Hello,

I have a problem on my newly rebuilt 1.8L engine, with L-Jet.

Yesterday as I was driving home the car simply quit about 5 blocks away from home. Until this point it was running very well. I had to have it towed home and now I started trying to diagnose it.

So far I've checked that the fuel pump operates when opening the flap in the AFM, so I suspect I got fuel pressure right. The starter spins the engine well.

I have strong spark on the main distributor cap wire (coming from the coil), and putting a brand new spark plug into one of the spark plug wires I have spark at that too. (Originally I was too lazy to pull an actual plug from the engine.) But this morning I tried pulling a spark plug from the engine, and it is completely black and covered in carbon. Not wet, just covered in a thick layer of solid black material.

I can't check right now whether the spark plug from the engine is fouled badly enough to not give a spark at all, or if it still is OK. (I need to wait for my son to come back in the afternoon to help me, this is a 2-person job.) But assuming the spark plugs are the problem, can somebody offer a guess as to what could have caused the engine to foul the spark plugs so badly and so quickly as to stop the engine while driving? Before that there was no indication something was wrong.

Other slightly strange things.

a) I've noticed the car burns a lot of gas. I barely get 20 mpg in mixed city/highway driving.

b) I have about 600 miles since the rebuild, engine ran well all along.

c) The only other issue with the car is that I can not get the idle right: it seems to idle at 1800 rpm most of the time, but if the engine is well warmed up (after about 1/2 hour of driving) or if I hold off the clutch as I come to a stop until the rpm's come down to 900, it'll idle at 900. I've tried two different throttle bodies, thinking it may be the throttle that sticks, but it behaves the same way with both. I started to suspect that the distributor is sticky and does not retard the idle sometimes.

Any suggestions, highly appreciated.

Thanks,
Andrei.

Sounds like you may have one or more leaky injectors. Pull out all spark plugs and post some pictures.

OK, will do that this afternoon.

As I said over on the Bird Board, you're running pig-rich. Check the oil; if it smells like gas change it.

Check that everything is plugged in, especially the CHT sensor near the #3 spark plug.

Verify the fuel pressure, don't guess. It's not that hard to hook things up backwards and get super-high fuel pressure.

--DD

newly rebuilt, check compression, you rings may not have seated

Here are 4 photos of the spark plugs that I pulled out. They are all 4 equally black and sooty.

I checked that the CHT sensor wire is connected. (It is.) But maybe I'll check tomorrow again the resistance between the pin at the computer plug and the ground, that should be fairly easy to check.

What else could it be making it run rich? I understand that a leaky injector could be a problem, but is it likely that I have 4 leaky injectors? All 4 spark plugs look the same.

What would be an indication that the rings have not seated properly? I can run a compression check sometime next week, **if** I get the engine running well enough to get it to warm up. But if it is coming from the rings, wouldn't it foul the plugs with oil, so they would be covered in oily, liquid stuff? And wouldn't I be smoking through the tailpipe? My exhaust is perfectly clear.

Finally, how do I check if I have gasoline in my oil? I don't want to dump all the oil; is it enough to smell it on the dipstick? My problem is that my garage anyway kinda smells like gasoline, so I worry I may not be able to distinguish it... My original plan had been to change the oil after the first 1000 miles, when I would also have done a valve adjustment, right before putting the car in storage for the winter.

Thanks,
Andrei.

One more thing, before I launch into the fairly complicated task of testing fuel pressure. After letting the car sit overnight, if I turn the fuel pump on (by activating the flap in the AFM) I can hear the pump running, and after a few seconds I can hear the pressure valve opening and letting fuel through back into the tank. Does this not indicate that I have it plumbed correctly? Otherwise I assume it would never let anything through.

OK, I went now and checked the CHT sensor. I measure 2000 Ohms (2K Ohms) between pin 13 of the ECU plug and ground, with the engine completely cold. I think that is OK, from what I remember.

