84 XVZ1200 - no spark, electrical help plz

[spartikus]

I have been on an epic journey the last 3 days playing with my new bike and posted a crap ton of details on another forum but hoping to get more sets of eyes here Alot of these details I have been typing over and over for several days so I'll try and just keep it to the facts at hand. Thanks in advance for any help or advice.

 

The bike:

- 1984 XVZ1200

- Hadn't been on the road in 4 years (or started)

- Got it running in a few hours. Ran awesome and started no problem

- Changed oil (twice, let it run for 29 mins and changed again) just to be safe

 

The Issue:

- After knocking a wire loose putting on the plastics the bike will no longer start. It turns over, all the accesories light up, headlights work, signal lights work, hazard lights work but no brake lights and wont start.

- Putting the plastics on the bike (they came to me in several boxes) I bumped a black wire that a PO had obviously jury rigged into something near the front of the bike. The wire came loose in my hands before I could trace it to where it may have been attached up front. It lead down to the rear brake switch which is a three wire switch (should only be two wire I think) and a PO had basically butchered up the wires down there I think making the three wire switch work on a circuit designed for a 2 wire rear brake switch.

- Before I knocked the wire loose the bike started and idled like a champ. All brake, hazard and turn signals worked perfectly.

 

What I know:

- The kill switch is not the problem tested many times with multimeter 9 ways from Sunday.

- The Tip Over switch is not the problem. Tested an equal number of times.

- Pulled the B/W plug from the TCI to bypass the interlocks perdiod (That stops them from interfering with the ignition yes?)

- I have 12V to the coils when the ignition is on

- I have no spark to the plugs cycling the engine with the starter

- The bike started and ran great for the 30 minutes I had it running and it wasn't until the wire fell off in my hand that it wouldnt start and the brake lights didnt work.

 

What I "think" I know:

- The bike should have a 2 wire rear brake switch not a three (based on the fact that the three wire switches are for bikes with venture cruise. My bike has a cruise control but it is just a throttle lock installed by a PO)

- A 2 wire front brake lever (which is what my bike has) shows a closed circuit in the free position and an open circuit when the lever is actuated. This is different from the 4 wire lever circuit.

- A PO had jury rigged the yellow wire from the rear brake switch over to the Yellow wire going to the rear tail light

- A PO had taken the brown wire lead from the rear brake switch and run it up to something at the front end of the bike. (this is the wire that fell into my hands and started this whole mess)

- A PO had spliced the brown and Green/Yellow wire coming back to the rear brake swithc together (I think but I am not positive as the electrical tape job and wiring mess was impossible to see as I pulled it apart). He then put a lead from the Br and G/Y wire he spliced together and wired it into the Green lead from the rear brake switch.

 

My querry(ies):

- I HAVE BEEN MAKING MY EYES BLEED FOR THREE DAYS TRYING TO FIGURE THIS OUT HALP ME!!!

- Whew ok now that THAT's over with As I stated the bike was running like a top until that wire came loose. Sure it could be coincidence but I sure would like to get this figured out.

- Does anyone know what the hell he might have plugged that brown wire lead from the rear brake switch to at the front of the bike? I'm guessing the computer monitor but man not interested in risking the CPU with a guess.

 

Any thoughts, suggestions or anything gratefully appreciated.. Even if it's just you telling me to go have a beer

 

Thanks in advance folks,

Mark

[MiCarl]

Without looking at a wiring diagram:

 

Yamaha typically uses brown wires for switched hot. He probably grabbed power for something from the brake light circuit.

 

Does the motorcycle have the original glass fuse panel? If so replace it. It's prone to failure with age and one of the "hacks" amateurs do is to steal power from elsewhere when it fails.

[bkuhr]

If you pulled these entire 6 pin plug with the B/W wire at the TCI, then you also disconnected the ignition pickups. this plug needs to be connected.

 

 

Sounds like a side stand switch issue. connect all 3 wires at the side stand together. If this fails connect the B/W wire at the TCI to ground to bypass the safety devices. do not leave like this!

[bongobobny]

This should help...

 

http://www.venturerider.org/wiring/84-85%20Yamaha%20Venture%20L%20Simplified%20Circuit%20Diagram%20Rev%20C.pdf

[spartikus]

*EDIT* Wow, typing 140 WPM without my morning coffee = almost unreadable

 

Thanks for the responses all.

 

Just to be clear I did not pull the ignition stuff out of the TCI. I disconnected the B/W lead only. I didn't know I should ground it though. I'll check that.

 

The PO had soldered a bunch of the fuse box up. As part of trouble shooting the issue I replaced the fuse box with a new AGC one. I'll replace it again with a mini plug but didn't have one available at the time.

