Hanover Fist Posted June 18, 2019 Share Posted June 18, 2019 (edited) Ok peeps! As the title stated, I'm chasing an electrical gremlin in my brat which ended up being a loose ignition coil grounding wire on my EA81. Long story short, my brat died on the road. Everything shut off. Opened the fuse box to a blown ignition coil fuse. (Now here's where I did the dumbest thing a person in my predicament shouldn't do.) I didn't have a 15v fuse. I only had a 20a fuse so guess what I did? Yup! Then I turned the key and blow the fuse again. Next day I towed it back to my shop where I had the right fuses. This time I went to turn it over but all I got was a clicking noise coming from my fuel pump. Time to chase the current with my voltmeter. First thing I noticed was the ignition coil appeared needing replacing as my Accel yellow super stack looked like a cork had broken and oil was leaking out the plug hole. The voltmeter read zero on the ignition coil so I replaced it with a new one. Now it reads 12.6V. (Happy I am.) I went to restart the brat but it just kept turning over. No FUEL coming in!!! So now I know I've got to follow the current from the ignition coil to the fuel pump. The ignition key switch reads 12.6V. When I turn the key on, I get 12.6V at the fuse box ignition coil fuse and when I follow the wire to the next point it leads me to the FPCU or revolution switch. Here's where I'm stuck! The FPCU has a 6 pole connector. When I test the switch I find only one wire hot and that is the single blue wire on the bottom row in the center slot. Now how does this relay work when on? Is the single blue wire the hot wire going IN? Isn't there another wire that's suppose to be hot as well going to the fuel pump? I did a test on the power connector going to the fuel pump and zero volts. So I got curious and popped open the FPCU switch. I think the circuit board took a hit when I dropped in a 20a fuse at the side of the road. Here's some pics of the board... Can you see the melted circuit around the resistors soldering points? I'm thinking this is the stopping point to my gremlin. So I decided to go to the junkyard and pull a couple switches that were identical to mine. Upon replacing the switch I see my voltmeter still shows only the one hot wire. The clicking noise stopped on my fuel pump. What else can I do? I had the disty, plugs and wires checked I'm at a lost here. Any advice is appreciated. Edited June 19, 2019 by Hanover Fist Quote Link to comment Share on other sites More sharing options...
FerGloyale Posted June 18, 2019 Share Posted June 18, 2019 First, there is no coil "GROUNDING" wire. The coil grounds through it's bracket. No ground wire, ever. The - side of the coil should have 2 wires on it. One from the disty, and one Yellow one that is TACH signal wire. That same TACH signal wire also goes to the FPCU. THE FPCU, will only pass power on to the Fuel pump, and to the Auto choke and anti-diesel solenoid on the carb IIRC. At any rate. There should not be any wire from the coil to ground. If you did that, that could explain blown fuses, and no TACH signal to the FPCU, hence no fuel. A side note, fuses are rated in AMPS, not volts. All wireing int eh car is 12v. The size of the load determines the AMPS needed for any fuse. Now, if you put a larger fuse in (20A instead of 15) the circuit won't blow when it should, and the FPCU may have been hurt by the grounded coil wire. Although honestly, that doens't really look burned.....trouble is likely somewhere else. make sure the yellow wire is on the - side of the coil, and no wires from either post to ground and try one of the new FPCU units. 2 Quote Link to comment Share on other sites More sharing options...
el_freddo Posted June 19, 2019 Share Posted June 19, 2019 Got an electronic ignition module in the dizzy? A dead coil will kill the module. So replace the module, get spark, fuel pump cut module magic box thing will send power to the fuel pump. Cheers Bennie 1 Quote Link to comment Share on other sites More sharing options...
