SUNOVA......TDCO is F........d

[great white]

Put the pump on the marks. You really have nothing to loose at this point. I'll bet it is out of the range of the stepper motor, Where it's at now.

That's where I'm going right now.

On another note, the design of this f'n engine is beginning to piss me off!

This has to be one of the biggest PITA designs I've ever worked on. It seems like you have to pull everything apart when you want to adjust or replace anything.

I mean really, To even get to the IP nuts I've got the intake top off, AC compressor out, rad shield off (to release teh belt to release the AC compressor), the AC bracket off for access to the driver side IP nut and even then I'm facing bending my high quality 12 point wrench to get on it......It's never ending, soon I'll have the rear bumper off to get to the IP! (well, not quite, you get the idea)

I'd like just 5 minutes with the design engineers of this "monstrosity" to work on.

5 minutes, a sound proof room and a baseball bat......

 

[JiFaire]

Put the pump on the marks. You really have nothing to loose at this point. I'll bet it is out of the range of the stepper motor, Where it's at now.

Yeah - what he said. It's obvious your timing is off now... it isn't gonna hurt your fine settings!

 

[Turbine Doc]

GW put it back on the marks, and maybe even a slight twist hair width past it to driver side, know anybody with an old MT2500 "brick" that will display TDCO and time when in time set, does your current tool have a time set command ?

for the IP mount nuts I snug the bottom 2 to just tight, and lock IP with just the top one.

 

[buddy]

You shouldnt have to take AC compressor off. Just need the correctly bent wrenches.

This is not something new. IPs get put on all the time, and people are told just eye it up it will run fine, no need to run TDCO relearn and time it properly. So it was probably replaced before and wasnt timed correctly, and you initiated the first relearn since.

Have you let it run for a while when it was stuttering? Maybe its in a TDCO relearn loop and every time it gets to temp it tries to do TDCO relearn. I dont have an OBDII but the experts say its supposed to go to 1000rpm idle during it and if you hit the fuel pedal and interrupted the process maybe its not done yet. That or when it attempted to go to full retard the stepper motor came unlatched or something, but it can still push the actuator around in cold advance. And you have to clear the code before it can reset TDCO.

During TDCO relearn it retards the timing as low as it can take it, which if yours wasnt set right before could be After Top Dead Center instead of before TDC like its supposed to be, about 3.5 degrees advance as the base timing.

 

[great white]

GW put it back on the marks, and maybe even a slight twist hair width past it to driver side, know anybody with an old MT2500 "brick" that will display TDCO and time when in time set, does your current tool have a time set command ?

for the IP mount nuts I snug the bottom 2 to just tight, and lock IP with just the top one.

Well, put it back on the old scribe marks (not done by me), put the accesories back together and warmed it up until I saw 77c on the program.

Success!

TDC learn was a non issue.

I'll be ordering either carcode or autoenginuity in the very near future.

There's almost no black smoke on acelleration, but there's now what looks like "blue oil smoke" from the tailpipe like you would see in a gasser burning oil.

Never did that before.

It's also a tiny bit "rattlier" than it was after I swapped in the new injectors, but quieter than it was with the old ones.

I assume once I get things closer to spec (scanner) much of what's left will clear up.

Now, questions:

was the pump retarded or over advanced?

Is turning it to the drivers side advancing or retarding the timing?

Timing is something I can wrap my gasser mind around pretty easily right now.....

:smile5:

 

[buddy]

You were probably way too retarded before ):h

Because like mentioned in previous post TDCO relearn takes you to the most retarded position it can.

moving it towards the drivers side advances the base timing, stock is 3.5 cam degrees and a -1.94 TDCO is about 3.8 cam degrees. So we get more performance by going from 7 to 7.6 crank degrees as base timing. I think its only because of IP case pressures that cause the performance increase and not timing.

 

[great white]

You shouldnt have to take AC compressor off. Just need the correctly bent wrenches.

This is not something new. IPs get put on all the time, and people are told just eye it up it will run fine, no need to run TDCO relearn and time it properly. So it was probably replaced before and wasnt timed correctly, and you initiated the first relearn since.

Have you let it run for a while when it was stuttering? Maybe its in a TDCO relearn loop and every time it gets to temp it tries to do TDCO relearn. I dont have an OBDII but the experts say its supposed to go to 1000rpm idle during it and if you hit the fuel pedal and interrupted the process maybe its not done yet. That or when it attempted to go to full retard the stepper motor came unlatched or something, but it can still push the actuator around in cold advance. And you have to clear the code before it can reset TDCO.

During TDCO relearn it retards the timing as low as it can take it, which if yours wasnt set right before could be After Top Dead Center instead of before TDC like its supposed to be, about 3.5 degrees advance as the base timing.

Compressor was 4 bolts and then I could get my stubby gear wrench on the drivers side nut. Easy peasy and I didn't have to butcher a wrench to do it. :thumbsup:

I let it run in that stuttering, missing, WWII Destroyer smoke screen sized cloud for 15 minutes and then I just couldn't take it any longer. Never touched the pedal. Tried it three times today. Let's just say I'm not popular with the neighbors right now...:rolleyes5:

Cleared all codes with my scanner program before attempting TDC. :dunno:

 

[Turbine Doc]

:thumbsup: Sounds like you are at some TDCO advanced value now , we don't know how much, way I set mine is in time set rotate IP so that actual timing it 3.8 ish avg which is up from desired factory of 3.5, this gives me a TDCO setting when commanded of -1.3 to -1.6 usually.

