no start problem, only sparks 1/3 CAS rotations
03-22-12, 08:58 PM
#51
Did you try unplugging stuff?
How about this. Can you de-pin a connector? It's actually pretty simple. If I were on my last nerve with it I'd try this one last thing. De-pin everything in the ECU connector except what goes to the cas and coils. Now see if it decides to spark only 1/3 of the time. If it does then, go back and one at a time plug in each individual wire into the ECU connector. Just make sure you label them all before removing the wires. One wire, spin the CAS, check for spark. Rinse, repeat.
How about this. Can you de-pin a connector? It's actually pretty simple. If I were on my last nerve with it I'd try this one last thing. De-pin everything in the ECU connector except what goes to the cas and coils. Now see if it decides to spark only 1/3 of the time. If it does then, go back and one at a time plug in each individual wire into the ECU connector. Just make sure you label them all before removing the wires. One wire, spin the CAS, check for spark. Rinse, repeat.
03-23-12, 03:06 PM
#53
I don't think you're getting what I'm saying. If there's a short somewhere, or wires shorted together, or signals getting crossed somehow, this will find the problem. So if all you have in the equation is power, ground, CAS signal, and output to coils, then that can rule out everything else as an issue. If you, at that point, get good spark signal, then you'll start plugging in all the other pins on the ECU one by one to see what is actually causing your problem. If you don't get a good spark signal, then you've got an issue with the ecu, cas, coils, etc. I'll be willing to bet that once you de-pin the ECU connectors, you'll be getting good spark when you spin the CAS.
03-23-12, 03:19 PM
#54
Rotary Freak
CAS wiring has one plug inbetween the CAS and the ECU. Find this plug that I mentioned in one of my earlier posts and see if its corrupt in some fashion. And or pull the CAS plug off and the ECU plug off that carries the four CAS wires and ohm them each out individually from end to end and at the same time see if one is going to ground (shorted to gnd).
IF good then find the two wire white colored connector for the Lead coil assy and pull it apart. Get on the yellow/green wire with a meter on dcvolts and key to ON. Slowly spin the CAS by hand and see if meters reading changes from zero to five vdc four times as you slowly spin the CAS by hand. Should do that.
My last post on this thread was just to show how a bad injector cannot cause your problem with spark nor could a bad EGI fuse cause intermittent spark unless the EGI fuse(s) were barely installed and making poor contact.
Also probably already mentioned............the coil assys themselves must be bolted on the fender with at least one fastener. No additional gnd need be added. just at least one good fastener holding it to the fender with no paint b/t the coil assy and fender.
IF good then find the two wire white colored connector for the Lead coil assy and pull it apart. Get on the yellow/green wire with a meter on dcvolts and key to ON. Slowly spin the CAS by hand and see if meters reading changes from zero to five vdc four times as you slowly spin the CAS by hand. Should do that.
My last post on this thread was just to show how a bad injector cannot cause your problem with spark nor could a bad EGI fuse cause intermittent spark unless the EGI fuse(s) were barely installed and making poor contact.
Also probably already mentioned............the coil assys themselves must be bolted on the fender with at least one fastener. No additional gnd need be added. just at least one good fastener holding it to the fender with no paint b/t the coil assy and fender.
03-24-12, 09:29 PM
#55
I had the privilege of seeing this car tonight, and it's definitely a puzzler. I verified the wiring was correct up to the ECU, but ran out of time eventually, so I didn't get to check everything I wanted to. I disconnected the large connector and checked between pins 1N and 1P for a small voltage AC signal, and I did get one. I also verified 1Q and 1T for the same thing. It's also not shorted to ground as well, so the signal going to the ECU is not being corrupted. I could definitely tell that the Ne signal is the 2-toothed wheel, and the G signal is the 24(IIRC, it's 24) toothed wheel.
Here's what I do know right now. The injectors are firing, at least. I really can't tell if the pulse width is proper, but the car is getting fuel. The engine has great compression, and it's definitely not flooded. It is getting leading spark, but only once every 3 rotations of the CAS. The trailing coils aren't firing. Period. That may offer some helpful information.
The next step is to do like Hailers said, and at the 2-wire connector, check for the 5v signal 4x every revolution. I doubt, though, that it's getting that signal. The same thing needs to get done for the trailing coils, but they don't work the same way as the leading coil does. The trailing coils are 2 separate coils with the ignitor circuitry attached. So pin 1U will be the trailing select signal, and 1X will be the trailing timing signal.
