Yes, I knew that was how to read where the cam was, although I forgot about halfing the crank reading, so I'll bet it would take 3 degrees at the cam to center it. It's probably okay the way it is, but I thought since I'm throwing parts at it and spending a million hours chasing my tail, it might be worth popping an offset key in there.

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That's up to you...I would not worry about it...........

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A Dalton

It must have been running doggy for years before it got a proper tune up. It amazes me what people will put up with thinking that the car is running OK.
Great contribution Joe!

"It must have been running doggy for years before it got a proper tune up. It amazes me what people will put up with thinking that the car is running OK."

That must the fun to kick a guy in the nuts from the safety of your keyboard.

Actually, it's always run fantastic and I've always kept it pretty dialed. Normally, it wasn't that big of a task, because I'd always had a reference point. In fact, I did the balls and sockets on the injection linkage about 6 weeks ago, and the reset valves, mixture, idle, timing, and dwell. It was really running beautiful.

That's when I decided to open the can of worms and once and for all, tackle the huge puff of blue smoke on start up. During the in-car valve stem seal replacement, I discovered the #3 exhaust guide was snapped off flush with the head...and that's where my oil smoke was coming from. So that led to taking the head off.

This round of in depth questions and tuning stemmed from my mistake with the timing chain, and having to reset the injection pump and distributor. I figured it was a good time to ask for some expert advice in case I was overlooking things without even knowing it. I'm always up for learning.

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I kind of want to dial in the cam timing to see if it cures the idle that still goes up and down just slightly...barely noticeable, but unless I advance the ignition timing, I can't get it to go away.

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Couple of things to check would be the CSV ...make sure it is not leaking fuel while at idle...
..and put a timing light on the crank and see if that is steady.
Do you get a steady vac reading?

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A Dalton

Mmm.....good thinking about the CSV. I'll check it.

I'll check the crank mark as it's doing it too. I don't remember.

The vacuum gauge was moving with the idle. It would drop maybe a 1/2" or less as the engine dropped 20 or so rpm.

I even sprayed all the injector bases, and intake manifold gasket w/ carb cleaner to see I had a vacuum leak. None found. Same with pinching off the air hose from the fuel pump, and removing the vacuum pipe from brake booster and covering the pipe on the intake manifold.....no change in idle quality.

The way it does it makes me think it's getting air from somewhere else. Originally, I unhooked the injection linkage and that made a difference (at that point I hadn't check and reset the lengths after having everything apart) so once I had the rods reset, it was much better. But still doing it just ever so slightly.

I'll find it....

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I would guess it's fuel/air related rather then cam/valve timing ..
I have seen many CSV that do seep ever so slightly and that would only be noticed at a low rpm/idle condition..it upsets the a/f mixture .
I was going to also mention that I always do these MFI tweaking adjustment with the booster hose capped , so I am glad to see you had thought of that..they always leak right at the booster hose port gasket.

Throttle plate wear can also cause this condition, along with a plate seat wear..that is why I use the cardboard cover trick..that assures any unmetered air is not coming past the plate seat.

The timing light on the crank will show dist shaft wear , which will change ign timing, so that is one of the reasons for that test...it also test the possibility of a leaking diaphragm in the retard element...all small things that are easily checked and any of which will attribute to flux in idle rpm...a finely tuned 129/MFI engine will run like a top with absolutely no rpm variance....

One last trick I have used for years that is another simple tell for fuel supply..
Get a clear poly plastic tubing about 3 feet long..I forget the daimeter..maybe 3/8..

Anyway , the concept is this ..you take the gas line fitting off the inlet of the main filter [ 19mm] ..slip the poly on that ball fitting of the feed line...Now, take the return line off the MFI pump and slip the other end of the poly on it . You now have a complete fuel system loop [ by-passing the Injection pump] that can be observed b/c of the clear tubing. A nice thing that can tell a lot.
Disconnect the coil 12v pos and turn the key ON ..that runs the fuel pump.
Watch that clear line for any air/bubbles...it is quite common to have fuel supply problems on these car b/c they use a swirl pot and if the loop is having any problems , it will show up as air in that clear line. This is not a flow or presssure test, it is a simple air in fuel line test and there should be NONE...if there is..you have a feed problem..and you know where to look for that.............

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A Dalton

All great suggestions, thanks! Now that I have it reeeaaaaly close I can go back and start looking at all of these "wear" items and see if I can find the source of the uneven idle.

The idea with the clear tube is also excellent. I do a lot of VW Rabbit Diesel work, not to mention their CIS system, so; this is all familiar territory.

Another thing that's untested is the injector spray pattern at idle. In the CIS cars, injectors that are pissing streams at idle instead of fogging cause poor idle, hard starting, etc. Same thing if the injectors are dripping after shut down, or the system loses pressure due to bad check valves at the filter or pump.

So one at a time I just need to go back through all of it. That's how I found that leaking cloth braided vacuum hose. Gave it a little tug and oops, the idle increased!

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Correct ...that is why it is so important not to have any air in the fuel feed line to the pump............

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A Dalton

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Yes.
If you look at the Factory Sevice books on these MFI systems, you will notice that the gauge they recommend/use for pressure and flow also has a clear glass U tube incorperated into the gauge...that is why it is there...for air bubble observation..
Eveyone knows about the 15 sec flow test and the psi test, but very few do an air test...

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A Dalton