Rb20 Ignitor Failing Symptoms Or Failed Coilpacks?

[rayj]

Hi

My rb20 engine is idling really rough.

While idling I took off each coil pack plug one at a time and found 2 coil packs weren't affecting idle, the other 4 would make idle even worse...

If an ignitor is failing will all coil packs be affected, or can it only affect 1 or a few?
Or, have 2 coil packs failed at exactly the same time?!

Cheers for any help

[GTSBoy]

The ignitor is 6 individual switches (transistors actually) so, it can be equally to blame. Move the coils around and see if the problem follows the coil or stays with the cylinder.

[rayj]

The ignitor is 6 individual switches (transistors actually) so, it can be equally to blame. Move the coils around and see if the problem follows the coil or stays with the cylinder.

Thanks for the tip, will try that tomorrow

[rayj]

Even after moving around coil packs the missfire remains on the same cylinders.

Both cylinder 1 and 5 failed at exactly the same time, which made me think this was highly unlikely to be a coil pack or spark plug problem.

I think it's safe to say the ignitor has died. Could it be anything else?

[GTSBoy]

Could it be anything else? Yup. Could be injectors. Could be something oily (like stuck valve, burnt valve, damaged rings). You can at least have a good go at eliminating the engine side causes with a compression test and perhaps a leakdown test.

Realistically, any of them could occur on more than one cylinder at the same time due to outside causes (dirty fuel) or blown headgasket etc.

[Sinista32]

Swap ignitors with known working one. Once illimnated as the cause then look further. Coil pack loom perhaps. When you do the checks on the coil packs do it at night or in a dark place so you can see spark. What were your plugs like? Especially 1 and 5?

It can give you you an indicator of what's going on.

[rayj]

I will check the ignitor soon. Have sourced 2 I can check with.

How exactly do you check injectors? I've searched on this forum. I know you're meant to take off the CAS, rotate it by hand and listen for clicks. But how am I meant to rotate it, one smooth complete revolution? Am I meant to hear 6 clicks independent of each other?

As I rotate I can hear the fuel priming and clicking...

[rayj]

Well it's not the ignitor either... I'm starting to fear the worst, like something is internally wrong with the engine...

[niZmO_Man]

The wiring?

[R_34]

I had some misfire problem under load, I swapped the ignitor for a newer one. It didn't solved the problem but the engine revved a little better on sudden throttle opening from idle.

I found out later that I had at least two coilpack coocked, the varnish on it had burned. In the meantime I tried to improve the ground of the coilpack loom and the igniter without success.

I just replaced the 6 coilpack by RB25 S2 superforma coilpack (a UK brand), wiring specialtes rb25 S2 coilpack loom, deleted the igniter and the problem disappeared.

As GTSboy mentioned it earlier, compresion test and leakdown test will give you indication on how healthy the engine is, and if not, what's worned/damaged but try to eliminate ignition related problems first.

Begin by 6 brand new bcpr5 ou 6es plug depending of the mods on your engine.

Check physically all the coilpacks, and check the primary and secondary resistance of the coilpack as explained in the factory service manual of the R32 (you can find it on the net).
Remove the rubber insulator and check if the spring are still here, and if the little piece of graphite at the end of the spring is still here and in good shape. You can try to elongate a little the spring to guarantee the contact with the plug. On the late RB20 the little piece of graphite was removed and a longer spring is used in place.

Check the coilpack loom, they're quite old now and very brittle.

The connectors break down easily, and the wiring can rust internally. Form the outside you can't see anything but once you remove the insulation of the wires you can see that the wires are greenish instead of the copper color. Check the quality of the ground of the coilpack onto the coilpack brancket and the engine itself. You must have continuity.

Check when the engine is running if you have a steady power supply to feed the coilpack (more than 12V).

If all of the above turns-out to be OK it might not be ignition related. Still it's better to change the coilpack and loom for brand new one, and possibly for S2 (w/o igniter).

[rayj]

So I've just done a compression test.

The test was carried out on a cold engine because the car barely even idles and usually just dies anyway.

Went and bought a brand new Stanley compression tester from Supercheap.

I don't know how accurate/calibrated these testers are, but here are the results:

1 150

2 150

3 145

4 145

5 145

6 150

I removed the fuel pump fuse, ignitor, coil packs, all spark plugs, and coil pack loom.

Throttle at WOT.

Then cranked 3 times per cylinder.

[GTSBoy]

Engine is fine. Cross that off your list. Look to injectors or coil loom.

[rayj]

Engine is fine. Cross that off your list. Look to injectors or coil loom.

What's the best way to check for injectors? Should I just do the screwdriver method?

Also, how exactly do you check injectors? I know you're meant to take off the CAS, rotate it by hand and listen for clicks. Am I meant to hear 6 clicks independent of each other?

[GTSBoy]

Take them out and flow test them is the ultimate way. It doesn't matter a shit if they're clicking if they happen to be blocked.....

[Scott Black]

What were the spark plugs like when you pulled them out. Specifically any difference between the two dead cylinders and the rest, if those two were really wet it would suggest a spark issue, if they were dry and a pailer colour to the rest it would suggest fueling

Edited May 18, 2015 by Scott Black

[rayj]

What were the spark plugs like when you pulled them out. Specifically any difference between the two dead cylinders and the rest, if those two were really wet it would suggest a spark issue, if they were dry and a pailer colour to the rest it would suggest fueling

Yeah there was a difference. The 2 dead cylinders (1 and 5) were dry and a lighter colour, sort of whitish. The other four were black.

Also, I was reading up about injector firing sequences on the RB20DET and apparently cylinder 1 and 5 together is part of a sequence. I'm not sure how true this info is...?

[Sinista32]

Prooves 1 and 5 have a fuelling issue (too little). Get your injectors cleaned

[rayj]

All injectors have been checked by a workshop and are flowing properly.

All cylinders have been checked for spark. Each plug (all new) has spark, therefore loom is fine, so is the ignitor and all coil packs.

Fuel hose disconnected, fuel is being pumped at ignition 'on' and when CAS is rotated by hand. Fuel hoses are connected properly.

Spark and injector clicking when CAS is rotated by hand.

The car will barely start now, won't even idle. Tries to start then immediately dies...

I have no idea what's going on...

[Missileman]

Air Flow Meter?

[rayj]

Shouldn't the car still fire even if the AFM is rooted? It will be rough (limp mode), but it should still fire up. I've tried the with the AFM plugged and unplugged.

Gonna buy an ECU to see if it's that

Could compression tests be inaccurate? My results are above, and all seems good at a cold engine...