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Need Help With Timing

Every time I hook to the scanner engine is <170F so reading is in advance, my drive to work these days unless at end of MS to Ga , or Ga to Ms is under 5 minutes so truck is not getting hot enough to see where warm idle setting is.

Lowest I've seen so far when I remember to check it has been 11 deg advance, I'm in MS now for the weekend, I'll do my darndest to remember grab it this weekend when I'm out & about and engine is warm.
 
OK Update. I checked it yesterday with GMTDscan.
M/D was 9.5 and TDCO -1.94. I have not touched it since Back in late May and it's a daily driver so am I good ? Also reading JD's input should I cut back the TDCO a little with cold weather approaching ?
 
If I want to cut the TDCO back to -1.5 do I need to do time set relearn first or just TDCO relearn. Also I am getting a much better picture boy that is alot of reading but you said(GMCTD) to note the M/D and TDCO then move the pump. why am I moving it ? I mean If I connect like I just did yesterday and the numbers are within spec and I just want to cut the TDCO back to -1.5 do I need to move the pump and do a releanr or just command relearn for TDCO and exit when -1.5 is reached ?
Sorry if I'm torturing you guys but it's the last thing I don't quite get. But am close. When I came ti the old site and met you guys probablyalmost 2 yrs now I knew nothing about a 6.5 at all and got screwed by the dealer for what I later found was PMD. Two weeks ago I diagnosed and fixed a dead 6.5 for sonmeone in 15 mins flat when two diesel mechanics could not with a blown PCM fuse. So I have learned much.
 
You should be able to just do a TDCO relearn. If you can't achieve -1.50 then you may have to rotate the pump and time set. Leo
 
Correct, a TDCO re-Learn should bring it down to base (the lower reading) TDCO for that position of the IP - however, the most important numbers you can post are ECT and IAT at the time of your scan - if engine has not normalized to operating temps, PCM will be calling for advance, and results will be anybody's guess - always note ECT\IAT first - if normalized at above 180* and 85* resp, then read D\M and TDCO - remember: TECH2 has built-in sanity checks and guards - GMTDScan is good but not operationally\functionally equal to T2 - 'nuther words, it's the operator's responsibility to know, and stay within, the design-spec lines if not using a T2 - and, yes, I do have and do use both scantools - and, remember, here: we're typing '94-'95 OBD1 with GMTDScan

Don't even confuse this with '96^ OBD2, as several functions were upgraded\changed in OBD2, which requires AUTOENGINUITY\equiv scantool - which I also have and use for OBD2 and CAN..................
 
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Acesneights1 said:
Also reading JD's input should I cut back the TDCO a little with cold weather approaching ?
Click to expand...

Listening to jd might be worth your while....

I am leaving mine alone for the time being....you should hear it starting at -10* C...LOL!!

It sounds like someone is standing inside the engine beating it to death with a sledge hammer....that's gotta do some damage.....whole truck shakes....

Not for the faint of heart....

EDIT - I promised a sound clip of a cold start...-10 isn't cold enough yet....
 
chrisk1500 said:
Listening to jd might be worth your while....

I am leaving mine alone for the time being....you should hear it starting at -10* C...LOL!!

It sounds like someone is standing inside the engine beating it to death with a sledge hammer....that's gotta do some damage.....whole truck shakes....

Not for the faint of heart....

EDIT - I promised a sound clip of a cold start...-10 isn't cold enough yet....
Click to expand...

Hey...LOL..! Here it can get below -25*c to-30*c`s, so mine really feels she`s got a Hang-Over...Okay, she is out all night or with A Knight in Shining Armour..... :rolleyes5:
 
Well, it has been waaaay more than 50 restarts since the last time I set my TDCO so I figured I would take out the laptop and snoop around.

After reading gmctd's explanation I expected to see a change in TDCO due mainly to the engine's age. The claim has been made (and of course is true) that the older the engine, the more wear and tear the timing chain has. Because of this, I expected the TDCO to have maybe slipped to -1.85 or -2.02 if it had in fact redone a TDCO learn on its own.

Lo and behold, the TDCO is still at -1.94. To my knowledge, the ECM has not forced a relearn of its own because of a 50 start cycle.

I then ran a timeset. Desired read '0' and actual read from high 2's to high 3's. I stopped the timeset at 3.4*.

I then ran a TDCO learn. It bounced from -1.7x to -2.02. I stopped the TDCO learn at -1.94.

Long story short - even with an aged (365 000 kms) timing chain, the 50 start cycle apparently did not happen with this OBD I machine...if it did happen, the TDCO would have wound up somewhere else....

After disconnecting the batteries for a couple of hours, the TDCO remained the same....

I don't think the 50 start thing exists.....at least not in my truck....just my 2 cents from personal experience....

