1jz starting problems(help!!)

[Oger Jr.]

I have a 1990 mk3 that put out 500hp I bought from a friend that been having this problem.whenever I try starting it when it stalls or basically after a drive it wont fire up but seems to be cranking.if i let it sit 20-35mins or more if im lucky it'll start but hard.I changed the battery, alternator, starter and plugs but its not solving the problem.I ordered new coil pack hopefully it'll do the job.car does need a tune and the other problem is while driving I guess whenever it gets to a certain temperature putting it into neutral the rpm will drop and cut off.any help will be great thanks.

 

[ifyouaint1sturlast]

Specs on the engine? Typically the fuel pressure regulator VSV would help hard starts after the engine is warm because it would allow more pressure to evacuate any air bubbles that formed in the rail. To get to 500HP I'm sure you have an aftermarket setup though, so specs would be needed!

 

[hvyman]

There is no fp up vsv on the 1jz...

First thing you should do is check the codes.

 

[te72]

and the other problem is while driving I guess whenever it gets to a certain temperature putting it into neutral the rpm will drop and cut off.any help will be great thanks.

The likely culprit in my experience with the 1j is that you might have a sticking ISCV. Sucks that the 1j unit isn't able to be disassembled like the 7m (point to you 7m...), and they are quite costly to replace. Does holding in the throttle after the car has warmed up a bit help keep it from dying?

 

[Oger Jr.]

Thanks guys..I'm not too sure on the specs of the car only basic stuff that I can see like the hks cams,gt 40,intercooler etc. cuz my friend did everything and I just bought it off him but i will ask him to update me on it.we did diagnose the code and the only code came up was for the speed sensor.and yes if I keep a little throttle not letting the rpm drop it won't shut off..

 

[Albert]

is the car over heating for some reason and you dont know it. Happend to my NA.

 

[te72]

I'd be leaning toward the ISCV sticking then. Tends to do that when it's warmed up a bit... do a bit of searching and you'll find the various fixes for that problem.

 

[T701jz]

Thanks guys..I'm not too sure on the specs of the car only basic stuff that I can see like the hks cams,gt 40,intercooler etc. cuz my friend did everything and I just bought it off him but i will ask him to update me on it.we did diagnose the code and the only code came up was for the speed sensor.and yes if I keep a little throttle not letting the rpm drop it won't shut off..

HKS cams will do that. You probably have a standalone controlling your idle speed. If not you have to adjust your throttle position a bit open.

 

[destrux]

When I disconnected my speed sensor to do the "speed limited removal mod" this is how my car acted. When I hooked the speed sensor back up it was fine.

Although, everyone tells me this didn't happen, so...

 

[Oger Jr.]

Thanks alot everyone ill check and do what you guys said and see how it turns out.as for the overheating it seems to be normal but ill double check.also I forgot to mention that the battery positive and negative wires smokes a bit when trying to start it for 5-10 secs if its not cranking over.im I over cranking it or is the wires bad that can relate to the problem?.

 

[te72]

If you have wires smoking, you're quite literally asking to have a fire in your car... I'd hold off on any more experimenting with that until someone can provide you with a more concrete CAUSE as to why your car is doing that. Unfortunately, I am not that person.

 

[ifyouaint1sturlast]

There is no fp up vsv on the 1jz...

First thing you should do is check the codes.

There's one on the 7M and 2JZ but not 1JZ?