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Guest Message by DevFuse
 

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Mystery Fuse, Timing Mark Location and '88 RX O2 Codes / BLACK Read Mem Connectors...


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17 replies to this topic

#1 88targarose

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Posted 04 July 2004 - 05:40 PM

Alright, more fun from me.

I dug more into the RX (For those that missed the first segment, 1988 EA82-T, d/r ft4wd w/diff lock, MT 5pd.) only to find the following,

First, The mystery Fuse (Click it, I got a "too many images in your signature or in your previous post" message so I made this a link) ...

I noticed this little black box chilling on the strut tower. Curious, I opened it to find a blown, 15amp fuse. I replaced it, however, I don't see any large difference now. I turn the Diff. lock switch to On and it makes no noise (Still have to diagnose the Diff Lock, it doesn't seem to work, no dash lights either), however, I then turn it off and hear a nice click from the engine bay. Being by myself, I've got no one to help me discern where the click comes from.

Second, Where the **** is the timing mark on this crank pulley?
Posted Image

I spend 25mins w/a timing light attached trying to find it, to no avail. Just those two holes on the left of the pulley, and I don't know if they're there for a reason or just there to be there.

Third, I spent a little bit of time chasing down the infamous White Read Memory connectors. I looked and looked and looked. I found some random connectors but none seemed to have a mate to plug into. So, on a whim, I connected these two black connectors:
Posted Image

I then turn the key to On, and what do I see? The O2 light flashing in a very pattern-esque method.
I write down the codes:
21
23
32
42
44
Now, the only error code list I can find that even lists #44 is This one for the MPFI 88+ Vehicles. So, I go by its list...
21 - Coolant Temperature Sensor or Circuit
23 - Air Flow Meter or Circuit (Exc. Justy)
32 - Oxygen Sensor or Circuit (No. 1, Right Side, On SVX)
42 - Idle Switch or Circuit
44 - Wastegate Duty Solenoid (Turbo Models)

Hmm..
Now, this seems a tad funky. The list mentions an SVX code. The RX is not an SVX last time I checked.... So, I'm a little confused.

Also, #44, the previous owner disabled the fuel cut and I run the boost up to 10psi (7.7:1 compression + 5280ft elevation makes it a dog off boost). Could this be causing the code 44? As for the others, (if the black connectors + the list is accurate) I'm at a loss. I'm new to Subaru's....

Thanks!
-James W.

#2 calebz

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Posted 04 July 2004 - 06:48 PM

Ok, from he top .. quickly because I am short on time.

-Fuse= I believe its part of the AC system.. can't remember for sure
-Timing marks. Not on the crank pulley on an RX.. they're on the flywheel.. Make sure you have your green connectors plugged in when you do the timing
-RM connectors. Yes, they are black on my car too (sorry for not posting pics).
- Codes.. clear them and start from scratch.. Don't be concerned about the 'SVX' code.. it applies to yours as well.. its just that on an SVX, that codes specifies which O2 sensor is throwing a code
--Disabling fuel cut. I would be curious to see how this was done. To my knowledge, no one has done a satisfactory job of disabling fuel cut on an 87+ EA82T.. Many of us run higher than stock, but as long as the OEM Ecu is used, fuelcut is an issue.Some have experimented with zener diodes/voltage clamps, but still waiting to hear the results of that.

#3 MilesFox

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Posted 04 July 2004 - 08:01 PM

the diff lock works with vacuum pressure from the RUNNING engine. it feeds from the vac reservoior on the left firewall.

but you should hear the relay click if you hit the switch. if the car was running or had vac you would hear some air.

although you may hear the mechanism operating, the diff lock itself wont engage without vac pressure, or it may need to be spinning(driving) to engace once the mechanism is tripped

pop off the little rubber plug under the pitch bar to view the timing marks. there will also be a separate 3 marks close together, those are for the cam timing, they represent the pistons are at the center of their stroke

#4 88targarose

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Posted 04 July 2004 - 10:03 PM

Timing mark - Go figure. I'll check that tomorrow.
Codes - If resetting the codes goes like this:
- Key off
- Green Plugs in
- Start car
- let run a minute
- turn all the way off, remove key
- unplug green plugs
--> Connect Read Mem plugs, read codes...

Then I did that, those are the codes I got.

Disabling fuel cut - I've got no clue how this was done, there's a solenoid of some type on the passenger firewall that's completely unplugged (bare pneumatic ends (2 or 3) expose, no tubes) but other than that, that's my best guess.... I'll post pics of it later, maybe it's the solenoid that's causing the diff lock not to work...

HOWEVER, I do know that @ ~22-25psi there is a jerk from the turbo. On the frontage roads once, I nailed the throttle headed back to work, boosting along happily when I get a hugggge jerk. I've got no clue what it is. But I've felt fuel cut before in a Mk3 Supra. So, on a hunch I look down at my boost gauge and nail it. Reaches 19psi before I decide that's enough for me. So, if I do have fuel cut it's in excess of 1.5bar (21psi)...

