Diesel Place banner

1 - 13 of 13 Posts

·
Registered
Joined
·
308 Posts
Discussion Starter #1
1996 / OBD2 truck,,,

Can someone explain the tech 2 procedure for seting TDCO and ip timing.


Also can you explain how the TDCO clear with the key on/throttle works.
I know how to clear the TDCO
(I have the manuels), but do not know what changing TDCO has on the timing, ( the 3.5 ) number.

Read many lenghtly posts, but to technical, just need the basics, as
I am getting a -2.5 tdco,

Runs good, no " excessive diesel ping,,,," want to understand the basics before I mess with the pump position....:confused:

If I set the TDCO will the IP timing set itself afterwards..?
 

·
Registered
Joined
·
2,991 Posts
Wow, where to start on this one...

Have you tried the TDCO Relearn already and your 'new' TDC Offset is -2.5? Are you sure that you got a succesful relearn? Was there a different value there before you did the procedure? Did you hear/feel the engine get quiet or stumble a few seconds when you did the relearn?

-2.5 for TDC Offset means you injection pump is too far advanced, to retard it you have to loosen the 3 mounting nuts, rotate the top of the pump to the pass side about 1-2mm referencing the timing cover and then relearn TDC Offset again.
 

·
Registered
Joined
·
308 Posts
Discussion Starter #3
Did relearn ( key clear method ) value cleared to 0.0,

Start eng, at 170 degrees -2.5 was set. engine did not stumble...

What I am concerned about is the Advance timing that is set into the PCM, I do not know how or if this is reprogrammed into the PCM when the TDCO is set...

I have a scan program for the laptop that has " TDCO SET & IP TIMING SET" functions
I am not sure of the reliability of the scan program and am trying to understand
the TECH 2 functions to compare to it.

I am resisting going to a dealer or diesel shop, as my experience in Jacksonville FL , with mechanics " has been less than satisfactory. ( have had to go back and fix things they screwed up..)

I did have the IP timed by a shop with a tech 2 but the TDCO was not changed , only timimg, do not understand this, and tech was not able to explain.

Looked at moving pump, unable to loosen,,,driver side nut ,

Also unable to figure out how to turn pump, guess I need special tools

Need to go to Maine in a week, with Truck camper, concerned about driving truck with
timing to far advanced ( as I understand, -TDCO is advancing timing )

Thanks for reply...
 

·
Registered
Joined
·
8,014 Posts
Try looking in FAQ see if that procedure helps, it's pretty much verbatim from my 98 manual, which does not have procedure for using T2 to set it, -2.5 is too much advance. with a T2 tool you may still have to move the IP toward pass side to retard, make sure you are already at 170F when trying to reset the value. Gotta run to do some Katrina repairs I'll check back later to see if you have any more ???? after readding FAQ how to.
 

·
Registered
Joined
·
308 Posts
Discussion Starter #5
Did the 'Clear 'procedure as in Helms for the 1996, TDCO was reset to 0.0.

Started eng and did TDCO learn, Learned a -2.5

Loosened 3 bolts on pump, not an easy job,

Could not move pump, I guess I need a tool of some sorts.
I see 2 holes on side of pump in flange, is there a " spanner" that fits in there.

Tryed a wooden drift and a 2lb hammer on the 'ear' of flange, some pretty good wacks, no movement, ? gasket stuck to pump ? Anyway I stopped at this point
for more advise, requested,

Before Diesel forums, I probably would have broken something by now...

What bothers me is why timing is so far off, Wondering if my Carcode scanner
is reading data correctly, Maybe I should find a tech 2 to compare the readings...
as truck seemed to be runnunig good...before and after I screwed with it...

Will the PCM compensate for incorrect mech timing by setting the pump timing.???
 

·
Registered
Joined
·
2,991 Posts
There is a special tool available from OTC, dealership may sell it to move the pump. But you can use a pry bar between the high pressure outlets at the back of the pump.
Don't push anywhere else on the pump, not the aluminum housing and DEFINITELY not the ESO solenoid, you can easily damage something.
 

·
Registered
Joined
·
308 Posts
Discussion Starter #7
Thanks, Made a spanner tool,

Removed lots of junk on top, Got pump adjusted to - 1.9

Do not understand the 3.5 pump timing yet( as referenced in forum ).

I am using Carcode/laptop as scanner.

IPTD ( inj pump timing desired ) 10.0 at idle, IPT( Inj pump signal ) 10.0 .
Do not understand the what the meaning of these parameters are...

