Got my aldl cable and did data log

[busafreak]

I know woo hoo who cares right? Took a video of it.. still dont know whats causing the rough/ missing at idle. New plugs, wires, cap, rotor, temp sensor, iac. I did find the timing was advanced a little, so i put it back to zero. Adjusted idle with tb screw, and adjusted tps. Noticed the o2 sensor voltage is all over the place. Wondering if thats the problem. Yesterday i went thru mcds drive thru and noticed the rough idle and miss was gone. Felt so nice and smooth. But then i got home, turned it off and started it again and the rough idle and miss came back.. monkey balls!
http://youtu.be/fHNOi2Tab4c

---------- Post added at 07:54 PM ---------- Previous post was at 07:47 PM ----------

And yes I did take a video of the log on my laptop with my phone. Sorry, im technology impaired.. lol

 

[SunlitComet]

Can you get a screen snapshot of the data to post. the phone is just not cutting it. Did you use the procedure for setting basic timing. Were talking 95-older right. O2 voltages go up and down all the time it is the averages you want to see. BTW the TPS is not adjustable.

 

[busafreak]

Yeah, ill try to get a snapshot after work today. I did the procedure to set basic time by unplugging the connector under the glove box. I have it dead on zero and confirmed it with the datalog. The tps is persay not adjustable, but there is a procedure to set minimal idle on the tbi. Consists of shorting the aldl, wait 30 seconds, unplug iac to keep pintle extended, start the hoe, adjust idle set screw. That throws off the tps, so widening of the tps mounting holes is needed to adjust it to its minimal voltage of .50

I have no vac leaks, tested the egr, and solenoids seem to be working as they should. Im wondering why the previous owner had the distributor advanced. I did test the coil with my meter and tests ok.

 

[SunlitComet]

Elongating holes on the tps was not required nor advised. What instructed you that your stop screw needed to be adjusted and the tps be tampered with to ensure a specific reading? Please read below. This is factory info.



Base Idle Speed The minimum idle speed air rate is set at the factory with a stop screw and is not adjustable. This setting allows enough air flow by the throttle valves to cause the Idle Air Control (IAC) valve pintle to be positioned a calibrated number of steps (counts), from the seat, during controlled idle operation. If Idle Speed is incorrect, begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis


Under 8500 GVW Transmission Gear Idle Speed IAC Counts [1] OPEN/CLOSED Loop [2] Manual N 660 +/- 25 5-30 CL Automatic D 525 +/- 25 5-30 CL [1] On manual transmission vehicles the SCAN tool will display RDL in Neutral. Add 2 counts for engines with less than 500 miles. Add 2 counts for every 1000 ft. above sea level. [2] Let engine idle until proper fuel control status is reached (OPEN/CLOSED loop).Adjustments Before performing this check, there should be no DTC(s) displayed, idle air control system has been checked and ignition timing correct.

1. Set parking brake and block drive wheels.
2. Connect a Tech 1 scan tool to the DLC connector with tool in open mode.
3. Start engine and bring it to normal operating temperature.
4. Check for correct state of PRNDL position (R-D-L) switch on Tech 1 scan tool.
5. Check specifications for controlled idle speed and IAC valve pintle position (counts).
6. If within specifications, the idle speed is being correctly controlled by the control module.
7. If not within specifications, refer to Rough, Unstable or Incorrect Idle, Stalling .

---------- Post added at 03:54 PM ---------- Previous post was at 03:53 PM ----------

Also what did you short out on the Diagnostic connector?

 

[busafreak]

Yes I did short the connector also when setting time. The untampered (until I got my paws on it) idle set screw was not stopping the tbi plates. All the way closed you could see a gap between the throttle lever and the screw. The plates where sticking. So After making sure there was no binding and making sure the tbi was clean, they where still sticking. So I went thru this procedure:


Jumper pins A&B on the ALDL (Assembly Line Data Link) connector under the dash. Pins A&B are on the upper-right-hand side. These are the same two pins to jumper to read codes from the ECM. Now turn the key on (the Check Engine light should be lit) and leave the key on for at least 30 seconds. The computer will extend the IAC plunger
all the way out to allow adjustment of the idle speed.

After the 30 second wait, unplug the IAC (square 4-pin connector on the throttle body) WHILE THE KEY IS STILL ON. This prevents the ECM from adjusting the idle speed while you make your adjustments.

Block the drive wheels, set the emergency brake, and start the engine.
Set the idle speed by adjusting the idle speed screw. The engine should be at operating temperature for this. The exact setting is on the emissions label on the radiator shroud, but in general, the idle speed should be about 500 RPM in Drive, 700 in Park / Neutral, or if you have a manual transmission, somewhere between 600-800 RPM. Remember that the truck is running during this adjustment, so stay clear of the fan, and make sure it cant roll or otherwise be put into gear while this is done.


Once the minimum idle speed is set, turn the engine off, reconnect the IAC, and remove the jumper from the ALDL connector. The TPS minimum voltage must now be set. Turning the idle-speed screw may have moved the TPS idle voltage away from the specification, so it should be adjusted next.

Connect a voltmeter between pins A (usually dark blue) and B (usually black, or black/pink) of the TPS, and turn the key on. Dont start the engine. Loosen the two torx screws holding the TPS in place, but dont remove them. Rotate the TPS until the voltmeter reads between 0.45 and 0.55 volts, with 0.50 being ideal. Tighten the mounting screws carefully, they thread into soft aluminum) and re-check the voltage to make sure its still within range.

 

[SunlitComet]

From where id this procedure come from?
Alldata claims the following:


With ignition "ON," engine stopped, the TP sensor voltage should be less than 0.85 volt if more than 0.85 volt verify free throttle movement. If still more than 0.85 volt, replace TP sensor.


With that you should have been okay.

 

[busafreak]

 

[SunlitComet]

EDIT:
I will review this a little

---------- Post added at 06:59 PM ---------- Previous post was at 06:55 PM ----------

Can you get a screen sot at say 2000 and 3000 rpm?

 

[busafreak]

Doing alot of research on tuning and data I found alot of tbi equipped owners from 3rdgen.org and fsc.com doing this procedure with pleasant results, so I opted to try it myself. Ill get another screenshot here from my drive to the gas station. Its storming out here in Illinois and will probably get hail, so its staying in the garage. btw, this is not my daily driver, so I dont drive it much. maybe 50 miles on the weekend if that, but this screenshot that I will put up was the day after a 100 mile trip.

 

[SunlitComet]

Sorry to be an irritant but how about when vehicle is not moving and at 3 different rpm range for say maybe 30 seconds each? What you should be looking for is consistent engine speed runs and looking for an inconsistent anomalies in the data for that run also how many miles and long ago did you do those new parts?

I am eying your 02 data but because you were driving it it is harder to diagnose. It does look like though it is spending most of its time in a rich mode which may indicate based on your part work perhaps a weak coil. Could also be arcing outside the coil at different periods. I can pass on a test procedure for that if you like.