As you can see by my sig, I have installed a set of PDR 190's and bumped the timing. While I was in there I was gonna set the pump up and found that the AFC collar was one turn from bottom already and full power screw is against the stop collar.

I have noticed that my cruise boost pressure has increased a PSI and EGT's are down 75 degrees. I have also noticed that the truck burns far better, cruise is smooth, black smoke doesn't look as dirty. The other thing I have noticed is my mileage has really dropped off.

This morning I have gone and turn the timing back a bit and turned the AFC collar up one turn. Went on a road test and found that my boost cruise pressure has increased another PSI, EGT is up too.

My question to you guys is: Should I go and increase my timing bump? The theory I had in my head is that the boost pressure increase is due to unburnt fuel that is still expanding in the turbo. I thought a decrease in timing would make the engine burn more in the combustion chamber and make better use of the fuel. With the set back of timing this morning, it has blown my theory out the window. I am open to any and all suggestions.

My background is with gas jobbies and computer controlled diesels. Man what a learning curve with these old but good engines! Thanks for your input/help in advance.

Glenn

 

another first gen called "MOOSE"... Love it!!

 

I have always been told that a 1/8 of an inch bumped timing helps fuel mileage and i reallly think it does although my odometer or fuel gauge doesnt work. but it idles smoother and doesnt smoke nearly as much. I think you lost fuel mileage because of the bigger injectors and and power screw that far in, WITH those last 2 things i mentioned your AFC star wheel needs to be turned counter clockwise i believe (turn it out). This will adjust when the boost comes in depending on how much fuel you have so if the star wheel is too far down then with the big injectors you may not have as much boost and too much fuel at certain speeds,therefore,bring mileage down. hope this helps [cool].

Brandon

 

Go back to the 1/8" bump. Sounds like the star wheel is set too deep for your injectors, back that off a bunch and mileage will improve.

 

Thanks for the input. I am gonna go out and follow the recomendations.

The reason why I am so worried about it is I have a 700 mile round trip to take tomorrow.

Worse case scenario is I could always flip the old injectors back in for the trip and then put the 190's in after and start some more testing.

Thanks for the input and I will keep you posted.

Glenn

 

Speaking of Starwheels -
the PO or someone obviously messed with mine - it's all the way down ! Jammed at the bottom, will not turn.....
Any suggestions on getting it loose so I can crank it up a turn or two?

 

Needle nose vise grips?

 

I've run the PDR 190's and found 1.85mm timing to be optimal. 2.00mm and higher . . . it runs kinda funny. (My 205 VE IP came OEM @ 1.4mm).

I had very good results cleaning up the wasteful heavy smoke with the star-wheel. Just get your main fuel screw where you want it and dial the star-wheel to where it smokes as you like at preturbo spool conditions.