• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Timing issues Help

Mudbath

Old Smoky
Messages
394
Reaction score
1
Location
Alberta, Canada
History of my vehicle

Always had hard to start when cold, would start run like crap for a few seconds and smoke like a SOB then something would change and instantly run smooth and clear up the smoke (blue smoke) Then would start like a champ after that as long as it had run for a bit.

PO had it into GM many times and it never was properly resolved, I have had it for 4 years now and have done the following ... Heath tune, Heath lift pump, Heath TM, Engine coolant sensor (in Thermostat housing crossover) Heath PMD kit, TDCO offset was @ -1.94 and recently drop it down with Engh's GMTDScan Tech to -1.75

Now I just did the HG on this truck and while doing that I replace the CPS as it looked original and was in rough shape. Did OPS while I was at it too (not relevant to this)

After running it a couple days I am getting even harder starts than before with more smoke, once warmed up much better. It is setting a code 34 DTC and engine light will come on and go out. So I warmed it up and thought I would recheck the timing and when checking DTC there is the code 88 which clears then comes back when rechecked.

I tried to do the Timing Set and Learn but both cause engine to stall. (TDCO shows as 0 and once got it to go to something else which was the undesired -2.02 setting the code 88) The Desire and Actual are sitting at 11.7 (use to be lower but can't remember number, 8.5???) which confused me because I never changed the IP position. While doing the HG job I also replaced the water pump and check the chain by moving the crank and watching the camshaft and IP gears, things were tight there. I am starting to think that PO had TDCO set when the CPS was bad and now that it is new I am getting timing problems OR I have a flaky CPS (Standard)

Got any Ideas for me? Do you think I will have to turn the IP a bit to get that 11.7 down? Which way and what is a good base timing to aim for if this is what has to be done.

Hopefully Buddy the timing Guru is listening! :D
 
I am not sure if that one reading I got was+2.02 or -2.02 and it is at 0 again so I am in the process of checking the actual timing marks on the pump. With the stalling when commanding Buddy thinks to far to passenger. I will get a picture of the marks and post them.
 
Timing and Marks

Here are the timing marks, PO used a punch to add more reference marks. So Now I know he screw with it. Probably to compensate for a bad CPS





GMTDScan Tech.jpgtiming marks.jpg
 
Forget actual and desired.What really counts is what it is set at in time set. You want + 3.5 while in time set. Then do tdco to -1.5 or whatever you want it at. Actual and desired is the ecm commanding the stepper motor and what is really happening. Time set puts the stepper motor all the way retarded. [base timing] Much the same as a old gasser unplugging the vacume advance.
How many miles on your timing chain?
 
Forget actual and desired.What really counts is what it is set at in time set. You want + 3.5 while in time set. Then do tdco to -1.5 or whatever you want it at. Actual and desired is the ecm commanding the stepper motor and what is really happening. Time set puts the stepper motor all the way retarded. [base timing] Much the same as a old gasser unplugging the vacume advance.
How many miles on your timing chain?

I have a Heath tune and Buddy figures 11 to 11.7 might be what Heath sets timing at. Timing chain was tight. We think timing was set by PO with bad CPS and now I have to move to drivers side before I can set timing. Set and learn both stall engine at present.
 
Well the picture shows the IP looks like its placed alright, but the -2.02 tells you it needs to go to the passenger side. If you have a factory chip you might try it with that once, although it shouldnt be the problem.

It does not look far off, so I dont understand why it would cause it to stall out. I have had it way over advanced with no issue.

Has it actually finished a TDCO procedure or died with each try? It doesnt look physically retarded either.

Maybe a PMD is causing stalling or something.
 
Dies every time and when it did give a number before going back to zero, I am not sure if it was -2.02 or +2.02. Would disconnecting battery clear the ECM or does GMTDScan tech clear it enough?
 
Buddy.jpgHere is a better picture of my timing marks, looks more to the driver's side than the picture in your write up.
 

Attachments

  • IMG00013-20110726-2018.jpg
    IMG00013-20110726-2018.jpg
    86.6 KB · Views: 23
AK Diesel Driver, after looking at my timing marks and what it should look like according to Buddy's picture you were right that it needs to go towards passenger side. Now to get the tools to get it done. Thanks
 
It still surprises me that it would stall. Have you set the timing with this chip installed before? Is the idle rpm really low? The TDCO will go to zero when the engine stalls out in a procedure because of some checksum error it corrupts and erases the PCM memory.

Do you know what resistor is in the PMD? I would check it or try swapping PMDs if you have another resistor, because when you run TDCO learn it checks that resistor value again. Although it shouldnt when you run time set, so if it stalls on time set too the resistor might not be an issue. Your calibration says "100 counts", so I am thinking that is like a low resistor number, 5 or below, unless its not reading correctly. A #9 would read 145 counts, and others would be 130 or 125 and yours is 100 right now, which could just be because it was corrupted too, but then Id expect the DTC56 for cal resistor.
 
