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> Badly fouled spark plugs
timothy_nd28
post Sep 21 2016, 06:52 PM
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I think it's time to ask your AFM a question. Remove the top black AFM's cover, and you will see a arm that swings that has contacts that touches a resistor plate. Make sure this arm swings freely, it should spring back.

Start the car and look at AFM, you should see it swinging back and forth slightly. Now, carefully put your hand on the center plastic part. Manipulate the swing arm so it's more clockwise. Try to simulate the way it moves, it constantly jiggles. Clockwise direction will make it run more lean, see if it runs better as you manipulate the swing arm.

What I'm hoping that you will report back is that you found the swing arm stuck/seized in a certain position.
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timothy_nd28
post Sep 21 2016, 08:52 PM
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Also, I run these plugs in my 914. They run a tad hotter.
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andreic
post Sep 22 2016, 08:30 AM
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Before I start messing up with the AFM (something I am afraid to do) I would like to get to the bottom of the problem with the blue smoke from the tailpipe. That is what's worrying me the most. I tried starting the car this morning, and it seemed to be running somewhat better -- it is not hard to get it to rev up to 4000 and 5000 RPM by quickly pressing the gas pedal. It still does not idle (shuts down if you take foot off the gas pedal) and at lower RPM's it runs somewhat rough, but there's some improvement (could be from moving the timing forward, something I did a couple of days ago).

But my concern is the bluish smoke coming out of the tailpipe -- there's still loads of it, does not seem to go away at all. Everybody says this is from oil getting into the cylinders. (If this is the case, it might also explain the perhaps overly rich mixture: if there is oil getting in, burning the oil uses up some of the oxygen that would normally be used to burn gasoline, making the mixture too rich.)

One potential cause for the oil smoke, if I understand correctly, could be some oil rings not seated well. I did drive it quite hard for the 600 miles since the rebuild (while it ran well) -- I kept it below 4500 RPM for the first 300 miles, but then I would occasionally go to 5000-5500. Anyway, I suppose I could try to jerry rig something about the idle and go for a drive with it again one of these days, revving it hard, in the hope of getting whatever oil ring is messed up to seat again. Is this a reasonable idea?

Other suggestions I heard from someone in my neighborhood was to try to use Seafoam to clean up the cylinder walls (in case they got glazed, I suppose). Is this something you guys would recommend? Would I put the Seafoam in the gas tank, or directly into the cylinders?

Any other home remedies you guys can think of for oil leaks? Or should I give up and try to take it to a garage for a leak-down test to see if indeed I have an oil ring leak? Would a leak-down test show an oil-ring problem? Wouldn't that be futile, given that the regular compression test I did at home seemed to be fine?
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timothy_nd28
post Sep 22 2016, 08:58 AM
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The fact that your oil level increased since your last oil change, your poor gas mileage, and the engine surging up when you disconnect a FI suggest to me that you are running rich. I don't think you're burning oil

See if you can get a mobile A/F gauge kit to take some readings, that should answer your fuel vs oil issues.
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injunmort
post Sep 22 2016, 09:28 AM
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seafoam is a good suggestion, put it in the gas. i use in all my engines twice a year. it will help cut the glazing and allow the rings to properly seat. you can put it in the oil but i would not drive the car or rev it agressively as it is a solvent and would thin the oil. it will require oil and filter change after you add it, like motor flush.
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HAM Inc
post Sep 22 2016, 09:37 AM
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Sounds like rich running washed down the cylinders.

Gas going past rings into the crank case - oil going past rings into the combustion chambers.

Fix the rich condition first (if that's what you have).

The rings may seat with heavy loads at low revs (lugging at full throttle). Have to "lean" on those rings.

High revs and low loads will not force the rings against the cylinder walls. They just zing along lightly and glaze the walls.

You must also consider the possibility that the rings were not installed correctly. It happens.
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andreic
post Sep 22 2016, 01:21 PM
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Hello Len and Timothy,

thanks for your thoughts. Your analysis seems to me to be correct, but I wonder where to go from here.

a) How do I figure out if I do indeed have a rich condition? I will try to look at the insides of the AFM later today to see if the arm is stuck. I tried looking into getting a portable air/fuel meter, but everything I've seen seems to require welding a wideband sensor in the exhaust. Are there meters that can just be plugged into the exhaust without permanent modifications?

b) What I do not understand about the current story is that if indeed the rings have not seated properly, I would have expected the degradation to be progressive, and to also show up on a compression check. For me everything happened very suddenly, car went from running perfectly to not running at all, and then to smoking to high heaven after the plugs were cleaned. Could it be that the extra rich fuel caused the cylinder walls to glaze, and then this started afterwards letting oil into the combustion chamber? If so, do I understand correctly that I should first fix the rich condition, and then try to seat the rings by driving it at wide open throttle in too high a gear, so as to have low RPM's?