Hanover Fist Posted June 19, 2019 Author Share Posted June 19, 2019 (edited) 15 hours ago, FerGloyale said: First, there is no coil "GROUNDING" wire. The coil grounds through it's bracket. No ground wire, ever. I have what's called a "noise reducer" coming off the Ignition coil. It is grounded. A mechanic in a Denver soobie shop put it on and explained to me why it was missing. has something to do with hearing the engine rev thru the radio. Here's a schematic showing it belongs there Is this incorrect? I'll take a pic of the condenser L8r today. You are also correct about the "V vs Amps" correction. It was very late when I posted my request and I dunno what the hell I was think'n (auto pilot I guess). Now what's this thing about a "newer" FPCU? Got a link or a direction you can point me in? And BTW thanx for your advice!!! Edited June 19, 2019 by Hanover Fist 1 Quote Link to comment Share on other sites More sharing options...
Hanover Fist Posted June 19, 2019 Author Share Posted June 19, 2019 14 hours ago, FerGloyale said: side of the coil should have 2 wires on it. One from the disty, and one Yellow one that is TACH signal wire FerG I'm not sure 'bout only having 2 wires again. I have a yellow wire coming off my NEG post and two black wires coming off my ignition coil. One leading to the condenser which I marked in the photo. Here's the pic 1 Quote Link to comment Share on other sites More sharing options...
naru2 Posted June 19, 2019 Share Posted June 19, 2019 (edited) The FPCU will not work w/o ignition pulses. If a test light on coil negative does not pulse when cranking,you are not going to get fuel. Fuse #5 supplies some FPCU power thru the ACC position of the ignition switch. Run position supplies other power.You should have power on 2 wires w/the key on. .Fuse #13 for the coil. Edited June 20, 2019 by naru2 1 Quote Link to comment Share on other sites More sharing options...
FerGloyale Posted June 20, 2019 Share Posted June 20, 2019 15 hours ago, Hanover Fist said: FerG I'm not sure 'bout only having 2 wires again. I have a yellow wire coming off my NEG post and two black wires coming off my ignition coil. One leading to the condenser which I marked in the photo. Here's the pic You are correct about that condenser. It should be on the + side on your model. And it's not necessary to make the engine run. Old school points disty required them, but not this setup, it's just for noise suppression. But I don't see the second yellow wire on the coil that would be the tach wire. Without that , the FPCU won't power the fuel pump. Quote Link to comment Share on other sites More sharing options...
el_freddo Posted June 20, 2019 Share Posted June 20, 2019 And yours needs a tacho wire regardless of a tachometer or not in the instrument cluster. Cheers Bennie Quote Link to comment Share on other sites More sharing options...
Steptoe Posted June 20, 2019 Share Posted June 20, 2019 FerG has got me with his coil grounds through its bracket. There is no coil body grounding in wiring diagrams I have. Having pulled an oil filled coil apart never found any connection to the coils housing. However, years ago a mate mechanic could not start a points based ignition car until I came along and put the coil in its bracket and mounted it where it belonged. Yep, brackets have that mean looking bent tab that looks to dig into coil body on some vehicles, so yeah I thought oil filled coils needed to be earthed, until same mate proved theory not necessary with another car another time Confused?? Quote Link to comment Share on other sites More sharing options...
naru2 Posted June 20, 2019 Share Posted June 20, 2019 (edited) On 6/20/2019 at 5:40 AM, Steptoe said: FerG has got me with his coil grounds through its bracket. There is no coil body grounding in wiring diagrams I have. Having pulled an oil filled coil apart never found any connection to the coils housing. However, years ago a mate mechanic could not start a points based ignition car until I came along and put the coil in its bracket and mounted it where it belonged. Yep, brackets have that mean looking bent tab that looks to dig into coil body on some vehicles, so yeah I thought oil filled coils needed to be earthed, until same mate proved theory not necessary with another car another time Confused?? Some vintage coils ground one end of the secondary winding to the case.These ones need to be grounded thru the bracket etc. I recall a hot rod V8 that would inexplicably increase idle RPM when you leaned over the motor and touched the block. Turned out that touching the body and motor at the same time improved coil grounding enough to increase idle speed. On our old Subes,only the optical distributor models need grounding thru the coil bracket.( for the primary winding transistor.) Grounding the coil case on the others merely provides a little bit of extra RF noise suppression. The coil primary grounds thru the ignition module (or coil bracket transistor if so equipped, Since the windings are connected(an autotransformer) the high voltage "grounds" to the other end of the secondary winding thru the block,battery, and coil positive whether optical type or not. Edited July 1, 2019 by naru2 + ground path detail Quote Link to comment Share on other sites More sharing options...
