TOP END REFINISHING

[XfireZ51]

Originally Posted by Schrade

The IAC pintle has HEAVY corrosion on it. I know this did not seal.

I hit it only with solvent, and THAT wouldn't touch what I have here...

It helps to clean the pintle and the IAC bore where the pintle moves into/out of.
And yes that is the port you block off. The outer port is the bypass air and the IAC controls how much of that air bypasses and controls idle.
So yes clean the pintle and bore. However, I would still block off the IAC port physically and see what happens w the idle.

[Schrade]

Originally Posted by XfireZ51

It helps to clean the pintle and the IAC bore where the pintle moves into/out of.
And yes that is the port you block off. The outer port is the bypass air and the IAC controls how much of that air bypasses and controls idle.
So yes clean the pintle and bore. However, I would still block off the IAC port physically and see what happens w the idle.

Cleaned pintle, and re-checked CL idle. Still high - 775 - 900, SLIGHT lope.

Pulled the IAC, tapered socket in a clean shop rag, in the IAC bore, TIGHTLY, but might have still let some air by???.

CL idle at 1475, steady, occasionally touching 1500.

[Schrade]

Well, first there was a moth, and now, an O-RING!!! (except I got the moth with the Shop-Vac)

It was idling at about 2,300, and I pulled the IAC, to put my finger on the IAC-to-plenum inlet, to MAKE SURE I had a seal.

A tip: DON'T DO THAT.

Never even saw the O get pulled; it was so fast. She never even hiccuped. I smelled a puff of burning rubber, and saw the missing O at the same time. By the time I shutdown, and smelled the exhaust tips, I couldn't even tell which side took it.



Anyone wanna' buy a Z? Complete with documented F*^#@-ups!!! I might even pay ya for removal...



Anyway, I got a new O-Ring at Advance, same size, slightly fatter, plugged it in, and everything SEEMS like it was before. Idling about 900, occasional lope up to 1,000, down to 825.

Would the burned rubber foul the O2 sensor? DM O2 readout didn't show anything different after the O pulled (I had watched O2 readout before).

[Franke]

Originally Posted by Schrade

Got it there Dom (too much 'life' in the way here)...

Cold idle perfectly smooth [high] @ 825...

...waiting CL here.............


Crept up to 900 post 4 minutes; still smooth....

7 minutes, still OL, but now an IRREGULAR, occasional slow lope, 775 - 925...

Still waiting CL.


CL; 850 - 950, more REGULAR LOPE (screenshot in a moment here...)

Schrade, in the above quote you indicate Open loop idle issue. Correct?

[Schrade]

Originally Posted by Franke

Schrade, in the above quote you indicate Open loop idle issue. Correct?

No Franke; it had gone to Closed Loop about a minute before...

It ran smoothly, although high, and just before CL, it began a mild lope - 25 - 50 rpm swing, then increased as it hit CL.

Why? What do you see?

I edited that post as it warmed up.

[Schrade]

Ok - FSM irregular idle diags flow chart -

#1 vac leak [no?]
#2 ECM ground NO WAY...
#3 throttle linkage NO WAY
#4 low FPR vacuum [no?]
#5 IAC...

Does DataMaster have 'IAC driver' capability?

[Franke]

Ok. My error on open loop. Sorry to mis-direct on that.
Datamaster is not able to drive the IAC as it is just a diagnostic tool to show what is going on with various sensors and parameters. You will need a tech 1A tool or a Mastertech 3100 to operate the various components and simulate sensors etc. It is also possible to simulate most of the various sensors and drivers electronically if ya know what function they perform and how they do it.
So it appears at this point that the CL threshold is reached and then the idle begins hunting. Does Datamaster show a steady IAC count? Is it steady at 0 or approx. when in OL? Does it move around a lot in CL at idle. I looked at my DM files and IAC was 0 in OL and CL with 725-750 RPM idle speed.

[Schrade]

Anyone got a Tech 1 that I can borrow?

I'll forward full cost Money Order up front, and you can return however much is appropriate after I get it back to you there...

PM me on it if you can...

[Schrade]

Alright; IAC blocked TIGHT (cold motor)...

Idling @ 875, smooth as silk...

Post 3 minutes - loping irregularly 125rpm's, sometimes still very smooth, from 825 - 950, still OL...

Now CL; started about 200 rpm lope IMMEDIATELY when it went CL...

2 minutes CL; settled down with only a 75 rpm lope - 900 - 975...............

3 minutes CL; smoothed out real well - 950 - 975.

5 minutes CL; now holding 975 tight as a drum.

9 minutes; now loping 900 - 1075 rpm's

12 minutes; now loping from about 875 - 1125. Shutdown...

Thoughts?

[XfireZ51]

Originally Posted by Schrade

Alright; IAC blocked TIGHT (cold motor)...

Idling @ 875, smooth as silk...

Post 3 minutes - loping irregularly 125rpm's, sometimes still very smooth, from 825 - 950, still OL...

Now CL; started about 200 rpm lope IMMEDIATELY when it went CL...

2 minutes CL; settled down with only a 75 rpm lope - 900 - 975...............

3 minutes CL; smoothed out real well - 950 - 975.

5 minutes CL; now holding 975 tight as a drum.

Chuck,

OK doesn't look as there is a vacuum leak however, it sounds like the throttle blades may be too far open or allowing some additional air. I assume the TPS is at ~.55v. Now if you can back off the throttle stop 1/2 turn and see if that makes a difference. Leave the IAC port blocked.