»  BC-BF Legacy Discussion »  Drivetrain
#4EAT - Clutch drum NA vs Turbo compatability?

Custom Search
Login | Register




Post new topic Reply to topic  [ 17 posts ] 
Author Message
 Post subject: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Mon Aug 07, 2017 5:17 pm 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
I am replacing the duty C solenoid on my 93 SS. I have the dreaded 14 flashes and some torque bind at low speeds when cornering. Hopefully the new solenoid will take care of the issue.

After removing the tail housing I noticed grooves in the clutch drum which is fairly typical. I've seen worse but since everything is apart I thought I would address the issue.

However, the part is no longer available new so I was wondering if the clutch drum from an NA legacy would be compatible. I would think that they would be but you never know.

Anyone have any idea if the NA drum would work?

Also, has anyone had success with filing/grinding the grooves in the drum?

Lastly, the clutch plates look good to me but is there a way to identify if they are going bad?

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 08, 2017 3:58 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
I pulled a transfer clutch drum from a 1994 NA leggy with 90k. Looks to be the same so I am going to install it. Has some grooves but not as bad as the original.

I talked to a few dealerships. One could not confirm the NA drum would be compatible. Another dealership said the drum was intechageable but the shaft wasn't according to the part numbers. So I am going to swap the drum from the NA shaft to the turbo shaft.

I would like to change the clutch plates as well but they would be 5 days out and I want to get the SS back on the road. The clutch plates appear OK so I think I should be good. I'll update when I am finished or run into a problem.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 08, 2017 5:41 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
I did some further comparison between the NA and turbo assemblies. I measured everything as accurately as I could with dial calipers. I am not going to post measurements since I did the measurements side by side and did not write anything down.

There are two key differences between the NA and turbo assemblies which I will get into below.

The reduction gear aka the transfer clutch drums are identical. The shafts are exactly the same, the bearings are stamped with the same identification marks, length is the same, the number of splines is the same, the placement of the bearings, etc. is exactly the same. The thickness of the 'basket' that holds the clutch plates is exactly the same. I did not do any hardness tests so I cannot say for certainty that the turbo shaft is made of some superior material.

Both NA and turbo assemblies side by side:
http://imgur.com/X5sEwLv

The two clutch drums side by side:
http://imgur.com/mg1tp8Q

The transfer clutch plates of the two assemblies have differences. The first selective pressure plates and snap rings are identical in thickness as well as the inner pressure plates. However the NA uses five pressure plates and the turbo uses six. This goes for the number of clutch plates. The NA has 5 pressure plates and the turbo has six.

NA clutch plates have two types of friction material (black and brown). The turbo plates have the same type of material on both sides (brown and brown):
http://imgur.com/hkBG20Y

The other key difference is that the outer hub snap ring groove is deeper on the NA hub. This is to accommodate less rings:
http://imgur.com/YvATbu5

I'll install everything tomorrow hopefully and report back.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Sun Aug 13, 2017 6:10 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
I installed everything and went for a test drive. The POWER light was still flashing, and then it stopped flashing when I cycled the ignition a few times. The torque bind went away so I was happy. Then I spent the next few days swapping in a new steering rack and changing the oil pan.

Now the flashing is back and the torque bind is still there. The TCU code is 24 for the duty C solenoid. I don't know what happened??? I had to solder the connections because I yanked the harness plug off when I separated the tail housing. I used marine grade heat shrink with adhesive over the solder as well.

I just don't know why the solenoid would be good for only one day? I guess I will do some more diagnostics and check the wiring. But after replacing the rack and oil pan and solenoid and still having the torque bind I am getting a bit fed up with the old turbo legacy and am considering selling it and getting a new car. The SS is my wife's DD and she really likes it but it sure takes a lot of work to keep it going sometimes.

I will try replacing the solenoid again and see what happens but for now I will just live with the small amount of torque bind. Replacing the solenoid for the second time should go a lot faster since I know what I am doing now.

At least the new oil pan doesn't leak and the steering rack isn't leaking anymore. The old steering rack was completely shot All seals were leaking like crazy.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 16, 2017 12:30 am 
Fifth Gear
Joined: Fri May 04, 2007 4:09 pm
Posts: 2235
Location: N. ID
Hi,

Good job on documenting the two.

