leseid

First off, thanks to everyone for the great info elsewhere on the sight on this topic. I have studied everything else I can find and am only cluttering up the forums with another thread because I have yet to find a magic bullet.

Issue: Installed a new long block and can only get the engine to idle roughly. By roughly I mean stumbly and shakey enough at 750 rpms m/l that I doubt it will pass smog.
What I have done so far:
Cap and Rotor OEM
Plug wires good
Plugs are new Bosch (Yes I know people have had problems with these)
Timing is at 10 BTDC
New throttle body gasket
Cat was new at rebuild
Air filter is new
All vac connections look okay. Running propane or brake cleaner at the connections and intake joints (including air intake hoses) produces no idle bump
Ruled out TPS. 75% sure on this because I initially had a hunting idle issue (bouncing from 1250 to 800) that I traced to the TPS. Suspect that I had gotten some part cleaner in it internally. Issue went away (along with TPS DTC) quickly.
No DTCs

Really feels to me like the issue is in being too rich—idle stays steady on the rpm but I can hear lots of stumbles and feel lots of shakes as it runs. Also had one cylinder on the old block whose plug smelled pretty gassy on removable, as well as having an injector that looked a bit more worn than the others. Thus the incoming injectors.

I will keep plugging away at other issues—test the cold start injector and installing new fuel injectors are next on the list. Trying not to spend on an oxy sensor as it is my experience on other engines that they throw a code pretty fast when bad. But before I do I had a couple of questions niggling at me that I wondered if anyone could answer:

1) When I installed the timing belt, I had the sneaking suspicion that it was about 1/2 tooth too small. By that I mean when I rotated it a couple of times, the cam marks stayed pegged correctly but the crank was 1/2 tooth before its tdc mark. Moving the belt a tooth clockwise just moved the issue 1/2 tooth past TDC. Decided I was being anal retentive and/or unfamiliar with acceptable lash on the 3vze so I gave up. Should I have?

2) Valve clearances, from the rebuilder, were fine on the ex. valves but just a hair tight on the intakes. .007 was the FSM minimum and my best guess was that I was about 1/2 thousandth tighter, i.e. .006 fit pretty easily. .007 did not fit. Decided, again to let it go and see what happened.

3) When I try to adjust the idle screw, backed all the way out gives no more than about 750 (measured on the dash tach—most of my tools are one state away). Tightening it all the way in, with the engine warm, stalls or kills the engine. I have read contradictory information on this all over this place—screw turned in SHOULD kill the engine, screw turned in SHOULD NOT kill the engine. Which is it? And is the fact I can't get the idle to bump any higher with the screw all the way out indicative of a dirty passage, too much fuel, anything else?

Any info appreciated. Not trying to ask anyone to do my searching for me, just trying to decide whether I should revisit the above before going deeper.
Thanks.

abecedarian

To me, sounds like you've thought through a lot of the potential issues.

With the timing belt, did you put it back after the second-thoughts?
Intake valves- spec is .007-.011". They should've set them to a loose .007 but you'll probably not have serious issues.

I'd say post back with what you find with the CSI as well as injectors when they come in. But in the mean time, cleaning the throttle body might not be a bad idea. Be carefull with the auxillary air valve underneath the TB- try not to mess with it's adjustments but do try to clean the coolant and air passages to/from it.

leseid

Will do. Would a gunky throttle body account for such a lackluster effect in turning the idle screw or am I just expecting it to do more than it really does?

I put the timing belt back on such that it "appeared" to be 1/2 tooth early at the crank. I say "appeared" because I stared at the marks for so long, and tried to measure the cam mark alignment in so many different ways that by the end of things I could not claim to be seeing anything straight. I can say that the cam marks were aligned, and it was six one way, half a dozen the other as far as choosing the crank tooth. I put it early as it seemed any potential stretching/wear would bring it closer to tdc that way rather than further away, if that makes sense.

abecedarian

Out of curiousity... did you let the engine warm up completely? Did it idle any better / worse? Are you sure you have all the spark plug wires installed in the correct firing order?

TNRabbit

If you're idle adjustment isn't working, there's a vacuum leak somewhere. I would suspect the TB butterfly isn't closing completely.