need help 1jz won't run

Old School

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Apr 26, 2011
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Minnesota
Just finished putting a 1JZ (soarer) in a 91 Supra. Needed to run the thicker wire to the solenoid and now it turns over great (didn't before). It pops and sounds like it wants to start, but will only go for a few revolutions. I keep trying things, but no luck yet. Anybody have any experience with this issue? The exhaust isn't on it yet, but I don't think that should keep it from running. I did run a wire from the battery to the alternator, that I didn't see on the write ups, but it was open.
Thanks.
 

Old School

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Apr 26, 2011
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I'm afraid you will have to help me out here. New at the Supra thing. I am very familiar with OBD2 codes on my reader with the newer cars, but not with respect to anything from 91. What do I need to do to check for codes here?
 

Old School

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Apr 26, 2011
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Minnesota
Went and checked it out this morning. It is throwing out a 12 and a 31 code. The 12 code makes sense with what we are seeing. The 31 code was a surprise. I looked at the inside of the ECU, and everything looks brand new, no leaking caps or corrosion. Any suggestions on the trouble shooting part?
 

f00g00

Supramania Contributor
Jul 2, 2007
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Kuwait
Is your map sensor plugged in? if you have a meter read out the TPS and Map sensor circuit and check for shorts or opens. They are interconnected.
 

Old School

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Apr 26, 2011
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Have to do some exploring for the map sensor signal. The codes say what I am missing is the RPM signal and the Air Flow meter signal.
 

f00g00

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Jul 2, 2007
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On the 7MGE and 7MGTE it uses an air flow meter, and 1J uses map sensor which is the manifold pressure instead of an airflow meter. it is connected to the intake manifold by a hose and the wires are close to the brake master cylinder on LHD cars. You can see the diagram here http://www.clickdesign.co.uk/supradupra/html/1jz_wiring.html
You want to check the VAC sensor circuit above the igniter, or if your lucky its just unplugged.
 

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Old School

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Apr 26, 2011
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Can't find the map sensor. Is that something I needed to buy with the switch over from the 7M NA engine? Also, exactly where does the "NE" and "G" signal come from, so I can trace it to the ECU?
 

Old School

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Apr 26, 2011
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Found out the NE signal is the crank sensor and the G signal is the cam sensor. Going to scope out if the signal is getting lost on it's way to the ECU. With the thin information out there for soarer 1JZ wiring conversion, anything is possible. I noticed that the ignitor I bought for the 1JZ doesn't have the third plug on it. Is that a big deal? The soarer was an Automatic, but is now a manual in the Supra.
 

f00g00

Supramania Contributor
Jul 2, 2007
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Yes you need the map sensor or the car won't start, it will crank but won't start. Get that and try it before you start reading wires. Did you find the plug for it? Make sure the plugs are on the crank and cam position sensors.
 
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Old School

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Apr 26, 2011
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Wow, those MAP sensors are spendy.....

---------- Post added at 01:42 PM ---------- Previous post was at 01:40 PM ----------

I have not found the plug for it yet.
 

f00g00

Supramania Contributor
Jul 2, 2007
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The plug is in the main harness as it comes up from behing the left valve cover. You can see where mine inserts into the harness.
 

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hvyman

Dang Dude! No Way Man.
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Apr 17, 2007
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Might have been cut. You can get a replacement from driftmotion or from dr tweak.

Find a used map sensor they go from around 80-110 used. Can also use jdm 2jz map sensor.
 

Old School

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Apr 26, 2011
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Minnesota
It appears the connector for the MAP Sensor is on the passenger side of the Soarer 1JZ wire harness. Definitely no sensor in sight, but the vacuum line is in the area. Still no idea why the crank and cam sensors aren't being seen, as the ECU wiring was left intact (other than splicing in about 3 feet). Now to find a Map sensor.