Timing is Off, Can't Set It

[Big T]

Going to need some help on this. After changing the timing chain, along with new HB, pulley, water pump, my timing is off. Took it to the dealer and they can't set the timing and they are saying it's internal.

So I have to retrieve the truck and tear it apart again to figure out what's wrong. I followed the instructions here to the letter. Lined up gears, etc. Now I'm lost and in territory where I've never been and no idea how to recover.

The neighbors whom my son works for and who's son he's visiting in Kansas to do some hunting this week, have offered to let him use their Expedition for the trip. At least he has a back-up solution, me not doing so good.

 

[Mudbath]

Is the truck running or not?

Is the IP lined up with the original scribe marks?

Did they say the mechanical timing is out or is it the ECM (computer control) of the timing that is out?

There is a nice little program by Engh call GMTD Scan Tech that can be loaded on a PC to do the computer timing end of it for the 94-95 OBD1 6.5.

http://www.enghmotors.com/

P.S. there is also an interface cable needed and sold by Engh

How to set the TDCO from Engh site

What steps do I need to take to set TDCO?


Start GMTDScan Tech.
Connect to your truck.
Go into the dashboard view and verify that the engine coolant temp is at, or above, 180 °F. If not, wait before proceeding.
Go into the DTC view and verify that no trouble codes are present.
Go into the TDC view.
Take note of the current DES/ACT/TDCO values. OEM is +3.5°/+3.5°/-0.5°.
Click the TDC Time Set ON button. DES should now read 0° and ACT should read +3.5° on average.
Click the TDC Time Set OFF button to go back to normal operating mode.
Click the TDC Learn ON button. The TDCO value will now fluctuate for about 20-30 seconds before setting itself. You can end the sequense prematurely by clicking the TDC Learn OFF button. The current TDCO value will then be set in the PCM.
If you are not happy with the TDCO you get you must turn the injection pump. Towards the drivers side is "+" and towards the passenger side is "-". A 2mm move equals 5° so take it very easy and do not attempt to turn the injection pump while the engine is running!
Repeat the TDC Learn procedure until the TDCO you want is attained.
Note:
You need to know what you are doing when attempting this procedure. If your mechanical skills are limited, leave it up to a skilled friend or professional to do it for you. You are on your own if something breaks. Engh Motors cannot be held responsible for damages, injuries or costs of any kind.

 

[Dave Barbieri]

OK, goofy question: Did you get the right timing gear/chain set for your year model? The electronic motors use a different crank sprocket. It has 4 'ears' that swing past a sensor and tell the computer what piston is at TDC. A timing set for a 93 and earlier non-electronic motor won't have those ears, so no crankshaft position signal to the computer.

 

[Matt Bachand]

The dealership knows enough to make sure its up to operating temp, 180 ECT, right?

 

[Dave Barbieri]

The dealership knows enough to make sure its up to operating temp, 180 ECT, right?

Maybe. Maybe not. I just paid $280 to a local dealership to have their ace electronics wizard troubleshoot a Check Engine light on my wife's car. Was told we needed a new ECM. Decided to get a second opinion. Turned out it was a bad camshaft position sensor. Installed that and updated the 'pooter and she runs SWEEEEET! :thumbsup: Oh yeah, the cost to R&R the ECM and reflash it - $1100. And then the electronics wizard would have discovered that there's STILL a problem. Our cost out the door - half that!

Bottom line, never assume the tech working on your vehicle knows all there is to know about it.

 

[Mudbath]

"Bottom line, never assume the tech working on your vehicle knows all there is to know about it."


:iagree:

Especially the 6.5

 

[Big T]

O.K. just picked up the truck and yes it's running. Paperwork says that advised customer unable to set due to timing set up wrong (in engine).

So I have to tear it back apart and figure out what I did wrong. I did not replace the timing gears, just the chain. I bought the chain off RockAuto and it's a 48-link by Cloyes. I lined up the marks when I pulled the chain, the gears never taken completely off. When I slid it back on the upper gear did not align with the key which was a hair to the right on the clock. I had to grab the cam and turn it back to the left a hair and then the gear slid on. I was thinking that was due to play/slop in the old chain, but now not so sure.

