Questioning my timing

[Thewespaul]

The OP's situation is precisely why I'm not a huge advocate of the mantra of TIMING TIMING TIMING.

From a previous post:

I've seen this discussion several times on this forum, and I respectfully disagree about the statement that the timing gun is the best way to properly time an IDI. That said, I not supporting the inverse: timing by ear. Instead, I'd argue that the timing gun is only a minor tool in the process of what I call "timing by performance."

I've owned a timing gun and ferret meter for years now. All a timing gun is good for it telling you a number. That number may have very little impact on whether your IDI is properly optimized for timing. So many factors play into the variability of how that particular IDI is "timed," that the arbitrary number is cool to know, but it's not likely the best performance for your engine.

Several factors can alter the "timing" of an IDI: how an IP was rebuilt, the inlet fuel pressure, injector pop pressure and rebuilding, cam and crank variations, different turbo variations, fuel screw rotation, injector line radii, etc. Slapping a ferret meter on and timing it just tells you that you have it to a specific BTDC degree, but depending on your setup, that might not be optimal. When you rotate your IP, you are altering that number, and just because it reads the stock (or turbo) timing spec, doesn't mean that it's done. Sometimes a neighboring timing degree might get the turbo to spool up better. A lot of factors come into play on these imprecise and mechanical diesel engines.

For the most part, getting it close to stock spec would be ok for the average IDI owner. But if you have modified or repaired your engine or fuel system (and who in this group hasn't), then I'd recommend "timing it by performance." This means to time it with a gun to get it to stock spec, then conduct several 0.5deg - 2deg timing variations and drive it, recording MPG, boost, EGT, and other performance data, while carefully recording fuel usage. Eventually, you'll find the optimal timing position for that particular engine. The optimal performance timing might end up being the stock spec, but it might not. It'll take some work to investigate the neighboring degrees relative to the spec.

The timing gun is also good for returning the timing (to the respective previously-tested "optimal" position), if you ever had to remove the IP or do a repair that required you to tear down your injection system. But if you buy new injectors or a pump, then you are back to timing by performance to find that optimal timing position. That's why I don't really take the digital timing spec as gospel. Stock spec might be close to ideal, but with more testing, you might find even more power, boost, or efficiency.

Why don’t you give pelky your timing equipment so he can fix his truck since you don’t need it?

 

[genscripter]

Why don’t you give pelky your timing equipment so he can fix his truck since you don’t need it?

If he's in Southern California, I'd happily time his engine for him to get a baseline. I occasionally use my timing gun just to make sure my timing is still the same and whatnot.

 

[pelky350]

@wespaul, theoretically should be "tuned" right its only got like 30k on it r and d 90cc. It shouldn't need more fuel it's fuel sheet had like 106cc of fuel at 1000 rpms. So the lever on the side retards the timing with throttle applied when that "cam" moves it? And if it's falling on it's face maybe I need to advance my timing till I can full throttle take off and not have it essietially bog Down? I'll make a video of acceleration and see if my phone will pick up that noise. It sounds like a cold powerstroke trying to take off with large injectors.

 

[Thewespaul]

The arm acts on a pin, the further into the pump that pin is pushed, the more retarded timing you will have. So by rotating the plate you change the behavior of the pump, it sounds like maybe yours is adjusted so it’s not retarding soon enough, so I would start by rotating it clockwise a bit.

 

[pelky350]

Oh, I noticed it was way closer than my first pump, basically any throttle applied and it's gonna me moving it almost couldn't be any closer to the roller that activated it without it starting to engage. Idk if I should be messing with it though if I'm still under warrantee on it?

 

[pelky350]

Oh, I noticed it was way closer than my first pump, basically any throttle applied and it's gonna me moving it almost couldn't be any closer to the roller that activated it without it starting to engage. Idk if I should be messing with it though idk If is under warrantee still or not I don't think it would be after a couple years now? His warrantee is kinda vague lol

 

[Thewespaul]

I don’t think you’re under warranty anymore, and his description of a “warranty” is a bit... special. Idk, if it were me I would mess with it, especially if you noticed it was different from the last pump