2003 Z150TRLB ECM Main Relay Issue

[Mr. Nice Guy]

This might sound dumb, but did you go through the troubleshooting section in the manual for the engine-does-not-start condition? It's actually quite good in most of the manuals I've read. It's meant to keep you out of rabbit holes.

I'm not sure I understand the reason for testing anything except continuity if the engine starts when you bypass the relay. If continuity is good from the start switch to the main relay, and the wires are in the right pins according to the diagram, I would take a break and go back through the troubleshooting map.

Never a bad thing to learn more about wiring though.

You make excellent points. My hope was that someone had experienced a similar issue and could provide some help in reaching a quick resolution. I will resume working my way through the troubleshooting guide.

[rejesterd]

I still want to know what the ECU peak voltage you are going to measure goes to(is suppose to do)

Transistor con*****ed ignition (TCI) uses a transformer to store charge instead of a capacitor (like in CDI systems). The charge is stored in the magnetic field created by the windings in the primary ignition circuit. At key-on, the main relay allows the battery to power the primary ignition circuit as well as the ECM. The secondary circuit is created by the magnetic field generated from the primary. The primary and secondary circuits make up the transformer. When the ECM receives a signal from the pulser coil, the ECM will interrupt the primary circuit (via a transistor switch). When that happens, the magnetic field collapses and releases the charge to the spark plugs via the secondary circuit.

Measuring the output peak voltage from the ECM tells you if the coils are being properly charged. If it's too low, then you have to check the output peak voltage of the pulser coil to make sure that's it's also not below spec. If the pulser coil is above spec and the ECM is below spec, that means the ECM is bad. If they're both below spec, the pulser coil should be replaced, and then the ECM & pulser coil peak voltages should be checked again to make sure they're ok.

[rodbolt17]

OMG
the amount of lack of knowledge is killing me.
if your looking at YDIS why bother checking relays?
TCI ignition DOES NOT store jack.
TCI uses a transistor like a set of points from years back.
if you understand how points worked for 80+ years TCI is the exact same.
my suggestion is, if you know nothing of basic electronics or how the subsystems work on HPDI, take it to someone who does.
if it will run by spraying a combustible mix down the intake why bother testing relays and such.
fix the fuel delivery system.
yes Virginia it is that simple.

[rejesterd]

the amount of lack of knowledge.. yeah, stunning.

The charge comes from the transformer collapsing. Yeah, it's not "stored" like a capacitor, but that's where the charge comes from.

[Mr. Nice Guy]

The entire concept of a forum is to share knowledge - and to help others be able to do these sorts of "simple" diagnosis...

If you truly want to help others - then do that graciously without flaunting your exasperation at their lack of skill.

Be part of the solution, not the problem. If you have knowledge of how to fix my problem, I'll gladly accept it. Yes, you'll have to speak slowly and maybe point out a thing or two... but, if you just want to get on a high horse - then, please, ride away on it.

No, I'm not good with electronics... but I'm humble enough to admit it and ask for help. This isn't rocket science...

[Mr. Nice Guy]

if your looking at YDIS why bother checking relays?

Because one relay isn't closing. The YDS shows green across the board.

if it will run by spraying a combustible mix down the intake why bother testing relays and such.
fix the fuel delivery system.
yes Virginia it is that simple.

Because, the relay that supplies the injectors isn't closing. There's a ground fault when the key is turned on coming from the ECM (or, something that's causing the ground to be faulty)...

I'll say it again for those just joining - if I jumper the relay... motor fires and runs without issue. Something is preventing the relay from energizing. I've traced it to the L/R wire coming from the ECM. For some reason it's not giving a "full" ground signal with the key on.

[boscoe99]

OMG
the amount of lack of knowledge is killing me.
if your looking at YDIS why bother checking relays?
TCI ignition DOES NOT store jack.
TCI uses a transistor like a set of points from years back.
if you understand how points worked for 80+ years TCI is the exact same.
my suggestion is, if you know nothing of basic electronics or how the subsystems work on HPDI, take it to someone who does.
if it will run by spraying a combustible mix down the intake why bother testing relays and such.
fix the fuel delivery system.
yes Virginia it is that simple.

