Yamaha 150TXRB no spark on 1-3-5 cylinders and we're on vacation!

[boscoe99]

Each head is grounded to the block via a jumper wire. If that wire is broken, or if the connections at either end are compromised, then possibly the starboard side head is not being grounded. In which case there might not be a ground reference to the plugs on that side.

One would think the head bolts would serve as an alternate ground but maybe not.

I would check that wire. Only thing I can think of in a 150TXRB that would cause the loss of all cylinders on one side. Innards of the CDI might do it but I have no knowledge of those innards.

Oh, 6G4X 1004437 is a model 150TXRB. No doubt about it.

[joelisajer]

Boscoe
Thanks for the advice, I'll check that tomorrow. Although I have been checking spark to the head bolts as you suggested and agree that that should be sufficient. I am perfectly perplexed on this. Without knowing the "innards" of the cdi, I can't trace this in any more detail.
Today after changing the pulser with no success, I decided to isolate the engine harness and ring out every wire for continuity or short. All is good. BTW- with the engine harness disconnected and jumping the starter solenoid, I still get the same results.

I measured resistance values on the charge coils, but don't know what the values should be. Any idea what it should be?

I'm open to anything right now. The only two things left in the ignition system is the stator and flywheel assy.

Thanks again,

Joe

[rodbolt17]

dude
on the time you have spent posting and chasing ghosties you could have bought a DVA adapter and simply tested pulser coil output,why I dunno buut it sounds good.
tested stator charge coil output,loaded and unloaded, then CDI output.
this would have found the failed component.

based on the 150TXRB model code its a simple 3 pulser movable timer base CDI ign system.
no magic in the CDI box.
it amplifies NOTHING.
all it does is rectify and store whatever the charge coils send it and discharches a capacitor into the coil primary based on signals from a pulser coil.
pulsers fire 1and 4
2 and 5
3 and 6.
odds of shorting one leg of 3 pulsers are slim to none.
that system uses a high and low speed charge coil so if one bank has charge coil voltage so will the other.
odds of 3 coils failing on the same side are slim to none.
play the lotto instead.

[boscoe99]

Rodbolt,

are you now saying the 150TXRB uses three pulser coils to fire six plugs and not two pulser coils and the crank position sensor to do this?

[boscoe99]

I just found this verbiage which I believe relates to your model.

The low speed charge coil is a two wire coil. The output voltage from one side of the charge coil supplies source voltage for cylinders 1, 3 and 5.
Output from the other side of the charge coil provides source voltage for cylinders 2, 4 and 6.
If the low speed charge coil should experience an open circuit, no voltage would be supplied to the CDI and no cylinders would fire. If one lead of the
charge coil should short to ground, three cylinders would not fire.

[rodbolt17]

on the 150TXRB the low speed charge coil provides operating voltage for ALL 6 cyl below about 2500 RPM, the the HIGH speed charge coil takes over.
the 150TLRB version was carbed and used 2 pulsers and the CPS to fire 6 cylinders the SX150TLRB used 6 pulser coils to fire 6 cyl.
see why model numbers are great??????
the SX pulser coil base is fixed the 150TXRB was movable.
the SX150TXRB uses a charge coil that is bank to bank, the 150TXRB uses a high and low speed charge coil.

on the 150TXRB if you lose a pulser you lose at least 3 cylinders.
if you lose the CPS you lose two cylinders.
this thread has hopped about so much I am getting confused.

but you can basically break the Yamaha 2.6L ign sytem into groups in that year.
1 smart motor, 2 pulsers and a CPS with carbs.
2EFI 6 pulsers and 6 throttle plates and 6 injectors.
3 HPDI with 6 pulsers 6 throttle plates and 6 injectors and a belt driven high pressure pump.
the smart motor uses 2 pulsers to control spark on 1&4 and 3&6 2& 5 are generated by the ECU based on CPS signals.
however if you lose a pulser the computer defaults to bypass mode and ignores the CPS and typically you lose 4 cylinders.

[joelisajer]

I just found this verbiage which I believe relates to your model.

The low speed charge coil is a two wire coil. The output voltage from one side of the charge coil supplies source voltage for cylinders 1, 3 and 5.
Output from the other side of the charge coil provides source voltage for cylinders 2, 4 and 6.
If the low speed charge coil should experience an open circuit, no voltage would be supplied to the CDI and no cylinders would fire. If one lead of the
charge coil should short to ground, three cylinders would not fire.

