TDCO -2.5

[rjwest]

I Ran the latest version of CARCODE scanner
program,

Tried the Inj test, seemed to work,

Than tryed injector timing tests. MISTAKE:

The TDCO went to -2.5 and the tdc actual would not match TDC Desired, until eng up to 1500 rpm,
also overall timing lower at all RPM's.
AND service eng & code set Inject pump timing.

Tryed all the TDCO learn procedures, no change,
Took it to a person with a TECH 1,
He reset timing and the error code no longer
comes on, but TDCO still -2.5 ( use to be -1.1 )
Does the tech 1 read TDCO,

Will -2.5 TDCO ( if in fact the scanner is correct) hurt the engine, It sounds good , no
diesel ping, Timing actual follows desired,
( slightly more advanced at high rpm ).

reluctant to move pump until i'm sure TDCO readings correct, besides , just loaded camper,
in case OLFELIA comes ashore...

Any tech 2 in ne florida ???

Also, manuel says: timing change could be due to
Crank sensor, or Damper slipped ( sheared Key ), ?
Any thoughts

[rameye]

I've gotta run outside to answer that about reading the offset with a tech 1.

Are you sure your offset is still -2.5 and not your injection timing? According to my manual, anything over -2.02 will set a code.

Ok the answer is yes you can, for sure read the offset with a Tech1. Goto the OBD controls, goto TDC offset learn, once there dont press any buttons, just wait your offset will appear.

One more thing I've found without the aid of a users guide is before doing the TDC off set learn, is to do a injection timing learn prior to doing the offset learn.

I find doing it this way yields a more desirable offset number range.

I'm off 95, 3 minutes, next time your passing thru if you want to check it.

ram

[rjschoolcraft]

Sounds like you need to bump the pump to the passenger side and re-learn.

[rjwest]

OK Thanks, Think I will not mess with it untill
huricane makes up it's mind.

Can the balance damper slip and make tdco change?

Florida S##ks.. i'll take a blizzard anyday...

[tom.mcinerney]

>>Can the balance damper slip and make tdco change?
I believe not , as the dampener is strictly mechanical....?
I think John 8862 set his tdc offset at -1.25 rather than -1.95 as a conservative measure , but he's runnin hi boost , lo comp.
Can't answer your later posts.

[rjwest]

Got brave and moved the pump, Made a spanner
for the pump flange, First try, TDCO -1.9
on the carcode scanner. More power than
when set at -2.5 . The timing does advance more
with RPM, Assume the PCM was pulling back on the advance. ( was getting a code occasionally )

Now I have to decide if I should leave it there or etard it some more, Running 12 psi boost max...

Looks like Carcode is reading correctly,

[rjschoolcraft]

The service manual identifies the TDCO learn procedure as a "backup" timing procedure. You should not need to do "Time Set" if you have a good "learned" TDCO.

I have run -1.94 with high boost and have seen no problems related to it. Others have as well.

[AndyL]

Originally posted by rjwest:
I Ran the latest version of CARCODE scanner
program,

Tried the Inj test, seemed to work,

Than tryed injector timing tests. MISTAKE:
How did you do the Inj Test and Timings tests? I have the new software and didn't see any way to start it!

[rjwest]

You need to download the latest software,
Aug/Sept,

Go to " Tests " tab, than select 'enahnced'

The pop up will be the test screen,
Do and ' enable' on top , should get another
pop up , select GM, than select,
L65 with allison ( it's a mistake ) it works ok.

Than do each test by highlighting,

This is where I got in trouble, When I did TDCO set,
I got -2.5, was not sure if program or truck,
I guess it was the truck, but I have not had an opertunity to verify it with a TECH 2.

[john8662]

Actually Kent on this board is using the -1.25 as more conservative TDC offset verses the -1.5 or -1.94.

I've got the same engine built for my Sub (like Kent's) and it's sitting on the engine stand waiting to jump in the engine compartment.

I'm leading towards a -1.25 because I don't think there will be any gain in going to -1.94, or any gain thats worth forcing the engine to endure more stress from a higher advance.

Adding more advance will make the engine louder, and the detonation knock more pronounced, especially at WOT near red line, which isn't a good sound in my book.. Just my .02

[rjschoolcraft]

Funny, the "detonation knock" on my engine didn't change at all going from -.7 to -1.94. It is marginally louder on cold mornings, but otherwise you can't tell it. It also sounds no different now with 18:1 pistons.

[Barry Nave]

Just to add with ronniejoe.
The -1.94 works with the DSG gear. I would stay with a lower number on chain drive.
May not be right yet the gear drive may be why this vaule works.(DSG going on 90k)
Cold starts are on my truck as RJ and not bad with noise once warmed.

[rjschoolcraft]

I ran -1.94 with the chain for 19,000 miles. I have about 4,000 on it with the gear drive and -1.94 now.

[rjwest]

At -1.8 now, seem to have a hesitation when rolling into the throttle at low rpm,,,

notice IPT drops lower than comes back up with rpm...


Any chance of screwing up engine at low rpm's and under load. I have a TCC lock up sw and run
up to 7-8 psi at 1700-1800 rpm in OD