Also I tried smelling the oil I wiped off the dipstick (I dipped it 4-5 times to get a good sample). Something strange is happening. The oil looks very good, and does not smell of gasoline to me (but I may be off; my wife says she thinks it does). But what is strange is that I remember clearly that when I put oil in I had it below the high mark on the dipstick, and now it is about 1/8" above the high mark. Could it be that so much gasoline has seeped past the rings that it made the oil level rise? Wouldn't then the oil smell of gasoline very strongly?

Bump. Anyone else with a suggestion why the L-jet may be running super rich? (If that's what my spark plugs seems to indicate.)

I wouldn't take a chance with a newly rebuilt engine, drain the oil. Gasoline is a good solvent, if gasoline and oil are traveling through the journals, bad things could happen.

The 5th injector could be leaking, which would cause all spark plugs to foul up. It would be nice to test all injectors not only if they are leaking but for spray patterns. It's also good to know the fuel pressure.

Lastly, this is only a theory. Perhaps before the rebuild, you had leaky seals that caused a vacuum leak, at that point, someone made adjustments to the AFM to compensate the vacuum leaks. Now with a newly rebuilt engine (maybe all new seals), the AFM is still adjusted from it's last rich running condition even though you have a now tight system.

Go over the basics first. Fuel pressure, FI spray patterns, timing (could be adjusted too far retard) and then we can look at the AFM.

Don't adjust anything on the AFM till the very last, you will need a A/F ratio meter to aid

Sounds like you really need to do that compression check. Doesn't have to be fully warm to give you an idea. If there is a problem you are goi g to see it.

OK, so this is the plan I have, let me know your thoughts about it.

a) Clean the spark plugs by brushing them with a wire brush; reinstall.
b) Attempt to start the engine to check if this was indeed what caused it to stop; only run it for a few seconds to check it.
c) Change oil and filter with Castrol 20W50 (what I've been using so far)
d) Start engine again, drive it for a bit, enough to get it hot.
e) Do a compression check.

After these items, which I know how to do, I should test the injectors, including the cold start valve (I assume that's what was meant by the 5th injector). But how does one test the injectors? Other than testing them that they "click" when one applies power, what else does one need to do? Should I try to take them out and pressurize the fuel system, to see if they leak? And how does one check the spray pattern?

Their history is this: I bought four injectors from someone here on the world, who said they had been rebuilt (seemed to be, came in sealed plastic bags with fresh rubber hoses, and looking nice and clean). Unfortunately two of them seemed to stick when I got them. One I managed to get unstuck, but the fourth one seemed to be badly enough stuck that I had to replace it with one of my old injectors.

Thanks a lot for all the suggestions.

I should have said that I'll do a fuel pressure check too, though that's bound to be messy (anyone have any suggestions on how to remove the pressure from the fuel system, so that when I remove the bolt that covers the pressure checking port I don't get fuel spraying all over the engine compartment?).

More oil in the sump than you put in is a classic symptom of gas getting into the oil. Gasoline does not lubricate your bearings very well...

If you can hear the pressure regulator opening, it is probably hooked in correctly--but it is still worth checking the pressure.

Make sure the vane in the AFM moves smoothly. Double-check all wires and hose connections.

--DD

OK, let's go with the assumption that it is some of the injectors that are leaking. I can't imagine all four being messed up at the same time, so with all four plugs being fouled this would clearly point towards the cold start valve (CSV) being the culprit.

I think I can pull it out and check if it is leaking. But could it be the case that the CSV is actually fine, but the thermo-time switch is messed up and keeps the CSV open all the time? I assume I could test this by pulling the plug off the CSV and measuring with an ohm-meter how long the thermo-time switch stays open after starting the engine, right?

I would like to not have to worry about changing the oil, then doing diagnostics, only to find that I've been leaking again fuel into the oil so I need to change the oil yet again... So I'd like to isolate the fault as much as I can before changing the oil, i.e., I'd like to test as much as possible without running the engine. But some of the tests (like checking the thermo-time switch, and checking oil pressure) require the engine to run, and from what I've heard I should not run it now until I haven't changed the oil.

