GDII's 1990 G-Limited

[GDII]

I'm not quiet sure at this point. Toyota have bumped prices slightly lately so i need to recheck.

This engine won't have been overheated. This engine is also incredibly quiet so the rotating parts are still fine.
For the intake, I'm only reusing the intake manifold and throttle body so everything else is going to be new. I'll make sure to do boost leak tests on the new stuff if needed. This isn't like a shitty GEN2 3SGTE with AFM so you can drive it without an intake system, just the throttle body alone is enough.

[GDII]

Just a few shots of the right side or intake manifold side of the engine. This is missing the powersteering pump and the massive brackets holding the transfer case onto the block.

01 Right Side Block.jpg (112.97 KiB) Viewed 655 times

02 Right Side Block rear.jpg (107.77 KiB) Viewed 655 times

Here you can see the knock sensor and a spare stud that was for the transfer case bracket.
Top left is the filter unit for the ignition. It filters out ignition noise from the cars electrical system so it doesn't get into the audio.
Top right is the FPU VSV (Fuel Pressure Up Vacuum Switching Valve) I'll cover this in far more detail later on. It's a very interesting little thing.

03 Underside of intake manifold.jpg (111.75 KiB) Viewed 655 times

04 Right side of block.jpg (113.28 KiB) Viewed 655 times

[GDII]

Prior to doing a lot of removal of mechanical parts I took off the wiring harness. Possibly easier to take off the intake manifold to do this however it can be done with it on. The first 2 photos show the crank angle sensor plug. It must get rather hot as the clip decided to break off. I've seen this on another harness before. No problem, this plug can be bought new so I'll just depin it and put the new one on. Sorted!

I didn't manage to get many photos of this, it's hard to show progress photos of this process. Pretty much, unplug everything and thread it through passed the throttle body.

01 Crank Angle and O2 Sensor plugs.jpg (85.08 KiB) Viewed 655 times

02 Crank Angle Sensor Plug.jpg (50.42 KiB) Viewed 655 times

03 Injector 1.jpg (93.94 KiB) Viewed 655 times

04 FPU.jpg (97.52 KiB) Viewed 655 times

05 Manifold Clip Front.jpg (54.82 KiB) Viewed 655 times

These earth points are quite often missed when people remove engines. Why are they critical? This first one on the lower side of intake runner No.2 is for earthing the coils. No earth, no spark, no start, no boost!!

06 Earth Point Coils.jpg (78.24 KiB) Viewed 655 times

This one is also critical as it earths the ECU. It is also on intake runner No.2 but a bit higher up and behind the vacuum canister bracket. No earth, no grounding of ECU meaning the ECU won't even power up. It also earths things like the O2 sensor and in addition to that earths Crank Angle Sensor, Cam Angle Sensor, Knock Sensor and O2 Sensor Signal wire shielding. Without this shielding earthed you will get interference signals in the wires and the ECU will get wrong information.

07 Earth Point ECU.jpg (73.86 KiB) Viewed 655 times

08 Intake Manifold MAP and IAT Sensor.jpg (97.2 KiB) Viewed 655 times

09 IACV plug.jpg (67.19 KiB) Viewed 655 times

10 Halfway Out.jpg (87.02 KiB) Viewed 655 times

11 All the Way Out.jpg (96.76 KiB) Viewed 655 times

12 Harness Out.jpg (133.79 KiB) Viewed 655 times

Harness out and stored in a safe place.

[GDII]

This is the cam angle sensor. It sits on the rear right of the head. The intake cam has a single arm on the back of it telling the ECU where the cam is compared to the crank.

This sensor is known for leaking, not only can the seal leak but the inside of the sensor can leak too. To get a new seal you have to purchase a whole sensor as Toyota do not have a separate part number for the seal. However it doesn't not seal the inside of the sensor.
Drift Motion has invented a seal that not only seals the sensor to the head but seals the oil out of the inside of the sensor too. It's for JZ engines but will fit the GEN4 and GEN5 3SGTE too.
https://www.driftmotion.com/Double-Lock ... dm3814.htm

Based on this photo, mine is leaking.

13 Cam Angle Sensor.jpg (91.41 KiB) Viewed 645 times

[GDII]

The GEN4 3SGTE along with some other Toyota engines uses a VSV (Vacuum Switching Valve) on the fuel pressure regulator to assist with hot starting and create stable idle. (Refer last image taken from the USDM GEN2 3SGTE wiring diagram).