Hanover Fist Posted June 22, 2019 Author Share Posted June 22, 2019 Took me a bit to locate another 6 pole FPCU (non turbo of course!) and like a country song played backwards - everything got fixed (wife comes back, kids love ya, truck starts run'n and you find your dog!) I mean electrical issues 1 - 4 got fixed - dash lights work! Idle is back to normal. Hell even my door buzzer is back! Thanks guys for the knowledge and advices! I'll do my best to stay on top of issues but goddamn this is a cool place to get help on an "immediacy" tip. **** To whomever reads this topic - DONATE to help this site stay afloat! If there was ever a site to keep up and going, this is one of them! **** Two-Fingers! 1 Quote Link to comment Share on other sites More sharing options...
Wannabebrat Posted March 19, 2020 Share Posted March 19, 2020 On 6/19/2019 at 10:11 AM, Hanover Fist said: I have what's called a "noise reducer" coming off the Ignition coil. It is grounded. A mechanic in a Denver soobie shop put it on and explained to me why it was missing. has something to do with hearing the engine rev thru the radio. Here's a schematic showing it belongs there Is this incorrect? I'll take a pic of the condenser L8r today. You are also correct about the "V vs Amps" correction. It was very late when I posted my request and I dunno what the hell I was think'n (auto pilot I guess). Now what's this thing about a "newer" FPCU? Got a link or a direction you can point me in? And BTW thanx for your advice!!! i think I am chasing the same gremlin....what happened with yours? Also I found that noise reduction thing in mine....looks like one end goes to the coil and the other is hanging....any idea where the other end goes? Quote Link to comment Share on other sites More sharing options...
Wannabebrat Posted March 19, 2020 Share Posted March 19, 2020 On 6/22/2019 at 3:34 PM, Hanover Fist said: Took me a bit to locate another 6 pole FPCU (non turbo of course!) and like a country song played backwards - everything got fixed (wife comes back, kids love ya, truck starts run'n and you find your dog!) I mean electrical issues 1 - 4 got fixed - dash lights work! Idle is back to normal. Hell even my door buzzer is back! Thanks guys for the knowledge and advices! I'll do my best to stay on top of issues but goddamn this is a cool place to get help on an "immediacy" tip. **** To whomever reads this topic - DONATE to help this site stay afloat! If there was ever a site to keep up and going, this is one of them! **** Two-Fingers! Hey where did you find the fpcu replacement? I think I need one as well. Thanks! Quote Link to comment Share on other sites More sharing options...
lrgvanman Posted July 10, 2020 Share Posted July 10, 2020 I have had an ongoing problem since the car died. I first replaced the disty, thinking of the high mileage, and was confident that the sensor pickup had gone bad and noticed high heat along that side of the disty. The change did not allow ignition but the next day after checking for voltages and ALL terminals were hot, I reassembled and it fired up! I ran it for about 20 minutes to recharge the battery. Shut down, the next morning...no start. I checked all terminals and found they were still all hot, i.e., lit the test light. Pulled wires from the sensor and B+ at both connectors. I have changed the disty w/sensor, coil (polarity is correct), and what's next? The ECU? If so, where is it locate? Behind fusebox? I somehow do have an extremely light spark from coil but makes no sense as there seems to be a constant B+ on both terminals of the coil (polarity is correct) and no pulse, solid light from test light. A Twilight Zone episode, extended version! Quote Link to comment Share on other sites More sharing options...
lrgvanman Posted July 10, 2020 Share Posted July 10, 2020 Just started. This is quite erratic! Quote Link to comment Share on other sites More sharing options...
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