#5 MilesFox

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Posted 04 July 2004 - 10:27 PM

on an 88, there are vac. lines from the turbo to 2 vac switches near left strut tower. you can bypass these switches like how it appears stock on 85-86 mpfi turbo(vane style MAF) just run the wastegate to the turbo outlet and that will work properly for the wastegate(or boost control)

#6 88targarose

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Posted 05 July 2004 - 12:36 AM

That does indeed sound like what I'm looking at.
Posted Image

Now, back to the question at hand. Would that throw a code 44?

#7 calebz

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Posted 05 July 2004 - 12:41 AM


HOWEVER, I do know that @ ~22-25psi there is a jerk from the turbo. On the frontage roads once, I nailed the throttle headed back to work, boosting along happily when I get a hugggge jerk. I've got no clue what it is. But I've felt fuel cut before in a Mk3 Supra. So, on a hunch I look down at my boost gauge and nail it. Reaches 19psi before I decide that's enough for me. So, if I do have fuel cut it's in excess of 1.5bar (21psi)...


What kind of turbo do you have on there to be getting 19-25 psi?!!??

Stock turbo is only good for about 15..

At 20psi, a stock EA82T should be reduced to a pile of blown head gaskets.

#8 88targarose

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Posted 05 July 2004 - 12:46 AM

What kind of turbo do you have on there to be getting 19-25 psi?!!??

Stock turbo is only good for about 15..

At 20psi, a stock EA82T should be reduced to a pile of blown head gaskets.


I believe it to be a stock turbo. Now, it wasn't efficent up through that range. It was just blowing hot air, but the gauge was registering as beyond 20psi. I think it's my altitude + low compression that saved me. But again, it was merely a spike, NEVER EVEERRRRR ran it like that for any period of time.

#9 MilesFox

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Posted 05 July 2004 - 01:04 AM

http://www.usmb.net/...e9.39782181.art

wastegate duty solenoid. that must be the deal not connected, as i described my last post. it never made a difference with me. you DO have a boost control valve, so thats more likely your boost spike i would think

#10 88targarose

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Posted 05 July 2004 - 02:28 PM

The 20+psi boost spike was caused by the fact that the wastegate line had popped off one of the plastic fittings. With the wastegate line unattached there was no pressure to tell the wastegate to open, therefore I ran boost until something else stopped me.

But, since the computer isn't controlling boost, and it can see that it goes higher than the stock boost setting, would that throw a code 44?

#11 calebz

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Posted 05 July 2004 - 05:17 PM

Code 44 = wastegate solenoid

In the pics you showed, the wastegate solenoid wasn't attached to anything. I would think that would be enough to throw a code

#12 MilesFox

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Posted 05 July 2004 - 08:24 PM

it would throw a code because it senses an inactivity, but that may not have to do with general performance, but the computer knows whats up.

just the ecu ability to sense it, not so much for its function, i would say.

#13 88targarose

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Posted 06 July 2004 - 02:36 AM

Hmm... I wonder if I could plumb a line into it, and cap the exit side of it. Just to make it think it's doing something and get rid of the code....

#14 MilesFox

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Posted 06 July 2004 - 07:41 AM

what about unplugging it? you could maybe make a T to it, if its not a flow-thru type device. i dont understand what it does anyway. it probably sends a signal to the ecu that the ecu doesnt factor into equasion.

#15 88targarose

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Posted 06 July 2004 - 12:10 PM

I assume it's the same as any electronic controled boost control solenoid. It watches boost levels, and when it hits the predetermined level, it dumps the pressure into the wastegate actuator, therefor limiting boost. In theory, if I T into it, it will only vent pressure once I've hit the stock boost level. That'll cause me to run richer, since I'm bleeding off metered air.

Ok, now that we've pondered that code, what can I do about the rest?

#16 All_talk

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Posted 06 July 2004 - 01:00 PM

I assume it's the same as any electronic controled boost control solenoid. It watches boost levels, and when it hits the predetermined level, it dumps the pressure into the wastegate actuator, therefor limiting boost. In theory, if I T into it, it will only vent pressure once I've hit the stock boost level. That'll cause me to run richer, since I'm bleeding off metered air.

Ok, now that we've pondered that code, what can I do about the rest?


According to the FSM the “duty solenoid” maintains max boost pressure at higher altitudes. I’m not completely clear on how it works but it does not appear to function as an electronic boost control. I don’t believe it ever vents to atmosphere, it does have a port that connects to the inlet side of the turbo after the MAF. At some point a plan to investigate exactly how it works but haven’t had the time.



Gary

#17 88targarose

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Posted 06 July 2004 - 05:28 PM

Technically speaking, it should never vent to atmosphere. It should intercept the boost line between the turbo and the wastegate. Since it's disabled though, it seems to throw a code. To disable this, I was going to T into the boost line, and then into the control solenoid, then block of the other side. This way, it thinks it's functioning, but isn't really.

#18 DaveSmed

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Posted 06 July 2004 - 07:59 PM

It may not vent into the atmosphere, but some turbo cars have control solenoids that vent into the suction side of the turbo, after the air meter. If the port for that vent is not capped, it would pull air in causing a lean condition. That brass valve in that picture looks like a Gills boost valve. That should be plumbed between the compressor outlet and the wastegate. It should not vent anywhere. You can use that valve to fine tune your boost level by loosening the locknut, and turning it in for more boost.




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