Boscoe,
Thanks for another suggestion. Where did you find that info about the charge coils? . I can tell Rodbolt is losing patience, but I have to say I understand all that he explained and agree with the logic- I understand that I have two charge coils(high and low speed), two pulser coils that switch based on cps to provide spark in pairs 1&4, 3&6,and 2&5 on the switch off , and a CDI that just rectifies and passes the pulse.

The question has always been how can I lose spark on one whole bank? No hopping around. This problem has been consistently "no spark 1-3-5". Rodbolt suggested that only the CDI could do that. Changed the CDI. Okay so maybe a bad input to the CDI. Changed the cps. Okay so maybe pulser signal is intermittent to the CDI. Changed pulser coil.

It should become very easy shortly to figure this out because the are no more components besides the charge coils and the flywheel. I've been racking my brain on this, so your two wire charge coil theory sounds plausible I suppose, especially if it can kill cylinders 1-3-5. Charge coils did test good though producing 177v and 55v, but maybe that is not the whole story.....

I'll certainly be sure to let you know the final fix. There are is definitely something missing in this equation though.

[rodbolt17]

on the EFI motor the charge coils are bank to bank and BOTH coils have the same resistance and the output voltage is the same.
on the carbed version it is high and low speed and each coil supplies voltage to both banks and the resistance and output voltage is dramatically different.
as they are two wire coils it is remotely possible to short a leg and drop the output voltage, not likely but possible.

[99yam40]

Charge coils did test good though producing 177v and 55v, but maybe that is not the whole story.....

Did you measure the loaded charge coil peak voltages while there was no spark on those cylinders?
Did you take CDI peak out put voltages at that time also and what were they to the good and bad sparking cylinders

[joelisajer]

Testing loaded is while running with all connections connected s normal, correct? So if it will continue to run on three cylinders, I can try. All my tests thus far have been during cranking. Would I expect to see significant difference between cranking and running testing loaded?

[99yam40]

Manual has specs for both, but is you cannot keep it running on 3 cylindrs it would be hard to take readings.
Was just wondering if you had good voltage from charge and pulser coil into CDI and what the voltages were coming out of the CDI to the ignition coils.

Seems this would be the way to see what is in spec and what is not, to figure out what problem is

[joelisajer]

Manual has specs for both, but is you cannot keep it running on 3 cylindrs it would be hard to take readings.
Was just wondering if you had good voltage from charge and pulser coil into CDI and what the voltages were coming out of the CDI to the ignition coils.

Seems this would be the way to see what is in spec and what is not, to figure out what problem is

99Yam,
From the get go I checked everything according to specification. I have the yamaha manuals, not the Clymer or after market. Charge coils were 177 & 55 volts cranking. Pulser coils read exact the same resistance and about 0.4 volts depending on cranking speed. This was done with a peak voltage digital multimeter on AC setting, but not with DVA. Ignition coils I performed spark test. All checked out with1/2 inch spark when connected to the cdi leads to the left bank. I redid all this again this week to double check and now seems I'm getting no spark on #2 in addition to 1-3-5. So only 4&6 firing now!

CDI , cps and pulser changed out in that order. I have not done the loaded test, but if I can keep it running to check voltages, what else could be wrong except the stator? Flywheel?

Thanks,
Joe

[ausnoelm]

I guess that it is possible that while replacing parts and "testing" you could have introduced a fault??? I have seen that before.

[boscoe99]

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[99yam40]

This was done with a peak voltage digital multimeter on AC setting, but not with DVA.

Just exactly what meter are you using?
From what I have read in the manuals the meter should be on DC not AC when taking the peak voltage readings, even with the DVA adapter

If it is not a meter made for these ignition systems then you need a DVA.

I know the Fluke 87 I have ,set on peak did not give the proper voltage reading to compare with the specs. Had to get a DVA

loaded can be taken at cranking speed also , does not need to be running to get the cranking voltage but higher RPM specs are not going to be got if you cannot get to that RPM

Need to know if peak voltages into and out of CDI meet minimum specs like the manual calls for on all Charge and pulsers.
Testing with proper test equipment works a lot better

I agree with ausnoelm, Changing so many parts you could have damaged pins/connectors or wiring already.
So I would start testing from the top again with proper test equipment