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Resistance Is Futile
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Discussion Starter · #1 · (Edited)
Hello,

I used to be very active on the board for about 7 years which stopped when I sold my brother my mr2 about a year ago. Since I don't actually own the car now, this thread is more for his benefit.

When I sold him the mr2, we did an engine gasket overhaul and upgraded the turbo to a brand new ATS turbo.

The problem is that we've had boost creep ever since we installed the CT27. Boost will creep up to 18psi and trigger the 3rd gen fuel cut in just about every gear. My brother has been driving the car using a light foot for a year now because of what happens when he goes WOT.

Here was the setup when we initially put it together last Christmas:

Gen2 3SGTE
ATS CT27 turbo
Gen3 EFI
Gen3 cams
550cc injectors
ATS Modified Fuel Rail
Walbro 255 fuel pump
KO Racing 3" Intake
Tial 50mm BOV with KO Racing hotpipe
Berk Intercooler
Berk 3" Exhaust with stock cat and downpipe (Damn TN emissions)
TwosRus MBC
ATS EGR Blockoff Plates
ATS TB Inlet
Every IC pipe connection has Berk/KO Racing couplers and constant torque clamps.
The clutch, pressure plate, and throwout bearing were replaced Christmas 09.

Things we've tried over the year (yes, it's been a year because I live in another state and we normally only take crack at it every time I visit) are as follows:
1. Removed the TwosRus MBC and connected the wastegate actuator straight to the turbo compressor nipple (like stock). You would expect boost to be limited to 9-10 psi, but we still hit 18psi.
2. Leaving the actuator configured as listed above, we replaced the stock downpipe with a modified eBay downpipe. Still hit 18 psi... Using the stock downpipe was actually a 2 part decision. We wanted to pass TN emissions but we also didn't want any problems with wastegate door clearance. Since both downpipes creep, I don't think that's the problem :(
3. Today we manually pressurized the wastegate actuator. Here are pictures of the results:




The wastegate rod only actuates about 0.5" as you can see by referencing the black sharpie line we drew on the rod. It seems like it's completely open ~15psi. The 0.5" measurement does not change when the downpipe is bolted on or pulled away from the exhaust side of the turbo. The wastegate action is very smooth and seems to be in great working order to me. The rod does not rub on anything. The T-VSV port on the actuator is securely capped and is not leaking. Finally, the compressor nipple is clear and does not appear to have any blockages that would impede its operation.

At this point I'm out of ideas. I'm pretty confident is saying that this is not a downpipe clearance problem but I don't know what else it could be.

I'm really just posting this to see if anyone out there has had similar problems and if so what you did to solve them.

Thanks for the help
Lane
 

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Resistance Is Futile
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Discussion Starter · #3 ·
scooterman said:
how many psi did it take to open the wg?
We're using a foot powered bicycle pump with ~ 5ft vacuum line to pressurize the actuator. It takes 1 pump to open it ~75% which shows up on the pump's gauge as < 10psi. The 2nd pump finishes the actuation before the pump even finishes the cycle. So about 1 1/2 pumps and <15 psi and the wastegate appears to be 100% open.

Lane
 

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Resistance Is Futile
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Discussion Starter · #5 ·
scooterman said:
make sure the rod is not bent, also the diaphragm inside the wg actuator could be broken. I've had one that was.
Thanks for the ideas scooterman. I'm pretty sure the actuator rod is not bent and 0.5" of actuation seems pretty reasonable to me considering the length of the actuator cylinder... Still, it's not like the BGB has any procedures for checking the curvature of the rod or even a measurement for how far the rod is supposed to travel, so that's all pretty subjective unfortunately.

Here are some pictures i snapped a few minutes ago of the rod. If anyone sees any problems please let me know.




Lane
 

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Interesting situation. My thought is wondering about what actually makes what happen at what PSI vs. vacuum to get what Boost. meaning, what mechanic operation does what for what? I'm thinking first off you have a vacuum leak, but my thinking is if that was the case you wouldn't get much if any boost You're getting to much, which has me rethinking you are not getting vacuum. MBC controls that, less vacuum means more boost?? I'm just running through this as I type, Hmm anyone else?
 

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Don't mess with Texas
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Where are you getting the boost source for the wastegate? The compresser housing?

Make sure the hose is good and put some zip-ties on the connections.

Also the other port on the wastegate is blocked off right?
 

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Resistance Is Futile
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Discussion Starter · #8 ·
RVFR said:
Interesting situation. My thought is wondering about what actually makes what happen at what PSI vs. vacuum to get what Boost. meaning, what mechanic operation does what for what? I'm thinking first off you have a vacuum leak, but my thinking is if that was the case you wouldn't get much if any boost You're getting to much, which has me rethinking you are not getting vacuum. MBC controls that, less vacuum means more boost?? I'm just running through this as I type, Hmm anyone else?
I would agree if there was a vacuum leak between the compressor nipple and the actuator nipple or perhaps a leak at the capped actuator nipple that goes to the T-VSV, but right now I have directly connected the compressor nipple to the actuator nipple with a 8" vacuum line (no MBC or T-VSV in the equation) like it comes from ATS racing and have the actuator nipples that goes to the T-VSV securely capped. I have tested both the vacuum line and the cap by pressurizing the actuator through the 8" line and noting that the system holds pressure and no air is leaking from the cap. I'm pretty confident in saying a leak in this area is the only type of vacuum leak that could affect the wastegate system unfortunately :(

Lane
 

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Resistance Is Futile
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Discussion Starter · #9 ·
Texas_Ace said:
Where are you getting the boost source for the wastegate? The compresser housing?

