gabs88gxl

iTrader: (3)

im wokring on a friends S4 with a s5 swap. The car turns over an everthing the leadings are sparking the the trailing have no spark but there is power going to the wires. I have tryed putting my trailing coil it to see if it makes any difference an nothing. I know my works cause i put it right back in my s4 an it started up an i drove 20 miles home. Could itbe the main relay that is causeing this to not spark the coil. Please some one let me know thanks
matt

Craiger

iTrader: (1)

It's likely no the relay.

First: is the coil bolted down properly? It grounds through the body of the ignitor so if it isn't bolted in place properly it may not be getting ground.

Second: I'd check your wireing. If you mix up the pin-out than i'd expect it not to run properly. Also make sure all plugs are in good condition and plugged in properly.

boostinfc3s

make sure the crank angle sensor wires on the ecu is not accidentally cut.. like mines

HAILERS

What is the wiring in the car? All original or????

Does the tach work? If it does, then the trail coil works.

gabs88gxl

iTrader: (3)

its a s4 turbo tii with a s5 gtu harness.. the tach was working for a little an thats when i got one side of the coil to spark. Then i pulled the dash to follow that wire put it back together an now its not working. Ive been going at this for atleast 3 months an still nothing

HAILERS

Here's something worthwhile you can do cheaply without a digital meter.

Go look at the LEAD coils assy. See the black bullet connector with one wire. It looks the same as the one on the TRAIL coil assy.

Now get a piece of wire that will reach from one bullet connector to the other. Bare both ends of that wire. Stick one end in the LEAD coils bullet connector and the other in the TRAIL coils bullet connector. Make sure they are in there firmly and not going to fall out.

Now start the engine. The tach should work if the wiring from the trail coil to the tach is good. If it does, then shut the engine off and remove the wire. Now you know for sure that it's the trail coil assy.

So say the tach works. Now you need a digital meter if your serious about fixing it other than change out a lot of parts needlessly.

PUll the plastci piece off the TRAIL coils and expose the wire terminals on each trail coil. Key ON. See if there's batt voltage on the two terminals. Probably is, but look anyway. If it's good, fine.

By the way, we assume the Trail coil assy has at least one of the inboard nuts holding the coil assy down. Bolting the assy down gives the electronics in the assy a ground. The thing won't work not bolted down. Don't add additional gnds if it's bolted down. Not needed in any way.

Now you have to go to the ECU and backprobe about three wires with the plugs connected to the ECU. Unbolt the ECU so you can tilt its plugs up so you can access the wires in the back of the plug.

The jpg shows those three wires going to the ECU. There are no plugs inbetween the ECU and the trail coil assy. So it's hard to see how the wires could be bad. They don't just break in two inside the harness.

A jpg of the plug is attached. You count the plug wires from the wire side and in a up/down fashion. The wire colors should match the colors shown in the first and second jpg.

HAILERS

Remember the wire we ran between the two bullet connectors? If that does not make the tach work, then you have a problem b/t the trail coil assy and the tachometer/instrument panel. There is one connector b/t the two and it's inside the car. So you'd find that connector and see if it's connected up or not. Probably is if other things on the instrument panel are working.

HAILERS

Ok. Series four turboii car with a series five GTU harness. Sooooo, how much is series five GTU wiring??????

One thing that comes to mind right off, is that the series four car uses FOUR wires off the CAS. The series five uses but three.

See the two jpgs. One for a series four and the other for a series five. On the series five, the gnd wire is shared b/t the two trail coil assy. So a lot depends on how much of this wiring is series five and how much series four.

ON a series four, there is a plug b/t the ECU and the CAS. But on the series five wiring there is not such a plug inbetween.

The whole thing is kinda messy, because the series five cas wires run in the EM harness but the series four cas wires run in both the Engine Harness and the Front harness (plug b/t the two).

We on this forum, have run across a similar problem with a conversion where the guy used a series five ECU and series five EM harness on the engine but a series four wiring in the Front and Engine harness. All he had to do was couple the two wires shown in the jpg of the series four pictue below, together and terminate them at the pin 3H on the series five ECU plug.

HAILERS

Well, I've rethought that a bit. IF you used a series five EM harness on the engine, then there should be no CAS problem, because those wires run in the EM harness only and connect directly to the Series five ECU.

So I'm a little puzzled about what harness and what ECU is being used on the series four car.

The harness on the engine: is it series four or five and what ECU.

Actually, the engine should start and run on only the LEAD coil firing. It should run just fine that way. Trail coil not firing should not be noticable. I forgot to ask, DOES THIS ENGINE RUN ON THE LEADING COIL?

RotaMan99

Its noticable. Atleast on my car and my friends car. Both had about 50% of their power reduced when the trailing was not firing.

HAILERS

Sick cars.

EDIT: I just went out and started two different cars with the trail coils disabled and with the engine water temp at 38.7*F. Both started like the champs they are.

RotaMan99

Starting the car on just the trailing doesn't mean much.

