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Need injection pump expert for timing problem

S

stickweld

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Location
Calgary
I just had a rebuilt longblock installed in my truck after putting a hole in #8 piston with 283,000 Km.

Can't get injection pump to give any advance. I may not have it timed correctly, or so far out of TDCO that it is confused. I have an autoenginuity scanner with the enhanced GM protocol.

Put new long block in the truck, only other change was installed new bosch injectors, can not get the truck to run well enough to drive it.

When I run the scanner the PCM keeps generating P0216 (Injection timing control circuit) and P1214 (Injection pump timing offset). When I installed the pump, I had to rotate it unusually far towards the drivers side to get it to idle smoothly.

The problem is that it will not provide any advance. I physically set the pump to a position where the actual injection timing is at about 12 degrees at idle. The desired timing at idle shows about 9.6 degrees. When you rev up the engine, the desired timing goes up as it requests additional advance from the injection pump, but the actual timing does not move up. When I use the time set command, the desired pump timing drops to zero, but the actual timing remains the same.

I thought maybe the injection advance stepper motor could be the problem, so I swapped it out with another one, but it made no difference. I ran the engine without the stepper motor in place, and the pumps advance could be adjusted in about a 24 degree swing by alternatly pushing down and releasing the spring that the stepper motor should be attached to, so it appears the pump is able to advance and retard correctly. With the stepper motor still disconnected but plugged in to the harness it seems to constantly try to extend the plunger (fully retarded pump position). Even if I physically move the injection pump to a position only 5 degrees advanced the stepper still tries to extend the plunger, when it actually should be pulling in to get more advance, not less.

If I preset the stepper motor on the injection pump with the harness off to a position midway in its stroke, as soon as I plug in the harness to the stepper motor it extends fully to fully retard timing again.

I have ohmed out the wires from the stepper and they are fine right to the PCM. Tried 2 steppers and they both do the same thing.

TDCO stays at -2.46 degrees after TDCO learn command with the AE scanner no matter what I do or where I mount the pump.


I am really strugling with this, the wife is cranky at me and holidays are a couple of weeks with no way to pull the trailer. Need help!!



Stickweld
 
Do you have the engine up to operating temp (180*) and all DTCs cleared when you try to set TDCO?
 
Yes, temp is high and DTC's are cleared, but when I restart the DTC come back in 4 or 5 seconds. With the autoenginuity scanner if you initiate TDCO learn, the TDC offset value stays at zero until coolant temp comes up to 171 degrees then brings up the -2.46 value which I believe is the highest it will show.

Tried unplugging the optical sensor and the truck starts easy and idles fine with the stepper motor actually pulling in some timing advance. Can't tell how much as no measurement is available with the optical sensor unplugged, but you can see the stepper motor has retracted. Once you plug the optical sensor back in and restart the steeper moves to fully retard the timing.
 
I suspect you are already too far advanced or retarded, set IP so that shutdown solenoid is pointing up about 12 oclock, this will get you in window, what is your timing avg in time set command, desired goes to 0 and actual is 3.5 degrees, also check history section any stored codes will not allow TDC offset learn to be activated, how are you tring to "learn it" KO/KO or with a T2
 
I think Turbine Doc is on the right track. Ran into this problem on a friends 97.

Could not set TDC offset and would not, advance when running. Spoke to a friend told me to get the truck to operating temp shut it off set pump on marks. do a key on hold accel pedal to the floor for 60 seconds plus 10. Restart truck and see where actual time was. shut truck off again and do same procedure, then try to set TDC offset again.

Three times later we finally got everything back to a zero position and were able to set the TDC offset correctly.
 
Thanks so much for the response. Will try again exactly as you have suggested, but since it is just after midnight here, will not be able to do it till tommorow. Below is what I have already done.

Have tried to set the FSO to a vertical position. I have two timing marks on the cover of this rebuild, one is a nice straight deep factory looking mark more towards the drivers side and the other is much lighter about 4 mm to the pass side. This lines the pump up near the much lighter mark. At that position, actual timing is about 8.5 degrees, desired reads about 8.9. If you try to rev it up, desired climbs, but actual stays fixed. When I do a time set command, desired drops to zero, actual remains the same fluctuating around 8.5. I would think that means I need to retard it more, but I have tried backing up timing progressivly farther toward 3.5 but the lowest I could go and get the engine to restart was about 7.0 degrees unless I disconect the optical sensor to give me more advance.