c) There is also one thing that puzzles me about the AFM. From looking at the schematics for the AFM it seems to me that between pins 6, 7, and 8 there is basically a potentiometer with total resistance 180 Ohms. So I should measure a resistance of 180 Ohms between pins 6 and 8, and some other resistances X and Y between (6 and 7) and (7 and 8) such that X+Y should be close to 180 Ohms. But when I measure I get X = 120 Ohms, Y = 190 Ohms. This suggests to me that maybe there is some dirt under the washer arm of the potentiometer, with a resistance of about 65 Ohms. (Instead of having X = 55, Y = 125 I get this added resistance of 55+65 = 120, 125+65 = 190.) Is this a cause for concern? How do I clean off the AFM resistor track? Would this be causing the engine to run rich or lean?

Thanks a lot.
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timothy_nd28
post Sep 22 2016, 02:10 PM
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You are correct with the thinking that a potentiometer should add up resistance wise. However, you first need to get the total resistance of the potentiometer which is pins 6 and 9. But, measuring pins 6 and 9 gives you the total resistance of the potentiometer plus a external resistor.

The manual doesn't spec out the resistance between pins 6 and 8, which we assume is the potentiometer itself, but as i have learned over the years is to never make assumptions. Pins 6 and 8 should be the total resistance, and measuring the wiper arm (pin 7) to either pin 6 and pin 8 should equal the total resistance between pins 6 and 8.

The manual shows a basic wiring diagram of the AFM, which gives one a basic understanding on how it works. But there's simply not enough detail about the AFM in the manual, the true internal schematic of the AFM may be different from what the manuals ladder wiring diagram shows. So, we must trust the manual

Manual says check pins 6 and 9, which should show 200-400 ohms

and to check pins 7 and 8, which shows 120-200 ohms.

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HAM Inc
post Sep 22 2016, 06:23 PM
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QUOTE
Could it be that the extra rich fuel caused the cylinder walls to glaze, and then this started afterwards letting oil into the combustion chamber? If so, do I understand correctly that I should first fix the rich condition, and then try to seat the rings by driving it at wide open throttle in too high a gear, so as to have low RPM's?


Absolutely. It happens all the time to engines of all ages and overall health.

New engines are especially vulnerable to cylinder wash down during the ring break in period.

Sometimes repeated heavy full throttle loading will bring ring seal back. Sometimes it won't.

Lugging from a standing stop through the gear box and coasting back down in high gear seems to work best. Wash, rinse, repeat.
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andreic
post Sep 22 2016, 09:35 PM
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More tests, more confusion. At the suggestion of a local Porsche mechanic, I tried the following test: start it, run it at a certain RPM, create a major vacuum leak so as to lean the mixture (if it is too rich). The goal was to see if I get an increase in RPM's -- as this would indeed indicate that the mixture is too rich. Or if it would try to stall, it would indicate that the mixture is normal or too lean.

Lo and behold, I did just that. With the engine running at 2000 RPM (my son holding the gas pedal steady) I removed the oil filler cap. My hope had been that the subsequent leaning of the mixture will make it run smoother and at higher RPM. No joy. In fact nothing changed at all, not the RPM, not the rough running!

But one strange thing I noticed: putting my hand over the oil filler neck (with cap removed) I could feel quite strongly the engine pushing air pressure out through the neck. Is this normal? It felt strange to me, but maybe it's ok.

And the smoke from the exhaust is terrible -- in less than a minute I managed to make a cloud of smoke that hung around the street for 10 minutes or more, smelling very bad (I am almost certain it is burnt oil). At some point I thought that someone played a prank on me and poured a quart of oil in my gasoline while the car was outside, but then I remembered that it is hard to even find the fuel tank if you don't know where to look for it... I am sure large amounts of oil get in the cylinder(s).

One last thought: if it is only one cylinder that is affected, maybe I could isolate it either by looking at the spark plugs (I already did that several times, but maybe after I've run the engine a bit more?), and/or maybe by pulling out one spark plug lead at a time, and seeing if the smoke diminishes (as then the offending cylinder would not fire anymore?). Is this a possible plan of attack? Is there anything inside the engine that could have failed and push oil into *all* cylinders? Like overly high oil pressure?

Final question: do you guys think inspecting the lifters and valves could reveal something useful? Could something wrong with the valve train be getting oil in the cylinders and making the engine run very rough?

