Jump to content
SAU Community

Recommended Posts

Of course I have searched. Yes, spark issues are everywhere but I've not found anything which relates directly to my issue.

My theory is the CAS, but I need someone with experience to tell me if the issues suggest that.

So, I have a Stag with a Neo RB25. It's a manual with Power FC, exhaust, eboost2 and that's pretty much it.

I bought it and it had a slight problem. Give it the herbs and it would miss. Not a single cylinder miss, more like an R&R miss. According to the Power FC knock would climb at that point.

The problem was fairly predictable and wasn't getting worse then a week or so ago I was at a mechanics and the car was idling for about five minutes. During that time it started pumping fuel clouds out the exhaust. I figured it was fueling up a bit and once it was driving again it would clear. It didn't. I drove to the shops around the corner and then home and it wouldn't take any boost or rev over about 3k rpm.

I parked it and then went down 3-4 times over the next few days and fired it up so I could poke around. it would idle ok, occasionally dropping off a bit, and then on the fifth attempt it would'nt start. Now, nothing. Lots of cranking but no ignition or even coughing.

I switched out AFMs, nothing. I've tried chasing every vacuum hose and plug to find something obvious, nothing.

I've had a feeling all along that the CAS is the issue. But I'm not familiar with RB behavior when the CAS goes.

I pulled the plugs today (what a prick of a job) and there's zero spark. I pulled three of the plugs and nothing on any of them. I switched in some brand new plugs and still nothing.

So, my question is what's up? Does that sound like the CAS? If not, what else could it be? Can Power FCs play up and cause this? I've checked the monitor and sensors on the Power FC, and everything looks ok, but again I'm not coming from a position of experience with RBs, or EFI for that matter :)

Anyone care to throw some ideas at me? Got fuel, got power, got no spark.

CAS?

Link to comment
https://www.sau.com.au/forums/topic/372581-diagnosis-rb-whats-the-ing-problem/
Share on other sites

  • Replies 64
  • Created
  • Last Reply

Top Posters In This Topic

Have you tried coilpacks?

They're known to fail in NEO RB25.

All of them in one hit? I pulled three out and none of them are sparking.

The car doesn't even cough when cranking so I'm pretty certain none of them are sparking.

Try starting the motor, pull one of the coilpack and see if the idle change - one at the time, if idle doesn't change that mean this coilpacks is failing.

Borrow someone with a S2 Stagea or R34 coilpacks and see if it fixes it.

Sounds like you have 3 of coilpacks that is failing - time for new coilpacks.

Also pretty sure it's usually 1 or 2 that fail over time but not all of them unless someone have whole set failing.

^it doesnt start at all now so cant do that.

have you got a multimeter? if so check for power at the coilpacks with the ignition on. also, how exactly were you checking spark? did you earth the spark plug properly?

The car won't start. No coughing, no nearly start, nothing.

I've heard coil packs failing before, and I'm not convinced that's the issue. It's similar, but the fact I have zero spark all of a sudden, across all six, kind of makes me think it's something else.

^it doesnt start at all now so cant do that.

have you got a multimeter? if so check for power at the coilpacks with the ignition on. also, how exactly were you checking spark? did you earth the spark plug properly?

Hmmm...I think I have a multi meter somewhere. What should I be seeing?

Pull plug out, put back into coilpack, hold against engine and crank.

the powerfc is solid state and unlikely to fail, but certianly possible

if it did fail you would likely see other side affects such as mangled idle, stalling, no power at all, psycho display on the hand controller or now power at all to the ECU

If your CAS was toast / slipping / mangled i dont think it would start, idle or run properly

if your AFM was toast / mangled / damaged / loose you would have the problem you are seeing

i would be checking the AFM voltage at the hand controller and jiggling the wires, i bet they are loose

and as grant said i reckon coilpacks would be on the way out

they would relpicate your symtomps you are having

they work fine on idle and cruise but when on power/boost - misfire/run like ass

Hmmm...I think I have a multi meter somewhere. What should I be seeing?

Pull plug out, put back into coilpack, hold against engine and crank.

iirc coilpacks should have constant 12v with ignition on.

holding it against a clean part of the head? i usually put a long screwdriver in the valley and sit the plug against the shaft.

Are the spark plugs clean and DRY? You didn't comment that they were covered in fuel. If so, then you are not getting fuel delivered to the cylinder. Have you tried listening to the injectors while cranking the engine?

Are the spark plugs clean and DRY? You didn't comment that they were covered in fuel. If so, then you are not getting fuel delivered to the cylinder. Have you tried listening to the injectors while cranking the engine?

I'm pretty sure there's fuel. There's a strong fuel smell when cranking.

Plugs were dry (but I hadn't cranked with them in as I was trying them) and covered in soot. Really badly sooted up.

