Fuel Pump Problems

[dbshep]

I'm working on a 85 vmax
turn the key on and run
i hear the vboost and fuel pump
once i start the bike the fuel pump doesn't come on, i have turned the fuel switch from res to on and vice versa
the fuel pump relay has power, low fuel bulb is good
also the tach is not registering anything when the bike is running

also checked low fuel sensor and it was ok
any help would be appreciated it's got me stumped

 

[Dragmaxster]

I'm working on a 85 vmax
turn the key on and run
i hear the vboost and fuel pump
once i start the bike the fuel pump doesn't come on, i have turned the fuel switch from res to on and vice versa
the fuel pump relay has power, low fuel bulb is good
also the tach is not registering anything when the bike is running

also checked low fuel sensor and it was ok
any help would be appreciated it's got me stumped

Once the carb bowls fill up the fuel pump will no longer make that noise.
Is it still getting gas though or is it running out and dying?
Tach is probably unplugged.

 

[dbshep]

it is running out and dying, the tach is on the same circuit I believe.
After the bowls are filled the pumps shuts off and stays off once the bike is running

 

[sdt354]

Just taking a stab at it. The res/on switch? If bad I think you could still get the pump priming when first turning on the key with kill switch on.
If you unplug the tank sensor on the right side of the battery, you can run a tank until dry. If the sender was faulty and gas is low in the tank.

 

[dbshep]

gas tank is full, low fuel sensor checks out good when testing it with meter

i will have to check the res/on switch, all i did with it was move it from res to on multiple times to see if that would change things

 

[dbshep]

well after doing more checking on the bike I have found that the front 2 cylinders are not firing at all, this would explain why my fuel pump and tach not working.
Any sugesstions on what to look at now as to the cylinders not firing would greatly be appreciated. There is no spark at all on either cylinder

 

[davesax36]

Are the coils hooked up backwards? Did you test the spark with the plug grounded to the frame or cylinder head?

Sent from my SM-N900V using Tapatalk

 

[jfeagins]

It sounds, to me, like you have grounding issues. On the right hand side of the frame, next to the battery, are some ground wires that need to have a clean contact with the frame. There are other places for the connections to go bad as well.....mainly inside push-together connectors. If gone sour, bad things can happen - not sure if that is your problem, but worth a look-see.

 

[dbshep]

coils are hooked up right, grounded plug to frame when checking for spark

checked the grounds on right side of bike they look good

 

[Miles Long]

well after doing more checking on the bike I have found that the front 2 cylinders are not firing at all, this would explain why my fuel pump and tach not working.
Any sugesstions on what to look at now as to the cylinders not firing would greatly be appreciated. There is no spark at all on either cylinder

Check your pickup coils (your bike has two). If not that, the ignitor unit itself. Early ones are not as reliable as later models.
If you don't have the particulars re testing the coils, let us know. If you are lucky, maybe it's just a bad connector.
Cheers!

 

[dbshep]

i checked the pickup coils with my ohm meter using black as the common and got a reading of 123 on each of the pins
I couldn't tell the color of the wires but from doing research on here i take it the black wire is the pin with the empty spot above it

 

[Miles Long]

i checked the pickup coils with my ohm meter using black as the common and got a reading of 123 on each of the pins
I couldn't tell the color of the wires but from doing research on here i take it the black wire is the pin with the empty spot above it

[/I

All the manuals say that the ignitor unit can't be tested, but it should be possible to check the output voltage of the yellow, orange, white and grey wires that go to the coils. Be careful doing this one!
The grey lead is the pulse for the fuel pump and the tach. Maybe use another active lead to confirm that the ignitor is the culprit???

 

[dbshep]

I just checked the connector going to #4 coil it's getting power which I had a reading of about 10 volts then I hooked a light tester to the pulse side and to the positive side of the battery and cranked the bike over and got nothing from the pulse side of the connector

 

[dbshep]

ok I just did the same check on the 2 coils I'm getting spark on and for some reason the connectors for #1 and #3 are getting power on both pins unlike the #4 connector which is only getting power on 1 pin

 

[Miles Long]

ok I just did the same check on the 2 coils I'm getting spark on and for some reason the connectors for #1 and #3 are getting power on both pins unlike the #4 connector which is only getting power on 1 pin

Any way you can beg, borrow or steal another Ignitor unit, for testing purposes?

 

[dbshep]

I don't know anyone with another 85 vmax or any parts for that matter

 

[Miles Long]

I don't know anyone with another 85 vmax or any parts for that matter

Sean Morley... God love him... has a test kit (which includes most electrical components), that he circulates free of charge.
I've never used this service, but I guess you just send it back to Sean when finished, or pass it on to the next requester..
Sure beats buying a bunch of electrical components from a dealer, which may not be refundable if you don't need them.
Of course, if you identify the bad actor, it would be cool if you order the replacement from Sean. His prices are competitive with any dealer.
unk:

 

[jfeagins]

Give Sean Morley a shout out at [email protected]

I believe.

 

[Dragmaxster]

I have 6 stock coils all are good working condition from a low milage '85.

 

[dbshep]

Thanks guys

I talked to Sean and have a test kit coming, will let you know what the problem was once I get the test kit