I had a similar issue after rebuilding a BMW engine with L-jet, the plugs fouled like yours and I had poor power and fuel mileage. It was due to a weak spark instead of high fuel pressure or leaky injector. I would rule out spark issues before assuming fuel issues. They are easier and cheaper to fix.

I ultimately traced this to the speed switch - a pin on the board inside the switch was barely making contact with the metal case thru an insulating sleeve.

I found that a gas soaked plug will not fire well again. Cleaning did not return proper performance even after fixing the weak spark issue.

WhIle a weak spark due to multiple possible causes will result in fouled plugs I would change the oil and monitor closely for a leaky injector.

The thermo-time switch provides the ground to the CSV. The power to the CSV is supplied by the yellow starter wire. Therefore, the CSV will only open while the starter is cranking.

It is possible for the CSV to be leaking, but a shorted TTS is only of concern while you are trying to start the car.

You can remove the CSV from the manifold and run the fuel pump to pressurize the system. If the CSV sprays or dribbles, it is bad and is at least one cause of your trouble. If not, then it is not the cause.

--DD

When I received my 2.2 (built by others), it exhibited the same thing / badly fouled plugs and soot in the tail pipe coupled with black oil in 200 or less miles....

It was unseated rings. The problem went away after running a few hundred miles and I agree with DD as to needing to change the oil along the way.... several times.Gas and Oil may mix but the two tether are a poor lubricant.

OK, did more work on the car today, and I am completely puzzled. Things I did:

a) Cleaned up all four spark plugs as best I could with a wire brush, and reinstalled them.

b) Checked that all 4 injectors "click" when grounding the corresponding pin of the ECU wiring harness.

c) Tried to start it -- started with great difficulty, ran very unevenly (as if firing only on 2-3 cylinders) and got to 2-3000 RPM only with great coaxing and pressing a lot on the throttle. Lots of foul smelling smoke came out of the tailpipe, looking like a haze (smells like burning oil).

d) Pulled a plug immediately after running it, and it was again black, but the sooty thing on it seemed a bit more like oil than like dried carbon deposit (what I had before).

e) Pushed car onto ramps, and drained the oil. Oil looks good to my uninformed opinion, no metal observed in the oil. (But I did not run it through a strainer.) There was more oil than I remember draining out at other times -- almost exactly a full gallon. Smelling it there is somewhat a smell of gasoline, but not sure. I have not yet pulled the oil filter, but will do that later this afternoon (after I buy new oil and a new filter).

Several questions:

a) I assume the oil smoke I see from the tailpipe suggests that oil is getting into the cylinders. How could this be happening? Could it be that having a higher oil level than the high mark on the gauge could somehow be allowing oil to slowly leak into the cylinders while the car is stopped?

b) If I do a compression check with the engine stone cold, will it tell me anything useful? I can't see how I could warm the engine enough to do a proper compression check with the engine running so badly. I don't dare run it more than 30 seconds, what with all the bad smoke coming out and the uneven way it runs.

c) Could the timing be terribly off and cause it to behave the way it does? Should I try to fiddle with the timing, or at this point I should leave it as it is?

At this point (or at least after I put the new oil in and change the filter), I am at a loss which way to go forward. If someone could tell me what would be the best steps forward it would be very helpful. Thanks.

I forgot to say what I was planning myself to do this afternoon:

a) Change the oil filter and add new oil.
b) Do a compression check with the car cold.
c) Check fuel pressure when fuel pump runs; also see how long the system holds pressure after fuel pump is stopped, under the assumption that if there is a leaky injector this would show up in a rapidly dropping pressure in the fuel system. Is this correct?

I don't really want to remove the CSV immediately since it seems to be a bear to take out and put back in.

Start the car again, unplug one fuel injector connector as its running. See if the engine stumbles. Do this for each cylinder.

Thanks, Timothy, I'll try that tomorrow, after I do a cold compression check (I now have all the spark plugs out...)