Have you tried the FWD fuse to confirm the Duty C is NOT working? If you put in the FWD fuse and it does nothing to the Torque Bind/TB, then it's the Duty C. IF the TB goes away w/the fuse it's mechanical and not the Duty C.

I DID file down the grooves on my turbo 4EAT as I had some minor TB and delayed engagement of the AWD. Filing the grooves is tedious, but it worked 100% better afterwards. I did on a spare clutch drum so it was ready to swap.

There should be lots of info on the USMB site w/pics - as long as they're not fotophucket hosted. :-(

Tangent: I also installed the Diff Lock switch...obviously for low-traction-only conditions - due to my delayed engagement issue, and thinking I might get some off-roading in. But I got into Autocross and lowered it instead. :-)

GL,
TD

_________________
Turbo Subies:
'87 GL-10 Turbo 4WD Wagon (pre-Loyale) - SOLD
'90 BJ, EJ22T/DOHC and 5-speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX GG-SOLD
'96 BD - turbo'd-SOLD


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 16, 2017 4:50 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
wtdash, I tried pulling the FWD fuse when I first saw the flashes a while ago and the torque bind persisted so I do think it is a duty C solenoid issue. As to whether it is truly a faulty solenoid or maybe a TCU/wiring issue I still plan on doing some diagnostics per the FSM to rule out a faulty TCU, bad ground of the TCU, or maybe I got a bad duty C solenoid out of the box (not likely, but stranger things have happened). Hopefully I can do some diagnostics tomorrow. Tonight I replaced some exhaust gaskets since I am hearing a squealing under boost that sounds similar to an exhaust leak which I first thought was transmission noise. I replaced one of the crossover gaskets and an exhaust mani gasket and the noise lessened (I think) so I will continue to work on that.

I used a dremel and mildly sanded down the grooves of the NA clutch drum. The NA clutch drum grooves were not as deep as the turbo clutch drum so I think I am covered there. I am considering buying new clutch plates if it turns out the diagnostics show it isn't an electrical issue.

I am going to preemptively pull a TCU from the same low mileage donor Legacy that provided the NA clutch drum, as well as the seatbelt tracks and the moon roof components.

I looked around on ebay and found JDM EJ20g w/4EATs for only $800 so that makes me feel better if I have to replace the 4EAT. I'd rather swap in a 5MT but my wife really likes having the 4EAT.

I'll report my findings with the diagnostics. I am hoping the TCU is faulty or the duty C solenoid ground is faulty since either of those would be an easy fix.

I considered the possibility that hard wiring and soldering the duty C solenoid connection could have changed the resistance but the range of the duty C is 8-15 ohms or something so I don't think adding one inch of wire would have caused the resistance to go out of spec.

I got a little upset when the duty C solenoid swap didn't work. I threatened to sell the SS but I have since come to my senses.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 16, 2017 5:02 am 
Fifth Gear
Joined: Fri May 04, 2007 4:09 pm
Posts: 2235
Location: N. ID
monkeyposeur wrote:

I got a little upset when the duty C solenoid swap didn't work. I threatened to sell the SS but I have since come to my senses.


Good answer....I still regret selling my '93 SS. :-(

Good luck w/the diagnostic...sounds like you've got it covered.

_________________
Turbo Subies:
'87 GL-10 Turbo 4WD Wagon (pre-Loyale) - SOLD
'90 BJ, EJ22T/DOHC and 5-speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX GG-SOLD
'96 BD - turbo'd-SOLD


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Sun Aug 20, 2017 2:04 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
I checked the resistance of the duty c solenoid and it is 24 ohms which is way out of the 1 ohm max range given in the FSM. The flow chart says to replace the duty C solenoid ground.

Does anyone know how to replace this ground?

EDIT: Here is some more info.

Links to FSM diagnostic procedure (same as a few posts above):
http://www.main.experiencetherave.co...id_c_diag1.jpg
http://www.main.experiencetherave.co...id_c_diag2.jpg

To check the Duty C solenoid's ground disconnect connector from the transmission, and measure the risitance between transmission connector receptacle and transmission case. I put the probe on pin 4 and the trans case and got a reading of about 28 ohms. The max allowed is 1 ohm so the reading I got would indicate a bad duty C solenoid Ground.

