Converting 84 245 LH 2.0 to LH 2.4

I will be converting an 84 245 that was an na auto car with lh 2.0 to 2.4, turbo and manual. For the most part I fully understand the mechanical side of things I need to do, I have an entire 90 244 chassis and car harness at my finger tips for help with this. My biggest concern is the 2 points where the engine harness plugs to the car harness.

First the big plug in the engine bay the fire wall seems to all line up, beside the 84 car harness having 2 extra wires that wont be occupied (brown, blue/red) would be sweet to know where they go.

Second is the plug under the glove box. The 84 has a 3 plug the 90 has a 9 plug. I assume most of that 9 plug is cruise control, electronic speedo, etc. I dont need either of those but I'd like my stock temp gauge and tach to work. The 84 has red/yellow, red, and blue/red. The 90 only has the red yellow in its end, where do the other 2 go?

I've followed multiple diagrams and have been able to figure out some wires and maybe itll all just jump out at me but any input is appreciated.

Will be using a mechanical speedo rig so I wont need any of the speedo signals or anything

Transfer over both complete harnesses and don't connect the wires you don't use. Be aware that you will need to separate the engine and trans so you can add the crankshaft position sensor. Then use and LH2.4 flywheel or flexplate setup if automatic.

Or, you can add only the fuel LH2.4 computer and use the EZK117 setup from a LH2.2 740. There have been a couple of threads about using that EZK 117 with the LH2.4 fuel computer. You have to change a few wires but it will allow you to continue using the hall sensor distributor on your engine and you won't have to add the engine speed sensor on the bell housing.

I have a 2.4 wheel and crank sensor in position already,

Scorpanio240 said:

First the big plug in the engine bay the fire wall seems to all line up, beside the 84 car harness having 2 extra wires that wont be occupied (brown, blue/red) would be sweet to know where they go.

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Look in the greenbook and you'll find a pinout for that connector early on, I want to say page 6 or so.

Scorpanio240 said:

Second is the plug under the glove box. The 84 has a 3 plug the 90 has a 9 plug. I assume most of that 9 plug is cruise control, electronic speedo, etc. I dont need either of those but I'd like my stock temp gauge and tach to work.

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See ZVOLV's LH2.4 Install/Conversion. Just 4 wires to make it run

My notes for a '89 9-pin connector are:
1989 LH2.4 engine harness to cabin harness connector - 9 pin connector
end view female
7 4 1
8 5 2
9 6 3

1 blue : switched +12v from ign switch run+start, to LH-35 EZK-6
2 green : A/C solenoid on (and pressure sensor), to LH-14
3 2x pink : dash CEL from LH-22 EZK-3
4 grn/red or gry/red : A/C switch on (and A/C delay relay), LH-15
5 blue/blk : speedometer Vss to LH-34
6 yel/red-small : +12v fuse 4, to O2 sensor power
7 yel/red-big : +12v to fuse 4, from system relay 87/2, fuel pump power
8 violet : dash shift light from LH-26
9 yel/blue : park/neutral switch (and ign start switch), LH-30

Pin 1 is essential.
Pin 7 is probably needed, unless you've rewired the fuel pump power separately.
Pin 2 and 4 help with idle when the A/C is on
Pin 9 helps with idle when going out of P/N on an automatic
Pin 5 Vss is discussed below.

Scorpanio240 said:

The 84 has red/yellow, red, and blue/red. The 90 only has the red yellow in its end, where do the other 2 go?

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In the past, I haven't been able to find a diagram for this connector. My guesses are:
red/yellow (thick) : power to fuel pumps
red : is this a thick wire? If so, it may come from the battery fuse in the engine compartment
blue/red : is this probably power from ignition switch 15 when in run+start positions

Scorpanio240 said:

Will be using a mechanical speedo rig so I wont need any of the speedo signals or anything

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Without the VSS Vehicle Speed Signal, you'll have high idle after driving. See: http://forums.turbobricks.com/showthread.php?t=342812
There are a few ways to deal with the issue:
- ignore it
- use a throttle body with adjustable idle stop and remove/block off LH2.4 IAC (this won't behave well if temperatures vary much)
- use cruise control pickup from cable speedo with modified PCB from electronic speedo
- add a 3-wire hall sensor with a bracket to sense the driveshaft bolts or add-on flags
- use a Dakota Digital converter - check the recent LH2.2 with EZK117 threads

You might also try these old threads - I haven't re-read them, but the pictures seem to be intact: https://forums.turbobricks.com/showthread.php?t=346831 http://forums.turbobricks.com/showthread.php?t=324743

-Bob

Take a completely different path and do it correctly. The dash harness is not much different between the two cars, 84 vs. 90. Install the 90 harness, rear axle and run the speedometer wires up from the rear axle housing. Nearly everything will be plug and play vs. hacked together.

<a href="https://ibb.co/fYQbwDF"><img src="https://i.ibb.co/vxDbnXq/lh2-4howto.jpg" alt="lh2-4howto" border="0"></a>

Blue power while cranking I hooked to wire that triggers starter solenoid wire.

Yellow blue to start switch on ignition. You might have to re-pin your starter switch so it has power while starting.

Red yellow other two wires to switched power.

Those are the four needed to run start lh2.4 9 pin harness connector.

Tach wire hooks to coil should be already there on old harness part of 84 car. I got pic somewhere let me see if I can find that.

Here is the pic of the tach wire on your old harness I plugged it into the 2.4 harness there by the coil and done if your 84 is like my 88 240 I upgraded to 2.4.

<a href="https://ibb.co/X5YB5QT"><img src="https://i.ibb.co/3FRXF3H/IMG-2834.jpg" alt="IMG-2834" border="0"></a>

As far as the stock temp gauge goes to first or closest to the front of the motor temp sensor. Rear temp sensor goes to computer or lh2.4 harness.

One of those extra wires there where the 2.4 harness plugs in under the hood on the firewall might be that temp gauge wire to the dash. Or it is already one of those wires in that plug if your 2.4 harness has the first temp sensor plug on it.

Very good thank you all I will take this info once I get the drivetrain back in the car and plug everything in. Like I said I'm used a mechanical speedo hookup so I wont need the electronic speedo wires. I also dont use an iac on this csr so most of that wont apply and I have a different way of getting around the a/c because I do plan on installing a 134a system in this car from my 92 parts car.

Scorpanio240 said:

Very good thank you all I will take this info once I get the drivetrain back in the car and plug everything in. Like I said I'm used a mechanical speedo hookup so I wont need the electronic speedo wires. I also dont use an iac on this csr so most of that wont apply and I have a different way of getting around the a/c because I do plan on installing a 134a system in this car from my 92 parts car.

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LH2.4 will be looking for a speed signal. It won't throw a code, but from what I understand it affects the way the car runs.