Did some searching, but am unable to find the next step in diagnosis...

I've got no spark, I checked the black/white wire to one of the solenoids with key in on position and it's getting power. Checked the Black/white wire to trailing coil with key in on position, it's getting no power.

How do I diagnose no power to the trailing coil?

I've got a Turbo S4.

 

Oh.. also--when I turn the key to on the Main Relay clicks.

 

The Black/Yellow wire is what powers the coils. W/key to on this wire should have power, and if it doesn't, then check the 40 amp EGI INJ fuse in the engine fuse box.

 

The Black/yellow wire to the coil has power with the key to on. The EGI INJ fuse is good.

 

Also, there is no B/W wire connected to the trailing coil and you likely confused the B/Y wire for being B/W, but again, this is the wire which powers the coils so if you have power to the coils via the B/Y wire your problem is then not a function of the coils not being powered as you already verified. If you barely pull the plug off the leading coil bore and try to start the car you should see spark and this is one of the easiest and reliable ways of testing for spark. If there is none then the problem could be ECU related or CAS related.

 

I just tried what you suggested on all 4 plugs and saw no spark. I pulled the plugs out just enough to expose a slight gap so I could see if there was any spark. Nothing. I checked power to the ECU by checking for power on one of the black/white wires to one of the solenoids with the key in on position and it had power. I've also tried 2 CAS's with the same result.

 

check the engine fuse inside the cabin by your left foot.

 

Since you have a spare CAS go ahead and disconnect the one mounted in the car and connect the spare CAS up to the connector, and w/key to on, spin the CAS and listen for a sound coming from the injectors as it should be audible. If they don't make a sound then there is possibly a bad connection between the CAS to the ECU.

 

That was the first thing I checked. It's good.

 

I just gave that a shot. Connected up the spare CAS, slowly spun the gear and got no sound from the injectors. Are there any connectors that you are aware of between the CAS and the ECU that I can eyeball/check to make sure the connection is secure?

 

There's one connector b/t the coil assy and the ECU. ITs name is FE-04 and has four wires in it the same color of the wires leaving the CAS.

Perhaps this is another of those cars who have lost the ref voltage created inside the ECU. One way to find out is to pull the elect plug off the boost/pressure sensor and seeing if there is approx 5vdc on the BROWN/WHITE wire in that plug. Key to ON. So? What happens if you do that?

Lets say you have 1-3vdc there on the brown/white...........then pull the plug off the afm and the TPS and see if the voltage goes up to approx 5vdc or not. What happened?

Having power to the black/yellow at the coils and power to the black/white on the solenoid rack means the Main Relay is pulling in and the computer should have power going to it along with injector power. Just FYI.

 

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As far as the B/W wire having power at the solenoids does not necessarily mean the ECU is receiving voltage. A check of pin 3I w/key to on would indicate the ECU is powered.

There are two plugs which are part of the CAS wiring and one is at the CAS. Make sure the pins are not pulled back or dirty providing for a bad connection. The other plug is an intermediate plug between the CAS plug and the ECU and it is found near the Brake Master Cylinder/trailing coil. The connector is called FE-04 and there will be four wires from the CAS in this connector of two plugs and the wire colors are Green, Blue, Red and White.

 

Key to on, 5vdc on the brown/white wire. Pull the TPS and the AFM plugs and the voltage stays at 5vdc.

 

After a little digging, I found that plug down under the Master Cylinder/Trailing coil. I've never unplugged any of those plugs down there (had the car for 13 years), so while I'm down there, anything else I could/should check?

 

Check the CAS ohms signal at the ECU plug (plug disconnected).

 

sounds to me like the ECU isn't coming online, can you pull codes to see if the ECU is actually doing anything at all?

 

Excuse my ignorance. How do I go about 'pulling codes'?

 

http://2ndgenrx7.freeservers.com/error%20codes.html

 

That's good. Means at least the ECU is getting power.

The coils assy is getting power 'cause you say the black/yellow wire at each coil assy is showing power (even though you described it as black/white and not the black/yellow that it really is).

We assume the CAS plug is on the CAS.

I'd do whatever all the above posts say to do.

Coil assys MUST be bolted to the frame with at least one fastener for the ignitor in the assy to work. Just FYI.

 

missed that, so the ECU is working and sending outputs. pulling codes still might not be a bad idea if it is an '88 or later with a check engine light.

next step, get a new spark plug and put it in one of the plug wires, lay it on a good ground point and have a helper crank the engine over. excuse my doubt but i find that at least 90% of the time when someone claims they have no spark 10 minutes later they come back and correct themselves.

the fact you can't hear the injectors may be true so you could be that one in 10 since the injectors and coils get power from the same source. but power isn't the issue here, it is the RPM output signal.

 

The Black/Yellow to the coil is *not* getting power.

 

In post #4 you said differently! If you are not getting power on the B/Y wire w/key to on then check for voltage at the Main Relay on the Black/Green wire no key necessary and it should have battery voltage. If it doesn't then either the EGI INJ fuse is no good or the wire connection from the engine fuse box to or at the Main Relay 4 wire plug is no good. If the B/G wire does have voltage then disconnect the 4 wire Main Relay plug and jumper the B/G to B/Y and the W/L wire to B/W in this particular relay plug and try to start the car.

 

IN that case I'd check and make sure the MAIN RELAY is passing the power on to the coils.

This is not hard to do. The power leaves the EGI INJ fuse in the enigne bay and goes straight to the main relay. Then leaves the main relay and goes to the injectors and the coil packs.

A good ENGINE fuse in the interior is required for the MAIN RELAy to pull in..........plus the gnd wire on that main relay plug has to be going to a good gnd point.

Key out of the ignition and meter out. Neg meter lead to a known gnd point and then find the two pin connector of the main relay. The black wire should be gnd and show less than one ohm. If you see 0.4 or 0.6 that's plenty good fine.

The black/white wire on that same plug should show batt power if the key is put to just ON.

And or you could pull the four wire plug apart on the main relay and jumper the Black/Green wire to the Black/Yellow wire and then also jumper the White/Blue to the Black/White in that same plug. Then go start the car or go look and see if the black/yellow at the coil assys is now there ......or not. Should be there if both EGI fuse are good.

Prior to that you might just pull the four wire plug off the main relay and see with a meter if the White/Blue and black/green have batt power on them. Should seeing as how they come straight from the engine bay fuse box. Then again maybe the Black/Green has a shakey connection at the bottom of the engine bay fuse box????????

I gotta get off this forum. I don't read all the threads anymored, just parts.

 

Just like you said..that Black/Green wire at the bottom of the fuse box had a shakey connection. Pulled it out, cleaned it up, spliced it back in. Now I've got juice to the coil. Problem solved.

Lotsa thanks to everyone that put in their .02 cents! Saved me about a week of pulling my hair out trying to trace this problem down.