To keep the correct amount of fuel going through the injectors the regulator increases pressure as boost pressure increases as the regulator has a vacuum hose connected to the intake manifold. However inline between the manifold and regulator is this valve with a filter on it. Doing tests on it, no voltage going through the valve means there is free boost/vacuum flow to and from the manifold, when 5V is applied to the VSV it blocks off the valve so no boost/vacuum reference can get to the regulator from the manifold. What this does is use atmosphere pressure to adjust the fuel pressure. Atmosphere pressure is higher than the vacuum produced at idle by the manifold therefore increasing fuel pressure for the hot starting and idle situations.

I did a bit more thinking so slight update after having a good think about how this system works for NA and Turbo Toyota engines. Boost pressure has nothing to do with the system so here goes.

As the 3SGE also has this system I looked at it again and figured out some more things. This FPU is for starting and idle, you don't see boost during starting or idle so the conclusion is. During starting the engine sees vacuum so the valve switches and locks off the manifold vacuum reference hose and opens the filter end. As the manifold is pulling a vacuum it won't increase fuel pressure, instead it would have dropped it so by opening up the valve to atmosphere pressure which is higher than what the engine can produce in this situation the fuel pressure is increased as much as it can be.

Thinking about how it works in an NA engine under acceleration made me rethink how this system actually works. Under acceleration the fuel pressure needs to drop to maintain the same differential pressure across the injector. Same goes for a boosted engine, as your boost increases the fuel pressure must increase to maintain the differential pressure across the injector. Base pressure is say 40psi, boost pressure goes up by 10psi, the fuel pressure must go up to 50psi still maintaining 40psi over the injector. Same for NA but it goes down instead of up. It's a complex system but I think I now understand most of it.

01 Fuel Pressure Up Vacuum Switching Valve.jpg (117.08 KiB) Viewed 607 times

02 Fuel Pressure Up Vacuum Hoses.jpg (90.25 KiB) Viewed 607 times

02 Fuel Pressure Up Vacuum Switching Valve.jpg (111.75 KiB) Viewed 607 times

03 Fuel Pressure Regulator.jpg (99.43 KiB) Viewed 607 times

04 Block for reference.jpg (113.28 KiB) Viewed 607 times

Screenshot_20200903-112422.png (401.15 KiB) Viewed 606 times

Screenshot_20200903-111459.png (255.24 KiB) Viewed 606 times

[GDII]

This is the vacuum canister connected to the boost control solenoid. It's purpose is to dampen the vacuum source from variations in pressure that the system creates when the control solenoid opens and shuts. The GEN2 3SGE and 3SGTE use a canister too for ACIS and TVIS respectively.

The canister sits inline between the turbo compressor housing and the solenoid. Then the solenoid vents to the idle air intake pipe for noise control on the OEM setup.

01 Boost Controller vacuum damper canister.jpg (79.93 KiB) Viewed 605 times

02 CT15b compressor.jpg (109.04 KiB) Viewed 605 times

03 Boost Control Solenoid.jpg (72.73 KiB) Viewed 605 times

04 Rear of Engine.jpg (116.36 KiB) Viewed 605 times

[GDII]

On the feed end of the fuel rail opposite the return end with the regulator is the fuel damper. It dampens out the pulsations from the injectors opening. Most GEN4 swaps remove this as the fuel hose uses an AN fitting threaded into the end of the rail rather than a banjo fitting like this. I want to retain this damper so I'll either get a fuel hose made up with a 90 degree banjo fitting or reuse this. This sits near the intake manifold on the upper rear right of the head next to cylinder 4 injector.

01 Fuel Rail Damper.jpg (77.22 KiB) Viewed 605 times

[GDII]

Here is the idle control valve. Also know as the IACV or Idle Air Control Valve. The large hose from below is the intake for it, this comes off the airbox. From reading the GEN2 3SGTE wiring diagram there are possibly 14 different parameters the ECU uses to control idle. One thing to note about the GEN4 3SGTE is there is no A/C idle up valve like the MR2 which is separate to this valve.

The 2 medium sized hoses are for coolant to heat the throttle body and throttle plate to stop it icing up as mentioned in a previous post. As a guess it also heats the idle air charge but not sure if that is it's primary purpose. Quite often people will remove the hoses and loop them back to the flow and return ports on the bypass pipes around the engine but I like the OEM complexity so it's staying for me.

The smaller vacuum hose coming off the manifold goes to the BOV as shown before in a previous post.

01 IACV.jpg (91.34 KiB) Viewed 605 times

02 IACV.jpg (96.49 KiB) Viewed 605 times

02 IACV Coolant Hoses.jpg (59.96 KiB) Viewed 605 times

04 IACV Coolant Hoses Off.jpg (89.58 KiB) Viewed 605 times

05 IACV Coolant Hoses Off.jpg (81.4 KiB) Viewed 605 times

06 Throttle Body.jpg (92.59 KiB) Viewed 605 times

[GDII]

Off comes the intake manifold. I'm sure there are a few things I missed like fuel return hose, removing a few vacuum hoses.