Here is how I have tried to do TDCO so far:
Had temp about 190 degrees, with engine running, I cleared current and pending DTC's, If I rescan at that point it comes up with P0216 and P1214 again. So the way I tried this was with engine over 185 degrees, the actual timing at about 7.0 - 7.5 degrees (engine is rough at this point with lots of white smoke). Turn engine off, turn key to run, but not started, clear all codes then turn off key. Turn on key, pedal to the floor for 50 seconds, release pedal, turn off key, wait 40 seconds, turn key on, wait for "WTS" to turn off and then start it. TDCO still stays at -2.46 (I think that is the max) I have also done the TDC learn through the autoenginuity scanner instead of the KOKO procedure with the same results. I am guessing it is not working because I still have too much advance on the pump.

Should I retard the pump to a position I think is about 3.5 before trying the KOKO procedure? I don't think it will restart unless I pull the optical sensor first, start the motor, reconnect the optical sensor, clear codes with key on, then do the KOKO procedure (that should get me enough advance to start).

I will try and get some screen shots posted from the AE scanner when I resume working on it tommorow.

Wife sure is pissed at me for putting all my time into working on this truck and spending so much cash, I might have to sneak home from work and do my testing before she gets home so she doesn't get any more PO'ed at me.

Mike
 
I understand about the wife thing. Now back to work. Reset the pump to the scribe mark that is most prevalent. If that is the factory mark, this is the basic zero time mark for the engine. The pump should have a mark on it, this is the mark for the basic zero time mark on the pump.

This may not be the proper time for your engine but at least we know what is zero or close to it.

Now warm the engine up do the accelerator pedal to the floor for at least a minute and a half the pedal must be in the 4.45 volt reference area so the pcm see WOT wide open throttle. OK good now this should re zero the stepper motor and the pump.

Start motor warm up clear DTCS and try to set TDC learn then try to set TDC offset in that exact order. If you still get a -2.46 move the pump back to passenger side slightly then re do the procedure. this should get you back to a tdc number that is not -2.46 or outside your window.

-2.46 means the TDC offset is to far advanced not your actual time. Two different things that are inter related on the pump.

It takes patience, I was the same until I realized I was jumping all over and actually caused my problem by moving the pump in large increments and not re-zeroing the pump when I moved it.
 
1 mm of movement = 2 degrees of timing so it don't take much, before messing wuth TDC which is a function of movement, lets get back to basic timing, run engine long enough to get 175F or better coolant temp, booksays 170 but if it cools while fiddling with moving IP it won't go into learn mode when you are ready to try to adjust TDC, also if engine is too cold; timing can be be overcompensated by cold advance.

As far as IP goes, loosen 2 lower nuts to just snug, and lock down with top IP nut after you make adjustments,

Going to square 1, after engine is warm, go into time set on your bi-directional tool, what you should see is desired time at 0, and actual at 3.5 avg, if below 3.5 avg move IP toward driver side advancing the timing, of above 3.5 avg which is where I believe yours is, move IP toward the pass side.

Once you have IP timing set for 3.5 avg in time set with a bi-directional scan tool, Tech-2, MT2500, Auto Engenuity etc. then we can start going after the TDC offset learn function to fine tune the advance.

BTW what bi-d tool are you using?
 
Some positive results........After about an hour and a half I managed to get an offset of -2.20 and the pumps actual and desired timming are tracking together again. The IP is now advancing like it should. It was very hard to keep running when using the time set command to get it to 3.5 degrees. It would usually stall. Same thing with the TDCO setting. Is this normal for it to run so bad at 3.5 degrees advance?

It sure is running rough at that setting and blowing a lot of white diesel smoke. Took it for a short drive and it is slightly better, but still pours out lots of white/grey smoke and runs rough up to about 2000 rpm. Seems like it needs more advance at idle, but the scanner says it is at 9-10 degrees which I think is normal for an idle. I am really surprised how far out it is from any of the original pump marks. Will be working on it tommorow again to see if I can get that TDCO to -1.5., but I don't think it will improve the rough smokey running.

