1JZ problems

[cressida_1jz]

Its been happening for about a month now.Il be driving along and then its starts to misfire and blow out white and black smoke.Its not water and its not oil but smells like un burnt fuel.Then when u pull over and turn the car off,it stops and its fine for like a day or 2.

No codes are coming out of the ECU.Does anyone think its going into LIMP mode?

If so,what kind of things can be causing this?

[Cressida91GLX]

bad plugs, or plug wires (leads). If it is petrol than definately it is not burnt and the reason for that will be no spark in the cylinder. check that system as it is not easily captured by ECU

[EldarO]

yeah, good time to change out the plugs and leads.

you may also have gotten fluid in where the plugs are?

Eldar.O.

[cressida_1jz]

I put plugs in about 10000Ks ago but only changed them a week ago again.

I forgot to mension that when it does it,you can hear the coil pack in cylinder 3 or 4 arcing out.I pulled the coil pack out and theres a hairline crack when u take the rubber boot off.All of the coils have cracks in them.I have a spare set to chuck on.There cracked aswell.I can only give it ago.

[Cressida91GLX]

Brad(umpagrande) on the toyotacressida forum has got the same problem with his 1jz. He was also trying to diagnose it and found one coil short on cylinder 3 I guess. Might be the same problem and might help talking to him.

[cressida_1jz]

Thanks mate.Il try and get in contact with him.

[urantia]

i have an occasional misfire problem when i first start the supra on some days, as if it's running on 5 or 4 cylinders then after about 30 seconds clear up, haven't taken the cam cover off yet as i don't have the right allen key.

Does this sound like the coils? once they warm up start sparking agian? common problem?

[Cressida91GLX]

to check for bad leads, at night where there is no light. Start the car and observe all the leads carefully, you will be able to find a faulty lead as it will be sparking with body.
Also check out the resistance of leads. When the engine is cold it needs good quality of spark otherwise it won't burn the fuel properly, so you will feel as if it is running on 5 cylinders.

[urantia]

Hmm i fail to see how this can be done on a 1jz with coils directly attached to the spark plug.

[YelloRolla]

I put plugs in about 10000Ks ago but only changed them a week ago again.

I forgot to mension that when it does it,you can hear the coil pack in cylinder 3 or 4 arcing out.I pulled the coil pack out and theres a hairline crack when u take the rubber boot off.All of the coils have cracks in them.I have a spare set to chuck on.There cracked aswell.I can only give it ago.

The arcing (or tracking as it is otherwise known) is VERY LIKELY to be your problem. It is unusual in that it is intermittent and not permanent. Definitely try a different coil and get back to us with the result.

It is funny how some have mentioned changing spark leads BUT, the later VVTi 1J's do have leads.

[cressida_1jz]

coils either 3 and 4 were the ones that were arcing out.So i put another set on this arvo.

Il see how things go this week.Number three had more than a hair line crack up the stem of it.It was about 1/2 a mm wide and all the rest if them had tiny cracks in them.

[YelloRolla]

I'll bet that fixes the problem. If it is still missing under boost you may want to try cleaning the spark plugs under that coil as they may have fouled. I would clean them with some carby cleaner (assuming that they are platinum of iridium).

[chris davey]

On the ignition topic, mate had iridiums in his car and we pulled them out and the tip was very pointy. I haven’t used iridiums before but when another mate had copper plugs that looked like that, we changed them and it definitely seemed to run better. I have heard iridiums are supposed to last longer but was unsure how old these ones are and if they have had it. The part of the plug that starts off as a square shape that is under the electrode. Hope that makes sense

[urantia]

Anybody got a part number for NGK plugs that are suitable for the 1jz twin turbo?

[chris davey]

ngk bkr6e for stock engine, bkr7e for slightly modded. Start gap at .7mm

*meant e not 3*