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86 505 STI XN6 Restoration


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Nice project.  Now I don't know the XN6 at all but on the KF2 injection engine, those rubber connectors between the intake manifold and intake plenum get swollen if fuel gets in there.  How it gets in there is via the cold start electro-solenoid (injector) on the end of the plenum leaking fuel.

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So I have some interesting results for the STI, me and my dad we using Carb Cleaner into a vacuum hole last night and We were fairly easily able to keep the engine running until i stopped spraying. Interestingly after the engine got going for a bit, I could stop spraying and if the throttle was held down around 3000rpm, the engine would stay running on its own (clouds of white smoke), if your foot moved a little to low rpm it would kill the engine. After it warms up the car can go a long while on its own. Occassionally you can get the throttle right, and it will last for a few minutes, but at some point it randomly dies, unless using carb cleaner. My guess is still injectors or maybe accumulator, anyone have some ideas?

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How old is the gas in the gas tank. Sounds like old gas perhaps fuel problem. Try draining the old gasoline and put some new gasoline. Did you do the same on the 405?

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White smoke, that's usually the flag of surrender (of the head gasket).  Happened to my 366K km 405 after it had been parked for a couple of years and we scrapped it right after.

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I was thinking the same thing at first Mike T, but it doesnt appear to be eating coolant or oil, and with the spark plugs out, the sound of each cylinder is the same, so compression seems good.

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My Experience is water in the fuel system, i don't know if you have run it enough to get out all the old fuel in the fuel filter, distributor and lines. You can try running some fuel system cleaner in the fuel tank and try to run it through, that is the worst way to go about it but i've had luck with it. Make sure it has oil and coolant and run it longer to see if it clears out. If all else fails there's always the italian tune up ( rev it to redline few times)

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Methyl hydrate / gasoline antifreeze will absorb moisture in fuel.

White smoke is moisture burning which is usually antifreeze - if it is coolant it’ll smell sweet as well.

Have you verified fuel pump is still getting power once running?

Have you checked plugs to make sure they’re not fouled?

Pulling injectors and inspecting / cleaning with carb clean might be good peace of mind as well - make sure they’re not real rusty or gummed up bad.

Rabin

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pump is getting powered once running.

new fuel filter just installed

smoke smells like combustion (definitely not sweet)

Checked plugs a very while ago, will take another look though, maybe replace them.

I think my next step is to replace injectors or at least take a look at them.

The outside of the injectors are pretty rusty looking.

Everytime I come inside from working on the car I smell like engine fumes, family hates it haha.

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The car is dead......

To be more specific here is what happened: I removed a little oil, so it would have the perfect oil level, and after I finished removing a little oil, I decided to start the engine. It started like it has been, until around the 5th try starting. It started, but before dying it made a loud bang. It did not sound like backfire, it was more like a clang, sortof. When hitting the key again the engine wont even turnover, and it makes a similar bang, but not as loud. After waiting a few minutes I hit the key again, and it barely turned over. Battery is fine. Going to try turning engine by hand. What direction do I turn. If I find the cause of the bang was something related to engine internals, or transmission, then the car will continue sitting probably forever, but at least until the Mi16 is done.

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Check the sides of the block for “ventilation” holes.  Ventilating a block usually means putting a rod through the side of the block.  

I’ve only done it once, and it was an XN6 that had the pcv system freeze up and it pumped all the oil out the front sling seal.  By the time I thought I saw the oil light flicker, I was looking at it when it lit properly and before I could even let off I heard the death rattle of oil starvation.  I knew the motor was toast, so I just kept my foot into it until it died catastrophically and we coasted to a stop on the highway.  :)

Damn shame that one was - it ran beautifully and got unreal fuel economy.

Rabin

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Hmmm sounds done like dinner.  This is why I am recommending a teardown for any engine that's been left a while.  You'd be surprised how not being used trashes them.

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8 hours ago, Mike T said:

This is why I am recommending a teardown for any engine that's been left a while.  You'd be surprised how not being used trashes them.