If you look at the pin out diagram you can see that the duty C ground is spliced into the signal wire going to the duty C. This is the line that I had to cut and splice.

The FSM flowchart states that if the ground line is out of the 1 ohm spec to repair the ground line. Unfortunately I don't have the transmission section of the first gen FSM. So in my mind the only way that I could replace the original ground would be to drop the trans, take it apart, and replace the internal wiring. Not an easy task.

However, in theory shouldn't i just be able to run a new ground wire from pin 4 to the chassis? It wouldn't be in a loop like the original wiring but that should provide a good ground for the TCU and should in theory provide a low resistance value?

If one looks at the wiring going into the 4EAT pin 4 ground loops into the duty C signal wire, so shouldn't running a new ground by tapping into the wire coming out of pin 4 work?:

http://i.imgur.com/AY6JuxJ.jpg?1

My other idea is to go and measure the resistance of the donor legacy at the junkyard and see if pin 4 of the donor car gives a low resistance measurement. If I get a high number then I know that something else is the issue.

When I follow the FSM procedure to measure the resistance of the duty C solenoid itself (pin 4 and 11 of the connector) I get nothing, which would make sense if I am not getting a ground.

So perhaps the duty C solenoid was fine all along and I just have a wiring issue. If anyone has any ideas please let me know. I'll post back any findings I get as well.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Mon Aug 21, 2017 4:13 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
Update (copy pasta):

I have been asking about this issue on NASIOC and there is some good information about the wiring schematic: https://forums.nasio...27#post45292427

I went out and did some more testing. I tested pin 4, same result as before. I tested pin 11. Nothing registered. I tested pin 4 & 11 again, and still nothing registered. Looking at the wiring diagram again I realized that the pinout of the transmission connector looked more like the female end that goes to the TCU. Was I reading it backwards??? Apparently yes! :roll:

I checked the correct position of pin 4 and got .3 ohms! So the ground line is within the 1 ohm range. I then checked pin 4 & 11 and got 13.6 ohms, which is within the 9-15 ohm range! :) So the ground line is good, and so is the solenoid! If I followed the FSM flow chart I would have checked the TCU output signal first, but I figured it was easier to check the ground and solenoid first.

According to the flow chart the TCU must be faulty. I'll pull the junkyard TCU tomorrow and see if it solves the problem. I'll probably check the output voltage of the current TCU and see what I get.

Maybe the original duty C solenoid was good all along, or went bad and helped fry the TCU? I'll be able to answer the TCU question in a day or two. I hope it all works!!!

At least I'm learning something.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 22, 2017 5:27 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
After work I went to the junkyard to pull a TCU. The 93 Legacy w/90k I have been salvaging was gone. I was going to pull the moonroof assembly and motorized seatbelt assemblies and stash them away.

From what I have read the 90-92 TCUs have different wiring than the 93-94s but I'm not 100% sure on that. Anyway I pulled a TCU from a 93 sedan with 4WD and then pulled a TCU from a sedan with FWD. They are different TCUs with different part numbers and the 4WD TCU is stamped 4WD and has the designation 'KY' in large letters.

http://i.imgur.com/llYP8JX.jpg



There are differences between the NA and Turbo TCUs although they can be interchanged. At first I assumed they would be the same but I poked around on bbslegacycentral before I installed the NA TCU. The main difference that was reported is that the NA TCU will go all the way to redline and bounce off the rev limiter at 7k, and exhibits different shift patterns and sometimes a rev hang.

I had yet to check the TCU output voltage of the turbo ECU and I wanted to know how it functioned so I swapped it in. It takes about 10 minutes at the most. Remove kick panel and remove the two bolts that hold the TCU in place and swap in the new one. The TCU is a gold box so it's hard to miss, it's left of the steering column.

Started the car and the 16 flashes were gone! Time for a test drive. I backed out of the driveway and did a tight slow turn and no more torque bind!

Did some WOT pulls and it would sometimes go all the way to 7k in first gear. bounce off the rev limiter a bit and then shift. Not too big of a deal. I then switched to POWER mode and it would do the same thing. It wouldn't always rev to 7k though, but almost always if you just mashed the pedal and ran it out. I could get it to rev almost to 7k, blip the gas and get it to shift so it could be worked around if you are paying attention. Felt pretty good to run it to 7k for the first time, lol.