One more thought... This car is (no offense) a jumble of different parts. It's a TII car, with an S4 NA engine, S4 NA wiring harness, an N326 ECU, an S5 UIM, and I don't know what else. I think you need to go through all the sensors and verify that they're compatible with the N326 ECU. So the AFM, pressure sensor, etc, all the numbers should match. The injectors should be the proper ones for that ECU, so I believe they should be low impedance injectors with a resistor pack. Those are some things I didn't look at while I was there, but I really don't know if they'll cause your problems or not.
It also stopped cranking right as I stopped trying to troubleshoot. Kind of weird.... it wouldn't crank any more, then the fuel pump wouldn't stop running until I turned the key off.
Now I'm starting to understand why some people just end up saying screw it and throw a carburetor and gslse dizzy on their FC.
Here's what I do know right now. The injectors are firing, at least. I really can't tell if the pulse width is proper, but the car is getting fuel. The engine has great compression, and it's definitely not flooded. It is getting leading spark, but only once every 3 rotations of the CAS. The trailing coils aren't firing. Period. That may offer some helpful information.
The next step is to do like Hailers said, and at the 2-wire connector, check for the 5v signal 4x every revolution. I doubt, though, that it's getting that signal. The same thing needs to get done for the trailing coils, but they don't work the same way as the leading coil does. The trailing coils are 2 separate coils with the ignitor circuitry attached. So pin 1U will be the trailing select signal, and 1X will be the trailing timing signal.
One more thought... This car is (no offense) a jumble of different parts. It's a TII car, with an S4 NA engine, S4 NA wiring harness, an N326 ECU, an S5 UIM, and I don't know what else. I think you need to go through all the sensors and verify that they're compatible with the N326 ECU. So the AFM, pressure sensor, etc, all the numbers should match. The injectors should be the proper ones for that ECU, so I believe they should be low impedance injectors with a resistor pack. Those are some things I didn't look at while I was there, but I really don't know if they'll cause your problems or not.
It also stopped cranking right as I stopped trying to troubleshoot. Kind of weird.... it wouldn't crank any more, then the fuel pump wouldn't stop running until I turned the key off.
Now I'm starting to understand why some people just end up saying screw it and throw a carburetor and gslse dizzy on their FC.
03-25-12, 01:49 PM
#56
Rotary Freak
When you say it has a series four non turbo wiring harness.......................and earlier say its a turboII car..............................does that mean just the EM harness on the engine is non turbo or???? are the other harnesses now also non turbo harensses in this turboII car?
We know non turbo EM harness will mated with turbo Front harness but the pinouts of the two are not exactly the same .............so if nothing has been done to make the wires in the EM mate proberly with the Front harness then that might be a part of the problem. This might have already been addressed in a earlier post.
Seeing as how the CAS wire from the ECU to the CAS are proved good, then get a meter on the yellow/green wire of the small white connetor on the LEAD coils assy and with key of see if the 5vdc on that wire comes and goes four times in a one turn of the CAS.
We know non turbo EM harness will mated with turbo Front harness but the pinouts of the two are not exactly the same .............so if nothing has been done to make the wires in the EM mate proberly with the Front harness then that might be a part of the problem. This might have already been addressed in a earlier post.
Seeing as how the CAS wire from the ECU to the CAS are proved good, then get a meter on the yellow/green wire of the small white connetor on the LEAD coils assy and with key of see if the 5vdc on that wire comes and goes four times in a one turn of the CAS.
03-25-12, 07:38 PM
#58
He told me it was an NA EM harness, and I assume it's the original TII front harness and everything else. So NA EM harness, NA S4 engine (w/ S5 upper intake manifold), S4 NA ECU (N326). I only got around to verifying inputs to the ECU from the CAS. They're good. Next logical step is to verify outputs from the ECU. Like Hailers said, using the multimeter on VDC, check the green/yellow wire at the lead coil for +5v, 4x every rotation of the CAS.
The trailing coils not sparking is suspicious to me as well. That has to be related in some way, so I'd start going down the path figuring out why you're not getting spark to them. There should be 2 black/yellow wires on one 2-wire connector that should have +12vdc with the key on. The blue/yellow wire has the same function as the green/yellow on the Lead coil, so it should have +5vdc 4x every spin of the CAS. The brown/yellow wire is the select signal, so its purpose is to tell the ignitor to toggle which coil to fire. I believe that one (back me up here on this one Hailers) should have +5vdc twice per revolution of the CAS.
