Rb20det no spark

[Sean360]

So I'm new here hopefully I posted this in the correct place.

Car: 1991 r32 skyline

Engine: rb20det

Ecu: apexi fc commander

The long story.
So I was driving the skyline on the 31st of December had a few miss fires at 4k rpm engine management light came on the red cat temperature on and off agen after the miss fires but  I managed to get it home it was running fine gave it a few revs all was fine again so turned it off. The next day it would not start so did a bit of looking found I had no spark bit more look and switch parts I found the wire for earthing the coil pack loom was pinched before so cut away the damaged part and put a new o ring thing on it put back together fire up fine and was working a way. On the 2nd January i was driving it again all was fine no miss fires or anything parked it up that night and now again this morning will not start and no spark agen.

The short story.
Was driving had miss fires at 4k rpm.
Would not start next day no spark.
Thought I found the problem with a broken earth strap to the coil pack loom.
Car was fine after repairing earth strap for 2 days. 3rd day same problem no spark.

I have tried.
Swapping coil packs
Swapping coil pack amplifier I have 2 spare
Swapping coil pack loom
New spark plugs ngk r and swap back to the old ones ngk iridium just to see all gap's 0.8
I've cut back some of the Loom to see if there is a broken wire any where but have not gone all the way to ecu and have not found anything there.

I have fuel i can smell from the back and I can hear the injectors pulsing away whit the cam angle sensor.

So I'm out of ideas now if anyone can help me and point me in another direction I might  have over loaded it will be much appreciated.

Thanks very much in advanced.

[r32-25t]

Check to see if you have injector pulse 

[GTSBoy]

19 minutes ago, r32-25t said:

Check to see if you have injector pulse 

Given the claims of having injector pulse and smelling fuel, not so much this. But the thought is totally valid wrt coil triggers.

I would go looking to see if perhaps the ignition MOSFETs in the ECU are still working. They could have been killed by the poor earthing situation at the igniter. The ECU fires the coils by providing a path to earth for the coil charging current (actually, for the current that runs the MOSFETs in the igniter, but close enough for our purposes today) and if they refuse to change state from off to on or vice versa because they have let the magic elixir out of them them, then you get no spark.

[Sean360]

@r32-25t

I have fuel i can smell from the back when cranking and I can hear the injectors pulsing away whit the cam angle sensor.

so I unbolted the cam angle sensor ignition switched on had a spark plug in coil 1 and spark plug leaning against cam cover turned the camera angle sensor by hand I could hear the injectors pulsing a kind of a zzz Zzz sound but no spark.

I know it can get flooded by doing this so I gave her a few cranks with no spark plugs in to clear it out the fuel and also left for a half hour before train to start again. 

Edited January 4, 2023 by Sean360

[r32-25t]

Injectors should tick not make a buzzing sound 

[Sean360]

@GTSBoy

So if I put a voltmeter on pin 1, 2, 3, 11, 12, 13 and test them while cranking 

Should I see 12v on them as they fire or should they just switch to ground as they fire 

[GTSBoy]

4 minutes ago, Sean360 said:

So if I put a voltmeter on pin 1, 2, 3, 11, 12, 13 and test them while cranking 

Yes, those are the correct pins. A digital multimeter is possibly not fast enough reacting to show you this. An analogue meter will do better because you can see the needle flicking around. Regardless of whether the ECU outputs 12V or provides an earth, you will see 12V come and go at those terminals (with a fast enough meter). It's just the duty cycle will be opposite with the 2 approaches. If the ECU provides earth then the 12V is visible there when the ECU is not triggering. And vice versa.

Having said that, the ignitor pack has a common earth on the triggering (ECU) side, which means that the ECU outputs 12V during MOSFET activation. To this end, if you wanted to, you could pulse 12V onto those terminals and see the result (if any) at the igniter and the spark plug. A quick dab on-off of a 12V jumper onto that wire will simulate the ECU charging the coil and firing it.

I would also open the ECU and inspect the MOSFETs to see if they or any of their circuit tracks show signs of being cooked.

 

[Sean360]

@GTSBoy

Thanks very much for your help I'll give this a try tomorrow as its 00.40 here now. I only have a digital voltmeter hopefully its quick enough to catch the pulses I'll see if I can get my hands on a analog one I have a power probe that can send 12v and ground down a wire so I'll give that a try as well.

I did open up the ecu just to check for water damage and if there was a burnt track i did not see anything obvious there was no smell of burnt electronics there was one capacitor that had a small bit of corrosion on on the underside where the legs get sorted to the board i cleaned it off whit sum electrics cleaner came up fine the sorter joints had no cracks in it the capacitor is no swollen or leaking so I believe it's all good.

I'll check for the pulses if that is a no go I'll inspect the board more closely.