3 nuts, 4 bolts, done!

01 Intake Manifold Bolts.jpg (121.93 KiB) Viewed 605 times

02 Intake Manifold Bolts.jpg (111.15 KiB) Viewed 605 times

03 Intake Manifold Removed.jpg (119.42 KiB) Viewed 605 times

04 Intake Manifold Removed.jpg (128.9 KiB) Viewed 605 times

05 Intake Manifold Removed.jpg (119.09 KiB) Viewed 605 times

[GDII]

The fuel rail is aluminium, but on top it's super dirty from the valve cover leak it would have had in the past. Underneath is a lot cleaner.

01 Fuel Rail Top.jpg (106.42 KiB) Viewed 605 times

02 Fuel Rail Bottom.jpg (127.62 KiB) Viewed 605 times

Removing the fuel damper and then the rail itself. I decided to remove the damper before taking off the rail as it would be far easier for the engine to hold it rather than me just holding the rail. I think it's a 24mm spanner, my biggest in the set.

03 Fuel Damper.jpg (84.61 KiB) Viewed 605 times

04 Fuel Rail Fixing Bolts.jpg (83.41 KiB) Viewed 605 times

3 bolts hold it to the head on some plastic spacers, then the injectors seal to the head with some rubber grommets.

Full dirt spec! Those injectors are meant to be blue! Lots to clean, hopefully the oil on the rail means there is very little corrosion on it making it easy to get how I want it.

05 Fuel Rail Top.jpg (100.96 KiB) Viewed 605 times

06 Fuel Rail Bottom.jpg (99.72 KiB) Viewed 605 times

07 Fuel Rail Fixing Spacers.jpg (93.88 KiB) Viewed 605 times

08 Fuel Rail No Spacers.jpg (86.36 KiB) Viewed 605 times

09 Bare Head.jpg (108.07 KiB) Viewed 605 times

[GDII]

A few shots of the intake manifold with a few parts still connected.

1. Bolted to the back of the manifold is the vacuum canister and FPU VSV. I covered these in previous posts. Also down here are 2 main earth points for the ECU and coils. These must be bolted on or nothing will work. I'll cover this in a future post with more details.

2-4. The inside or front of the manifold contains a few parts that are critical for the engine operation. First off is the MAP sensor (Manifold Absolute Pressure) The GEN4 3SGTE uses this sensor to measure manifold pressure to adjust fueling along with other sensors. This sensor has a purple sticker with 2 bolts holding it to the manifold unlike the MR2 where this sensor is bolted to the rear firewall next to the OBD1 Diagnostic Port.

Next to that is the Manifold Air Temperature sensor. It's brown with a great 2 pin plug just below the throttle cable bracket. This along with the MAP sensor allows the ECU to adjust fueling.

The little beige vacuum port that connects to the MAP sensor also connects to the FPU VSV mentioned in a previous post. I'm not 100% sure why this is a dual port with 1 threaded fitting together but there is obviously a reason.

The 2 larger vacuum ports near cylinder 4 runner, furthest away from the throttle body, are for the PCV (Positive Crankcase Ventilation) and brake booster vacuum. The straight port connects to the valve cover and the 1 way PCV valve. The angled one connects to the brake booster. You can connect the standard MR2 hose to it with a little bit of a stretch.

There are 2 small brackets that hold the wiring harness in there mounted between runner 1 and 2 and 3 and 4.

On the top is the throttle cable bracket, which is a rubber and metal component.

Right next to the throttle body is a large vacuum port for the BOV and on top of the throttle body is a small copper right angled port for the EVAP canister purge port. Fuel vapour from the charcoal canister is sucked in during vacuum conditions controlled by a valve so it doesn't blow boost out the wrong way.

Last but not least is the throttle body with the TPS (Throttle Position Sensor) and IACV.

01 Intake Manifold Runners.jpg (168.25 KiB) Viewed 605 times

02 Intake Manifold Front.jpg (88.97 KiB) Viewed 605 times

03 Intake Manifold Front.jpg (148.15 KiB) Viewed 605 times

04 Intake Manifold Rear.jpg (157.71 KiB) Viewed 605 times

05 Intake Manifold Front.jpg (147.68 KiB) Viewed 605 times

06 Intake Manifold Front.jpg (154.39 KiB) Viewed 605 times

07 Intake Manifold Rear.jpg (162.93 KiB) Viewed 605 times

08 Intake Manifold Rear.jpg (157.71 KiB) Viewed 605 times

[GDII]

Time to pop off the valve cover and see what's inside. I've taken out each bolt and placed them in a piece of cardboard to make sure they all go back in the same place. The 3 middle ones are longer.