Mike

Scanner is an autoenginuity ver 6.0 software. I disabled the injectors one at a time using the scanner and you can feel the roughness increase for all injectors, so no dead cylinders as far as I can tell.
 
Okay, got TDCO offset to -1.58. Truck runs terrible, barely idles, white smoke continiously comes out of the tailpipe at idle. Very rough as you try and get it to rev up. Literally clouds of white smoke until you hit about 2900 rpm, and is really hard to start, not good at all. Does not throw any codes when starting or running, but does not run good enough to even take it out of the driveway.

I unplugged the optical sensor to see what that did and it started right up, idled smooth, no smoke. When you rev it up, it is still a bit rough but better than with it plugged in. Still some white smoke you try to rev it up, but way less.

What are the symptoms of either the timing gears or injection gear being out of time? or a sheared key? Since I did not put in this motor (truck won't fit in my garage) I can't say I know for sure that the injector gear was installed correctly. The motor came from a small reputable rebuilder that does these regularly so I hope at least the cam/crank gears would be correct. The place that installed it would have only had to install the injection pump gear taken from the old motor.




Mike
 
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I don't know the AE tool, to know if there are some display issues, on my MT2500 -5.4 displayed is -1.5 on a T2

how does it do in time set mode 0 desired & 3.5 actual avg, still trying to die on you ???
 
Yes, still tries to die in time set, but if you can keep it running it is at 3.5 actual when time set is commanded (varies a bit but 3.5 on average). TDCO offset is also problematic. As soon as you command TDCO learn the truck usually dies, so you have to restart it and try it mutiple times until it will stay running long enough to complete.
 
Since you didn't do the work yourself you'll need to verify it, possibly you can go to where it was built and see if they can make it run, because if you go into it by yourself, they may claim you messed up the timing.
 
Turbine Doc said:
Since you didn't do the work yourself you'll need to verify it, possibly you can go to where it was built and see if they can make it run, because if you go into it by yourself, they may claim you messed up the timing.
Click to expand...

Why can't we leave TDC offset at the current setting. Now this is not conventional but I have done this on my own vehicle.

TDC offset is set at -1.5 leave it alone. Do not set TDC learn or TDC offset after this procedure. THE QUOTE from GM, Moving IP pump position without resetting TDC learn will not affect engine timing.

BS: So leave the TDC alone rotate the pump towards the driver side until the engine will run at idle smoothly. Desired time and actual will be out of spec. If they are not to far out the vehicle should at least run, Take the truck back to the engine manufacturer if this procedure works. The timing gear may be one or two teeth off.
 
It may work that way Slim, sort of what I had to do in CT with Dave's truck, my scanner would not display the value for the offset, so I rotated the IP until we got some reaction, it coded PO1216 >.-2.02, we kept rotating & initating learn via ko/ko & APP to floor until it no longer set a code and left it at that.

Odd thing Dave's truck was only one I've put scanner on and not been able to see TDCO change, his also was a 96, I wonder if in transition to OBD-II 1st year 96 there isn't some communication issue with non GM scanners.
 
Today I started by marking my -1.58 TDCO IP position with a punch. When I moved the truck to a flatter area on the driveway the FSO does look almost perfectly vertical. This is an interesting site showing pictures of how far the marks can be out. I saw no advertising so I think it is okay to post the link.http://www.v8dieseltech.net/pump/62timing_e.htm Mine line up perfectly according to the pictures.
I then slowly moved it over a 1/16 inch at a time towards the drivers side without doing anything else. By the time it was running and sounding right at idle it was about 1/4" from the marked position. Puts the FSO leaning way over to the drivers side, almost to the limit of travel. No smoke at all at idle, runs really smooth, about the right amount of hammer, but no advance anymore, and codes comming up. Actual timing was 20.1 degrees, desired was 9.0. I even took it for a drive today, runs pretty good at low RPM, blows a bit of grey/white if your into the throttle, but it had no problem getting up to highway speed with minimal smoke if you accelerate moderately. Not right because it has no advance, but by far the best it has run.

If memory serves me correctly, I think that 1/4" would be the spacing of one gear tooth on the injection pump gear? What do you guys think?
 
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