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Discussion Starter · #1 ·
As the title says, my 1J will not rev past 2400rpm. It consistently stops at the same rpm. The idle is lumpy and the computer locks me out from any higher rpm. I was thinking MAP sensor? Anyone have any clues?
 

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GT40 1.5JZ
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1,210 Posts
have you tried reseting the ecu? pull the EFI fuse located in the fuse box for atleast 30 secs.

-joseph

BTW, even if your map sensor was disconnected (vaccum hose), your car should still be able to rev.
 

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check timing on cams...if off by one tooth itll screw everything up
 
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Discussion Starter · #5 ·
Do the cam wheels have timing marks on them? If i find they are out how do i adjust it, do the cams have to come out or can it be done with just removing the cam belt? I just bought this car as a parts car and it seems the last owner had the engine apart, may have put it back together wrong.
 
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Discussion Starter · #6 ·
Ok, found the markings on the cam gears. Turned crank pulley to TDC and both cam gears match TDC. Could the pulleys be attached to the actual cams wrongly, is this possible? Or, if everything lines up on the pulleys does the problem obviously lie somewhere else?
The engine bay does have some hella dodgy wiring tho, so could a bad earth cause any of this?
 
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Discussion Starter · #7 ·
Bumpity. This problem is really frustrating me - is there any other symptoms I should look for to diagnos this as say a bad earth or an electrical short? I've searched the engine bay and it appears everything is wired up as it should be, but I can't see into some places without a hoist.
 

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there is no way the cam timing can be out if the markers on the gears are correct. It is like a key when you put them on.

I don't know for sure, but I would check cam angle sensors, Throttle position sensor and crank angle sensor.
 
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Discussion Starter · #9 ·
Thanks chris, will do. I checked if maybe something was shorting to the engine block, btu there was no continuity between positive and the block so nothing there. There is full continuity from negative to the block and body so earthing seems ok. Disconnected the ECU fuse for a minute, put it back in- nothing's changed. The engine idles roughly, climbs to 2400rpm but hits a hard cut - fuel or ignition I'm not sure which. If i persist in holding it just under the cut it coughs pops and splutters and belows dark grey smoke from the tailpipe. It sounds like a tractor when revving, I think its not running on all cylinders. I'll have to check coils and injectors as well I guess.
 

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HMOOB VWJ NYOB MINNESOTA
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7MA70 said:
I just bought this car as a parts car and it seems the last owner had the engine apart.

Why worried? its only a parts car. Just grab what you need from it and recycle the rest. :dunno:
 
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Discussion Starter · #12 ·
Disconnected the TPS, idled even lower (around 400rpm) and rougher, as soon as I applied any gas it died, but fired back into idle when I lifted off. Will not rev at all with TPS disconnected.
I've discovered there is a very strange 'whirring' noise coming from immediately under the intake manifold when the engine is running. Not from the injectors, but underneath manifold. All I can see there is a clump of crossing-over cabling. It sounds almost like a small electric motor or pump. I may have to put the car up on stands to see under there.

Where do I find the crank anglesensor and cam positon sensor? Are they at the back or font of the block?

And to answer your Q jza71, I'd like to have the engine to sell to recoup some costs or to have as a spare to build-up.
 

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there are 2 cam sensors, they are at about cyl3 and cly 6. They are on the intake mani side up the top. 2 big plugs near the injectors.

The crank angle sensor is down the bottom of the engine, near the front on the turbo side. Sort of near the crank pulley and sump.

I am sorry but I don't know how to check them :( I just know that if the crank angle sensor is stuffed it won't do very much at all.

Does it sound like a tractor when idling normally? If so, pull off one coil pack connecter at a time until you find one where the note doesn't change when you pull it off. If this is the case, then that cyl isn't firing. It can either be air (valves), fuel (injector clogged) or spark (electrical to do with spark plugs).

good luck
 

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Your "whirring" sound may be your power steering pump or a intake manifold leak. Where is your idle at? You say your getting gray/black smoke out of the exhaust? If your try to rev it does it hit 2400 and then fall back to 1000 and repeat or does it stumble and try to keep reving in the 2400 range.
 

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This is a known 1J swap problem and from memory is something to do with the tach.
 
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Discussion Starter · #17 ·
stroker said:
Your "whirring" sound may be your power steering pump or a intake manifold leak. Where is your idle at? You say your getting gray/black smoke out of the exhaust? If your try to rev it does it hit 2400 and then fall back to 1000 and repeat or does it stumble and try to keep reving in the 2400 range.
It stumbles and tries to keep revving past 2400. I actually got it to 3000 last night as the sun was going down, but it reverted back to the 2400 cut-off after that. I'll try to find out how to check all the sensors mentioned. I think its overfuelling a shiteload too - maybe fcucked FPR or stuck open injectors? Where is the FPR located?
 

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on the front of the fuel rail closest to headlights. Small dome looking thing that should have an air pipe going to inlet manifold.
 

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i had the same problem before. they attached different tps. when i disconnected my tps, it idles poorly but revs to the red line. try lookin at the book of 7m and check tps, it talks about how it cuts off on certain rpm.
 

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You need too check your tps like suprace suggested. i used the 2jz service manual as a reference to set mine. Here is a link to help you set that properlyhttp://www.supraforums.com/forum/showthread.php?s=&threadid=127498&highlight=TPS+Jeff+watson& Look for a post by Stroker 6 it has all the info you need to set it. You might want to check your coils also they tend to crack and could cause a similar problem. Have you found out what the whining sound you mentioned is?
 
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