Make sure the hose is good and put some zip-ties on the connections.

Also the other port on the wastegate is blocked off right?
Yes, the wastegate actuator nipple nearest to the firewall is connected directly to the compressor housing nipple (no MBC). The actuator nipple that normally runs to the T-VSV is securely capped and zip tied. All the clamps between the actuator and the compressor look and feel very secure to me. I also tested the line in-between the two as stated in the reply above.

Thanks for the suggestions guys

Lane
 

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connect your boost gauge to the hose between the turbo and wastegate and tell us what you read when it boost cuts. Does the power seem "right" when this overboost is occuring? Cams installed correctly? Timing correct?
 

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Resistance Is Futile
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Discussion Starter · #11 ·
Eric Hux said:
connect your boost gauge to the hose between the turbo and wastegate and tell us what you read when it boost cuts.
I like this idea Eric. Thanks, I'll give it a shot and report back.

The power does seem like it's creeping up to 18psi of boost. The car feels MUCH MUCH faster than it did when I had it on the stock CT26 running ~17psi of boost.
We haven't had any other signs that the cams were installed wrong. We did the 3rd Gen cam install right before the turbo install, but everything was lined up before and after I pulled the tensor pin. Thankfully it wasn't my first timing belt install on the 3SGTE. I checked the timing then and it was 10* BTDC. Checked it again in June and it was the same. Pretty sure I haven't slipped a tooth on the belt or anything like that :)

Lane
 

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Resistance Is Futile
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Discussion Starter · #13 · (Edited)
RVFR said:
That's good idea, also hate to think that a bad boost gauge is the root of this?
Could be, but my 3rd gen boost cut is working correctly (thankfully) which means the 3rd gen MAP which is a second indicator that I'm actually getting to 18psi. It seems like my Omori boost gauge is working correctly because boost cut kicks in right when my boost gauge hits 18psi. Currently my boost gauge taps into the nipple on the rear of the intake manifold (passenger side).

I'm still going to try Eric's suggestion because I would like to know what's going on between the compressor and the actuator. If it's not getting pressurized correctly, that would explain things, but that's the only thing I can think of that would...
I can say without a doubt that the turbo is producing more that 10 psi which should not be happening the way the wastegate is setup if everything in the setup is working correctly.

Lane
 

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Resistance Is Futile
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Discussion Starter · #15 ·
RVFR said:
awe. didn't catch you had an Omori gauge, so more than likely it's the actuator thingamajig. ;)
No worries. Its always a good thing to double check the simple things :)

Appreciate the help so far guys. Might have to to the boost gauge relocation a little later in the week. So far I've been pretty busy this weekend trying to help my parents move.

Lane
 

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I have another test for you. This will take 2 people. Hook up you bike pump with a long enough hose to reach the passenger seat. Have a trusty passenger pump till the wastegate is open, just like in the test. Attempt to put the car on boost and see what happens.
 

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Resistance Is Futile
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Discussion Starter · #17 ·
Eric Hux said:
I have another test for you. This will take 2 people. Hook up you bike pump with a long enough hose to reach the passenger seat. Have a trusty passenger pump till the wastegate is open, just like in the test. Attempt to put the car on boost and see what happens.
Whoah! I like this one even more. Thanks for thinking outside of the box Eric. I'll give this a shot too :)

Lane
 

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Resistance Is Futile
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Discussion Starter · #19 ·
Ok, so we had another shot at fixing the problem over the holidays.

First thing we did was install the Berk downpipe that my little brother got for Christmas :D

After taking the mr2 for a spin, my brother reported that the car was still hitting the 18psi fuel cut and he was confirming those levels on the boost gauge.

At this point I am 100% positive that this IS NOT a wastegate flapper clearance problem. We have tried the stock downpipe (with cat in-tact), ebay 3" downpipe, and now a Berk downpipe. All three had uncontrollable boost even when the turbo compressor nipple was connected to one port of the wastegate actuator and the other port was capped.

Moving on, we decided to try Eric Hux's first suggestion. We moved the boost gauge reference line from the rear intake manifold port (capped after removal) and tee'd it into the line that runs between the turbo compressor nipple and the wastegate nipple closest to the turbo. After taking it out for a spin my brother reported that the car was still hitting the 18psi fuel cut and he was confirming those levels on the boost gauge.

So... The wastegate actuator is seeing the same pressure that the intake manifold is. At this point I am almost 100% certain that the issue is being caused by a faulty wastegate actuator (faulty since the day we received the turbo), but I would like to see what you guys think....

Anyone still around from when I originally started this thread? :p

Lane
 

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Just to confirm...
You have one pipe out of the actuator blocked off, and you have the remaining pipe plumbed up to the intake manifold?

Shouldnt it be connected to the turbo compressor housing nipple not the intake manifold??
 
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