So, last week I raced my friend's 1988 f250 NA 7.3L Extra-cab 5speed 3.73:1 vs my truck in my signature.... and he won! I was shocked and disappointed. Sure, his truck is 600lbs lighter and has a 5speed but I have a turbo and better 4.10 gears. He also gets better fuel mileage (18-19mpg) than I do. A friend following us said I made lot more black smoke when I was loosing too.
So after some brain storming, I concluding that my timing was off. I bought the $200 ferret timing tool to ensure I wouldn't be embarrassed by a N/A diesel again.
I got the tool in the mail today and hooked it up according to the instuctions.
I ran the engine at operating temperature and got some strange results.
RPM---Timing
700 15.5btdc
800 15.5
900 14
1000 13
1100 11
1200 11
1300 11
1400 11
1500 11
1600 11
1700 11
1800 11
1900 11
2000 11
.
.
.
3000 11btdc

So, as you can see, my timing advance is stuck.

Does anyone have a timing curve that I can compare to? Its not hard to make one if you have a timing tools and 15 minutes and I would really appreciate having something to base my timing on.
Thanks,
Dave

 

Idk about stuck, but definately too advanced. You want to be 7-8* @2000

 

Where did you get your ferret?? Just wondering

 

Ferret Instruments V765-01 Injector Tester - Fuel System Tools

 

Following this one

 

Watching this. Mine doesn't have a curve. Its 8.5° from idle on up.

 

You guys are lucky, mine bounces around about 10* but does retard about 7* from idle to 1500

 

The more throttle position and less RPM you have, the more retarded your timing is going to be, and vice-versa, the less throttle position and more rpm you have, the more advanced your timing will be... Unless your pump is wore the hell out like HBN's, where in that case, the tolerances can cause the hydraulic advance mechanism to be all over the place. You need to set your base timing to 8-8.5* (@2000rpm), and no more, you don't gain anything from any more timing than that.

Those aren't strange results, totally normal timing curve, just a little advanced. That's all.

 

I set mine around 7.5 and it cleared my black smoke up. She's not as lazy on the bottom end either.

 

So, this is what I found... I pulled the pump out and began taking it the timing advance mechanism apart. It took me a long time to understand what pressures were used to move the timing advance plunger and what moved it back to the retarded position. I realized that housing pressure moved it to the retarded position and found out that the check-ball in my housing pressure regulator was missing. So basically, my engine was running like the Cold Timing Advance was on the whole time. After a 1 hour trip to my local international dealer, they supplied my with a new Housing Pressure Regulator for $23. I reinstalled the pump and fired it back up. The results weren't how I expected them. Timing didnt really change much and the idle timing was still higher than my 2000rpm timing. But atleast the Cold Timing Advance system worked now. I removed the pump again and looked for more answers. One thing I noticed was that my timing plunger was backed-out almost completely. A quick call to my friend confirmed that his db2 wasnt in this position, it was cranked 2/3s of the way in. Using an allen wrench, I turned mine in to approximately 2/3rds and re-installed the pump. During this run up, I noticed that Idle timing was about 1 degree below 2000rpm timing. So I was heading in the right direction. Using a cut down allen wrench, i was able to crank in my plunger setscrew another turn and re-tested it. After setting my 2000rpm timing to 8*, my idle timing was at 4* which I felt was correct based on some military tech manuals about diesel timing. So, now my timing table looks like this;
RPM----- Timing
700rpm 4DBTDC
800 4
900 4
1000 5
1100 5
1400 6
1500 6
1800 8
1900 8
2800 8

With these changes. Idle noise is way down. I use to need ear muffs when checking my trans fluid. Its much quieter now. Fuel mileage has gone up to 15mpg unloaded andtThe exhaust smoke problem is almost non existent. I may crank my fuel screw up one flat to see what happens.

 

Youve gone about this backwards.... its SUPPOSED to have more advanced timing under no / light load, this way it burns cleaner and gets better mileage.

In a perfect world, it would be like thus in my mind. Idle 15* 1/4 throttle 12* 1/2 10 3/4 - WOT 7*

That is however impressive you were able to adjust the timing curve that much. I will say that curve would definately favor a turbo setup, but i imagine is going to be tough to fire up in the morning.

 

Mine did this all of a sudden. It reads 14 at 2000 rpms. If I get it close to 7-8, it's really retarded to the drivers side. I set it by the sharpie mark trick, which is slightly advanced past the marks on the housing and ip, and the truck was a smokey pig. I mean powerstroke with tuner smokey! The egts jumped up way too fast. I have a ferret and tried setting it, but something's wrong with my ip.

 

KLA, check the battery in your ferret before you do anything else, when it gets weak, the meter will do some really screwy things.

 

Thanks Mac, I will. But even if I just advance the timing just a little, it runs like crap. It ran good after I got all my fuel problems fixed, then one day, the thing started running like crap. I have to feather the clutch and play with the throttle just to take off. Even in 1st gear. I've always been able to just let out on the clutch and go, even when it was loaded. I'm afraid that my air intrusion problems have done damage to my ip.

 

Sorry for the but I had a very similar problem a while back, and even wrote a post about it, which I've yet to update...
Anyway, it sorta randomly started running very poorly until I made 2k rpms, then ran ok. Couldn't take off hardly at all.
So I adjusted the timing, and I got WAY worse. Maybe my meter has the weak battery, who knows. The timing was supposed to be perfect as it was.
The thing that worked for me was this:
I ran out of fuel due to how crappy my fuel mileage was with the IP running like that, and only had ATF in the truck. So I put in 2 quarts of ATF to get her home(only a 1/2 mile away) and let the truck sit overnight.
Next fuel-up she ran really well, and since then I've backed off the timing and she no longer has the ****-poor low-rpm response. I'm messing with a few things right now to tweak it but shes running the best I've had on this crappy pensacola diesel rebuild so far.

As for the OP, I'd agree with Hairy on the timing. Keep in mind that each pump is calibrated independently and comparing one pump to another isn't always going to tell you where a certain set-screw is supposed to be. I read somewhere recently - "They aren't like carburetors. You can't just bottom out the screw and turn back 2.5 turns."

As a comparison, I just checked mine and it's right about centered on the threads.
However I like that you're posting about this and taking pictures and measurements and keeping us in the loop on the results. It's good info and cool to see the way the timing responds.