I have a Heath tune and Buddy figures 11 to 11.7 might be what Heath sets timing at. Timing chain was tight. We think timing was set by PO with bad CPS and now I have to move to drivers side before I can set timing. Set and learn both stall engine at present.

Your timing chain will always appear to be tight if this is how you are measuring it. Your chain is going to stop in a "Bound" posistion. and always appear to have no play by turning the crankshaft and watching the gears. Try turning the crankshaft backwards and watch for the play. The only way to accurately gauge timing chain wear is by measuring the deflection while installed. Which you have to pull the timing cover to measure. How many miles on your chain? They wear out and when they do you will have issues with timing. The alternate marks that the PO inscribed should be a tell in itself that something is amiss if he had to re-scribe them. May have been a flakey CPS initially but now other wear has come into play. If you have over 70 or 80k on a chain replace it, Its not that hard can be done in several hours and is a sub- 100.00 part. If you dont know how many miles are on the chain assume that it is the same as what your odometer is reading. Which I suspect being your truck is a 95 model is 200k plus. It is an easy variable to remove from the equation. And would give us a better picture in regards to what is wrong
 
@ Buddy I have set timing with this chip, I had no problem getting -1.94 or -1.75 before the HG and CPS the pump was not physically moved in the 4 years I have had it. The PMD is only six months old with harness from Heath, don't know the resistor ohms. Engine runs good once warm and timing seems to be from after new CPS. The PO definitely screwed with the IP timing to compensate or try to correct bad CPS.

@fallout About 145km miles and when I checked the chain I rocked the crank back and forth and the cam gears instantly move. The PO changed the oil religiously at 4,000 miles and did regular maintanace and it showed when doing HG (e.g. cylinder wear)


I am going to get another snapshot tonight and plan on moving the IP to the passenger side a bit to bring Actual down to 8.5 and try again.
 
While just idling, operating normally, not in a timing process, you will not be able to control the actual/measured timing by moving the IP. Thats what bk95td was saying. You can only affect the TDCO and base timing seen in "Time Set" process (which will appear as actual timing during the process). The actual timing during the "Time Set" should be around 3.5* while the desired is 0*. When the desired is 11*, thats what the computer is asking for, and only a reflashed chip can change. Now there is the possibility when you have a bad or incorrectly installed CPS or corrupted TDCO that the wrong desired timing will be displayed, the errant sensor signal confuses the PCM. So setting the timing can sometimes cause a change in the desired, but its not normal, and shouldn't really happen. I have not had that issue with mine when the TDCO was not set, but I saw it on an OBD2 truck. And it would be common for an incorrectly installed CPS.

Did your CPS have a solid single piece body and mounting tab, or an attached metal tab for the mount?

I do agree with moving it a little to the passenger side a little, so the timing wedge lines up with the IP flange edge, or just a hair to the drivers side of that point. Although mine has never stalled in about 120 times of moving the IP and running the timing procedure, even when purposely way out of tolerance. So I suspect there is another issue that you may need to hunt down after moving the IP.
 
The CPS was a Standard and was comprised of the sensor with a metal mount bracket already assembled. when installed it was according to this reference picture.

IMG_0865.jpg Notice the two dots. It needs to be installed with those vertically aligned and towards the radiator.
 
Making progress

Scan-110728-0001.jpgMade some progress, was able to get through Learn by increasing idle long enough to get a -0.7 TDCO. Now the code 88 is gone and truck seems to run well. Will be interested to see how it starts cold at this setting. I have included a snapshot of relevant info. I don't know what the actual injection pump timing should be but that looks high. What should it be?


View attachment 28658
 
What is the timing in time set? Desired and actual is all set by the tune in the chip. If base timing is wrong it won't be able to go to full advance or full retard. That's why it has to be close to +3.5 in time set. Setting tdco without having time set right is useless.
 
If I go into Time Set or Learn it will stall out engine. So I can't look until I figure out why. In the snap shot it shows Actual injection pump timing at 33.7*, what should it be? Will turning IP to passenger side bring this down to what it should be, what every that is. If I do this when I get the tools, then maybe I can get into Time set and Learn without it killing the engine.

Also now that I got a -0.7 at least the code 88 is gone and has not come back. I need the truck urgently on Saturday so I am afraid to go into Time set again to test if it works, now that I temporarily got rid of code 88.
 
The actual of 33 degrees is alright, its high because you have high advance at idle. Its tuned hot at idle, much more than stock in 95, which was likely 8.5 degrees at idle, so you are 6 crank degrees more advanced at idle than stock. That should cause any problems, but something is fishy with the electronics. At 656rpm idle and advanced as it is, it should not stall. It could be that the OS is marginal, maybe needs the eye cleaned off. The idle fuel rate is a little high, if it were low that would be concern about the OS not being calibrated. As it is, you would stand to make some more power though if you bumped it so you are showing 8mm3 fuel at idle. Its actually the same fuel volume, but the computer is a little fooled, on the safe side right now. If you were to take it out to clean you could do a slight bump. Otherwise there may be something fishy with the PMD and its resistor, double check all of the grounds, the one on top of the PMD, and the ones on the back of passenger intake for sure. Also could be a PMD extension cable thing potentially. Ruling out PMD and ground issues is easier than cleaning the OS.
 
