Ignition control unit faulty?

[BillCon]

I, have an 88' DT150 with an ignition timing issue, I, have narrowed it down to this, on the TVS, mine has a G/r, Br/Y and black wire when testing according to the manual I, can only get 1.2 volts at best on the G/r, Br/y, I, have 12.5v going into the pink wire to the ignition control unit but only 1.2 coming out then it fades to zero, the manual says min 3.6v am I, correct in assuming the unit is faulty? thanks for anything I'm over looking.

[Solarman]

88, dt150, timing issue

What was your original problem? No fire? Not starting?
The gear counting coil, and timing/ pulse coils, along with the magneto are where to look for timing issues. Have you checked any of these?
I am interested in what happened and have others with similar issues.

[BillCon]

Thanks for the Re, the motor started missing through out the rpm ranges,yet all spark plugs seem to fire, I, suspected the timing was jumping around, so I, completely went thru all the coil systems and the wiring, every thing was good, the only thing that doesnt check out is power to the TVS according to the manual should be between 3.64 and 4.39 which is a fixed value, I'm only getting 1.2 then it fades to zero the TVS checks out according to ohm readings, I'm not sure how often these things can go bad.

[Solarman]

TVs not getting power

Can you give me am ohms reading on your TVs wires, first disconnect the throttle linkage. I need the ohms at zero throttle, and the ohms at full open - by hand.
Well let you know something shortly after. Thnx.

[BillCon]

At the fully closed position it will read around 170 ohms and as the throttle is about 1-1.5 degrees it starts to jump and tops out at 240 then goes off, the continuity test shows the same on then off as soon as its advanced, when disconnecting the 3 wire harness and testing only the lead coming from the ICU there is about 1- 1.5 volts then goes to zero, I'm now wondering if there is not two different problems going on here as the manuals are kind of vague on the details

[Solarman]

88, dt150, running issues

Check the gear counting coil. If not close enough to flywheel, you will get missing on all cylinders.

[BillCon]

Good point, I, have not checked the distance on any of the coils come to think of it! thanks, you are a great help on suggesting some missing procedures.

[Solarman]

gear counting coil

The gear counting coil is the only adjustable coil. The timing/ pulse coils under the flywheel are fixed position coils. Can't be adjusted. However, it is important to inspect the magnets under the flywheel, if the epoxy is cracked/ magnets are loose at all, then do NOT use. You do not want magnets coming loose to eat up the magneto, as mine did.
Let us know how it's going.

[BillCon]

Well I, did a check on the all the coil distances and with a pulser coil tool I, borrowed, the counter coil was off from the .003 the manual shows it was at .015, but still strange volts of power coming out of the ICU that fade out, the engine will start and run even rev up under a load, but misses and lacks full power, I, really just dont know where to go from here, its not the carbs they are completely cleaned and fresh fuel, so I, guess its back to the beginning unless somebody sees something I'm missing.

[Solarman]

dt150, 88, running issues

Have you removed your flywheel yet? Easier to visually inspect rust or damages?
Do you have the wiring diagram for your stator/ magneto assy?
I need you to do a resistance reading on all your coils in the magneto.All the wires come out from under the magneto by the control module. If you have wiring diagram, you can identify what the wires go to without removing flywheel. Can check timing coils (3), gear counting coil, primary coils (1&2), charging coils (2).
Can you slide a couple small wires into the connector (back or front, while it's still plugged together?) for your tps voltage test? I'm not liking that it goes off, unless you moved it passed where WOT should be? Test for ohms with key off (unplugged, tps wires only), test for volts with key on (plugged together, not running), should be steady volts. Ohms should be steady at neutral (lowest reading), and increases to WOT (highest reading).
Can test tps before unplugging magneto wires for testing.
Let us know the coil name and values, wire colors won't help me, just you.

[BillCon]

Yes, Thanks I, do have a diagram, I, took off the flywheel, there was minimal rust which I, sanded clean and checked any loose magnets, I, can only imagine yours when one came off, that had to be ugly!, LOL But went thru every coil according to the manual and all of them were in specs and the counter coil is now at .003 I, just put on the inline test wire for the TVS the 3 wire one with G/r Br/Y and Black, one minute I, can get a reading on ohms when testing it by itself unplugged then its gone when I, plug in the test wire and turn the key on it will read 2.83 volts sometimes it fades to zero, when it does stay and I, advance it slowly its gone as soon as you touch it, then its hard pressed to even get a .05v reading, I'm now wondering if this TVS is causing the problem now.

[Solarman]

88, dt150 running issues

So you lose voltage from the icu, and you're using the proper test wire for this test? Where does someone get these wires?
It actually sounds like the icu may be acting up. You tested the tps according to the book, and sometimes the voltage drops to zero? And manual says constant voltage?
Does book give any other tests for icu??
Let us know.

[BillCon]

I, got the 3 pin test wire from speedsupplies.com part #09930-89230 $15.53 I, have a Downloaded Suzuki workshop service manual that covers motors from 2-225 thru years 1988-2003 the manual says more testing can be done with the stevens model 77 peak voltage tester, but I'm thinking of just taking the ICU off and take it down to the suzuki repair shop to be checked out, rather than buy a tester, but with the TVS not being constant enough to find out even on ohms test , I, could be chasing my tail here, I, started the motor last night on the muffs and it cranks right up and idles it even has the big block with a cam sound and all plugs were firing but but when "slightly" advancing the throttle it something happens to the timing it seems, so thats why I, went into thinking it was the TVS or ICU, I'm hoping when this gets solve it may help others.

[Solarman]

TVs, or icu

BC, I'm thinking if you bite the bully on the TVS you will be able to decide if you have to go farther. It is much less costly than the icu.
I think you've done your homework here well.
I let's recap...
Out starts fine, idles ok, but the moment you advance the throttle, it starts acting up, is this correct? Very much like your test of the TV sensor, the moment you advance out started acting up.
If you do a search for your TVS part number on Google, you might get a number of hits, may even be a little cheaper?

Maybe you can help a few people here online that have a similar motor iron out some of their readings. That's what helped me the most. I have acat, with two motors, if I have problem with one motor, I check readings on the other to figure the problem out. For example, when you get a moment, check the thread, listed as ”peter13”, name is dkshooter. Read dk's thread and see if any of his readings seem off. Thnx.
Good luck, let us know how it all goes.

[BillCon]

Thanks for your help on this I, will be relentless on this until I, find it and share the findings here, I, have read a lot of threads on this also that are similar, we can all work together on these problems and maybe save people lots of time and money, and yes it all seems to revolve around the TVS I'm really thinking this is timing related, so I, took it off to test the ohms again, it tends to jump on the readings instead of a smooth change, the idle is like a big block with a cam like they should be and when you so much as touch the throttle or the idle speed screw it jumps up 500+ rpms, didnt notice that before, so I, just ordered one for $79 will let you all know what I, find out.