 

I now understand completely. To be honest when I heard the clunk, I was just thinking to myself "dang I should of listened to that Mike guy, and hes probably gonna say "told you so"". Haha

I had a look in the oil filler hole, and it is so black, and gunky, and slimy, but kind of dry. Was like this before car banged, sooo.

*Tears*...  Time to do my first engine rebuild. How hard is rebuilding that engine?

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If you take your time and really prep a motor that’s been sitting before starting you can avoid a lot of issues.  Taking a motor apart is usually (imo) only required if it’s stuck or has significant cylinder bore rust verified by a bore camera.  (Or it’s so pricey / rare that you simply don’t want to chance it.)

I’ve saved many motors that have sat a long time (7+ yrs) just with proper prep.  Soaking cylinders in 50/50 ATF/acetone mix for as long as possible, fresh oil change before cranking motor with plugs out until you see oil in the valve cover, and only then do I install plugs to try and get it to fire.

I always cringe when I see cold start videos that crank and fire motors with nothing but fuel added.  There’s no way to know that water hasn’t gotten into a motor over time, or if coolant leaked into the pan.  Since oil floats, water or coolant would be the first thing to get sucked up.  That’s another reason I always do an oil change first.

In your case I’d recommend either using the car as a parts car, or finding a good donor car.  505 xn6 cars (or any 505 for that matter) isn’t a lot of money to buy and your money is better spend buying a better car and restoring that one.

’Course you might just find the motor is still good and it’s the starter that’s making all the noise.

Rabin
 

 

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I shall check the starter, but after I get as far as I can with the Mi16, the plan is to get my dad outside, and he will help me take apart the engine, i'm not giving up. (Jon wont get rid of Peugeot's... but also wont buy anymore, so I have to fix what I have).     At first it started out with me trying to get Jon to work on the car, which was hard to get him even outside.... but now he is getting out there quicker, and doing some of the work. This 505 STI is the only one of the 5 I never rode in :(.

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I don't think it's done any major damage, there is not chance to snap a conrod on starter motor even if the engine run at idle, i'm suspecting a starter motor that stuck out. Or something had fallen in the clutch if its a manual or some of the front drive had sized, i've seen a frozen water pump block the engine solid. Try removing the drive belts and spinning the engine out of gear by hand. With the spark plugs out incase its hydrolocked.

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On 10/22/2020 at 4:06 PM, Goce said:

I don't think it's done any major damage

Turns out your right, no major damage appears to have been caused!! Turns out it was hydrolocked - I took out the spark plugs, and in Cylinder 4 is gasoline laying on top of the piston. I Hit the starter and gasoline goes flying out... like a lot... a whole lot of gas. Dont think any fuel flew out of the other cyclinders, only cylinder 4. Guessing its those dang injectors haha. Time to get those injectors out of there! woooh, engine not dead! (yet)

 

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Great to hear the motor is OK?

Change the oil ASAP, and monitor the oil level to make sure it doesn’t go up.  I’d also lube the cylinders with atf with the plugs out while you’re at it.

Definitely pull those injectors and test flow and spray from them!

Rabin

 

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I'll be honest it was the most depressing thing when the engine wouldn't turn over. Thanks goodness the motor is ok. Will definitely get that oil changed out now that gas is in it, at least I think gas is in the oil stream, because when I pulled off the oil filler cap, it smells strongly of gasoline, as does the dipstick.

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As Rabin said, drip some ATF in that cylinder that had gas in it, now that all the gas has evaporated needs a bit of lubrication, also don't leave the engine opened too long, without spark plugs or open injector ports or plug them with something. You've said you have couple of parts cars, do any of them have the same engine so you can still the injectors off. It's not the best to install old injectors but if they are working then who cares. I would dry test them first, connect them to the lines and put water bottles under them crank the engine, look at the spray pattern and measure how much they have flown out, find the best matched 4 and install them. The practice of matching injectors with water bottles is done here even at main dealers on diesels.

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