Well at least I can adjust pump, making progress, Thanks for all help..
 

·
Registered
Joined
·
1,254 Posts
IIRC, the 3.5 degrees of timing is a reference to the value that will be seen on a scan tool (Tech 2 for me) when you perform the Time set command. When this is done, the timing stepper motor will back to fully retarded position and the 3.5 degrees of actual timing will be shown. This assume all factory settings (in ECM, pump position, and timing components within reasonable wear limits)...

BTW - Could you post a picture and dimensions of the spanner tool that you made? I tried to buy one on ebay, but missed out and would like to make my own...

Thanks!
 

·
Registered
Joined
·
7,135 Posts
Not to hijack the thread, but is there a company making a program to use your computer on a 95. I'm one year off to use the OBD2 carcode and was curious if there was another company out making something for the OBD1 guys. The only scanner that seeems to do much of anything on the OBD1 6.5 is the tech2, and borrowing one is easier said than done.
 

·
Registered
Joined
·
308 Posts
Discussion Starter #12
Goldsburg: No camera, Just to cheap , will see if I can get a picture when the sisinlaw comes by.

I had a an old bracket from a lawn mower, close to the shape needed and it had a square hole for a breaker bar,. used 3/8 bolts for making spanner to fit holes on pump flange.

If you have a piece of bar stock ( Approx) 18 x 3/4 x 1/3 you can fab one with
a 3/8 tap and a torch to bend it. ( may not need to bend it if you remove enough stuff)

The holes in the pump flange are 3/8 , and are 2.168 inches center to center.
Drill and tap holes for 3/8 bolts, use bolts with an unthreaded shoulder.
, screw in tight and cut off heads of bolts so about .400-.500 is sticking out
( this goes into flange holes ) also cut off excess threaded part, flush.

you will have to grind a 'crecent' shape' into bar stock between bolts, so tool clears
pump body, if bolts not quite lined up, you may have to file oval shape to get into holes, also heat and bend bar stock to lever is vertical when installed.

I had to remove the return line hose on top of pump to get my breaker bar in,
also removed fuel shut off solenoid for clearence.
And the intake plenum, and moved the AC unit forward,
pluss some plugs.
Used a long 15 mm wrench ( expensive kind ) for driver side nut,
'S' wrench and 'moon' wrench' for ouher 2 nuts.

once I decided to do it and remove things it turned out to be a 1/2 hour job.

Hope this helps, If I find some bar stock, i'll try to make up another and send if you still want it, or lend you mine..
 

·
Registered
Joined
·
1,254 Posts
Goldsburg: No camera, Just to cheap , will see if I can get a picture when the sisinlaw comes by.

I had a an old bracket from a lawn mower, close to the shape needed and it had a square hole for a breaker bar,. used 3/8 bolts for making spanner to fit holes on pump flange.

If you have a piece of bar stock ( Approx) 18 x 3/4 x 1/3 you can fab one with
a 3/8 tap and a torch to bend it. ( may not need to bend it if you remove enough stuff)

The holes in the pump flange are 3/8 , and are 2.168 inches center to center.
Drill and tap holes for 3/8 bolts, use bolts with an unthreaded shoulder.
, screw in tight and cut off heads of bolts so about .400-.500 is sticking out
( this goes into flange holes ) also cut off excess threaded part, flush.

you will have to grind a 'crecent' shape' into bar stock between bolts, so tool clears
pump body, if bolts not quite lined up, you may have to file oval shape to get into holes, also heat and bend bar stock to lever is vertical when installed.

I had to remove the return line hose on top of pump to get my breaker bar in,
also removed fuel shut off solenoid for clearence.
And the intake plenum, and moved the AC unit forward,
pluss some plugs.
Used a long 15 mm wrench ( expensive kind ) for driver side nut,
'S' wrench and 'moon' wrench' for ouher 2 nuts.

once I decided to do it and remove things it turned out to be a 1/2 hour job.

Hope this helps, If I find some bar stock, i'll try to make up another and send if you still want it, or lend you mine..
qwestqaz -

Thanks for the offer of a wrench, but you don't need to go to that trouble as you have given me the info that I need to make one! I have access to all types of machining and fabricating equipment, so it would be NO problem (now). The info that you gave me was the piece that I was missing, as getting "down in there" to measure the hole spacing and diameter was the biggest issue!

Thanks again...:exactly:

Gary
 
1 - 13 of 13 Posts
Top