Sorry for the many questions, but I really really don't know where to go from here.
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andreic
post Sep 22 2016, 09:41 PM
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And Timothy, I did the measurements you suggested: pins 6 and 9 show 240 Ohms, while pins 7 and 8 show 150 Ohms (as stated before). So at least according to this the AFM appears to be OK. But it does not seem to make any difference! (See my previous posts...)
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timothy_nd28
post Sep 22 2016, 10:06 PM
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AFM could still be bad. If the flap is seized or hanging up, it won't operate correctly.


https://www.youtube.com/watch?v=-4nDzPI_kZ4
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injunmort
post Sep 23 2016, 05:47 AM
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you need a new engine
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VaccaRabite
post Sep 23 2016, 07:43 AM
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The oil filler cap? That is not an air leak point. Removing the cap should have next to no effect on the running of your car, except for the possibility of oil splashing out.

Creating an air leak means opening a line between the intake manifold and the cylinder head, allowing extra un-metered air into the combustion chamber. IE, vacuum hoses attached to the intake plenum. There is a big one there on the 1.8 plenum you can pull off to introduce a huge air leak.

Zach
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catsltd
post Sep 23 2016, 08:00 AM
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I have a 1.8L.
If I pull the oil cap,or any other hose,it will die,and it will Not start.I think,going to try it right now.
My compression is 90PSI hot motor,and it runs good,burning lots of oil though.

It really seems like you have a vacuum problem,or leak.

I would never use old tired injectors after a rebuild,or after 40 years period.

My injectors looked okay,till I pulled them and saw how much they did leak by marks on them.
There is a aftermarket injector that works great on the 1.8L and its cheap,so are the sealing part for the injectors.Someone would know??/

Im a Noob,just trying to help.
Good Luck
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injunmort
post Sep 23 2016, 08:02 AM
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oh, not to mention, an air leak would cause a lean condition, not rich. the only answer is a new engine.
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earossi
post Sep 23 2016, 08:16 AM
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I've been looking at your posting and all of the comments you have received. Please consider that you may have two or more issues going on that may or may not be related.

Of those to consider, the one that I am fairly certain about is that you have not properly broken in the rings. Properly done, you should have seated your rings in the first 500 miles. Actual mileage to seat rings depends on ring material. If ring material is iron, seating takes place fairly quickly. If you installed chrome rings, then seating can take a lot longer. Regardless of ring material, if you fail to seat the rings rapidly, they will build a glaze in your cylinders.

Another issue that promotes glazing is whether or not you "oiled" the cylinders before installing the pistons. Newly ringed pistons should be installed in cylinders that are properly honed and are "dry". Oiling the cylinder walls allows the rings to slide over the cylinder walls rather than to seat. Although the oil will be removed in the first few seconds of run time, you have nonetheless promoted glazing.

Once a cylinder is glazed, I do not know of a way to remove the glaze other than removing each cylinder. The glaze is not very hard, and can usually be removed with Scotchbrite. There have been suggestions in write-ups that you can run some abrasive material through your engine to rough up the glazing; but, I have never read of someone reporting back that such a scheme worked.

Which brings us back to proper engine break-in. The temptation for someone who has not rebuilt a lot of engines is to soft pedal a newly rebuilt motor. Which is exactly the reverse of the way to break in an engine.

A rebuilt engine, once started, should immediately be run up to about 2500 rpm and held at that speed (without a load) for about 10 minutes. Doing that forces the new valves and bearings to seat in properly. That first run is also the time when any debris in the engine will wash out into the oil. So, after the initial run in, you should change out the oil and filter.

The second phase of engine break-in can now be initiated. As someone posted above, you should take the car out and drive it like you stole it, limiting engine speed to about 5000 rpm. The driving cycle should include putting a high load on the engine by "bogging" the car in higher gears. Usually 3rd or 4th gear works well. The procedure is to shift into a gear and then allow engine speed to decay as car speed decreases. Then, just short of stalling, apply full throttle which will cause the engine to begin to pull out of the stall. This puts a very high pressure load on the piston rings, forcing them to move "out" into the cylinder, which promotes ring seating. Maintain full throttle until you reach the rev limit mentioned above. Repeat this "lugging" cycle about 6 or 7 times during that first run.

Then continue to drive the car "like you have stolen it" for 500 miles, paying attention to not allowing the engine to over rev (past 5000 rpm) during that period. Rapid engine acceleration is what you want, but not to exceed the rev limit. You won't hurt the engine doing this. So do maximum acceleration movement through the gears without going above the rev limit.

At the end of the 500 mile break-in period, change your oil once again (as well as your filter). Then you should be good to go until a normally scheduled oil change is due.

