accurate schematic of my 99 forester igniton system failed.