VVTi 1JZ engine running rough, low rpms, stalling, lacking power

[slide86]

yo,

after i picked up the car (its a jzx100), it ran bit shit. i put this down to fuel, and also a good suggestion of ECU relearn....

it soon cleared up and the engine was running mint for an entire week

the other day just as i was getting to work it started running like crap again. very low idle, almost stalling.

the scary thing that happened was i lost all power assistance to the brakes!!!! i had to stand on the pedal to get it to stop = no vacumn at the booster

also, when the fault was occuring, i could hear the hecktik flutorz through the air filter, even at idle.....

so, went to drive the car tonight......

- ran awesome for 20 mins
- then as if i flicked a "run like shit" switch it just started playing up....real bad

- would not boost at all, it would start to spool then just go quiet. as if the gate opens all the way and stops boost
- on light throttle, round 1700rpm its ok
- on decel or idle its absolutly terrible, sounds like a rotary out the exhaust
- i tried cooling the coilpacks with compressed air, no difference.

- as quick as it came, it just stopped. i had it idling in the workshop, it stalled, i restarted it and it revved up for a second then just cleared up and started to run perfect again.

- its still puffing and fluttering in the intake when this fault is occuring


could it be plugs and coilpacks? ive read alot in the last 10 mins that 1jz coils and leads are a problem point

[JP]

I'd remove the coils and check them for hairline cracks, also check the plugs to see if they're fouled up or too cold.

I had a 1J exhibiting similar problems until I swapped out the HKS plugs that were installed in it with the standard denso platinum PK20's.

[Anthony]

Just a thought..

unplug the vvt solenoid and see if the problem is still there.

[drifter** *]

sorry to dig up an old thread, did he figure out what it was?

[slide86]

yeah the VVTi solenoid was cactus......was holding the cam at once spot causing no inlet manifold vacuum.

replaced it with a new one (available from toyota) and sure enough.....good as gold

[recon440]

I have a similar issue but the symptoms are a little different... how did you end up figuring out VVTi solenoid was toast? Was there a way to bench it?

[pandaah]

unplug it, there will be a noticable difference in powerloss if you have unplugged it and its not your problem

[drifter** *]

I don't think it's the same problem. The car runs fine and then cuts out for a second, when it does it bad enough it brings the check engine light on. I've checked the codes and it keeps bringing up code 14. which means igf signal to ecu. I'm thinking the problem is either igniter, cam sensor or crank sensor. I'm going to scope the igf signal today end then go from there. If only knew someone near me that had a jzx100!

[pandaah]

usually the IGF signal comes from the crank angle sensor, and by the sounds of things sounds like if its effecting the motor in such a way it would be a good chance that its your problem..

i had the same no IGF signal problem with my car so i changed my dizzy which houses the crank angle sensor and it fixed it, before this i changed my ignitor and it did not... hope this info leads you on the right path..

[drifter** *]

Thanks allot for your help, it's much appreciated

[JP]

IGf comes from the ignitor, it's the ignition confirmation signal back to the ECU. If you've got IGf problems then it's more likely to be related to the Coils/Leads.

[drifter** *]

I have replaced the plugs. The coils don't have any signs of burning on them. I haven't tested the leads though. Can you throw an IGF code without any missing/ breaking down under load/boost?

[JP]

then only time I've seen a jz throw a code 14 when it's not coil or lead related is when the caps in the ECU are leaking.

[drifter** *]

Well thought I'd post up the results for people searching for the same problem. Turns out it was the ecu, sent it away for repair and it fixed the problem. Sounds like jp was right, must of been the caps. Thanks eveyone for your help.