 

[JiFaire]

Glad re-timing fixed it, BJ... Drivers side is advanced. You want it a bit high to take up some of the timing chain slack the older engines develop, but you really can't get it there without a scanner and a timing tool, so...

Thanks, Matuva for spotting this first! :thumbsup: There's a long-distance diagnosis for ya!

 

[great white]

You were probably way too retarded before ):h

Because like mentioned in previous post TDCO relearn takes you to the most retarded position it can.

moving it towards the drivers side advances the base timing, stock is 3.5 cam degrees and a -1.94 TDCO is about 3.8 cam degrees. So we get more performance by going from 7 to 7.6 crank degrees as base timing. I think its only because of IP case pressures that cause the performance increase and not timing.

So, similar to a gasser, advancing the timing provides a performance boost?

Are there negative aspects to it like a gasser? (ie: hard starting, overheating, etc)

 

[great white]

Thanks, Matuva for spotting this first! :thumbsup: There's a long-distance diagnosis for ya!

Yes, thanks for putting me on the right road...:thumbsup:

 

[great white]

:thumbsup: Sounds like you are at some TDCO advanced value now , we don't know how much, way I set mine is in time set rotate IP so that actual timing it 3.8 ish avg which is up from desired factory of 3.5, this gives me a TDCO setting when commanded of -1.3 to -1.6 usually.

Thanks, I'll keep that in mind for when I get some "proper" gear...

So, what is the timing pointer on the crank for?

Static timing?

If so, how would you even use it with a diesel?



Need to get back into that FSM I guess....

 

[Turbine Doc]

I have had to remove the AC the 1st time I do one and bottom nuts aren't at snug, the bend in the wrench isn't quite rite for those of us with the dual stat setup and newer dricer side ac compressor, I broke my 1st IP wrench trying to heat it & rebend it, the broken stub jammed into a 3/8 deepwell socket in a 12" extension 3/8" drive makes a good wrench now so that I don't have to pull the ac compressor now.

 

[Turbine Doc]

So, similar to a gasser, advancing the timing provides a performance boost?

Are there negative aspects to it like a gasser? (ie: hard starting, overheating, etc)

Too far advanced LOUD clatter in winter and smoke at startup if you don't let it full cycle glows, other than that no issues

 

[Turbine Doc]

Thanks, I'll keep that in mind for when I get some "proper" gear...

So, what is the timing pointer on the crank for?

Static timing?

If so, how would you even use it with a diesel?



Need to get back into that FSM I guess....

static marks for timing the chain/gears initially, after that timing is electronic controlled via PCM, sensors & IP feedback

 

[great white]

This little odessey has made up my mind on one thing though:

This sucker is getting a carputer.

I've been keeping my elm327 module in the dash to read trouble codes, but it's not enough.

A carputer will be able to interface with the OBDII system and do all these tests, on board and anywhere.

And I've got most of the bits and pieces in the shed, ready to go...

 

[great white]

Too far advanced LOUD clatter in winter and smoke at startup if you don't let it full cycle glows, other than that no issues

Ah, I see.

That kind of jives with what it's doing right now and your "slightly advanced" comments....

 

[Turbine Doc]

While not zactly correct way it is easiest for me to splain it and make sense to a old school gasser guy, the chain/gears get mechanically set with marks on gears/pointer, then IP goes in.

Then you set "base time" with a scan tool that shuts off the PCMs desire to control timing so desired reading on tool goes to 0, and actual is supposed to be set to a 3.5 avg if out of spec per GM you shutdown retard or advance to meet the avg, check again and adjust, once you meet that come out of time set and look for the TDCO setting factory is -.25 to -.75 to meet emission std. if out, again rotate to advance/retard for that setting.

For a little more grunt -1.5 to -1.94 is where most of us like ours, TDCO is kind of like a little distributor vac advance adjustment or advance curve weight to the computer for the IP timing curve

PCM is always in charge of timing unless you are in time set mode.

 

[matuva]

Glad re-timing fixed it, BJ... Drivers side is advanced. You want it a bit high to take up some of the timing chain slack the older engines develop, but you really can't get it there without a scanner and a timing tool, so...

Thanks, Matuva for spotting this first! :thumbsup: There's a long-distance diagnosis for ya!

Yes, thanks for putting me on the right road...:thumbsup:

Glad to help That did happen to me 2 weeks ago after we finished replacing an IP.

The truck was running fine, till I did the time set + TDCO relearn : white smoke, rattle,
rough iddle, yada yada.... and suspicious eyes from the owner who was there ):h

In fact, the IP was way too retarded, +2.2, but before the TDCO relearn,
PCM was running with the previous setting at -1.50

After 10 mns and several fight with the wrenches and IP, relearns, TDCO was set at -1.67 and everybody were happy

 

[bison]

Pensacola diesel only 160 some.
I could,ve sold ye a good PMD with that IP,would've come in handy now eh:smile5:
Disconnect batts for a bit,retry KOKO.You need a scanner to see where TDCO is at though

On edit,I'm a little late in the game,i missed a couple pages