Screwed Up My Timing, Can't Get It Back

[ANXIOUS-SUBMAN]

Well I guess I just couldn't leave well enough alone. I have Autoenginuity and made the tools to turn my pump. I wanted to get closer to an offset of -1.94. It had only been -0.44. So on Saturday I gave it a try. I moved the pump just a smidge to the drivers side and did a relearn and I think it went right to 2.46 (or was it 2.64, can't remember) At first I didn't notice that this was a positive number and not a negative so I thought I just moved the pump too far. So I moved the pump back to it's original spot and tried to get things back to normal.

At one point I had my high idle switch on to make sure the engine was at full temp. During this time I brain farted and either attempted a time set or a relearn and this is when things got crazy. Truck ran really rough with lots of white smoke. I can't remember if I had the pump back to it's original mark at this point or not but with it set back there a time set only shows about 1 degree.

To get it to run smoothly again I have the pump hard over on the drivers side (which is less than 1/8" from the orginal mark. Time set floats anywhere from just over 3.0 to 3.7. Offset is currenly +1.5. It starts normally and seems to run just fine. However, I think EGTs come up faster and higher unless I'm just being paranoid.

At first I thought that the stepper motor was stuck. Today it was just cool enough in the garage that when I started it, it high idled slighty and then stepped back down as it warmed up so I think the stepper motor is ok.

Someone on another forum had something very similar happen and it turned out to be his PMD. I have a new one on order.

Does anyone here have any ideas as to what may have happened. Especially when I did a base time set (I think) at high ideal?

Thanks,

(I forgot to mention that I was getting pump timing out of spec codes until I put the pump hard over to the drivers side. Currently I have no codes. I did notice that in sensor outputs in AE that my #1 throttle sensor is showing .6 volts and shows in green but sensors 2 & 3 are showing over 4 volts but show up in yellow. However, I have no check throttle light on in the dash.

[rameye]

quick question....

did you do a pump change or move the pump without a relearn and fired it up???

read the numbers and were happy???

betcha...

[ANXIOUS-SUBMAN]

I'm not understanding your question at all. I moved the pump no more than a mm to the drivers side (offset had previously been -0.44) and then fired it up (and brought up to temp) and then did a relearn. This is when offset went to +2.46. Moving back to original mark had base timing at only abour 1 degree. This required moving the pump hard over to drivers side to get base timing back to near 3.5 but the best offset relearn could do was +1.5

[rameye]

First things first...

You have to get the base timing right..you have to get it up to temp and do a time set operation ...DES INJ TIME should be 0.0 ...Act INJ TIME should be 3.5 (average) you may have numbers in the 8.5 range at this point ...this is typical....after the reset they will change.

Again.... you must reset the timing, read the actual timing, adjust the pump (1mm of rotation is 2 degrees of timing) restart....reset the timing ...Act Inj Time until the average is 3.5...it will flucuate (sp) rinse-lather -repeat until its right..

Do not do the TDC offset learn yet!!! Not until the base timing is in spec.....your motor will stall....etc.

Note: When you reset the timing the motor will run different...its OK

[ANXIOUS-SUBMAN]

Thank you for your help, Rameye, but I don't think you understand what happened here. The first attempt at a very small move and relearn went bad. (went to +2.46 I believe, from the original offset of -0.44...I thought that maybe the stepper motor had stuck) So, I moved the pump back to exactly where it was originally but time set only showed about 1 degree then and offset relearn did not respond. (and it ran like crap and set "out of spec" codes, the codes are likely why the relearn did not respond although I thought I had them cleared at one point)

Now, to get it to run right the pump is hard over to driver's side to get time set to something over +3 with no codes and offset relearn only responded to +1.50. (des and act are around 11)

The question remains: Why does base timing not come back to something even close to reasonable when pump is returned to original mark?

Is the stepper motor a problem, though I believe it functions as act timing will follow des when RPM is increased. I can also hear the idle step down as the engine warms up after a cool start.

[rameye]

Ok what were your numbers when you started??

Actual?? Desired...I read the offset was -.44

Just trying to get some history....has this pump been changed??? and if so did you ever do the TDC reset and offset procedure...

I ask this because I just did a pump swap...fired right up...numbers were in spec...however the pump didnt know I moved it around until I did the TDC learn,,,,,,,then it changed into a whole new kettle of fish...ran quite different and I couldnt get my -1.50 offset that I had before...best I could do was -.25 which is still in spec. My ACT is a little on the low side...I know it has to be advanced a bit...then I can pick up some more advance.

One other trick...get the base timing close to +3.5 and when you do the offset learn procedure rev the engine a bit to get better numbers to show up.

Is there anyway the pump is off a tooth on the timing marks???

It sounds like something is a little off here...I know you figured that already !

PS to be clear you are doing a TDC reset and not the offset learn,,,,,,2 different procedures

[ANXIOUS-SUBMAN]

By "TDC reset" are you talking about checking the base time setting which commands desired to "0" to see what the actual is without effect from the computer (and stepper motor)? Or are you talking about clearing the existing offset from the previous learn before relearning a new offset? Can that be done?

Yes, I always do a new time set to see what the base time is before doing a relearn. This is how I know the base time was only "1" degree when I returned the pump to original position. However, is it possible that if the stepper motor stuck, even briefly during the first relearn (which is possibly the reason offset went to +2.46), that this held the base time out of spec when moving back to original mark, therefore setting code and preventing a new relearn???

I had the truck to the dealer yesterday. (one that I visit about every other week as I am the fleet manager where I work and they work on all our Chevys) The tech there found a little more movement left in the pump to the driver's side and got the offset closer to "0" with time set something over 3. He thinks everything was in spec and the truck still runs without setting any codes. He said it was the best running 6.5 he's ever driven. But I am obviously still concerned....

[JohnC]

I think you are making more of this than necessary. Run TDC offset learn. If the engine stalls in the process, advance the pump. Otherwise, advance or retard the pump as necessary to get it into the desired window, IMHO around -1.50. No need to mess with time set as it will cone in automatically when the offset is correct.

[Warren96]

I had trouble making OFFSET adjustments WHEN A CODE WAS STORED. First clear any codes then make any OFFSET adjusts.

[rameye]

Subman..

I guess your saying you cant get anymore advance out of the pump??? You cant physically move it any more to the drivers side???

It sounds like you need some more advance...

If this is the case

I would do as suggested..run to temp.....clear all codes...then do the TDC Offset Learn..as the learn is running...raise the rpm up and down to get offset numbers you are looking for..

Maybe you have a stepper motor problem...I would think it would set a code however..nor run all that well..I'm pretty sure the stepper motor is always in play making adjustments.

Maybe you have some chain slop which requires you to move the pump more than usual.

All that aside...if it runs and starts well...has reasonable economy and power...and is not posting codes...I would live with it until the time comes to deal with it (after trying the idle variation trick)

[Splitrimz]

Maybe I will oversimplify this but I had same problem. Was truck running OK before you turned pump? Did you open the fittings on the lines? If not, loosen all pump bolts enough to allow the torque in the lines to return the pump to it's original position. Bolt it down and try to start it. Splitrimz