RX7 allnight

my leading coil is not getting power trailing is. what do to...1988 GTU 950 miles on new rebuild

Phantomkid

hows the motor run? if the trailing is getting power so should the leading are you checking the right wire the g/y wire. Im pretty sure it only gets power when the ecu puts out power when the ignition should be firing. I thought i would be ground controlled but the wiring harness looks like that ecu sends power from pin V 2nd from the left on the bigger connector from the fornt harness and its grounded through b/y...

Phantomkid

my bad no from a second look...jeeze the wiring harness is a little confusing... well anyway i believe it is ground controlled. g/y goes to the ecu and grounds when needed to be fired. B/Y is going to be your power and should be constant, well it recieves power from the main relay so whenever that is energized it will have power. koeo...if the trailing has power the leading should have power also. if not there doesnt seem to be any fuses so you will have to dig back into the harness looking for a break... may want to try and see if there is continuity between the B/Y and main relay before tearing up the harness

Aaron Cake

iTrader: (1)

Only no power to the leading? How are you testing this?

You should be checking for 12V at the black/yellow wire with the key set to IGN.

If you have 12V there, then check the + connection on the coil. You should also have 12V present with the key on IGN.

If you are missing 12V from the black/yellow, the problem is with the EGI fuse or main relay.

RX7 allnight

i didnt want to go get my ohm meter... i was in my second garage.. so i just hooked up a timming light to the wires... put it on my leading wires turned it over and no light. than put it on my trailer wires.. and i get light.. now its the next day i have sun light iam going in with the ohm meter to see whats up.

RX7 allnight

motor almost wants to run on just the trailing is this possible?

FrankV702

iTrader: (14)

Im having the exact same problem, but with opposite coils. I get signal with the timing light on my leading, but none on the trailing.

RX7 allnight

makes more sense sense the power comes from the leading coil correct? so somewhere from the L coil to the T coil there is no power..

Phantomkid

well both recieve power from the main relay. thats what makes it confusing to have power at one and not the other. The wiring diaghram showes them having seperate branches in parallel. so there is a possiblity that one may have power and not the other. which would mean somewhere from the mainrelay to the connection theres a break in the line. Quite unusual unless some mouse got hungry. you were check with the key on right? and what tested the b/y wires at the trailing?

RX7 allnight

i tested with a timing light. also the trailing plugs dont get flooded the leading do so thats another indication i would assume iam going out there right now to check with an ohm meter where and where not iam gettiing a 12v source

RX7 allnight

ok so iam getting 12v source @ black and yellow wire, i swapped coils last night with a known working one that didnt help.

Smoken'

iTrader: (1)

From what i'm reading, your assuming that you dont have power to your coil. Am i saying that correctly. If your hooking up your timing light and not getting spark, it could just be a bad coil.

RX7 allnight

L coil is getting 12v, coil sparks three times before dying when first cranking

Aaron Cake

iTrader: (1)

Pull the CAS from the engine and spin it manually with the key on IGN. The leading coil should spark (do NOT use a timing light to test for spark) as long as you are rotating the CAS. If not, then you will need a scope to do further troubleshooting without swapping parts around.

RX7 allnight

if the cas is bad than wouldnt i not get fuel?

Funkspectrum

iTrader: (5)

I was over at the house looking at the car and we used a spare CAS to test for spark. We got nothing. I'm assuming that the CAS we used was fragged or something. I'm almost willing to bet that there's probably some sort of break in the harness somewhere or something.

I spoke with Icemark and Karack over the phone about this particular issue and all three of us find it bizzare that the leading coil would spark 3 times then go dead on cranking.

I'm stumped.

FrankV702

iTrader: (14)

Will the trailing spark by spinning the CAS manually with the IGN on? Or is there a similiar method to check for spark on the trailing side??

Aaron Cake

iTrader: (1)

Correct.

All ignition channels will be fired when you spin the CAS. And if you open the AFM slightly then the fuel pump will run and injectors will fire as well.

RX7 allnight

iam swapping AFM's as mentioned by icemark the batt is dead iam charging it now and iall see what happens, stay tuned..

RX7 allnight

i changed AFM's and now i have consistant spark

RX7 allnight

its running i thought it was the afm, but than i put the old one back on for ***** n giggles and it still ran so iam stumped but it runs.. so as we all know.. dont fix it if it aint broken

Aaron Cake

iTrader: (1)

Sounds like you have an intermittant connection somewhere. Check around the AFM and CAS.

RX7 allnight

along with swapping afms, i reconnected alot of connectors including the ecu,cas,afm also my ground wasent hooked up tightly below the drivers strut tower.. what ground is that for, it runs with the harness..