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86 505 STI XN6 Restoration


Jayden M
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Definitely sounds like it’s dumping way too much fuel in which would align with the high idle, and rough running, smoke, and high oil level.  
 

Fuel will actually wash down the cylinder walls and into the oil.  This needs to be addressed ASAP as with no oil on cylinders wear happens fast.

You should be able to pull injectors and put them in glass bottles.  Moving the air plate manually should flow more fuel so you can see which one or if all are messed up.  
 

Did you do anything with the air plate / distribution block?

Rabin

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I cleaned off the air plate and arm with carb/choke cleaner extremely well. (it was a used distributor). The injectors I have replaced with brand new ones, since my incident with one exploding., and tested recently that they are working. The only way for it to send more fuel is if the air plate moves more right?

Also I just let out about 1 quart of oil (though it had a strooong smell of gas), so that the oil level is smack between the 2 marks on the dipstick. I then let the engine warm up, and it started smoking again. After I shut the engine off, the level had gone down a fair bit. The smoke appears mostly grey/blue. So definitely oil.

This probably doesnt mean anything, but I can see 'rings of smoke' out the exhaust like this picture:
image.jpeg.61fdd96cc0b8be5977e21fc529e30161.jpeg

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Okay, so here's a thought.  It sounds to me like the crankcase breather might be plugged.  That would pressurize the crankcase and possibly force oil vapour past the rings into the combustion chambers.  Doesn't explain the very high oil dilution, but that could be a separate problem.  I'd suggest removing the oil filler cap and running the engine without it, and noting if you get a LOT of vapour being pushed out.  The oil burning should also cease if that's the cause.

That might be a long shot, but I've seen it happen so it's worth a try.

Have you ever done a compression test on this car, by the way? High oil consumption and excessive oil dilution are both symptoms of badly worn piston rings.  A compression test should help determine their condition.  If one or more cylinders are showing really low values, squirt a bit of oil into those cylinders (not a lot - just a couple squirts from an oil can) and repeat the compression test.  If the compression comes up after that, the problem is the piston rings.  If it doesn't, it's the valves not sealing properly.  At least you'll have more information after this.

Clean coolant and no bubbles is a hopeful sign; hopefully the head gasket is okay.

I'd echo Rabin's comments about the damage that excessive amounts of fuel can do, so that needs to be figured out right away.  There is an air/fuel adjustment screw on that airflow sensor/fuel distributor assembly, but it's far more likely that one or more injectors are leaking or the system pressure is way too high.  There is a feedback system on the K-Jetronic with Lambda system that the XN6 uses, and it works by regulating the fuel pressure in the return line back to the fuel tank.  If that system is not functioning, an excessively rich mixture could result, but it's unlikely that you'd get massive oil dilution if that's the only problem.

The good news is that I have a Bosch manual, and somewhere on this computer I have pictures of the appropriate pages.  I'll see if I can find them for you and upload them here.

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Crankcase breather on the side of the motor could be plugged, but that usually pushes oil out the slinger front seal and your oil level drops pretty quickly.  One of my favorite cars died when I thought I’d be fancy and installed a pcv breather filter on the xn6 and it ended up freezing up on highway, which pushed oil out the front slinger until it seized the motor at highway speed.  Oil light flickered once and was very quickly followed by rod knock.

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The distributor I replaced it with had likely been tampered with (air/fuel mixture screw) as it was a used one from another xn6 car with crap loads of miles. I don't know how to set the air/fuel screw up correctly though.

49 minutes ago, PeugeotPilot said:

I'd suggest removing the oil filler cap and running the engine without it

I'll try this

 

49 minutes ago, PeugeotPilot said:

Have you ever done a compression test on this car, by the way?

I dont have the equipment for it.

 

49 minutes ago, PeugeotPilot said:

There is a feedback system on the K-Jetronic with Lambda system that the XN6 uses

Tell me more about this.

 

49 minutes ago, PeugeotPilot said:

Doesn't explain the very high oil dilution

I'm not sure the gas mixing into the oil is an issue anymore, Just needs the oil to be changed now that it runs better

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19 minutes ago, Bean said:

Crankcase breather on the side of the motor could be plugged, but that usually pushes oil out the slinger front seal and your oil level drops pretty quickly.  One of my favorite cars died when I thought I’d be fancy and installed a pcv breather filter on the xn6 and it ended up freezing up on highway, which pushed oil out the front slinger until it seized the motor at highway speed.  Oil light flickered once and was very quickly followed by rod knock.

Helluva way to lose a car...

I hadn't thought of the front seal.  Yeah, I suppose that's a more likely symptom if the breather is plugged.

Back to the drawing board.

