1JZ Crank Angle Sensor CAS Faulty - symptoms

[cptsideways]

My 1JZ is playing up, misfire at 5000rpm onwards, not throttle postion dependent, have done a diagnostics check & I got a code 78 which IGF (ignition return to ECU failure) so I'm assuming a duff Crank Angle Sensor.

Has anybody else had the same or similar issues, I've ordered a spare CAS in the hope it cures the problem. Just wondered though if there was anything else that can give a similar fault??? or something that makes the CAS give a duff signal?

I only have a few days before the next Drift round so need to make sure I have all my bases covered.

I've gotten a TPS faulty code but I assume thats as I've not set it in the right place

Cheers in advance

[JP]

have you checked your coil packs for cracks?

You can get an IGf code under load if the coils short out to the head.

[The Witzl]

have you checked your coil packs for cracks?

You can get an IGf code under load if the coils short out to the head.

Quoted for truth. There's been a couple of guys here post up the exact same problem and it was due to hairline cracks in the coil packs.

IGf is the return "fire" signal to the ECU from the ignitor.

How it works is: ECU sends the IGt signal to the ignitor, telling the ignitor to fire. The ignitor fires, and if the spark was successful it sends back an IGf signal to the ECU telling it that everything worked.
No IGf signal means spark went missing.

[JP]

The last 120,000km 1J I got had cracks in all six coil's, I repaired the cracks with epoxy after dremmeling them out so the epoxy could get right in. Then wrapped the stem in electrical tape and put the boot back on. They've been working perfectly since the repair.

Here's two pics of a cracked coilpack:

[wilbo666]

I thought the code for IGf was 14....

Anyway there is a code for the CAS and for the Cam sensors. The codes get thrown if there is the wrong number of CAS pulses between cam pulses, or wrong number of cam pulses between CAS, or missed CAS etc...

I doubt the CAS is to blame... (as already said!)

Cheers
Wilbo

[Ribfeast]

I had a code 14 when my CAS got smashed and the sprocket was snapped off the timing belt cog.

[wilbo666]

I had a code 14 when my CAS got smashed and the sprocket was snapped off the timing belt cog.

Haha, fair enough; I wonder why they bothered making a code for the CAS if it never gets thrown?!

Cheers
Wilbo

[lojik]

Mine has been doing this recently too.
But only when cold, perhaps the plastic is expanding with heat and self-sealing.

Interestingly, while this is happening my boost gauge tells me I can get up to 12psi by free revving in neutral. Anti-Lag for free!

[cptsideways]

OK Update

Well its definately NOT the coilpacks, as they have now been ditched in favour of a Driftworks 6 Pack wasted spark system & the symptoms are still there.

Engine is currently half out so will be checking the cam sensor drive thing on the crank pully, then rewire the output feed to the ecu to see if that fixes it.


Any other ideas??

[chris davey]

Firstly, did you change anything to make the misfire?

What plugs do you use?

Also, why did you go to waste spark system? I assume you are still running stock ecu.

I would be pulling the plugs after a hard run (instantly) no idling and taking a good look at them with a magnifying glass (google "how to read plugs") and see if you can tell anything from that.

Are you sure your fuelling is adequate?

[cptsideways]

Its had two set of new plugs & thats not cured it, I have a VEMS wideband system & it does'nt run lean so not a fuelling issue.

The key thing is: it does its free revving the car with no load at all

[Turboterrifik]

No run it far a couple of turns and then pull plugs

[Turboterrifik]

do plugs look any good?

[cptsideways]

Plugs have been replaced so as new a few times over, its not coil or sparks but appears to be pre-hightension system

[BeRad]

sounds silly, but ive had the same problem and it was the coil pack so, if your sure its not them , could it be the leads are earthing out on the head or something simple.

when you say it does its free rev thing comment? do you mean it still misses at 5000rpm or it doesnt miss at 5000rpm