Mine would start and run on just the TRAILING (Without the leading hooked up).

Both mine and my friends are non turbos. Go for a drive and then disconnect the trailing and go for another drive, you should see a difference.

HAILERS

The IDEA here is, if the car won't start, don't blame it on the trail coil not working. The Lead coil is all that is required. I suspect this car isn't starting and while the trail coil should work, it does not have to work for the car to start and run.

RotaMan99

Im guessing the car does start.

I was only trying to clear up the fact that there is a noticable difference in performance with the trailing unplugged. I didn't mean to take the thread of course.

To the OP, can you probe all the pins related to the trailing coil and CAS at the ECU so we know what is really going on?

Is it possible that some wires in this "not original" harness have been rerouted to different pins by Mazda?

gabs88gxl

iTrader: (3)

ok cool ill try what you toldme to do in the morning ill let you know if anything happens an what the out come is. thanks for helping me out ill see what happens

HAILERS

I'm curious. Does the engine run?

EDIT: I guess it does since you said the tach worked for a while in your second or third post.

Soooooo, if that's so, I'd just get that piece of wire that's long enough to reach b/t the lead coil bullet and the trail coil bullet, and jumper those two bullet connectors and start the car. That'll tell you if it's tach related or Trail coil related.

gabs88gxl

iTrader: (3)

yeah if you turn the key to start it an floor it it starts but it runs really rich. an if you let off it dies... but if you pull the trailing when the car is kinda running still nothin no spark. i havnt got a chance to check an do what you told me to im getting ready to go down there tonight an check it out an see if that helps.

HAILERS

There might be something else wrong other than the trail coils not working.

Plug wires on wrong? Just in case. Jpg attached of where they are. No insult meant here.

Maybe a broken apex seal. Pull the lower plugs. Have someone spin the engine while you hold you thumb/finger over one hole and then the other. The pulses from each rotor housing should be like the other. IF a apex seal is gone, you'll feel the ODD pulse from that rotor housing.

Really badly fouled Trail plugs Might cause one not to fire. If memory serves and I read the site right, if one Trail plug does not fire, then the ECU stops either from working. Memory there. Then again, Trail plugs not firing shouldn't cause a engine from running or idling in a normal manner. Just does not happen.

You might check all the plugs and see if a couple are fouled real bad. That might mean a bad plug but could mean a bad apex seal too.

Did you ever hear this particular engine run good?? If not, then I'd do the cheap and quick compression test I mentioned above first.

gabs88gxl

iTrader: (3)

yeah i drove the car before we gave it to that shop to fix an he screwed us over an didnt go anything but let it sit there in the back. He drove it once an then i drove it after. It would run but start to bog after a few good shifts like it had a rev limit in it at 3000. So i know the motor is good after he put the interior harness in the trail wouldnt spark. so im not sure. but on my s4 if i pull on of my trailing wires off. the car runs like crap and my car runs fine. does the trailing start the combustion an the leading finish it

HAILERS

Does it have a series five ECU???? You said it has a series five motor.

If it's a series five ECU, then the problem might be the electric OMP causing the ECU going into LIMP mode.

The interior harness you mentioned. Does it run across the right passengers foot well then over to the drivers side? And extend into the engine bay on the LEFT side of the engine bay?

gabs88gxl

iTrader: (3)

yeah it has a S5 ecu in it. thats what i was think that it was going into a safe mode. Or like you said a limp mode thats why we took it to that guy. I did all the harnesses from the emissions to the interior one that went from the ecu over the tunnel to the fuese box out to the front of the car. Also the one from the fusebx to the tail lights. Like i said i had it running good before an it was fast as heck but it would go into limp mode.

the dude we took it to use to own rotary specialist in colorado. he said he would do it cause he owed my friend money after his shop got closed but screwed us over an just put the harness in an left the car to sit. I still think he took some parts off the harness an stuff cause there was the clutch switch was missing i still think theres some relays missing an stuff. i have to really look over it

HAILERS

Seriously, I think the only way to figure this out, is to backprobe the ECU with the key to ON, and comparing the readings to the series five FSM.

gabs88gxl

iTrader: (3)

ok ill do that an see what i can find. I know this site that has all the factory manuals but i dont know. it www.wankle.net an i got all the service manuals back to 82 i think so ill read what the voltage is an back probe the harness like you said. Im just really bumbed out about it cause i had it running right but going into limp witch was probley something easy. an we sence that dude had it its been just hell for me. thank you for helping me. im going down tonight to the car so ill do all of what you told me so far an we can take it from there...

HAILERS

The thing about that Limp or fail safe mode is, that, from what I read, the car will run fine for a while and then go into the fail safe mode. That does not seem to be what is happening with your car.

I don't own a series five, so I can't say from personal experience.

gabs88gxl

iTrader: (3)

yeah i really wish i could get this going im going to try to find a s5 ecu. even if its non turbo it will determin if the ecu is not letting the trailing spark. or if its a wiring problem. are there any fuse's or relays that spark the trailing