 

The kickstand sensor I didn't test but it correctly shows on the computer readout up or down. That being said I'll try jumping the wires (I'll confirm on the electrical diagram first) as that is one interlock I havent tested yet.

 

Whatever the PO did to the brake wiring was actually working fine if I could just figure out where he had that 12V lead tied in.

 

Anyways, as part of my troubleshooting I am going to see if I can get my hands on a 2 wire rear brake switch as that is what the bike should have I believe.

 

Thanks again for all of the suggestions guys.

Edited September 23, 2014 by spartikus

[Neil86]

Actually the b/w interlock wire from TCI has to be open (not grounded) for TCI to operate.

 

Yes the sidestand switch closes when stand up but the sidestand relay opens.

[spartikus]

Thanks to Neil's help I did some further testing:

- 11.3 V between the TCI R/W and B leads with ignition on. (had to clean up the fuse block grounds a bit. Rest of the grounds seem fine.)

 

Going to test the resistance on the stator sensors next.

[venturesome]

I had a similar problem when the connector to the pickup coils came loose. It is located below the seat near the front (left side).

[spartikus]

Thanks venturesome. I will double check but I did do a coil test and was getting 116ohm on 3 and 113 on the last coil. That is withinspec I believe (110 +/- 15%)

 

I'll double check the connector though

[Flyinfool]

Since you have pulled the B/W wire from the TCI it can not be the side stand switch or side stand relay since they work by grounding the B/W wire from the TCI.

 

On the bigger of the 2 connectors on the TCI check for 12V from the Red/White to the black wire. This will verify both the power and ground sides of the ignition.

 

It normally would sound like 2 distinct issues with the brake and ignition going out at the same time, they are very unrelated. But since the PO was playing with the wiring, anything might be possible.

 

As for the brake switch, that sounds like a mess. from what you are describing it sounds like the PO bypassed the Computer monitor and wired the brake switches direct to the brake bulbs. The computer monitors are very well known for bad solder joints that if/when they fail the brake light will no longer work. This can also happen to the headlights and tail lights as they all go thru the computer monitor.

 

You can leave in the 3 wire rear brake switch just use the 2 wires that have the correct switching to work and insulate the third wire.

 

Here is the wiring digram for your bike with all of the connectors shown.

http://www.venturerider.org/wiring/84-85%20Yamaha%20Venture%20L%20Wiring%20Diagram%20Rev%20C.pdf

[Flyinfool]

Stupid puter.......

[spartikus]

TCI voltage is 11.3V

 

While cranking it drops to ~8.5V but seems normal that it would drop under load with the starter pulling the majority of the power.

 

I was out in the garage until 11:00 last night with the multimeter. All measurements are coming in on spec. I am a total rookie with bikes but from what I am reading it sounds like a bad TCI :/ Want to check the secondary coils on the ICs but the primaries were all about 3.2 Ohm

 

What does a working used TCI sell for generally? Sounds like most guys keep a spare around when they can find em.

[Prairiehammer]

TCI voltage is 11.3V

 

While cranking it drops to ~8.5V but seems normal that it would drop under load with the starter pulling the majority of the power.

 

 

AH HA! If the input voltage to the TCI is dropping to 8.5 volts, then that is most likely your problem. Historically, voltage of less than 9 volts at the TCI translates to 'no fire'.

[spartikus]

Hmm.. Interesting. Would I be completely insane to jumper from the 12V 40A fuse to the R/W on the TCI and try cranking just to see if I get spark again?

 

Again I am no electrician but I am definitely getting 12.8V out of the main fuse but only 11.3 into and out of the fuse block. That drain of 1.5V somewhere could definitely be an issue.

 

Also any thoughts on what a good price is for a used TCI? A couple I have a line on right now.

[Neil86]

Keep in mind that the more often you crank engine with no start, the battery is getting weaker and the voltage drop cranking increases.

 

You are recharging the battery?

[spartikus]

Battery is being fully maintained between test sessions.

 

At the battery 12.8V

At the 40A fuse 12.8 V

At the ignition 2 wire plug (R and Br) 12.8V

 

At the fuse block 11.3V on all 12V leads

 

At the TCI 11.2 between R/w and B but when cranking drops to ~8.3-8.5V

 

Two ground connectors (left side to frame and right side to lower part of crankcase) tested thoroughly no corosion, rust or broken connector.

[Neil86]

Good.

 

I would get the fan wiring sorted so it isn't on while cranking, that certainly can't hurt raising the voltage on the TCI.