I also verified the coils are properly grounded. Seems like he did a good job of sanding the fender down and cleaned up the bottom side of the coil bracket. Resistance checked out at 0.0 ohms from bracket to negative terminal.
The trailing coils not sparking is suspicious to me as well. That has to be related in some way, so I'd start going down the path figuring out why you're not getting spark to them. There should be 2 black/yellow wires on one 2-wire connector that should have +12vdc with the key on. The blue/yellow wire has the same function as the green/yellow on the Lead coil, so it should have +5vdc 4x every spin of the CAS. The brown/yellow wire is the select signal, so its purpose is to tell the ignitor to toggle which coil to fire. I believe that one (back me up here on this one Hailers) should have +5vdc twice per revolution of the CAS.
I also verified the coils are properly grounded. Seems like he did a good job of sanding the fender down and cleaned up the bottom side of the coil bracket. Resistance checked out at 0.0 ohms from bracket to negative terminal.
03-26-12, 07:50 AM
#59
I have another working S4 TII ECU that has only touched one car, but im afraid to try it in the case it gets f'd up too lol
Originally Posted by AGreen
Now I'm starting to understand why some people just end up saying screw it and throw a carburetor and gslse dizzy on their FC.
03-26-12, 12:07 PM
#60
Rotary Freak
On the Trail assy.............the brown/yellow will have a voltage that will vary from 5vdc to 0 dcv. Each time it goes to zero a trail coil will fire and when the volage comes back to 5vdc the OTHER trail coil will fire.
I was coming to the conclusion the 5vdc ref voltage device in the ECU is bad...............but then it needs this same source for the injectors to fire , so I don't know about that . Seems just looking at any of the brown/white wires on say the pressure sensor or TPS plug would prove if this 5vdc ref voltage device in the ECU is bad or not. Takes but a moment to look.
It's be interesting to know if each time the key is put to ON from OFF if the tach needle makes a small movement or not. I asked about that previously and got no answer. The tach needle bump means a trail coil hase fired.
I was coming to the conclusion the 5vdc ref voltage device in the ECU is bad...............but then it needs this same source for the injectors to fire , so I don't know about that . Seems just looking at any of the brown/white wires on say the pressure sensor or TPS plug would prove if this 5vdc ref voltage device in the ECU is bad or not. Takes but a moment to look.
It's be interesting to know if each time the key is put to ON from OFF if the tach needle makes a small movement or not. I asked about that previously and got no answer. The tach needle bump means a trail coil hase fired.
03-26-12, 08:35 PM
#61
On many ECUs (I'm no Rx7 ecu expert, though) there is one circuit that takes the 12v and makes the 5v reference voltage for all sensors. There may be more. If a shorted sensor has blown something in that circuit (or is shorting all the 5v to ground) then that may be a what's causing your troubles.
You may know something more than I do, but the ECU pulses ground to the injectors, with a constant 12v applied to the other side, right?
I didn't notice if the tach moved when starting it, but I seriously doubt it was, since there is absolutely zero trailing spark. That's something Trevor needs to check out.
I despise the factory ecu on the FC, and always did have some sort of little issue that I couldn't quite iron out. On top of that, I started dialing up the airflow with a bigger turbo, so now I'm a much happier camper with my Megasquirt.
Originally Posted by Hailers2
but then it needs this same source for the injectors to fire
I didn't notice if the tach moved when starting it, but I seriously doubt it was, since there is absolutely zero trailing spark. That's something Trevor needs to check out.
Originally Posted by gxl90rx7
or a standalone..
03-27-12, 12:11 PM
#62
Rotary Freak
I don't work for a living on cars, but I've yet to see a RX7 that would make spark or with working injectors ........that had a VREF less than what it should be on a RX which is approx 5vdc. If it's like 3.5vdc.....ain't a gonna get no spark nor injector pulses.
Yes, I know the ECU pulsed a gnd signal to a given injector for it to open/shut.
IF the ref voltage on the computer your on right now loses it's ref voltage.........ain't a gonna work no 'mo.
http://en.wikipedia.org/wiki/Voltage_reference
Yes, I know the ECU pulsed a gnd signal to a given injector for it to open/shut.
IF the ref voltage on the computer your on right now loses it's ref voltage.........ain't a gonna work no 'mo.
http://en.wikipedia.org/wiki/Voltage_reference
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