3 plugs are on the rich side but not real bad ,you still have a brown colour on the electrode centres,however the 4th plug has signs of unburnt oil on it ....not good,have you run this engine in properly,I personally don't like any "run in oils" ,you need to work the motor up and down to vary good gas pressure on the rings for about 500 miles or more.
As mentioned make sure your ignition system is totally up there,you need the best "fire in the hole" for running it in.
Change the oil regardless ok ,the rest has been mentioned,good luck

Ditch the Castrol oil, stuff is shit in a aircooled.

How are you driving it? are you babying it? Running below 3000rpm?
This is all bad at this point, you need to seat the rings...you need to drive it like you stole it.
Running below 3000rpm is bad at anytime.
You can actually ruin rings by babying the engine after a rebuild.

Goetze rings and a few others are hard as hell to seat and can take up to 1000 miles to seat proper.

OK, I am now officially stumped. Here are the latest developments, and if someone could suggest where to go from here, I'd highly appreciate it.

a) I did a cold compression check on all 4 cylinders. (Throttle wide open, fuel injection disabled, all 4 plugs out, crank it with gauge tight in each hole in turn.) I have 125 PSI all around with very little variation from cylinder to cylinder.

b) Cleaned spark plugs again, this time with brake cleaner. As far as I can tell they are good to go. Changed timing slightly (advanced it). Tried starting it. Started almost right away, but again runs very rough, will not idle at all (dies if I take foot off throttle) and lots of blue-ish smoke billowing out of the tailpipe.

c) Took spark plugs out again. They seemed to have a fine layer of dusty soot, but also some wet spots, which I could not tell if they were gasoline or oil. The spark plugs looked roughly all the same, maybe the one on cylinder 1 was slightly dirtier but not much worse.

At this point I have two things I can think of that may have gone wrong: either I run way too rich, or I get oil somehow in the cylinders.

In favor of the oil contamination hypothesis is the fact that I blow out blue smoke. But if I had bad rings on one cylinder wouldn't I be seeing a loss of compression in that cylinder? I can't quite believe that all 4 have gone bad at the same time... Remember that the car had been running just fine before it stopped suddenly.

In favor of the "running too rich" hypothesis I guess I have the dusty residue on the spark plugs. But could running pig-rich cause me to smoke badly, with blue-ish smoke? I could certainly imagine some scenarios where some electrical connection for the L-Jet has gone bad and is causing it to put way too much fuel, but would that be causing rough running? I changed the throttle body about a week before this all started, and in the process I fiddled with the WOT switch and the AFM plug.

Please help... I feel like I'm losing my mind.

Are you using a zinc additive? I thought that was needed. . or one of the special oils with lots of old-timey zinc in it. Probably isn't causing this problem, but could cause others later?

Well, for now my biggest challenge is figuring out why the car runs so badly. I'll worry about the long term things (like the zinc additive) later. For now I fear needing to replace the engine, frankly.

blue smoke, 125 on each cylinder. still think rings, comp should be around 140. blue smoke is oil. as suggested previously, drive it to get the rings to seat.

Remember the 125 is with the engine stone cold. It would probably be higher after warming up.

And how on earth could the rings not have seated after 600 miles of running well? Suddenly I get oil through?

if they dont seat, cylinder walls glaze allowing blowby and oil consumption. if you drove it gently, they may not have seated. i know builders that immediately after rebuild will hammer the shit of the engine to seat the rings. i dont subscribe to that but the engine does need to revved to get the rings to seat properly.

Try my test, might be harder now. With one hand on the accelerator linkage keeping the engine from stalling, and the other hand taking off one fuel injector connector. Listen for the engine to stumble, if it does, re-insert the FI connector. Repeat this for all 4 cylinders. I think you may find that one of the cylinders that you had removed the fuel injector connector, it may not cause the engine to stumble.

I'm going to throw this out there. I just had almost the exact thing happen to me. Ran good. Then bad and fouled plugs. Ended up being the points or condenser. Changed both so unsure. I suspect the condenser which oddly enough was new. (Empi crap). As far as the compression. I only have 90psi on all four of my tired cylinders and I do not blow smoke.

Also I've found in the past that once plugs foul? I can never get them to run right no matter how much I clean them.