After the test drive I tried to measure the output voltage from the turbo TCU and NA TCU but I was using my multimeter wrong. I think I know what I was doing wrong so I'll test it in the next day or two.

So in the meantime the NA TCU is going to be a great fix. I am asking around for a turbo TCU so I should be able to find one sometime soon to swap back in.

I then took apart the turbo TCU to see if there was anything visually wrong with the circuit board.

http://i.imgur.com/MTqOcDI.jpg?1


I've done a bit of soldering and repair with RC helicopter boards so I kinda know if something looks wrong. Visually the board looked fine. No loose bits or burn marks. I'm going to do some research and figure out if there is any way I can diagnose and repair the TCU.

Once I measure the TCU outputs and resistance of the wiring harness I will post what I get.

I think that the original TCU was probably on it's last legs and since the Duty C solenoid is activating all the time that wears out the TCU components. And perhaps the solenoid actually went bad that taxed the components even further. I swear the duty C solenoid was working for the test drive after I installed it so maybe then the TCU just crapped out. Just a wild theory but I'd like to think that all that work wasn't for nothing. I guess we'll see how this plays out.

If anyone here has links to threads on how to repair the TCU please let me know, or if you have a TCU for sale! :)

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 22, 2017 5:57 am 
Fifth Gear
Joined: Fri May 04, 2007 4:09 pm
Posts: 2235
Location: N. ID
Good job...I may have a TCU.....been awhile since I checked my stash...let you know tomorrow.

_________________
Turbo Subies:
'87 GL-10 Turbo 4WD Wagon (pre-Loyale) - SOLD
'90 BJ, EJ22T/DOHC and 5-speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX GG-SOLD
'96 BD - turbo'd-SOLD


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 22, 2017 4:51 pm 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
Cool, I hope you have one laying around! :)

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Tue Aug 22, 2017 6:09 pm 
Site Admin
Site Admin
Joined: Tue Oct 15, 2002 11:37 am
Posts: 27124
Location: Houston, Tx
Great troubleshooting and diagnostic work.

The one thing I have found is that the transmission grounds through engine, with the exception that there is a small wire that runs from one of the case bolts on top of the transmission to a point just near the rear pitch stop mount.

A friend was having issues with a shift solenoid that was just on the edge of the recommended resistance range and should have been fine, but he was get the power light to blink. What we discovered is that small ground wire was broken. I reconnected the ground wire and the problem went away.

So I strongly believe having good grounding throughout the chassis and drivetrain components can help some of these weird issues, especially with older cars and wiring. You may want to check the resistance of the ground wiring between the negative post of the battery and the starter and also between the ECU/TCM ground point on the back side of the driver's side intake manifold. Also check that you have a ground wire going to the transmission, it's just a small wire. If there's not one there you could add one. All these little grounding variations can play havoc with the computers. With these cars and the wiring being as old as they are you'll see the resistances increase over time.

Anyway, just a thought before completely ruling that turbo TCU is bad.

_________________
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 23, 2017 4:45 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
Funny you should mention ground lines! I was out doing some more diagnostic work and was looking at the wire going from the transmission pitch stop area to the chassis and measured the resistance and it was quite high. I got some wire to replace it and as I was undoing the lower pitch stop bolt I touched the socket to the positive terminal of the starter and had some arcs to the tranny. Surprised the crap out of me! Took me a few minutes to figure out what I had done. It was getting dark so moved on to removing the airbox to tighten a hose clamp on the low pressure power steering line which has a small leak.

I agree with you on ground lines. I have run a few new ground lines to the engine and chassis but I could stand to do more, especially the ground to manifold you mentioned. I'll check the resistance of the battery terminal wiring and plan on replacing the transmission ground tomorrow. Maybe it will help! Maintaining the SS is almost like a second job right now. :roll:

I have more evidence that the TCU may be bad. I measured the voltage output of the TCU with the FWD fuse in and the accelerator pedal released and it was 11.9 V. This is in the specified voltage range of 8-14 V. The NA TCU output voltage is 11.4 V. However the output of the TCU with the FWD fuse removed and the pedal depressed is 10.2 V. The specified range is 0.5 V max. What is strange is the output of the TCU under the same measuring condition is 4.8 V. So both TCUs are out of range, but the Turbo TCU is a lot farther out of the range.