This engine has been opened before in New Zealand between the cam belt being done at 103,000km, being imported at 125,000km and me buying it at 307,000km. The valve cover seal has gasket goo on it, that's not normal to do if the seal is ok. It's still soft rubber, not hard like my old 3SGE. I was expecting the valve cover to fight me for removal but a quick lever on the front cover and it lifted off.

01 PCV Valve and Valve Cover.jpg (63.14 KiB) Viewed 605 times

02 Valve Cover Bolts.jpg (50.32 KiB) Viewed 605 times

03 Coils.jpg (86.96 KiB) Viewed 605 times

04 Valve Cover Seal.jpg (57.31 KiB) Viewed 605 times

05 Valve Cover Seal.jpg (61.24 KiB) Viewed 605 times

Let's take a peek inside the valve train. I was extremely surprised to see how clean it looks. Sure, it's not clean by any means but it's not as black and burnt as I was expecting after 307,000km. It's been looked after well enough. My old 232,000km engine was darker and had more dirty oil caked on the inside. Even though it's high KMs I think it's a good pick for what I wanted it for.

It's interesting to see the exhaust side is cleaner than the intake side.

Some of the valve clearances looks a little bit tight based on the wear makes in the dark oil on the back of some of the cam lobes. I'm not sure if this is true, I'll check them when I get a chance.

In the last image I gave a little part a quick wipe and it came off mostly.

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07 Cams.jpg (74.33 KiB) Viewed 605 times

08 Cams.jpg (75.77 KiB) Viewed 605 times

09 Valve Cover Underside.jpg (89.54 KiB) Viewed 605 times

10 Valve Cover Underside.jpg (89.79 KiB) Viewed 605 times

11 Head Cleaning.jpg (128.32 KiB) Viewed 605 times

[GDII]

Removing the rear coolant tree. As the Caldina is front engine and you can fill the coolant system from the radiator there is no filler bolted to this tree.

On the Caldina GTT tree there are the following ports. The main radiator top return. The small turbo coolant feed next to it. The heater flow. The recirculation port for when the thermostat is closed. Throttle body coolant flow and the coolant temp sensor. In this sensor unlike the MR2 it has both the ECU and gauge sensor in one unit so it has 3 electrical pins. You can either use the standard wiring from the Caldina sensor and wire it to the guage sender wire or use the older sensor for the gauge and bring that wiring to the GEN4 harness.

Unlike the GEN2 it has 2 coolant feeds off the head like the GEN3. This can make it a bit harder to use in an MR2 if your car had a GEN2 engine originally.

A few options to get around this problem. Weld a filler fitting to this tree, add in a filler t junction on the radiator flow hose to connect to the MR2 filler neck, buy an adaptor plate that converts the GEN2 to GEN3-5 head or use a gen3 tree of you are lucky enough to be able to find one. Then you just need a way to feed the turbo. Or you can also buy a fully CNC machined tree and filler.

01 Caldina Coolant Tree.jpg (90.41 KiB) Viewed 605 times

02 Caldina Coolant Tree Rear.jpg (102.12 KiB) Viewed 605 times

03 Caldina Coolant Tree Underside.jpg (108.95 KiB) Viewed 605 times

04 Caldina Coolant Temp Sensor.jpg (152.03 KiB) Viewed 605 times

05 Caldina Coolant Temp Sensor Pins.jpg (116.38 KiB) Viewed 605 times

06 Caldina Coolant Tree Removed.jpg (113.72 KiB) Viewed 605 times

07 Caldina Coolant Tree Removed.jpg (110.11 KiB) Viewed 605 times

[GDII]

Removing the cam belt. The 3SGTE (except the GEN1) always uses a hydraulic tensioner but they are not all the same. The JDM GEN2 3SGTE from 12/89-05/91 uses one type, then up until the GEN3 3SGTE from 11/93 it uses another which uses a different mounting bolt position. The GEN3 and GEN4 uses the same part number as eachother but not the same as the GEN2 parts.

2 cam shaft pulleys which are twice the diameter of the crankshaft pulley. A tensioner bearing that pivots on a large bolt, an idler bearing, the water pump and the oil pump.

[GDII]

The tensioner bearing is fixed to the head with a bolt but it uses a 10mm Allen key instead of a 14mm bolt head like the idler bearing.