I gave them a light sand and tried gain, but still nothing.

I had considered fuel, I thought maybe it was a dead/lazy fuel pump, but I crimped the return line and it made no difference. While this isn't definitive, it does suggest fuel isn't the issue.

Combine that with the plumes of fuel smoke when the problem got really bad, makes me think it's not fuel related.

Edited by Cowboy1600

AFM @ 0.20V with ignition on and from memory would be up around 2.5-3V when cranking.

Edited by Cowboy1600

AFM should be at 0.9V while cranking and approx 1.1-1.3v while idle.

You need to do an ACTUAL spark test and physically determine if there is spark or not

You need to check injector pulse as well.

If there is no spark, but there is injector pulse, then the problem is likely to be coil packs, power to the coil packs or the ECU (last resort)

If there is no spark and no injector pulse, then the CAS is most likley to be at fault.

Check 12V to coils and 12v to injectors

The CAS does not provide you with spark, it merely provides the ECU with a reference so it knows when to. You cannot have a dead CAS if there is injection pulse or spark or both

AFM should be at 0.9V while cranking and approx 1.1-1.3v while idle.

You need to do an ACTUAL spark test and physically determine if there is spark or not

You need to check injector pulse as well.

If there is no spark, but there is injector pulse, then the problem is likely to be coil packs, power to the coil packs or the ECU (last resort)

If there is no spark and no injector pulse, then the CAS is most likley to be at fault.

Check 12V to coils and 12v to injectors

The CAS does not provide you with spark, it merely provides the ECU with a reference so it knows when to. You cannot have a dead CAS if there is injection pulse or spark or both

Hrmmm...

Plugs were dry. But when it was starting there was lots of fuel. Now it's not starting and the plugs are dry. Upon reflection I didn't get any fuel smell today while I was stuffing around.

Right, need to check injectors. So no fuel coming through and no spark is a symptom of CAS?

I'll go and hook the induction back up and crank it and see what I get for the AFM values.

Also how does one do an ACTUAL spark test? I've always done it the way I did today and it's worked in the past, but then this is only the second car I've ever owned that had a computer managing it.

Edited by Cowboy1600

Pull out the CAS and see if it spins freely or if it feels a bit rough. If it is a bit rough it means the shaft has snapped in half and is rubbing on itself. It should make next to no noise when it spins.

Sounds very similar to when my CAS failed (was due to me overtightening the bolts and putting to much load on the shaft). Car ran fine then got really rough and started missing and then died on me. Would not start at all once it died, simply kept trying to start but wouldn't fire.

So check the CAS first since it is an easy thing to rule out.

I can't help but think it's the CAS.

Do I just take it off the base plate (ie, undo the couple of small screws) or do I need to take the base plate off as well?

Sounds like you have 3 of coilpacks that is failing - time for new coilpacks.

20.creation.jpg

Even with three good coilpacks, the car would probably start.

And I've been down fluffing around and I'm pretty confident there's no fuel.

I couldn't get to the injectors, but crank it over with plug out and I'm not getting any sign of fuel. Same goes for plug in. Comes out dry.

For it to be the coil packs I would have t have had all six fail all within a couple of seconds of each other.

Is there any monitor on the Power FC for the CAS?

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
    • But first....while I was there, I also swapped across the centre console box for the other style where the AV inputs don't intrude into the (very limited !) space.  Part# was 96926-4GA0A, 284H3-4GA0B, 284H3-4GA0A. (I've already swapped the top 12v socket for a USB bulkhead in this pic, it fit the hole without modification:) Comparison of the 2: Basically to do the console you need to remove the DS and PS side console trim (they slide up and back, held in by clips only) Then remove the back half of the console top trim with the cupholders, pops up, all clips again but be careful at the front as it is pretty flimsy. Then slide the shifter boot down, remove the spring clip, loose it forever somewhere in the car the pull the shift knob off. Remove the tiny plastic piece on DS near "P" and use something thin and long (most screwdrivers won't fit) to push down the interlock and put the shifter down in D for space. There is one screw at the front, then the shifter surround and ashtray lift up. There are 3 or 4 plugs underneath and it is off. Next is the rear cover of the centre console; you need to open the console lid, pop off the trim covering the lid hinge and undo the 2rd screw from the driver's side (the rest all need to come out later so you can do them all now and remove the lid) Then the rear cover unclips (6 clips), start at the top with a trim tool pulling backwards. Once it is off there are 2 screws facing rearwards to remove (need a short phillips for these) and you are done with the rear of the console. There are 4 plugs at the A/V box to unclip Then there are 2 screws at the front of the console, and 2 clips (pull up and back) and the console will come out.
×
×
  • Create New...