I found a thread on USMB about repairing a fried TCU with torque bind: http://www.ultimatesubaru.org/forum/top ... ad-duty-c/

My board shows no signs of damage like the board in the link above. I checked each of the transistors paying special attention to the transistor that is connected to pin 3, the duty C solenoid pin. They all read the same! So so far I have no indications that the transistor for pin 3 is in any way falty. The resistors measure in spec and I was able to follow the circuit all the way to one of the tiny black thingys on the back side. The black thingy looks like a small fet but I am not sure what kind of component it is.

I found a local electronics repair guy and with some persuasion I might be able to get him to repair the board if it needs it, or at the very least diagnose the issue. He feels working on older TCUs is potentially dangerous and I can see why for liability reasons.

I am also trying to figure out what JDM 20G transmissions may be compatible with the SS. There isn't a lot of information on them and I haven't come across any JDM wiring diagrams with which to compare to the SS 4EAT wiring. I am considering buying a complete 93ish JDM 20G 4EAT drivetrain and swapping that in next summer just to freshen things up. Although I would rather do a 02-03 WRX harness merge and build another 205/22T hybrid to modernize things a bit.

Once I know more I'll update. But so far the NA TCU is working nicely so that's a success. Still looking for a Turbo TCU.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 23, 2017 5:29 am 
Fifth Gear
Joined: Fri May 04, 2007 4:09 pm
Posts: 2235
Location: N. ID
Found it.
Links:

1993 Turbo 4EAT TCU
Click What This Fits

_________________
Turbo Subies:
'87 GL-10 Turbo 4WD Wagon (pre-Loyale) - SOLD
'90 BJ, EJ22T/DOHC and 5-speed swap - SOLD
'04 FXT, Forged internals, VF39, STI TMIC, Cobb AP- SOLD
'93 Legacy SS - 5-speed, SOLD :-(
'02 WRX GG-SOLD
'96 BD - turbo'd-SOLD


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Wed Aug 23, 2017 2:47 pm 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
Awesome! I'll take it! Let me know how much! :)

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  
 Post subject: Re: 4EAT - Clutch drum NA vs Turbo compatability?
PostPosted: Mon Aug 28, 2017 1:56 am 
First Gear
Joined: Mon Feb 20, 2012 5:44 pm
Posts: 191
Location: Salt Lake City, UT
Swapped in the turbo TCU I got from wtdash. No change. Still flashes. So maybe both TCUs are bad? I feel like something else is going on that is separate from the TCUs but I'm stumped at this point. The NA TCU seems to work just fine so I'm going to just go with it at this point. Maybe the turbo Duty C solenoid is different than the NA and I got sent the wrong one?

I'm still confused as to why the output voltage of the TCUs (including the NA) is so much higher than the 0.5 V for the FWD fuse removed diagnostic condition. I replaced the ground line to the transmission and that didn't do anything.

One difference between the na TCU and the turbo TCU is that during the diagnostic test with the FWD fuse removed I can hear a buzzing in the transmission area when the turbo TCU is installed and the shifter is in D. With the na TCU there is no buzzing. This is the case for both turbo TCUs. Strange!!! Out of my pay grade at this point.

At least I fixed an exhaust leak today. Tried to fix a leaky power steering line but I discovered that it's shot and there is no way to fix it so I will have to fab one up or try and locate a new OEM one. Last time I checked the OEM assembly is over $300 iirc.

Anyway, that's it for now and I've run out of ideas. I'll double check duty C solenoid part numbers.

Edit: Pretty sure I have the correct Duty C solenoid.

_________________
93 SS - Wife's DD, Walbro 255, Boost gauge, POWER mode!, RobTune on the way!!!
03 WRX 22T/205 20GXT 350 whp
95 BK - Sold to my neighbor.


Profile  Offline
Reply with quote  

Display posts from previous:  Sort by  

Post new topic Reply to topic  [ 17 posts ] 


Who is online

Users browsing this forum: No registered users and 3 guests

Panel

Top You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
Search for:
Jump to:  
 cron
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Dizayn Ercan Koc