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84 Gl Won't Start ..No Spark Coil.Not pumping Fuel Also


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15 replies to this topic

#1 roadsubiedog

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Posted 29 April 2012 - 07:25 PM

84 Gl ran one day...next day won't start.

checked ign fuse. even put in new one. test lighted fine. checked all fusible links. even exchanged them with my other good running 84 gl.

checked both posts of coil and they test lighted OK but NO spark at end of coil wire when turning over motor.

exchanged coil from good running 84 gl and same thing. power to coil but no spark. even changed coil wire.

also no fuel pumping to fuel filter. even changed fuel pump.

so with no spark and no fuel pumping does this point to the ignition switch?
is it in the key? or can i check something else?

i am just stumped on this one.

#2 naru

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Posted 29 April 2012 - 09:18 PM

If the test light lights up on coil negative but doesn`t flash when cranking,you can be pretty sure the ignition module in the disty has failed.

Rebuilt disty is the simpliest fix.

No ignition pulses = no fuel pump

#3 roadsubiedog

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Posted 29 April 2012 - 10:21 PM

If the test light lights up on coil negative but doesn`t flash when cranking,you can be pretty sure the ignition module in the disty has failed.

Rebuilt disty is the simpliest fix.

No ignition pulses = no fuel pump



how would that explain no spark coming from coil? sorry if dumb. just a layman.

#4 naru

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Posted 29 April 2012 - 10:51 PM

how would that explain no spark coming from coil? sorry if dumb. just a layman.


No current is flowing thru the module or coil. No current = no spark.

#5 roadsubiedog

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Posted 30 April 2012 - 07:11 AM

ok, i'll check that out. thanks

#6 roadsubiedog

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Posted 30 April 2012 - 07:26 PM

No current is flowing thru the module or coil. No current = no spark.



Naru........update

looking at similar threads found a suggestion to remove coil bracket and clean for ground to transistor. did that and now i have spark.

motor would run as long as i poured gas into carb. fuel filter is bone dry.

isn't the fuel pump on the same circuit as the coil? so how do i troubleshoot the fuel pump?

thanks in advance.

#7 naru

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Posted 30 April 2012 - 11:49 PM

That is curious.
84s don`t have transistors on the coil bracket.

Fuel pump isn't on the same circuit as the coil.
Check fuse.
Look for voltage at the pump connector w/cranking.

#8 roadsubiedog

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Posted 01 May 2012 - 10:20 AM

That is curious.
84s don`t have transistors on the coil bracket.

Fuel pump isn't on the same circuit as the coil.
Check fuse.
Look for voltage at the pump connector w/cranking.

tlt

this 84 wagon has power everything. digi dash, cruise, power steer , everything. title says 84. maybe should check vin.

anyway, will check fuse and volt. thanks

#9 roadsubiedog

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Posted 06 May 2012 - 09:36 PM

i checked power to fuel pump while cranking and did not get any.

is the fuel sending unit under the dash on the side the next step. is it a black box about 3 by 2 inches with a plug?

btw the fuse is ok.

#10 Cougar

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Posted 07 May 2012 - 10:49 AM

If you haven't checked the fusible links under the hood yet using your test light probe to make sure they are ok, I suggest you do that next. The green link should supply power to fuse 1 in the dash panel. Make sure that fuse has power getting to it. Most likely the fusible link is bad or it has a bad connection.

#11 GeneralDisorder

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Posted 07 May 2012 - 11:47 AM

Make sure you have a tach signal on the yellow wire from the coil negative that is not going to the distributor.

If you do then you need to check for power at the fuel pump control unit (revolution sensor). It's a black box attached to the hood release cable bracket near your left knee - under the dash.

GD

#12 roadsubiedog

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Posted 08 May 2012 - 03:28 PM

Make sure you have a tach signal on the yellow wire from the coil negative that is not going to the distributor.

If you do then you need to check for power at the fuel pump control unit (revolution sensor). It's a black box attached to the hood release cable bracket near your left knee - under the dash.

GD



cougar... i'll recheck the fuse and fusible link. GD... i''ll check that also. thanks. it will have to wait till sunday, but i'll update.

#13 roadsubiedog

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Posted 28 August 2012 - 02:05 PM

Make sure you have a tach signal on the yellow wire from the coil negative that is not going to the distributor.

If you do then you need to check for power at the fuel pump control unit (revolution sensor). It's a black box attached to the hood release cable bracket near your left knee - under the dash.

GD



i took the fpcu out and unplugged the plug. when i put the plug back in with the key on i hear the fuel pump buzzing but it only buzzes for a second or 2 then it stops.

i hear and feel a click from the box. i can unplug it and wiggle the plug and the the fuel pump will buzz for a couple seconds and then that click and it stops.

does this suggest the fpcu may be bad or maybe a bad wire?

i took the fpcu apart and plugged it in and felt a click on a black little rectangle thing ( transistor? )

could this mean it's not grounding properly or do you think the fpcu is bad?

#14 roadsubiedog

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Posted 28 August 2012 - 10:33 PM

[quote name='roadsubiedog']i took the fpcu out and unplugged the plug. when i put the plug back in with the key on i hear the fuel pump buzzing but it only buzzes for a second or 2 then it stops.

i hear and feel a click from the box. i can unplug it and wiggle the plug and the the fuel pump will buzz for a couple seconds and then that click and it stops.

does this suggest the fpcu may be bad or maybe a bad wire?

i took the fpcu apart and plugged it in and felt a click on a black little rectangle thing ( transistor? )

could this mean it's not grounding properly or do you think the fpcu is bad?


update: played with the plug going into the fpcu and got power to the fuel pump. got it started but the fuel pump is making a knocking noise all the time while running. it's a new pump too.

the car idles fine but when i try to rev it up it stalls. if i pump the pedal i can get it to rev high but as soon as i let go it stalls. but it will still run at idle?

#15 Cougar

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Posted 29 August 2012 - 10:23 AM

So the bad power connection was at the FPCU and not the links. Verify the pump motor is getting full 12 volts to it when you rev the engine. If that is ok then there may be fuel line blockage. Have you replaced the fuel filter?

Edited by Cougar, 29 August 2012 - 10:26 AM.


#16 roadsubiedog

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Posted 29 August 2012 - 08:46 PM

So the bad power connection was at the FPCU and not the links. Verify the pump motor is getting full 12 volts to it when you rev the engine. If that is ok then there may be fuel line blockage. Have you replaced the fuel filter?



good idea. i'll get on that and report back.thanks.




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