I am not ruling anything out yet, but I have a very strong spark on all 4 spark plugs, so I don't think somehow that the problem is with the points, condenser, or the plugs themselves. After I isolate the main problem I may try to improve on these items too, but I don't believe this to be the problem.

Timothy, I did your test right now. All 4 injectors behaved exactly the same way: immediately after removing the injector connector the engine would speed up (quite a bit, 3-400 RPM I would guess) and run much better, then a couple of seconds later it would come back to almost exactly the same RPM as before. I had my son hold the throttle pedal steady while I was doing this test, at about 3000 RPM.

Two other strange things. At some point while doing this test I noticed that one of the main hoses had become disconnected from the main FI rubber body -- the hose that goes to the Auxiliary Air Regulator and to the Decel Valve. But even though I had this huge vacuum leak, the engine still ran mostly the same. In fact I reconnected the disconnected hose to the main FI rubber body while the engine was running, and the engine kept running almost the same.

Second, I decided to do a strange test: I pulled the AFM plug, and just shorted the two leftmost pins with a wire (so as to get the fuel pump to run). I tried running the engine this way, and again it ran just as before through quite a range of RPM's.

Do you think this might indicate that either something is wrong in the AFM or in the wiring harness (at the plug of the AFM?) so that the ECU does not read correctly the AFM signal and thinks the engine runs at full power and needs maximum fuel? (Hence the fouling of the plugs, perhaps running uber-rich?)

blue smoke is not uber rich, its uber oil.

I know that blue smoke is oil being burned. But I am trying to explain to myself how I could start all of a sudden to burn oil: truly from one moment to the next the engine was running good, with no smoke at all, and then it went dead. I would have thought that not having the rings seated properly would cause things to deteriorate slowly. And if it was a sudden problem with oil leaking in one cylinder, I would assume the other three would still work well (and when I disconnected the injector for that cylinder the smoke would stop, wouldn't it? and the test would show a loss of compression in that cylinder?).

My current explanation for the brief revving up of the engine when I disconnect one injector is that the engine is now putting in too much fuel, and when the injector is disconnected, for a short while the mixture goes down to what it should be.

Question: I am thinking that I can test for an injector or cold start valve leaking by pressurizing the fuel lines (by running the pump) and then seeing how long it takes for the pressure to go down. My thinking is that if the CSV is leaking fuel into the intake, then the pressure will go down pretty fast, in a matter of 30 seconds or so. Am I right?

I had spark too. But it was intermittent as the engine ran! It was crazy. The condenser and points were new. I started replacing parts that I had spares of. I replaced the coil. Engine ran great! Thinking I fixed it. I started putting away tools and making an area to move the car so I could do my brakes and rotors. Went to move the car. Problem came back! I had spare points and condenser so I replaced them both. Problem went away permanently! I'm leaving out all the wiring repairs I did because I suspected it to be electrical. Fixing PO shoddy repairs. Best of luck to you! You will figure it out eventually!

Scott

914 fuel system is not sealed like newer cars. When the pump shuts off fuel bleeds back to the tank through the pump and probably through the fuel pressure regulator.
You need to pull the injectors and watch for fuel leakage while the pump runs.

Have you checked fuel pressure?
High fuel pressure from a bad pressure regulator can cause overly rich running.

Jim

I will check the fuel pressure in the next few days, when I find some time. (Lately I've spent way too much time on the car, I need to do some work as well...) But since the car seems to behave exactly the same on all tests I've done on all four cylinders, I suspect I may have a CSV that's leaking (or something else I haven't found yet...)

What else could be causing the system to run super-rich? Bad ECU? I've checked now the AFM connections and everything seems to be fine -- 380 Ohms between pins 6 and 9, and 180 Ohms between 7 and 8. While there I also tested the TPS, and it appears to be fine. (Between pins 3 and 18 it is an open circuit until WOT, and then it is 0 ohms.) I had tested the CHT sensor before, and it's right on the nose.

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.

Also, I run these plugs in my 914. They run a tad hotter.
Click to view attachment

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?

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.

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.

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.

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.

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.

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.

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.