Ok, I ran my the 10 gallons through. I calculated 16.7 MPG. Hey quite the improvement!

I have adjusted the AFM both the wiper setting and the spring tension with 148 grams of weight, it was about 12 teeth off. the car seemed to be a little gutless so I backed the tension down about 4 teeth, Wow what a difference! I thought the car was running good before. Now it seems like a different car. 10 gall added and I will calculate again my mgp. I think I am there now! Also I will pull the plugs look at them clean and read them again after 100 miles or so. Stay tuned and thanks again.

Sounds good! 12 teeth off with the spring tighter (lean) or looser (rich) ? I'm assuming rich since your mpg is low

it was 12 teeth to loose I moved it 12 teeth CW but backed it off about 4. So in all I tightend the spring by 8 teeth.

Bingo! Another hack's "fix" undone! Cool!

Sooooooooooooo....... It is to early to tell so far, but since I had to back the tension off a little to make it run right, could this mean that after setting everything back correctly that I could have been running lean!!! putting my car into the same scenario as Yours? (Fastwoman's and Coseye's).

Oh and did blue do the write up at Atlanic Z? whoevere did gets a huge thanks also.

Edited July 10, 201114 yr by grantf

I'm guessing that's Blue's handy work. If not all his, it seems to be largely his. It's a wonderful resource!

If I understand what you described, before you loosened the spring a tiny bit, you had tightened it a lot more. So you would have been running rich. The weird thing is that extremely lean running can appear superficially like rich running, in that the incomplete combustion results in tons of soot deposition. Also the exhaust smells similar because of unburnt hydrocarbons in both cases.

The other thing is that your engine had multiple issues, just like almost every other old engine I've seen. Some issues lean out the mix (e.g. vacuum leaks), and some richen it (the tampering someone did with your AFM). I bet someone adjusted the AFM so far out of whack once to compensate for a massive vacuum leak. Some of these problems may cancel each other, but they do so at the detriment of the overall operation and responsiveness. Then when you fix one problem (e.g. your vacuum leaks), it might make the engine run worse, not better. It becomes tempting to undo the fix, but that's not a path to putting the engine right. Anyway, you persevered, and you got the payoff in the end.

Edited July 11, 201114 yr by FastWoman

grantf, you've made some serious progress from your original "change spark plugs, get injectors cleaned" post, one month and a few days ago. Not bad, I don't think I moved that fast after I got mine. Congratulations. You'll be on to Megasquirt soon, I can tell.

Ok my last calculation is 18.5 mpg. That is mostly in city and some Seattle freeway (these days that is stop and go). So not to bad I think. But at times now my engine sputters and I here a little popping on deceleration. Could this be lean due to leaky manifold?? My car did not due this till I made my adjustments.

Exhaust pops on deceleration are more symptomatic of (slightly) rich running, but I wouldn't stress on it too much. Just check your TPS to make certain the switch does close when you come off the gas pedal. This cuts fuel delivery on deceleration when the engine speed is >2500 rpm.

I don't know about the sputtering. I assume you mean it does this on acceleration? Maybe your mix still isn't quite spot-on, and you might still need to tweak a bit. I'd suggest putting in a new set of plugs, running them for a couple hundred miles, and reading them. The insulators should be a nice mocha color, not sooty/black (rich) or chalky/white (lean).

You might still have intake leaks, so you might not be home-free. As I said before, there's no ambiguity in the yogurt cup test. You should be able to just about empty your lungs into your engine, and you'll build up a bit of pressure. That pressure should take maybe 20 sec to (mostly) leak away. If it leaks away in maybe 5 sec, you've got a leak. Again, you should see a BIG difference in how fast the pressure dissipates when you pull off your little HVAC vacuum hose.

Anyway, 18.5 mpg is about what you should expect. I think I get about 19 combined mileage. That seems to be a rather typical real world figure. These aren't the most efficient cars in the world!

ummmm ok Something new. BAD water temp sensor. I was suspecting this the last few days. I should have listened to cozeye.

I took out the temp sensor and put it in a pot of water with a thermometer and tested the resistance. I got a sideways 8 (no my meter does not really show that). So off to the parts store I bought a new one and tested it for fun and the readings were all spot on. Put it in the car and now the car runs great! I am thinking of putting the spring tension back to the calibrated setting and calling this thing done.

But I am still going to look for vacuum leaks and there is a sticky spot on the afm, about 3/4 open it sticks, I am wondering what to do to rectify this. Hmm.

You can actually take the AFM apart. There are screws, glopped over with glue, on the "waffle" side of the thing. I suspect the main shaft runs through a bearing that is pressed into place in the main housing. I've not actually been inside one of these things, so I can't tell you anything more.

I'm a little bit surprised that your engine would run much at all with an open temp sender. I once forgot to plug in my CTS, and I was blowing black smoke out the exhaust. I'm just making a guess here: I suspect you were running a bit rich before you straightened out the CTS, and now you're running a bit lean -- due to a large vacuum leak. FAIW, my biggest vacuum leak was between the intake and head on my #5 and #6. Compounding the problem, I had sooty exhaust blowing from exhaust manifold leaks on the back end of the engine, so exhaust gasses were getting sucked up directly into the #5 and 6 intake. I could tell this because of the soot residue leading from my exhaust ports through to the intake ports. That is, there was soot underneath my intake and exhaust manifold gaskets.

Maybe you could do a repeat of the yogurt cup test with a friend who smokes. Just fill the intake up with with a chest full of cigarette smoke, and see where it blows out.

Edited July 16, 201114 yr by FastWoman

Those darn water temp sensors!!! I wonder what your gas milage will be now?