We have not had one like this in a long long time.

[boscoe99]

Well, I've been doing more research - and, I've found a supplemental manual for my specific model - and, the colors match!! I'll post the "new" diagrams shortly. I'm working on trying to figure out exactly what each pin-out on the ECM represents.

Something is not adding up on my end.

The service manual that you say you are using is LIT-18616-02-82 (68F-28197-1F-11). That is not the SM for a Z150TLRB model.

The service manual supplement that you have mentioned is LIT-18616-02-22 (68F-28197-Z9-11). That supplement is applicable to SM LIT-18686-02-10.

I suggest that you get the correct SM for your model. Then start a completely new thread (sorry, this one is now useless) wherein you fully describe the problem that you are having.

[99yam40]

Transistor con*****ed ignition (TCI) uses a transformer to store charge instead of a capacitor (like in CDI systems). The charge is stored in the magnetic field created by the windings in the primary ignition circuit. At key-on, the main relay allows the battery to power the primary ignition circuit as well as the ECM. The secondary circuit is created by the magnetic field generated from the primary. The primary and secondary circuits make up the transformer. When the ECM receives a signal from the pulser coil, the ECM will interrupt the primary circuit (via a transistor switch). When that happens, the magnetic field collapses and releases the charge to the spark plugs via the secondary circuit.

Measuring the output peak voltage from the ECM tells you if the coils are being properly charged. If it's too low, then you have to check the output peak voltage of the pulser coil to make sure that's it's also not below spec. If the pulser coil is above spec and the ECM is below spec, that means the ECM is bad. If they're both below spec, the pulser coil should be replaced, and then the ECM & pulser coil peak voltages should be checked again to make sure they're ok.

this peak voltage you speak of from the ECU to the coils is battery voltage, is it not?
there is nothing in the ECU generating voltage

But why even go that direction on ignition/spark if his problem is not spark related?

I agree, this thread is long and full of all sorts of bad info even from the OP at the beginning , maybe a new thread started with the real known problem and what you are actually looking for would be a good idea.

( why the injector driver relay will not energize)

[Mr. Nice Guy]

I suggest that you get the correct SM for your model. Then start a completely new thread (sorry, this one is now useless) wherein you fully describe the problem that you are having.

Thank you. I'll do just that. Is there any way I can remove this entire thread?

[boscoe99]

I don't know how to delete a complete thread. Might not be doable.

One more thing plz. Look at the main engine wire harness for the part number of same. Usually it can be found near the ten pin connector at the front of the motor.

[99yam40]

are you thinking someone replaced the motor wiring harness maybe?

or just trying to be sure what motor he has?

I wonder if the OP flagged this thread or just one of his posts and asked for the thread to be deleted that might work

[rejesterd]

this peak voltage you speak of from the ECU to the coils is battery voltage, is it not?
there is nothing in the ECU generating voltage

I didn't say the ECM generates voltage. Maybe I incorrectly worded it in my first draft, but the quote you noted is what I ended up posting. I said you have to measure the peak voltage from the output of the ECM going to the ignition coils.

But why even go that direction on ignition/spark if his problem is not spark related?

Because it won't start unless the relay is jumped, and he noted that someone stuck an incorrect relay in there at some point. The end of the line in troubleshooting this is the ECM. Seems better to rule that out first (because then you have some decisions to make about whether you want to fix this or not) and not get lost in a wiring rabbit hole.

[Mr. Nice Guy]

I don't know how to delete a complete thread. Might not be doable.

One more thing plz. Look at the main engine wire harness for the part number of same. Usually it can be found near the ten pin connector at the front of the motor.

If you're referring to the round connector that is for the controls/gauges - I can't find any label or indication of a part number. It looks like maybe there was a sticker of some sort on it at one time... but, nothing now.

[fairdeal]

I said you have to measure the peak voltage from the output of the ECM going to the ignition coils.

I would certainly like to know more about this.

Can you elaborate for us, exactly how this "output of the ECM" goes "to the ignition coils" ?