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Vvti 1jz problems

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So I've been driving my jzx73 for a couple weeks now since we finished the swap, and the first couple days it would have a slight hiccup under WOT around 3-4k rpms. Went away for a while and now it's back somewhat consistently. Also the car has never really liked to idle After driving around town, however on 1hr+ drives it idles fine right of the exit ramp and from then on until I reach my destination. I'm thinking coil pack, plugs, vvti solenoid, or ecu. Haven't had a chance to check much yet, but I'm going to fully investigate in the next few days. Anyone else experience these symptoms? It's a 97 vvti 1jzgte from a jzx100, wired in correctly to a 87 mx73. All stock minus 3in exhaust from the turbo back at 11.5psi of boost.

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ive said it before and ill say it again, i had issues with my x7 not getting enough air threw the intercooler, but that may have just been isolated to my car.

It used to run a bit rough, and have a fluctuating idle, occasional bog under load. raised my intercooler to catch more air threw the grill and a whole bunch of weird little problems dissapeared haha.

 

Probably not related but just thought i would throw it out there

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Try blocking off iacv/bov individually.

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The bov is controlled electronically with that solenoid beside it, not a perfect design really, I swear using it I only had boost half the time. I finally put an ic in my car and a bov, but I run the bov fully closed right now(or it doesn't run), and I had it cut out under boost like a fuel cut once since maybe it was a spike.

 

The idle may be the iac but it should happen more frequently if it was. Mine doesn't idle up on start up because the iac is dead. There is a diaphragm that blocks boost from traveling through the iac piping though.

 

On the jzx world forums the have a thread about modifying the factory bov to work more like a traditional bov.

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It's not tough to do that mod either iirc. My vvti has a nasty hesitation at anything over 1/8th throttle. I hate maf. Map gives you a false sense of security that everything's just fine haha.

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Would it be more beneficial to get the flange adapters to get rid of the factory intake/bov pipe, and run a traditional piping setup with atmospheric bov and just deal with a rich condition between shifts? Since my bov does the flutter and already seems weak I think this may be the best route especially if the bov is the culprit of my hiccups.

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If you do a atmospheric bov and it opens at idle your car will die/idle at 9:1 afr. I put one on because I'm going map but just have it fully closed full time until I switch over.

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Well that would make sense then that my oem bov is bad, sometimes I have more vacuum at idle than others. And maybe the interstate/hard driving is preventing it for hanging up?

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maybe you have a vac leak/boost leak too but fix the bypass valve first

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Kinda sounds like you've got a few issues manifesting as a few different symptoms. I think your blowoff valve is the least of your worries.

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Have you done anything or are you just sitting around waiting for the magic fix? There's some good solid leads here. Try them one at a time to help pinpoint the problem and eliminate it.

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What are your VAC readings at normal idle when it is not acting up?

What are they when it wants to start to die?

You can also grab a can and spray hose of carb cleaner and shoot it around vacuum lines while running to find a possible leak.

I have also seen guys pressure test their intake system (car not running) to find boost/vacuum leaks as well.

All of the advise above me sounds like more than enough info to head you in the right direction.

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Vac is indifferent when it acts up. Maybe .3 psi max. I tried unplugging the secondary throttle servo an it made no difference really. I'm starting to lean more towards simply the iacv and bov seeing as this motor could've sat for quite some time before I bought it.

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Update: on the way home tonight it started misfiring pretty bad at WOT on 11.5psi of boost. Gonna get plugs tomorrow and better investigate in class.

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