I have a s4 na and put a s5 na into it with the stock comp & harness also hooked up two rpm switches for the5 & 6 port also the vdi.

here's my issue my trailing coil pack isnt working... no spark comes from the coils. but my tack still works and my rpm switches still get signal from the coils.
now I checked both t & l coils once the motor was dropped in and they had spark.

what could be the cause of this?
I hooked up my rpm switchs exactly how summit wanted them hooked up.
could it have been from the rpm switches or did something just go bad.
help please

 

whatcha yall think?

 

Gonna probably need more information on this. s4/s5 swaps are a nightmare with the stock wiring (not gonna even ask why you did it). What did you wire the port switches to? I don't know where the tach gets it's signal from in your car, but if it is not the leading coil pack it could be that the coil functions but the ignitor is broken, or vice versa. Time to bust out the multimeter methinks...

 

I know s4 to s5 swap not the best idea but my s4 blew a coolant seal and I bought a wrecked s5 for a good deal so in the s5 went untill i get my s4 fixed.l (trust me I miss my s4).

The actuall swap is VERY simple there is no wiring nightmare with the swap. blocks are almost identical.
I used my s4 harness & computers and put all my s4 sensors on my s5 block so I didnt change any wiring over, its all the s4 wiring.

the only thing I did was wire 2 rpm switches together and plugged the 2 rpm switches wires that sence the rpm settings to open the 5,6 ports and VDI into the bullet wire on the trail coil.
whitch is what 88ROTAYROCKET has pointed me out to do along with a bunch of other members.
I cant see that being the reason but everything else seem good untill that got wired in.

I dont know what other info is needed on this.

basically what causes the trailing coils to go bad?
could it be my rpm switches?
or could it just be a bad coil?

Like i said the tach still works, the rpm switches still get a signal from the coil just NO SPARK.

WHY?

 

ok i messed up.
I meant the LEADING COIL not the trailing... if it means anything sence ONE person has responed,,,

 

Remove the Summit Racing switches and put it back to stk and see if the LEAD coil fires or not.

Where did you install the Summit Racing switches? To which coil assy? Shoulda been at the Trail coil assy.

 

You can pull a tach signal off either coil. I ran 2 RPM switches off the leading coil because it was closer to my mounting point.

 

Ok. I had a Summit sw at one time and took the signal from the trail bullet connector with the Y/L wire. I had a suspition that the bullet connector on the Lead would read wrong. Wrong susption I guess.

I'd still remove the Summit switches and put it back to stk to see if it works or not.

Just where are you pulling the rpm signal from? The wire location.

 

Yeah, I'd have to agree. Back track and see if something you did caused the problem.

 

I pulled off the leading coils bullet connector.
Here's what I basically did, wired the two switches together, the two grounds-to the chasis, the two + switched wires, wired to the green six plug connector by the battery, and the two tach input switches into the leading coils bullet connectors.
then I ran two seperate + wires from a +12v source whitch I ran from my e fans +t-stat wire that was ran from the positive battery post to one side of the siloniod and last I ran the ground wires from each rpm switches to the other side of the silonoid that gets grounded when the set rpm is reached.

wrong or right?
Ive thought this out before i hooked this up and triple checked it.
lmk if this is wrong.
Itl is still functioning how it should. The only thing wrong is that the leading coil is dead.
I also unplugged the tach imput wires from the leading coil, and still no spark.

I cant see it being the rpm switches but not 100% sure.
my car also has close to 180xxx on the stock coils so maybe the leading coils just died....

 

Well if you unplugged from the single wire bullet connector on the lead coil and the lead plugs are not firing............the coil/ignitor assy's are bad or not recieving the 0-5vdc signal from the ECU. No reason to think the ECU isn't doing its job since evidently the engine runs on the trail coils only. Right? Engine does run but only on the trail coils? Right??????????????????????

The lead coil has a two wire connector coming from the ECU. One wire in that white two wire connector is colored green with a yellow stipe. The other wire is black/yellow.

A person sould be able to put a meter on dcvolts and get on the green/yellow wire. Meter neg to a known gnd like the batt gnd. Then with the key ON only, turn the crank pulley by hand and the meter should read zero volts then as you hand turn the pulley it will show 5vdc for part of a turn of the pulley and then zero again. Proving the ECU and CAS are doing their job.

I've done this procredure with the cheapest of cheap digital meters from Harbour Freight and it works for me when I grab the front pulley by hand and turn it. Matters not if you turn the front pulley the wrong way or not. The five volts should show up for part of a pulley turn and then return to zero volts. Proof the CAS and ECU are good.

You don't have to spin the pulley fast at all. Just a hand turn of the pulley will do.

The green check connector ..................your probably getting the power off the wire that is black/white in that connector. That's just fine and dandy. Switched power source.

Engine runs CRUMMY on the Trail coils. Right?

Several yrs ago I bought spare Lead coil assy and the cost at the junk yard was twenty bucks. Cheap stuff. I've never had a coil assy failure yet. I'd never buy a new lead coil assy. Cost waaaaay too much money.

I assume the lead coil is getting the batt voltage on the black/yellow wire mentioned in the words above and the coil itself ohms out like the FSM mentions.

I have not used a Summit switch in five years so I don't'know if yours is wired right or wrong. I wonder what I did with the sucker. Got a RTEK to replace its function in life.

 

The wiring sounds right, and if your switches have an LED that comes on when the switched ground is triggered, that's an easy way to tell you did it correctly. Rev to the RPM set point, and if the LED comes on, you're good.

If the leading coil won't fire, and the test Hailers posted yields a 0-5v signal, all signs point to a dead coil.

 

yeah it runs, but LIKE SH*t on those trailing coils.
I got both coils from a rep member so Ill just throw it in to replace what Im assuming is a bad leading coil. it does have 180xxx mile and NUMEROUS REDLINE+ REVS LOL

ill update once there in and HOPEFULLY RUNNING.
Im dying to see what this motor can do and the differance in the two sence I had my s4 street port in before built by glen at azrr.

 

yeah there the ones that have the leds and they come on when there suppost to.
green when theres power and blue when theyve reached their rpm setting

 

Just FYI.....the coil assys must be bolted to the chassis with at least one fastener becasue the electronics of the ignitor gets its ground from the body of the coil assy making contact with the chassis.