As my wife said, the good news is that everything is nice and clean.:mad2:

I'm having a beer and watching football, pondering my fate.:rolleyes5:

 

[Big T]

Is the truck running or not?

Is the IP lined up with the original scribe marks?

Did they say the mechanical timing is out or is it the ECM (computer control) of the timing that is out?

There is a nice little program by Engh call GMTD Scan Tech that can be loaded on a PC to do the computer timing end of it for the 94-95 OBD1 6.5.

http://www.enghmotors.com/

P.S. there is also an interface cable needed and sold by Engh

How to set the TDCO from Engh site

What steps do I need to take to set TDCO?


Start GMTDScan Tech.
Connect to your truck.
Go into the dashboard view and verify that the engine coolant temp is at, or above, 180 °F. If not, wait before proceeding.
Go into the DTC view and verify that no trouble codes are present.
Go into the TDC view.
Take note of the current DES/ACT/TDCO values. OEM is +3.5°/+3.5°/-0.5°.
Click the TDC Time Set ON button. DES should now read 0° and ACT should read +3.5° on average.
Click the TDC Time Set OFF button to go back to normal operating mode.
Click the TDC Learn ON button. The TDCO value will now fluctuate for about 20-30 seconds before setting itself. You can end the sequense prematurely by clicking the TDC Learn OFF button. The current TDCO value will then be set in the PCM.
If you are not happy with the TDCO you get you must turn the injection pump. Towards the drivers side is "+" and towards the passenger side is "-". A 2mm move equals 5° so take it very easy and do not attempt to turn the injection pump while the engine is running!
Repeat the TDC Learn procedure until the TDCO you want is attained.
Note:
You need to know what you are doing when attempting this procedure. If your mechanical skills are limited, leave it up to a skilled friend or professional to do it for you. You are on your own if something breaks. Engh Motors cannot be held responsible for damages, injuries or costs of any kind.

And now that the truck will be down again, I will order the GMTDScan from Engh.

Next question though is where do I get a tool for the IP nuts with the dual crossover t-stat housing in place?

 

[Acesneights1]

The idiots at the GM dealers rarely know how to set timing on the trucks. What you have not said it how do you know your timing even is off ? Are you assuming tha because you changed the chain or is there a symptom ? Did you drive the truck home or tow it ? Is the CEL light on ?You can't set TDCO if there are stored codes. I woud not "tear it apart" until someone with knowledge of a 6.5 checks the timing. did you check the member locator stickie to se if anyone near you have GMTDScan or a Tech 1/2 ? If not you are on the right track ordering it. These things can run basically fine even if timing is off a little. The talk of setting at -1.94 like it's 6.5 gospel confuses people. That ios optimal for performance. There is actually a decent window for TDCO where the truck will still run fine. My point being, until someone with 6.5 knowledge checks the timing I wouldn't take anything apart. The dealerships are thieves.

 

[Acesneights1]

The tools were made by Kent moore. You can scrounge eBay but it's really not nessicary. You can buy a double box 15mm craftsman club and heat it with a torch and bend it in a semi circle and are far as a turning tool that can be improvised as well.. Take 2 3/8 bolts about 1 inch long(IIRC) and stick them in the holes on the IP where the tool would go and then use a small prybar between the bolts to turn the IP. .

 

[Acesneights1]

Here's the tools

 

[Matt Bachand]

The tools were made by Kent moore. You can scrounge eBay but it's really not nessicary. You can buy a double box 15mm craftsman club and heat it with a torch and bend it in a semi circle and are far as a turning tool that can be improvised as well.. Take 2 3/8 bolts about 1 inch long(IIRC) and stick them in the holes on the IP where the tool would go and then use a small prybar between the bolts to turn the IP. I have pics of this posted somewhere but the site won't let me use the pics again. Never quite got that rule.

You just stick the bolts blind into the mounting holes to turn it? Or is there a made spot for the bolts Aces? I'm going to do this over the holiday, but I guess I thought I could do it by hand

 

[Big T]

OK when I first started it, which took several attempts to catch, there was huge billows of white smoke. The engine would studder during acceleration. I ran it in place to operating temp and though the smoke dissipated somewhat the engine still did not run like it had.

