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Discussion Starter · #1 ·
When I am driving my car and have it in neutral or have the clutch in, the rpms go all the way down to zero and the engine turns off. What would cause this? Also from 4k+ rpms the power the engine produces is the same. What would cause that?

TIA,
Kyle
 

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Vacuum leak? Check the large hose between the AFM and the TB for cracks.
 

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Discussion Starter · #5 ·
I think that hose may have a crack in it but at the very end. But what about the engine cutting off? Thanks!

Kyle
 

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If you have a significant vacuum leak, it will allow the air door in the AFM to close, shutting off the fuel pump.
 

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Discussion Starter · #7 ·
But this is when I am driving, not Idle. So then there would be lots of air coming in. I wouldnt think I would be that big of a vacuum leak.

Kyle
 

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What is the idle rpm when the engine is warm? Can you experiment with a higher idle speed, say aroud 1,000 rpms and see if it still occurs.

Just a wild guess:
You could try removing spark plug leads, one at a time and see if the idle speed changes. You may have a fouled spark plug or clogged fuel injector.
 

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Discussion Starter · #9 ·
No Ron it idles just fine, infact perfect. The problem is that from 4k+ rpms the power the engine produces is the SAME, and also sometimes when I push the clutch in or have the tranny in neutral the engine will turn off. Another problem too is that I lose coolant when I drive it, but like just a few days ago I think it stoped. Whenever I will check the coolant maybe an hour or two later the coolant will spew out, but before it didnt. It may be a cracked head, I dunno for sure. This engine tends to have a lot of problems lol.

Kyle
 

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May be the TVIS is not opening.
When you say the engine turns off, is this while the caris stopped and idling or when you are driving the car?

Is coolant filling the overflow bottle and is the cap tubing connected correctly?
 

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Discussion Starter · #11 ·
This is when I am driving the car. It may be the TVIS. I took the one bracket thingy off that those vacuum lines went to, and then I took peices of hose and hooked it up to the ports on the throttle body and tranny thingy so then it would leak air out. For the TVIS i found a small skinny pipe sticking out ftom the bottom of the intake mani and ran that to the TVIS thinking it would give the valve the air, or something like that. Is this wrong? And I dont have the over flow bottle on. I just took it offf and ran that long hose from the coolant pipe to the coolant thingy on the tranny. I havent seem any coolant in the hose. It would leak ALOT so I wouldnt think it would be connected wrong. Them again it could lol. I will fill it full of coolant and then after I drive it to work and back in one day (around 15-20miles there and back) there was bearly any coolant showing in the pipe.

Kyle
 

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What is your objective for modifying the engine? It makes it very hard for board members to diagnosis your problem when you don't reveal the modifications you made. I suggest you bring it back to stock condition.

Here is the vacuum lines for the TVIS
http://www.mr2ownersclub.com/online_parts_catalog/emissions/41758393.gif
I think you may have hooked up the TVIS so that is is always under vacuum and the TVIS does not open over 4,200 rpms.

I don't understand the reason for removing the overflow bottle. I think you currently have the overflow tube from the coolant fill cap connected to the coolent bleeder tube attached to the thermostat housing. That basically creates a closed system and when the coolant heats up, creating excess pressure that has no where to go. The pressure in the cooling system must be leaking out somewhere. May be it is coming out of the waterpump weep hole.
 

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boostman said:
I think that hose may have a crack in it but at the very end. But what about the engine cutting off? Thanks!

Kyle

The one I was talking about?
Or ITA?

Fix it and you will see what we are talking about.
 

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If you've re-plumbed the vacuum to the TVIS, and eliminated the vacuum switch (which is what it sounds like), Ron is right - you are applying constant vacuum to the TVIS and it's never opening. That would explain the "engine producing the same power" part. The TVIS uses vacuum to close it, and shuts off the vacuum to open it via the internal spring. Also - you really don't want it open all the time either. It will run like crap at lower RPM.

Also, you say it dies when you have it in neutral or have the clutch in - while you're driving. Does it not return to idle at that time - at least temporarily?? And if the vacuum leak is in the big hose, it could cause the AFM door to slap shut when you drop the throttle (especially if the dashpot isn't working properly - and as screwed up as you evidently have the vacuum system, I'll bet it's not) and kill the fuel pump.
 

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Discussion Starter · #15 ·
Yeah it does it at Idle. So I will fix that. And I will also put that bracket back on. Thanks for your help! Hopefully this will fix it and the losing of coolant will stop. This engine has 118k miles on it and has broken an ignitor, headgasket, messed up the spark plugs, and maybe a few other things and have had like for like 2 months lol.

Kyle
 
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