Diagnosis Rb: Wha'ts The %#^$Ing Problem?

[Cowboy1600]

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?

[Count Grantleyish]

Have you tried coilpacks?

They're known to fail in NEO RB25.

[Cowboy1600]

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.

[Count Grantleyish]

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.

[JonnoHR31]

^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?

[Cowboy1600]

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.

[Cowboy1600]

^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.

[paulr33]

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

[JonnoHR31]

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.

[blind_elk]

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?

[Cowboy1600]

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 July 31, 2011 by Cowboy1600

[Cowboy1600]

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

Edited July 31, 2011 by Cowboy1600

[Count Grantleyish]

What sort of spark plugs?

[Cowboy1600]

What sort of spark plugs?

NGK Coppers. Heat range 6 and 1.1mm gap.

It was pushing 11psi when it was running...badly.

[The Dan]

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

[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

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 July 31, 2011 by Cowboy1600

[PM-R33]

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.

[Cowboy1600]

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?

[caaraa]

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

[Cowboy1600]

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

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?