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Guest Message by DevFuse

RX with engine troubles...mostly solved

Started by Guest_wjmgl10_* , Jul 25 2003 11:09 PM

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29 replies to this topic

#1 Guest_wjmgl10_*

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Posted 25 July 2003 - 11:09 PM

Ok, here's the deal...1989 RX, FT4WD D/R of course, and turbo (duh)

Once the manifold reaches atmostpheric presure/eqalizes, and then boost comes on, power drops off dramatically, acceleration almost stops. Its like she boogs, but the engine just stops producing power, and just runs. No power. Let off, and no boost, power back on. At some point, when you floor it, power will come back, but not much. One time, while she was cold cold, she gots lots o power....but that never happend again.

I fixed the overheating issue, fresh water/coolant, and a 180 t-stat after flushing everything.

So.........any ideas on why the engine and system are doing this? Please post anything that might do it.....keep in mind this car stayed in West VA for a time, and the owners never really took "proper" SUBARU care of this thing.

What could be it...........?

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#2 Guest_tomrhere_*

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Posted 26 July 2003 - 03:49 AM

Not fersure on this, no turbo experience. But sounds like the exhaust is restricted. Not enough to hinder the engine with no boost, but won't flow good enough under boost....Tom

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#3 Guest_UltimateRX_*

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Posted 26 July 2003 - 08:04 AM

I would check the bypass valve diaphram on the turbo, sounds like it is opening too soon. These are touchy little guys, sometimes they work forever, other times you'd thing they had a mind of their own. They are not hard to replace, if you have another turbo engine, swap them and see if that fixes it.

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#4 Guest_offroadsubaruguy_*

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Posted 26 July 2003 - 11:06 AM

check for leaks to the intake anywhere after the turbo.. make sure everything is tight... i had the same problem once, then i remembered that i had forgotten to re tighten the hose clamp that holds the intake on to the t/b....ran fine with no boost, then nothing when you hit boost, it just leaked out before it got to the engine......

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#5 Guest_wjmgl10_*

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Posted 26 July 2003 - 01:18 PM

tomrhere:
Its got the downpipe...with nothing in it at all. So there is ZERO backpressure. So...thats one area out....

UltimateRX:
I've got a few laying around, I'll swap it and see what happens.

offroadsubaruguy:
Indeed the turbo to intake plenum was loose, I fixed that before i posted here...I WILL be checking for leaks everywhere, it does sound like there IS one...somewhere...

Anymore suggestions.......?

I plan on making a downpipe that doesnt leak, its going to be catless, and will have a muffler to quiet the RX...so I can hear any more boost leaks...

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#6 Guest_wjmgl10_*

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Posted 27 July 2003 - 06:38 PM

Alrighty...cleaned the FI temp sensor and all 4 of the FI connectors, and the muffler is installed. She runs a little better now...she's STILL got the power dropoff when boost comes on........

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#7 Guest_oobnuker_*

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Posted 27 July 2003 - 06:51 PM

Maybe a bad knock sensor? Malfunctioning and telling the ECU to retard the timing?

Just a guess.

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#8 Guest_Hondasucks_*

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Posted 27 July 2003 - 10:40 PM

Or he's got a batch of shibby gas that is makin his engine ping, and the computer is doing its job.
I have a vacuum gauge that I got for Christmas, that is supposed to double as a fuel pressure gauge for carbureted systems (reads up to 10 PSI), but I find it works as a good boost gauge. They run about 25 bucks, but are a GREAT tool to have around. Mine is an Equus I think..
Anyhoo, get one and hook it up to a free vacuum connector (Make sure it is connected directly to the manifold, and dont' hook it to the little hose going to the wastegate diaphragm unless you T it!) Now, go drive the car and see what your boost gets up to. If it doesn't go above 1 or 2 PSI (Only takes like, a hair above 0 to get the light to come on) you are prolly having wastegate issues. WOT should kick that turbo up to 7PSI within a matter of seconds, I know my 87 does.

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#9 Guest_wjmgl10_*

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Posted 28 July 2003 - 05:23 AM

I did put 6 gal of 93 in it...still ran like this, this could mean one thing...rusty gas tank...

I'll check out the knock sensor as well as the waste gate.

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#10 Guest_UltimateRX_*

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Posted 28 July 2003 - 06:01 AM

Yea, that's what I meant, the waste gate diaphram, it still sounds like that is openning early and allowing the exhaust to bypass the turbine side of the turbo. The knock sensor would be more of an electrical thing, cutting spark to the engine. If the diaphram is weak, the pressure from the exhaust could be opening the waste gate.

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#11 Guest_wjmgl10_*

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Posted 28 July 2003 - 09:41 PM

Im going to check out all the other problem before I take all that stuff loose and replace the wastergate actuator...that just might be it. All the other things need checking anyhow, since it IS my car now, and its going to rally.

