TFaoro

Hopefully Mike will chime in.... I thought I remembered him saying the VP recognizes if the timing is off and corrects for it, but I can't remember.

^^ This is correct. Fly by wire does not have an actuator. The manual trans started fly by wire sometime in 01, but no one is quite sure when things changed.

The VP can not time far enough to spray more than just a tiny bit outside the bowl - millimeters. But we are talking about cruising timing...usually max timing is a WOT where there is high boost and high temps so cylinder washout is not an issue. A lower pop pressure means the injection event is going to start sooner, so you increased your timing already. That's probably why you don't see an economy gain. You also have to remember a lower pop pressure will decrease atomization, which can lead to lower fuel economy.

This isn't the CR section... again yes I know how they work, I've tuned them, and I've been very successful. You can only raise the rail pressure so high until you get a nasty injector rattle. That's where UDC and EFI comes into play. So back to VP trucks.... have you read anything I've posted? Higher timing = greater mileage (Within moderation of course)

If you don't know where the actuator is, it's under the driver side battery. Are your HVAC controls working?

So when you increase the rail pressure you shorten the duration, or the amount of time needed for the same amount of fuel to come in. The injection event ends sooner, thus in effect increasing the timing. Most people with programmers see better fuel mileage. Why? At cruising the timing is increased. Let me rephrase on the duration statement...... How long the injector is determined solely by how much fuel you want in the cylinder. You can not have the same duration at idle as you do at 2,000 rpm. While you can achieve this with a CR injection system by increasing the rail pressure it is not possible on a VP truck. So when you say you increase duration all you are doing is squirting more fuel into the cylinder.

You can't change the duration on a VP truck. Duration is simply how long the injector is open, and on a mechanical system the duration will remain the same. Thus the only real control is timing and the amount of fuel (foot controlled) I know how CR's work. I've been tuning them. Now I'm telling you simply raising the timing increased economy. I did not touch the duration or the rail pressure. Obviously it's not the only factor but lowering the timing alone reduces fuel economy. So then as mike just said raising the timing and giving that fuel time to atomize and completely burn would increase the economy.

Higher timing on the CR gives it better mileage..... Smarty's claim for the "mileage" setting (on a S03) has the highest timing. That's where I get my best mileage. Are we sure making the IAT warmer doesn't advance timing? Discuss

Interesting... my IAT temps tend to sit around 25-30 deg above OAT. I guess that cold air intake doesn't do squat!

The pintile on a vco nozzle seats against the holes that atomize the fuel. The pintile on a sac nozzle seats above the holes. Some say the sacs are dirtier.... I had the opposite experience. My 90 vco nozzles were much dirtier than the 125 sacs. While it's unlikely either tip will crack a vco nozzle is more prone to cracking due to where it seats.

That's different than when you let off for sure. The letting off an dying is common. Research my friends.

-19 deg F on the injectors in my sig and starts just fine!

I wouldn't say it's too much... it's just what happens when you're fueling hard at high RPMs. Nature of the beast when it comes to the VP.

Mine will do it if I go from WOT to completely off the throttle and the TST is on. It doesn't quite die, but it sputters and almost dies for a few seconds.

Thanks John. I'd like to get enough miles on it to switch by winter, but I'm not sure if I'll have enough run time on it yet. It's got about 2,500 miles and I'm putting on around 500 each week. I don't think I'll be able to plug it in during the winter so synthetic would really help those cold starts.

What size injectors do you have? If they are larger than stock it's possible you're using every bit of fuel in the VP then when you take your foot completely off of the throttle it "air locks" it. In other words it's normal, you just have to let off the throttle easier.

Try loosening it and retightening it a couple of times. If that doesn't work pull the crossover tube out and inspect the O ring. You can pull the tubes out without having to pull the injectors, just make sure you put the same tube back in the same hole. If that doesn't work take the line off and the tip of it until it is smooth and try re-seating again. I used 400 grit to start with.

I am very overfueled.... haven't turned the TST above level 6 and don't need to until I get another turbo. It's just blowing raw fuel out the pipe. With the cam I chose I can tell a night and day difference at high rpm, and the turbo does spool faster. It spools now in 100* weather like it did in 10* weather last year. I chose the tighter housing and smaller wheel because of the altitude and because I DD it in the city sometimes. It tows great so no complaints here! So I had a fantastic day.... I left for work at 4am and noticed a vibration going down the highway. There was also a bit of a chirp at low speeds sometimes. I limped it to my brother's house after work and crawled under it. There was a nice coating of transfer case oil on everything, so I was thinking something in the transfer case was broke. I checked the fluid, put a bit in and finished limping it home. I then could tell my U joint on the rear pinion was bad, just one cap. The vibrations caused the seal around the top of the T case to start leaking Been fine the last 10k miles. O well so I pulled the T case out, resealed everything, drove the U joint out and re-installed the T case. I now see that I need a set of front brakes, and both front U joints are getting bad (One I knew about.) So now I'll be tearing that apart in the morning. Here's some pictures from tonight.

Now this I agree 100% with! I can see the misconception by some thinking that the ring actually contacts the cylinder surface, but I have been taught better. Thank you for the clarification. The 24V isb is the same as the B series as well. There is a cam bushing at the very front of the motor and no bushings on the rest, just a nice film of oil. Above 4500rpm though it's recommended to have those bored out and bushings installed.

Do you honestly think there is no "seating" that takes place? If you believe that, please let this thread take its course. Now I can say this truck had a lot of blowby right after the rebuild. It has progressively become less and less. There was a very noticeable difference after hauling and working the engine hard.

I would recommend putting a little bit of grease or oil on the battery cable. This keeps mine spotless year round! Glad you figured it out though.

I would never break-in an engine with synthetic that was not originally designed and built for it. The rings won't seat properly, or it'll take excessively long for the rings to seat. Doing some research I've seen 10k.... I've seen 5k.... I've seen after the first oil change or two.... I'm not sure what I'm going to do. I've been waiting for AH64 to show up.

I still need to call on that to check pricing.... my PLAN is to have a pretty south bend dual disc 3250 and an input shaft in around Christmas time. Then get it broke in and dyno after that, but we'll see. Another "plan" is to order a mishimoto intercooler within the next week or two. We'll see how that goes given my credit card information was borrowed by someone in California. If I can get that straightened out ASAP I should be good to go.

That's a pre-rebuild video.... I don't know if my clutch/input will hold if I dyno it now. Settings were smarty 7 with default adjustments and TST on 9

Doesn't look too bad with the new wheels, but I definitely like the "Laramie" wheels better. I finally got my dyno video uploaded too. Can you hear when the TST is flipped on?