Here is an old snap shot of mine for ya to compare

TDC offset: -0.18

Snapshot created 2/26/2010 9:09:58 PM
__________________________________________________________________
ENGINE SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Engine run time: 00:46:45
Boost pressure (MAP): 14.01 PSI
Desired EGR: 11.68 PSI
Desired idle: 638 RPM
EGR pressure: 11.53 PSI
EGR duty cycle: 39.1 %
Engine coolant temp: 190.1 F°
Engine speed: 638 RPM
Glow plug relay feedback: 0 Volts
Glow plug voltage: 0.2 Volts
Ignition voltage: 13.6 Volts
Wastegate duty cycle: 72.3 %

__________________________________________________________________
INFORMATION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
PCM Calibration ID: 7135
Current DTCs: 0
Accel. ped. pos. 1: 0.59 Volts
Accel. ped. pos. 2: 4.43 Volts
Accel. ped. pos. 3: 4.08 Volts
Barometric pressure (BARO): 13.4 PSI
Battery voltage: 13.7 Volts
Fuel temperature: 79.8 F°
Intake air temp: 74.1 F°
Throttle position: 0 %
Turbo boost (Calculated): 0.61 PSI
Voltage reference sensor: 1.3 Volts

__________________________________________________________________
INJECTION PUMP SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Actual injection pump timing: 28.78 Deg °
Cam reference missed: 0 Counts
Crank reference missed: 0 Counts
Fuel calibration: 120 Counts
Fuel rate: 7.5 mm³
Fuel rate - Cruise: 0 mm³
Fuel rate - Idle: 7.81 mm³
Fuel rate - Maximum transient: 42.5 mm³
Fuel rate - Throttle requested: 0 mm³
Injection pulse width: 1.66 ms
Injection timing - Measured: 6.9 Deg °
Injection timing - Desired: 6.9 Deg °
TDC offset: -0.18 Deg °

__________________________________________________________________
TRANSMISSION SENSORS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
3-2 PWM solenoid duty cycle: 0 %
Cruise target speed: 0 MPH
Cruise speed error: 0 MPH
Current gear of transmission: 1 Gear
Current torque signal pressure: 25 PSI
Current transmission ratio: 1:4 Ratio
Error between desired and actual shift times for latest 1-2 upshift: 0.3 Sec
Error between desired and actual shift times for latest 2-3 upshift: 0 Sec
Force motor (PCS) - Duty cycle: 42.2 %
Force motor (PCS) - Feedback current: 0.8 Amps
Force motor (PCS) - Reference current: 0.8 Amps
Time of latest 1-2 upshift: 0 Sec
Time of latest 2-3 upshift: 0 Sec
TCC PWM solenoid duty cycle: 0 %
TCC slippage: 13 RPM
Transmission input speed: 626 RPM
Transmission output speed: 0 RPM
Transmission temperature: 139.6 F°
Turbine speed: 626 RPM
Vehicle speed: 0 MPH

__________________________________________________________________
STATUS FLAGS
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Shift lever:
Park/Neutral

Cruise control:
Cruise Off condition

TCC mode word 1:
TCC is being forced off
TCC enable solenoid valid
Low threshold for COPETCC selected
Use hyst. for vehicle speed
TCC is in release mode, slipping
TCC is in locked-adjust mode
TCC is being applied
• Negative slip recently prevents apply

TCC mode word 2:
TCC PWM is on
Perform release
Perform apply
• Min. threshold occurred
TCC Bus. is valid
NDT occurs
Delay is in progress
Min. throttle occured

IOD port A:
Glow plug relay - Closed/Open
• Stepper motor inhibit - Run/Inhibit
Service Throttle Lamp - On/Off
• EGR vent enable - On/Off
• Shift A - On/Off
Shift B - On/Off
TCC enable - On/Off (4L60E only)
• Force Motor enable - On/Off

IOD SOD status register:
Coolant temp. pullup select - On/Off
Trans. temp. pullup select - On/Off
Fuel calibration temp. select - On/Off
Check Engine Lamp - On/Off
PWM1 - Reset/Normal
PWM2 - Reset/Normal
PWM3 - Reset/Normal
PWM4 - Reset/Normal

System status word:
FM shut off due to low battery
Force Motor pulse in progress
• Power is On/Off
COP2 is being serviced
Delco instrumentation PROM
• Powertrain is in motion

Discrete flags:
Brake - On/Off
A/C Compressor - Engaged/Disengaged
Power enrichment - Active/Inactive
Kickdown pattern - Active/Inactive
Four-Wheel Drive Low - Active/Inactive
Cruise low - Active/Inactive
Diagnostic - Requested/Not requested


__________________________________________________________________
 
Back
Top