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#12 Guest_ozsubie_*

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Posted 28 July 2003 - 10:10 PM

I had something similar with my 86 Turbo caused by a blocked fuel tank return line. This caused way to much fuel pressure at the injectors and when the green turbo light came on the engine flooded and lost all power. In my case it was easy to see that it was getting way to much fuel because of the black smoke screen left behind the car. If anyone was following me they would literally see me disappear in a cloud of smoke.:rollin:
In my case it seems while the ECU is running in closed loop mode (getting feedback from the oxy sensor) it could keep the mixture about right, however when the green turbo light came on and it switched to open loop mode and rich fuel mapping that's when the problems started. If you're not seeing any smoke like I was perhaps you might have the opposite problem, a dodgy fuel pump or pressure regulator not giving you enough fuel?

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#13 Guest_wjmgl10_*

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Posted 28 July 2003 - 10:19 PM

Ok, now heres something.........after a time of running, 5 mins or better, there is some sort of resonating, humming, or whatever, from the fuel pump area after the thing is shut off after running for 5 mins or better........blocked return lines? With the history this car has, YES. That will be the next thing for me to check out. First thing tomorrow!

I'll let ya'll know how it works out. Thanks for the info!

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#14 Guest_wjmgl10_*

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Posted 30 July 2003 - 03:52 PM

Ok, cleared the lines...no change. It did seem to pick up alittle pep...but not much. Next I am going to pull the cover off over the fuel sending unit, and pull that out, and see of the tank is rusted or whatever.

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#15 Guest_wjmgl10_*

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Posted 31 July 2003 - 07:39 AM

The tank is clean................

??????????????????????? What is it the problem????????

edit: bump.

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#16 Guest_UltimateRX_*

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Posted 31 July 2003 - 06:29 PM

I'm still waiting for you to check the waste gate diaphram. At this rate by the time you get around to that, you'll have replaced or cleaned the entire fuel delivery system.

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#17 Guest_wjmgl10_*

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Posted 31 July 2003 - 09:49 PM

LOL :rollin: :rollin: :rollin: :rollin:

That will be the thing I do next Corky!

Although I suspect the injectors COULD use a cleaning...I know that the GL-10 ran MUCH better after I cleaned them!

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#18 Guest_PoorManzImpreza_*

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Posted 31 July 2003 - 10:04 PM

so I assume the GL-10 is holding up well @ stock boost?

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#19 Guest_wjmgl10_*

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Posted 01 August 2003 - 03:54 PM

yes. I get on it more often, and after 11k miles, everything is great.

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#20 Guest_wjmgl10_*

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Posted 01 August 2003 - 04:54 PM

Hey Corky:

I replaced the waste gate actuator with a known good one from 1986. MUCH better when boost comes on...but the engine still lacks...BALLS. Its also got a stumble when you start to step on the pedal at idle...Skip has emailed me a few things to check...but i was wondering if anyone else has any ideas now...? Maybe changing out plugs and coil would work? I already replaced the wires.

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#21 Guest_oobnuker_*

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Posted 01 August 2003 - 05:32 PM

Does this car have an EGR valve? On my SPFI motor, I just cured a weird stumble issue that was caused by a faulty EGR Solenoid. It wasn't idle though - it was at very light throttle while cruising. If I wanted to cruise at a certain speed, it was tough to hold it, and when I went to accelerate out of it, the car would stumble...

So, don't know if this helps or not. The EGR Solenoid that was bad showed no continuity on an ohmmeter between the two contacts.

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#22 Guest_wjmgl10_*

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Posted 02 August 2003 - 02:16 PM

Ok, after messing with the dist and the timing, and going thru a broken timing belt, and replacing the main accessory drive belt (all that did was stop the PS and ALT squeekage!!)...I go out...and mash the pedal to the floor...MASSIVE clutch slippage, some horribly high G's on the accelometer, and the power is ON now!!!! I had also put 6 gal of fresh 93 octane fuel yesterday and drove it some.

Now...I need to fix that horrible factory intake system, run some fuel system cleaner thru it, install the inner fender well covers (if I can find some) and start working on things other than the engine now!

Mods to come:

Synthetic oil, oil cooler and remote oil filter.
Better intake and exh. system.
Replace clutch and pressure plate...lighten flywheel?
Install 5 point simpson harnesses and racing seats.
New steering wheel (MOMO?)
Modify the D/R selector (shorten) and make a short shifter (like Flowmastered87GL did)
Some other small things......
Spyder intake, WRX intercooler, higher output ALT and install my rally lights.

SEAL UP THE WHOLE CAR!! Need to keep all the dust and water out of places that it doesnt need to be!

Oh, I shoudl fix the brakes...new slotted rotors and EBC pads if i can find them. DOT 5 fluid and rebuild the whole brakesystem.

And most important for the car as a whole....CAMBER. I really need to get these camber plates made.

Ofcourse, the USMB will be kept up to date on the progress of my GL-10 and RX mods.

Is this a long post or what? :rollin:

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#23 Guest_baccaruda_*

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Posted 02 August 2003 - 03:07 PM

yeah, but you deserved it

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#24 Guest_UltimateRX_*

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Posted 02 August 2003 - 10:37 PM

Good luck on getting EBC brake pads, I scanned the pads off a XT6 front disc and sent it to them, at their request, they never got back with me.

Glad to see it running now. My GL-10 does the stutter from idle sometimes, but what gets me is the hesitations while under normal accelerations, if I floor it, the hesitations go away. Go figure.