Briggs Vanguard 380000 series

Bret4207

Well-known Member
No spark unless I unhitch the wiring harness, no fuel delivery (pump is pumping) at all. I'm lost. Got to be a wiring issue or a sensor. Not sure where to start beyond establishing I don't have spark and I'm not getting fuel. This is a re-powered Bobcat. Not sure how to bypass components on somethign this new or if I can.
 
I am pretty sure that Vanguard engines have a solenoid on the carb that shuts off the fuel delivery when no power is applied to that solenoid.

I also believe that Vanguard engines use a type of magneto ignition instead of ignition coil and points or ignition coil and some sort of solid state trigger. The coils are individual and are mounted under the
front cowl. To start the engine, you just have to apply power to the starter motor and spin the engine. The magneto's produce the needed spark all on their own. Now if you have been applying 12 volts to
the wires coming from the magneto coils, then it is my belief you have burnt them out and you will never get that engine to run until you replace two very pricey magneto coils.

If you go to Briggs and Stratton, you will find manuals there to read or download.
 

Thanks Tom,but no I haven't been supplying power to anything. All I've done is found is that if the wiring harness for the engine, not the starting circuit, is unplugged I do get spark. The carb appears to have a fuel flow solenoid at the bottom (2 gray wires) but I'm not putting juice to anything or grounding anything until I know for sure whats what. Like you said, expensive. My thought is I either have a bad sensor (oil?) or something else killing both fuel flow and spark. Oil is well up the dipstick, not at the point you'd think it would need more and the machine was sitting level. I'm calling the engine supplier tomorrow (SMW) and asking for a wiring diagram since Vanguards doesn't match up with what I have.
 
What is it on? if you don't have spark until you disconnect the wiring harness, there is a problem
on the chassis somewhere and the ground circuit is grounded. If you tried to bypass the interlock
system anywhere, I can't help you.
Then, when you disconnect the wiring harness, you also deprive the fuel solenoid of power, so no
fuel.
 
Bret, There are diodes under the shroud to the mags. There is a disconnect that goes thru the shroud on left front of engine this is looking from the rear. But I think if you have a bad diode it still kills both mags.
What carb ans can you verify a solenoid on it. Tom
 


I'm 99.9% certain that the problem is that I have a broken power wire at the 5 spade connection/distribution plug. Unfortunately, I can't tell where the wire is supposed to run to and none of Briggs schematics are any help. SEW provided what they have, which is picture showing a red wire (the definitely broken one) leading into the plug, but no clear pic of which spade it goes to. I've been on hold with Briggs for an hour, I'll try again tomorrow.
 
33897.jpg
 


In the picture above on the left side you see a white wire in front of the "WARNING" label, and below that a red and grey wire going into a connector block. That red wire is the broken one on my machine, but I can't determine where it runs to. It looks like it connects to the grey (fuel solenoid) wire in the pic, but theres no sign they were ever connected together. What it looks like to me is that the ice tore the wire and spade clip right out of the connector block, I can't tell where it goes. I'll call Briggs in the AM.
 
White wire with blue insulator is definitely the kill wire. Is the black block with what appears to be four wires a relay socket? This almost looks like a work around from the factory or added later for a low voltage problem during cranking. It may be a feed for something else also. Tom
 

Okay, the harness I referred to above leads to a 30A relay. I'm fairly sure the relay divides the power to the fuel flow solenoid and opens the kill circuit for spark. I just can't determine which spade the red wire runs to. I've sent this info to the Tech Rep at SEW, but no reply yet. Here's a PDF of the relay, perhaps someone better at reading these things can clue me in.

http://www.mouser.com/ds/2/418/NG_DS_V23234-X0000-A001_0314_234_0314-124805.pdf
 

Well, Small Engine Warehouse isn't willing to help. I've offered to pay for the information, we'll see how that goes.
 
Bret is this pic a shot of your engine?
I need to know if that black connector has a relay poked into it. If it does you can remove the relay and the numbers on the pin side of the relay will correspond to what you see on page 2 and 3 of the mouser PDF. Pins 85 and 86 are power and ground, if the relay is used to do the grounding of the mags that will be done with 87a but then in the off position there has to be ground somewhere to something I would assume a feed back and it will have to go to #30 which is usually hot all the time.
The way it should work, would be power being supplied to the 85/86 circuit closing the contacts hence energizing the feed from 30 to 87 and to whatever 87 connects to.
Your application appears to only use 4 connections at the block. Hence changing the perfect solution. What do the black wires connect to?
Is the wiring harness briggs or bobcat?

if you poke here http://www.vanguardengines.com/service-support/operators-manuals/ and type in model number as instructed you can download the parts list and owners manual. if you take the model number and google it you can most likely find a service manual also. Tom
 

Thanks 4435, I figured it out. I kept coming back to the chance the fuel wire and power wire went to the same terminal. The plug only had 4 of 5 lugs used, that kept me guessing. Used my cop skills to observe the spade connector the fuel wire ran in had broken wires in it that didn't correspond to the fuel wire. Took a chance and ran power to that lug and it starts and runs fine. No other place for it to go. The 2 black wires ground and so does the white wire. Absolutely no sign the 5th lug ever had a connector of any kind on it.

I had already tried Vanguards manuals. Nothing in them like what I have. But, at least it's running. What a bunch of stuff to go through though!
 

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