Went to start it this morning and again it was very hard to start and tons of white smoke when it finally did catch. Ran it down to the dealership (about 7 miles) and the smoke dissipated on the way. Engine ran smooth, though I did not mash the pedal. On braking to a stop, several times there was a shudder in the engine as if the entire engine slid forward on its mounts. My son (following behind) reported that he saw puffs of black smoke when it did this. RPMs at idle was a hair less than 600, which is lower than normal. Sorta rough on the idle. SES engine light would come on at idle once engine reached operating temp.

I spoke directly with the diesel tech and informed him all that I had done and that I wanted the timing set at -1.94. Now they say they can't do it and it's an internal problem outside the IP adjustment limits.

 

[turbovanman]

I lined up the marks when I pulled the chain, the gears never taken completely off. When I slid it back on the upper gear did not align with the key which was a hair to the right on the clock. I had to grab the cam and turn it back to the left a hair and then the gear slid on. I was thinking that was due to play/slop in the old chain, but now not so sure.
beer and watching football, pondering my fate.:rolleyes5:

I guarantee you the timing gears are bang on from what you describe, what you did is exactly the symptoms of a worn chain.

Next question though is where do I get a tool for the IP nuts with the dual crossover t-stat housing in place?

You don't need special tools, I use a 15mm open and box wrench and a fine tooth ratcheting wrench, but i do move the a/c out of the way when its a 95 and newer, the one held down with 4 vertical bolts.

As for not setting time, exactly what everyone said is right, most don't know how to do it. I had to redo one a dealer did and said they couldn't set it, they were right but it turned out to be a bad PCM, to which they said the IP was bad, morons, :mad2::mad2:

Are you sure you put the IP on correctly or did you not take it off? There are 2 holes for the pin, one elongated and one round one, make sure you used the elongated hole.

 

[Big T]

Turbovanman, in comparison to the timing chain I took off, the new one was as tight as that a$$ in your avatar.:thumbsup:

Like my wife, the IP gear only went on one way and that is with the peg in the elongated hole.):h

There was a previously chisel mark in the timing cover, the IP has a barcode tag on it as it was replaced about 45K miles or 3 years again. I pulled that back and scribed a scratch to match the chisel mark in the timing cover and that is where I lined it up. Really, never removed the IP, nor touch the lines to it. Only pushed it out of the timing cover housing. I had to rotate the pump to line the marks up in the respective gears.

So I guess I need to order the GMTDScan and then do some Uri Geller spoon bending on a box wrench?

 

[turbovanman]

I guess its possible your IP took a crapper, I would just find someone in your area that knows 6.5's and have them retime it for you.

 

[bison]

you could be a tooth out on the gears.
the timing chain sprockets marks are to face each other at 180 degree(straight up and down,then rotate the crank a full turn so the cam timing gear mark is straight up and in line with the crank and cam centers,now postion the IP gear so the mark lines up with the cam gear mark,you will have to turn the IP along to keep the dowel in line with the slotted hole in the IP gear,then bolt the gear down to the IP.

you may have to fabricate a IP nut wrench and a lever to move the pump

here a pic of the lever

 

[Big T]

I guess its possible your IP took a crapper, I would just find someone in your area that knows 6.5's and have them retime it for you.

IP pump was working fine before I started the cooling upgrade with changeout of the timing chain.

 

[Big T]

you could be a tooth out on the gears.
the timing chain sprockets marks are to face each other at 180 degree(straight up and down,then rotate the crank a full turn so the cam timing gear mark is straight up and in line with the crank and cam centers,now postion the IP gear so the mark lines up with the cam gear mark,you will have to turn the IP along to keep the dowel in line with the slotted hole in the IP gear,then bolt the gear down to the IP.

you may have to fabricate a IP nut wrench and a lever to move the pump

here a pic of the lever

Bison, I had to do exactly as you described to get the IP gear to align with the cam gear mark.

 

[Acesneights1]

You just stick the bolts blind into the mounting holes to turn it? Or is there a made spot for the bolts Aces? I'm going to do this over the holiday, but I guess I thought I could do it by hand

Stick them in the blind holes the IP turning tool would go into. They fit nicely . Then use a prybar between them. I acyually have the tools now but when I did my Tahoe I did it with the bolts. I found a set of tools cheap on eBay and bought them later on cause I'm a tool junkie.