[Sean360]

@r32-25t

I know what you mean very hard to write a sound down I'll get a video of the injectors pulsing so you can hear the sound when i turn the cam angle sensor by hand there tomorrow as it 00.40 now.

I really do think I have fuel as there is a serious smell of unleaded when I'm cranking coming out of the exhaust and it's not making any attempt of firing not a cough or hiccup nothing. Just swinging and swinging.

Maybe the pulse is to long or something.

I'll have a video tomorrow.

[Sean360]

So a small update I trade a different ecu a oem one rather than the apexi fc I have no joy there☹️.

I also tried a different cam angle sensor no joy here either😭.

I'm wondering where does the ecu get the signal to fire the coil packs from is it all down to the cam angle sensor🤔?

Also the 2 green relays in the passenger footwell I can 100% hear one of them clicking but not sure if the 2nd one is clicking i try unplugging one to see if I could hear a click all that happens when I turn on the ignition is the fuel pump sounds like it's not getting enough power and that is whit either one unplugged. So I'm wondering if one of these are not working will that cause the coil packs not to fire

The one I have circle in the picture is that one of the green ones that are in the footwell.

Thanks very much again for any help in advance.

Edited January 8, 2023 by Sean360

[GTSBoy]

Yes. Coils are powered from that 2nd relay. You can bridge terminals 3&5 to take the relay out of the equation, but you can always just probe the terminals to find out if the relay is closed or not (when it would need to be, ie, when you need power to the coils).

[Sean360]

So I'm still not having any joy whit this.

Have I over looked something silly.

So I was waiting on a r8 coil conversion kit to arrive I have it ordered before this issue started. I have fitted it to the car I also ground it directly to the battery negative terminal just in case the engine had a bad earth.

There was a Hawk alarm fitted to the car way before I got the car it was never working since I got the car I was tracing back sum wires when I found it I also found a real that was wired to 1 of the green relays so I cut that relay out and put the green relay wiring back to factory.

Where does the ecu get the signal to fire the coils from is it all from the cam angle sensor I'm wondering now if the ecu is not getting the signal the hand commander is showing rpm when it is cranking so I might be looking in the wrong place.

Thanks again for your help.

Edited January 19, 2023 by Sean360

[GTSBoy]

The CAS signals let the ECU know what the engine angle is and the ECU fires the coils at the appropriate angle.

[Sean360]

I feel like a broken record😭, I still have no joy here🥺.

I have checked connectivity whit all 6 pins at the coil amplifier to the ECU there fine I have checked if the ecu is pulsing it I have .36v to 1.2v at them it keeps jumping around it is a digital voltmeter so might not be sensitive enough to pick up the pulses accurately.

The 3 pin plug that is beside the coil amplifier I have 12v in the centre pin earth on 1 of them but I don't know what the 3rd wire is for if any one knows might be my problem?🤔

I checked the cam angle sensor as well I have power earth and signal back to the 4 pins to ecu.

The 2 green relays are clicking I had the ignition on and unplug and plugged back in the relays and heard them click.

I was thinking it might have been the blue relay for ignition the one under the steering wheel in by the fuse box the one to the right of the obd port.

 

I have a few projects on at the moment so I don't have much time to be at the car so my apologies for not updating.

Thanks once again for any help and advice👍👍.

Edited February 1, 2023 by Sean360

[Spiffs]

I'm. having similar issues since about the same time. difference is that my car doesn't drive yet. I had the car running and starting first time fairly reliably. but it got harder to start and one day turned off while it was running and now doesn't start at all. 

I have gotten a new CAS which I've had no luck with do far but today I did hear a buzzing noise similar to what you described coming from. somewhere. I'm about to open up the ecu to give it a look too. 

I'd love to hear if you had any luck. with anything. I've gotten a set of r33 s2 coils coming and I'll bypass the rb20 ignitor which may help but if I find a fix I'll also keep you posted :) 

[FiXtUrE]

Have you put a multimeter on your spark plug leads? They should have 5 ohms. if they have less than 5 ohms there rooted 👌

[GTSBoy]

3 hours ago, FiXtUrE said:

Have you put a multimeter on your spark plug leads? They should have 5 ohms. if they have less than 5 ohms there rooted 👌

Are you deliberately trolling? Where are these spark plug leads of which you speak? On an RB30E perhaps? f*kken Jeezus!

[PLYNX]

Hmmmm . . was just wondering if there is a difference between 8mm and 11mm spark plug leads in regards to onhm reading on my R33 ?

Was thinking about up grading to the 11mm !

[GTSBoy]

Just tell him (the doofus, not Spiffs) that you can buy 22mm leads and he'll be all over it.

[r32-25t]

20 hours ago, GTSBoy said:

Are you deliberately trolling? Where are these spark plug leads of which you speak? On an RB30E perhaps? f*kken Jeezus!

He’s either trolling or incredibly stupid, either way his posts just need to be ignored