Another poster mentioned oils including break-in oil and brand of oil to run. The difference between break-in oil and your normal oil is that the break-in oil will be a single viscosity (usually 30 weight) and break-in oils have very high levels of zinc and phosphorus. The high zinc is required to properly break in any contact surfaces such as engine tappets running on camshafts. Once you have properly broken in an engine, at the 500 mile point, you should replace the break-in oil with your oil of choice.

Regarding oil brands, there are much better oils on the market other than Castrol. I don't want to touch off a firestorm debate on oils, but though Castrol is OK, you should look for a better product. Whatever oil you choose should have higher levels of zinc and phosphorous. Government regulations have forced oil formulators to reduce zinc and phosphorous levels to very low levels, which are OK for modern engines, but will ruin the older engines such as we run in our 914's. The zinc and phosphorous additive put into most oils is called ZDDP. which is an acronym for the chemical formula of the additive. Proper levels of ZDDP are usually 1300+ ppm, rather than the 700-900 ppm currently being run in oils meant for street use. You will find the proper ZDDP levels in oils labeled "for off road use only". Or, you can purchase Mobil 1 synthetic motorcycle oil which comes in the 20W50 weight our engines were built to use. That oil (don't recall its trade name) can be purchased at your Harley Davidson store, or over the internet. It's formulated to run in air cooled engines and has the higher ZDDP needed.

Gasoline contamination of the oil does occur during the run in period; however, to build oil volume rapidly (as you described) is an indication of something else drastically wrong having to do with your fuel management system. You are obviously running way to rich. Gasoline that has made its way into your oil system is usually at a very low rate and will vaporize as oil temperature increases and be pulled off the system by vacuum.

And finally, your statement that the car was running perfectly and then suddenly stalled indicates to me, that you have suffered some electrical or technical malfunction. But, that malfunction is more than likely divorced from engine break-in.
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catsltd
post Sep 23 2016, 08:23 AM
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QUOTE(injunmort @ Sep 23 2016, 07:47 AM) *

you need a new engine

It is freshly rebuilt,I wonder if its something else???.

I just went out to my 74-1.8L pulled the oil cap.
Car will start,but then dies right away.

If the car is running and I take oil cap off it dies,almost instantly.

If you pull the oil cap off and it does nothing,then it makes me think you have a vacum leak,or something is pulling out oil from somewhere and trying to burn it from a vacum line hooked up wrong.

Just my 2 cents worth,again just trying to help.

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injunmort
post Sep 23 2016, 08:38 AM
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^i was also trying to help. at least four diffent posts suggesting rings. the only thing that has not been verified is rings. injection works well enough to start/run car. blue smoke, 125psi compression on newly rebuilt engine is low even cold. the plugs are coked up and dry, does not appear to me to be a rich condition or plugs would be wet, pictures show dry. as stated before the oil cap has nothing to do with intake (and yes it does pulse in there due to that crankshaft rotating.) if a line was incorrectly hooked up to where it was pressurizing the crankcase, it would be blowing oil out of the breathers on the heads and oil filler, no mention of this. so it has to be the tires. new tires should fix everything.
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catsltd
post Sep 23 2016, 09:06 AM
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QUOTE(injunmort @ Sep 23 2016, 10:38 AM) *

^i was also trying to help. at least four diffent posts suggesting rings. the only thing that has not been verified is rings. injection works well enough to start/run car. blue smoke, 125psi compression on newly rebuilt engine is low even cold. the plugs are coked up and dry, does not appear to me to be a rich condition or plugs would be wet, pictures show dry. as stated before the oil cap has nothing to do with intake (and yes it does pulse in there due to that crankshaft rotating.) if a line was incorrectly hooked up to where it was pressurizing the crankcase, it would be blowing oil out of the breathers on the heads and oil filler, no mention of this. so it has to be the tires. new tires should fix everything.

I am just trying to help.Like You.

The fact that the car was running great,then died suddenly and would not start,does not make me think it is the motor.But i am just guessing,just like everyone else.

125 PSI is not great like you suggest,but its not bad either,I run 90 PSI.

The plugs Look exactly like my 1.8L car when I first bought my car,(wish I could find the thread.).
I replaced my injectors,seals,and connectors,it did help,running 2 sets of used 40 year old injectors seems to be a bad idea at best.

What I found was the old connectors to the injectors dont work anymore,they dont plug into the injectors tight,and caused misfires,and fouled plugs.When you plug them in 1 of the pins would slide back and not have a proper connection.(It sure made my plugs foul).

It seems he has not fixed the problem yet,so I am offering up my suggestions,nothing more.

I know running new injectors,seals and plugs for the injectors wont fix the problem,but it will help eliminate problems down the road.

Again Just trying to help,like everyone else.

Cheers. Grant
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