If the poppet injectors are new, and working properly, I wonder if it's possible that the cold start injector is running continuously for some reason?  That would add a lot of extra fuel into the equation, and it might be worth checking to see that it's operating as intended.

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17 minutes ago, PeugeotPilot said:

cold start injector is running continuously

Checked now - It turns off after it starts

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Alrighty, I just went out and ran until warm again - This time with the oil filler cap off (Weird I had to use a prybar to get the cap off.... wtf weird). Still had a lots of smoke. AND I noticed smokey vapors coming out the oil filler hole. What this means... i dont know Lol

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58 minutes ago, Jayden M said:

Alrighty, I just went out and ran until warm again - This time with the oil filler cap off (Weird I had to use a prybar to get the cap off.... wtf weird). Still had a lots of smoke. AND I noticed smokey vapors coming out the oil filler hole. What this means... i dont know Lol

That's normal oil vapour from the crankcase.  With the cap on, that vapour is actually routed into the intake manifold and burned.  Nothing to be concerned about, unless it's excessive.  Of course, when I say that I'm not really helping you because I can't describe what "excessive" means in this case.  Rabin is right though - if it was pressurizing the crankcase the oil would find its way out of the front seal, and you'd have a big leak.

I think your running issues are most likely related to the fuel system, and you're in luck - I found my picture files from my K-Jet manual and put them into a PDF. I can't seem to upload it here for some reason, but I'll find a workaround.  It's got all the information you should need.

By the way, a compression tester is a worthwhile investment, and they are not all that expensive.  I'd invest in a fuel system pressure tester as well for this car.  Well worth the money to have the right tools around, especially when dealing with older cars that nobody knows how to work on anymore.

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Aha.  Just had to make the file smaller.  See attached.  I'll put it in the Technical Resources section too.  This covers both the standard "K-Jetronic" version and the "K-Jetronic with Lambda" version used by the XN6-powered 505s.  This is from an excellent manual called "How to Tune and Modify Bosch Fuel Injection" and it's saved me a lot of headaches.  If you skip to page 29 in the PDF, Chapter 10 deals with your specific system and it includes troubleshooting, plus the various pressures.  Read this and you'll understand how the system works.

Bosch K-Jetronic + Lambda.pdf

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  • 4 weeks later...

Oil was very gasoline smelly. Changed the oil today, and there is literally 1/10th the amount of smoke!(yes its actually smoke and not condensation). Im thinkin about driving it at last

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Just driven it now, and the brakes are terrible obviously since the rotors are rusted (Just needs more road time)

The engine doesnt missfire, and it runs mostly ok, weirdly it seems to run worse the warmer it gets. (and the warmer it gets the more smoke). The oil level is not changed much, which is good. It also does not smell of gas. The smoke coming out is so much less Its hard to say the color, though I think its still oil being burnt. Pretty squishy ride though. Clutch is alright, but probably needs to drive more to clean the rust off. 

This was my first time driving a manual car.

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You likely just need more time in the motor.  Back in the day there was a deadpan “treatment” where you would get a motor up to temp, and then feed seafoam down the carb/into the intake via vacuum line while revving the motor.  The idea was to keep the engine barely alive with the throttle while revving the motor.  Just before the can was empty you’d dump it in to stall the motor.  Wait an hour or so and restart.

It was supposed to clean combustion chambers and rings, and seemed to do a pretty good job of it.

It’d smoke like crazy while you did it, but I had great success with motors running much better.  I’d follow the treatment with fresh plugs and an oil change.

Rabin

 

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34 minutes ago, Bean said:

It was supposed to clean combustion chambers and rings

Blackie had a problem compressing at first most likely due to the rings not sealing, took a while before it started compressing properly, but this STi has ran alot I would think it'd be cleaned off by now (assuming its rust)

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Drove the car for well over an hour last night, and had a great time since I got to learn manual driving. The smoke has pretty much gone away. You can see a little smoke if you floor it, otherwise nah. The suspension is pretty comfy though :)

Lots of things that need attention: Tires are flat spotted (shaky ride), Brakes are weak (rusted rotors, and pedal goes flat to floor its so light), Engine runs rough but not to bad, Coolant temp gauge reads high (right on the 2nd line) though it may be broken gauge.

Even in its poor state this car gets up and goes much quicker than the Turbo.

2 peugeots driven, 1 more to go :)

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Sounds good, Jayden.  The brakes should be a top priority at this point.  505 brakes are generally very effective, so if your pedal is going all the way to the floor you should be really concerned.  They will need to be bled at the very least, and you will want to make sure that the hoses are in decent condition and that there are no leaks.  Fortunately the job is not difficult.  Get those sorted out and your enjoyment of the car will increase immensely.

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