Snapshot created 11/2/2008 4:48:42 PM
__________________________________________________________________
ENGINE SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Engine run time: 00:03:24
Boost pressure (MAP): 13.61 PSI
Desired EGR: 15.23 PSI
Desired idle: 656 RPM
EGR pressure: 13.78 PSI
EGR duty cycle: 0 %
Engine coolant temp: 186.4 F°
Engine speed: 638 RPM
Glow plug relay feedback: 0 Volts
Glow plug voltage: 0.1 Volts
Ignition voltage: 12.9 Volts
Wastegate duty cycle: 92.2 %

__________________________________________________________________
INFORMATION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
PCM Calibration ID: 4735
Current DTCs: 0
Accel. ped. pos. 1: 0.69 Volts
Accel. ped. pos. 2: 4.35 Volts
Accel. ped. pos. 3: 4.02 Volts
Barometric pressure (BARO): 12.86 PSI
Battery voltage: 13 Volts
Fuel temperature: 127.7 F°
Intake air temp: 97.7 F°
Throttle position: 0 %
Turbo boost (Calculated): 0.75 PSI
Voltage reference sensor: 1.3 Volts

__________________________________________________________________
INJECTION PUMP SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Actual injection pump timing: 33.09 Deg °
Cam reference missed: 0 Counts
Crank reference missed: 0 Counts
Fuel calibration: 115 Counts
Fuel rate: 9.06 mm³
Fuel rate - Cruise: 0 mm³
Fuel rate - Idle: 9.38 mm³
Fuel rate - Maximum transient: 68.75 mm³
Fuel rate - Throttle requested: 0 mm³
Injection pulse width: 1.82 ms
Injection timing - Measured: 10.9 Deg °
Injection timing - Desired: 10.9 Deg °
TDC offset: -1.94 Deg °

__________________________________________________________________
TRANSMISSION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
3-2 PWM solenoid duty cycle: 0 %
Cruise target speed: 0 MPH
Cruise speed error: 0 MPH
Current gear of transmission: 1 Gear
Current torque signal pressure: 31 PSI
Current transmission ratio: 1:4 Ratio
Error between desired and actual shift times for latest 1-2 upshift: 0.42 Sec
Error between desired and actual shift times for latest 2-3 upshift: 0 Sec
Force motor (PCS) - Duty cycle: 35.9 %
Force motor (PCS) - Feedback current: 0.62 Amps
Force motor (PCS) - Reference current: 0.62 Amps
Time of latest 1-2 upshift: 0 Sec
Time of latest 2-3 upshift: 0 Sec
TCC PWM solenoid duty cycle: 0 %
TCC slippage: -14 RPM
Transmission input speed: 43 RPM
Transmission output speed: 0 RPM
Transmission temperature: 159.8 F°
Turbine speed: 43 RPM
Vehicle speed: 0 MPH
 
Gotta agree with Chris. I didn't do Timeset but I checked my TDCO and it was same as I set it 6 months ago. Truck is a daily driver averaging 250 miles a week plus occasion trips. I'm only at 9.5 D?M though. TDCO Locked at -1.94 (which BTW like JD said sounds painful on a cold morning. I am going to reset it tommorow).
 
It only sounds bad @ -1.94. I fixed that by blending in some wvo. Now it is very quiet on start ups.
 
How many 50-start things you reckon occur over 50kmi? - 75k? - 100k? Point is not to change TDCO, but make timing corrections so properly-set TDCO will remain as-set - change a pump with no TIMESET procedure, and PCM will do the correction (that you didn't) to bring it in spec

OBD1 requires TIMESET and TDCO LEARN for major changes - OBD2 combined TIMESET into the TDCO LEARN procedure to implement the ko-ko diddy-wah fingersie footsie thingy
 
I hear what you are saying but after my recent IP replacement, the TDCO did not reset.

Only after I forced a learn with the scanner did I get my TDCO problems that you helped me solve months ago....

jd - I hear what you are saying but I just don't see the actual effects in my truck...
 
I tried to reset mine and when I exited GMTDScan it was still jumping around-1.94 - -2.02. I also did the timeset first. That one acted funny too. It was jumping around. Des went to 0 and meas was bouncing around the 3.5 but when I exited it was still boncing around a bit but finally ended up at 9.5 D/M. Couldn't get TDCO down to -1.5 but as per my other cry for help I got a bad feeling about Mr. IP
 
BTW Chris, remember that snapshot I showed you that showed the INJ pulse width at like 2.02 or somthing and you said that was too much ? When I scanned it today(before ESO issues) it was at 1.8. I wonder if new batts had anything to do with it or cold weather making pump housing tighter ?
 
Increased voltage at the Fuel Solenoid, as from new batteries, results in shorter Inj PW duration, and vice versa (and, I do like my vices versa:ihih:) - that's one reason why we stress grounding and connection issues be resolved first

That's because you're expecting to see TDCO change, Chris - it is not supposed to change unless the position of the IP has changed, which position PCM measures by moving the OS around the timing disk\rotor between the limits dictated by that position - TDCO is a calculated number based on that position, used to factor any timing changes seen as the OS timing disk\rotor\shaft slowly retards due to timing chainset wear - the distributor cannot change timing, as it's firmly secured to the IP body, which is locked down to the timing cover - the rotor, however, does retard over time\duration, as the shaft is driven by the timing gears off the camshaft by the timing chainset off the crankshaft - if you reread thru the preceeding posts, you may notice I keep stressing positional change, as in replacing the IP, resulting in TDCO change and a new number if the IP was not installed to the exact positional orientation as the previous unit

The automatic change will also occur if you do nothing but replace the timing chainset after beaucoup kmiles - you will eventually hear the rattle change as PCM makes the correction sometime during a period of 50 starts

Now: is that clear as mud (even Canadian mud)?
 
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