[spartikus]

Would I be insane to temporarily jumper 12V from the Main fuse to the TCI just to see if I get spark again Neil?

[Neil86]

Certainly could try it, preferably fused.

[bongobobny]

Hmm.. Interesting. Would I be completely insane to jumper from the 12V 40A fuse to the R/W on the TCI and try cranking just to see if I get spark again?

 

Again I am no electrician but I am definitely getting 12.8V out of the main fuse but only 11.3 into and out of the fuse block. That drain of 1.5V somewhere could definitely be an issue.

 

Also any thoughts on what a good price is for a used TCI? A couple I have a line on right now.

IMHO there is no such thing as a good used TCI these days. They are far and few between on Fleabay and go for $100 on up and still are used TCI's with no guarantee! Buy one of those Ignitech modules member Dingy sells instead!

 

The good news is any TCI from '84 to '89 will work if you still want to go the used route.

 

You really need to find the drop from the main fuse to the system fuses. The issue could be the ignition switch or possibly the kill switch...

[spartikus]

Thanks Bongo. I did test the voltage and continuity on the engine stop switch but I cant for the life of me recall if I got 12.8 or 11.3.

 

Is it safe to say from your post that the 1.5V drain is not normal then? I'm used to old muscle cars and having that kind of voltage loss through the old wiring is total normal but obviously on a bike with an electronic ignition control that expects over 9V when cranking and I'm getting 8.4... that 1.5 loss is potentially messing with me.

 

I'll take a look at the price of the aftermarket unit. New in box is worth something to me

[Neil86]

Well I would still try a known good unit (my spare)as a test.

 

Regarding the 1.5 V drop...the thing is its after the ignition switch (brown wire)and lower on the power side of fuse block.

 

Another question...on your battery posts do you have any extra wires or solely the cables?

[spartikus]

Just the main cables Neil. 1 main power feed and 1 main Neg feed. I have removed all shenanigans from the fuse block. (with the exception that I still have the splice in place that the PO had to the rad fan so that it is always on. I assume either his thermostat sensor is shot or he was running hot)

 

I'll put a switch on the fan to remove it from the equation for sure.

 

I would really hate to think that this is a bad ignition switch. It sounds like a real pain in the backside to drill out the bolts that hold it in. Not like the last 4 days haven't been a huge pain in my ass

 

The real stupid thing here is that the bike was starting just fine before the brake wiring fell apart. I know the accessory fuse was blown after that but I can not say for sure it wasn't blown before. Anyways at this point it sounds like a 1.5V drop to the fuse block is not cool and it would certainly put me back up over the 9V during cranking.

 

Can anyone positively confirm for me that 11.3 at the fuse block is not cool? On these bikes I don't know what kind of V loss due to wiring is acceptable.

 

*EDIT* Just FYI. It occurs to me that the cooling fan is actually a non-issue as the voltage loss of 1.5V is before it even gets to the fan. There is a difference of .1V between the power to the fan and the power at the TCI (11.4V vs 11.3V).

 

I'll still remove the fan from the equation by tossing a manual switch in between it and the fuse box.

Edited September 24, 2014 by spartikus

[Neil86]

If you have battery voltage on the brown wire, there is no drop on the ignition switch

Red is power in, brown is power out to fuse block...both test the same.

[Flyinfool]

Check the voltage across the battery while cranking. If the battery is dropping down to 8.4 while cranking then it is either a bad battery or a bad charger.

You mentioned that you have the battery on a maintainer while doing the testing. A battery maintainer is made to maintain a fully charged battery, most will not do a good job of charging the battery if it is low. You need a charger to bring the battery back up. there are some charger/maintainers out that can do both, but they usually have very slow chargers that may take days to bring up the battery to full. If you are not already then get a real charger on there.

 

The voltage at the red/white wire at the TCI should be withing .1 or .2 at the worst of what ever the battery is reading under the same conditions.

 

You can check the voltage drop by connecting your volt meter from the battery pos and to the red/white at the TCI. This will read the actual voltage drop whether cranking or sitting. If it is more than .2 volts, you have either a bad connection or a damaged wire "somewhere". 1.5 volts is bad.

 

Yes the fan running will cause the battery voltage to drop a bit and leave less power available for starting. That is why the headlight turns off while cranking, just to have as much power as possible available for starting. As you mentioned it could have been a bad thermo switch or an over heat problem or even nothing more than a perceived problem. It is normal for the temp gage to get right up to the red before the fan comes on, some people do not like that and start changing things to fix something that is working perfectly.

For now just disconnect the fan and the brake light. If the engine wont run those are both not needed. We can figure out those issues once the engine will run.

Edited September 24, 2014 by Flyinfool