Jason's 1990 MR2 project

[born disturbed]

This project is coming along real nice Jason, I hope you get that boost issue sorted with minimal problems

[JasonFriday13]

So I have done a bit more testing, culminating in removing the wastegate hose so that it's always open to the air, and still the same result. So I took the heat shield off and tested the actuator movement. I couldn't move it on it's own with a pair of pliers, so I had to lever it off the actuator bracket to open it and it pops closed again. So the actuator is fine.

So the turbo is the problem, next is which part it is. I have felt the shaft play and there is next to none in any direction. I don't believe the compressor side is the problem as the intake is holding boost, and because I removed the BOV from the intake so that it vents to atmos, you can hear the boost when you lift off the throttle. In the garage when I was revving it I could not feel any air coming out of the bov until I closed the throttle, which I was greeted with a small gust of wind.

So this points me to the turbine itself as the last link. I haven't had the manifold and the turbo apart, so I haven't looked at the wheel from the entry side. The discharge side looked fine, but I reckon there is something else going on.

Looks like I will have to get it inspected and rebuilt, and I will probably chuck one of these in for good measure: http://www.ebay.com/itm/Toyota-CT20B-Sm ... 0655871038.

[EssDub]

So I took the heat shield off and tested the actuator movement. I couldn't move it on it's own with a pair of pliers, so I had to lever it off the actuator bracket to open it and it pops closed again. So the actuator is fine.

Replace the entire actuator assembly. You should be able to move the rod with a small amount of effort with pliers. If its jamming up inside the vac tank, it'll hold it open and you'd never know about it. Recently had this issue with a local GT and fixed it by using copper grease and working it up into the vac tank. Only works as a temporary fix and it'll need a new vac tank soon.

[JasonFriday13]

So even though for testing I didn't have the actuator plumbed to anything, ie open to the air, why is it not free boosting, oh turbo god?

FYI the actuator won't move on 2psi of boost because the spring is a 7 psi one stock. I have only ever gotten 2psi on this engine, nothing more.

[EssDub]

Another way of testing the WG is using a bike pump with a pressure gauge on it. stick the pump nozzle into the WG vac line and work air into it. at around the 5-7psi mark the actuator should start to open. If it opens, slowly let off the air and see how fast the WG shuts.

[JasonFriday13]

So after a little talking at the AGM I was offered a used ct26 for free to get this car going while the ct20b is being rebuilt. I can't thank Reuben enough for his generosity. The turbo will be swapped in this weekend, and if I can get my act together I might be racing it this weekend in a clubsport event. Here's hoping .

[JasonFriday13]

So the CT26 is already in, took about five and a half hours from start to finish. I haven't driven it yet as I have had a couple of small problems; small leak from the coolant gasket on the turbo, and broke the threads on the air temp sensor in the throttle body, so a quick rewire to use the stock gen 3 sensor. Also had to swap the throttle body over, which also means having to reset the idle, then setting the range for the tps. Pics to follow soon.

[JasonFriday13]

So I have swapped over the dashes, the doorcards will follow soon. Pic is the dash in the white car.


This is what my engine bay looks like now. A bit of a step backwards, don't you think?


The thread snapped off on my air temp sensor, which ruined my throttle body. I had a spare anyway, so no big deal if this one got ruined.


This is the CT20b off the engine, compressor looks fine, next to no shaft play in any direction.


And the turbine side looks good too.


My small collection of tyres .


And the wiring is all done in the cabin, this is now ready for the dash to be installed.


I am getting closer to finding out what my boost problem is. Why is the idle valve still open when going on to boost?

[Benckj]

Interesting. Wonder if I have a similiar problem a my engine does not see full boost. Might just plug ISC line to see if it makes any diff.

[EssDub]

I was pretty sure the ISCV was operated by the stock ECU, so that it'd open/shut as required to keep a steady idle...so if you don't have an output allocated to it, it'll probably just stay wide open the entire time.

[JasonFriday13]

Apparently the idle control has a one way valve in it, which is why after replumbing the idle hose to just before the throttle plate there is no difference. Also, there are three wires on the idle solenoid, 12V, open, and close (not in that order). They are hooked up to the Link, I have ISC solenoid hooked up to open, and ISC slave hooked up to close. 12V is hooked up to 12V, funny that.

I am running out of stuff to troubleshoot, no doubt the problem will reveal itself very soon.

[JasonFriday13]

So think I finally found my boost leak:



Judging by which runners were leaking, I reckon the flange warped a bit concave. If it warped convex then runners 1 and 4 would be leaking.

What I did was pour a bit of petrol down each runner, then I jacked the car up to see if any petrol was leaking out past the gasket. Each time I jacked it up a bit more fuel came out.

Time to swap the intake out for another spare I have to see if that fixes it (fingers crossed). I reckon this swap will be harder than the turbo swap.

[JasonFriday13]

So the intake is now swapped over, the gasket looks almost new. Went for a drive and ... still no boost . So it's gotta be the injector seals, theres nowhere else it can leak from. The easy fix is high temp RTV, but I wonder if new seals would be a better fix. Funny thing is I never removed the rail, and when I bought the engine, it looked like it had been sitting for ages.

Oh well, it's just one of those things. I haven't spent any money troubleshooting this problem, and since the ct26 is installed right now, I might as well thrash the nuts off it .

[EssDub]

I fail to see how something so small could possibly leak soo badly and NOT be audible. 7-10psi even from a bike pump is clearly audible... Are you sure that all the joiners are in good nick and that the IC hasn't got some stupid tear or hole in it? The piping looks kinda rough and being a stock IC, [Expletive Deleted] knows what kind of condition its in...

[JasonFriday13]

The piping looks kinda rough and being a stock IC, [Expletive Deleted] knows what kind of condition its in...

All that piping is just temp stuff so I can drive it around for long periods of time, plus most of that piping came from my first turbo you and I scrapped, which hasn't been used since then. This will be getting the factory water to air system that came with the engine, that's why I bought a Celica ST205 half cut in the first place. If I wanted an air to air setup, i would have bought an MR2 half cut instead. In fact, why do I have to justify myself? This is what it is, and you don't want to know how many hours I have put into this conversion, along with all the troubleshooting and swapping parts out.