Advanced timing and lost boost/power?

[rlyons]

I just advanced the timing on my truck and I lost boost and power. I tried to go about 1/16 of an inch and the boost dropped from 32 max to 28. The power also dropped from a dead stop to about 45mph. I then advanced it to about 1/8 inch and lost more boost, went to 25 max. The engine runs smoother or at least sounds smoother. I did have a heavy clatter at about 2250 rpm comming from the pump I believe as it seemed to vibrate through the gas pedal. That is not there now but I can not seem to get the power back up. I just turned the star whell down another turn to about 1/2 turn from the bottom but have not driven it yet as I am to busy tonight. I will check it out in the morning. My question I guess is it possible to have too much advance and lose power? The truck does not smoke near as much on light acceleration now and seems to have lost a lot of the black smoke on hard throttle. Almost like I am running leaner with the timing advanced? Any ideas before I retard it again? I really do like the cleaner exhaust but want my seat of the pants power back.

 

[Greenleaf]

I have done that. Made one adjustment a tad bit too far and you wonder what the heck just happened. I also backed my timing off a bit because it was doing strange things. Not all these pumps act alike. I have tuned several and they ALL act differently. There is little rhym or reason for it. You have to experiment with your particular set-up.





Case in pont. I performed some simple adjustments on my pump. Everything was working just fine for five months. Now, after turning a few screws, I can't even drive my truck.



Back to the drawing board.



GL

 

[rlyons]

Well I backed the timing off today to exactly 1/8 inch advanced and drove again. The power was much better. I then turned the smoke screw down level with the locknut and drove again. The power was good and I only have smoke at the shift points and under a hard pull. I have a little less low end power than at factory timing but it does run smoother and has a lot less smoke. The clatter I had at 2250 rpm is gone and at higher rpms it sounds much better. I think I will leave it at that until I get a chance to pull my 5th wheel and see how it does. Guess I should leave the hood shut and just drive but then again what fun would that be.

 

[cerberusiam]

If you are running close to stock settings on the fuel delivery advancing the timing will generally kill the power and boost. You need more fuel to extend the burn time with the advanced injection event.



Then again you may already be at the optimum timing setting. If you have not found true TDC and set the pump with the gauge you could be off as much as 3 degrees either way. That will definitely make a difference in power and smoke. You tend to lose a little with advanced timing anyway so you need to some how compensate with, you got it, more fuel.



Ahh, the quest for power with $5/gal diesel. :{

 

[Greenleaf]

Yes, I have been giving this lots of thought... ... ..... the price to pay for power/per gallon I mean.



GL

 

[rlyons]

In my case I have had the best of both worlds. When I bought the truck it was bone stock and got 20 mph. I added the guages, injectors, turbo housing, turned up the fuel screw, adjusted the star wheel and diaphram, put on the 31/2" exhaust and K&N air filter and swiss cheesed the filter housing. I now have twice the power and pull my trailer with ease and I still get 20 mpg empty and about 15 towing. Seems the increase in power if used properly made no difference in miles per gallon. I love these trucks!