Well, some of the readings I was getting for the Ltrims sure made it look like the fuel pressure regulator wasn't doing it's job. Today I got a mechanical fuel pressure guage and checked the pressure with and without the manifold reference attatched. It shows 32psi at idle and when I took the reference off it stayed at 32psi. I think idle pressure should be around 50psi and raise to 58-59psi with the reference removed from the regulator.

The low pressure would explain why I had to really crank the injector flow rate WAY down to get the ltrims in check at idle. The bad regulator that isn't raising pressure as manifold pressure increases explains why my ltrims slowly rise as manifold pressure increases.

Once this is fixed I don't see tuning these injectors in as being a problem. They actually idle great and drive smooth.

John

 

cool, what did you do to that regulator? you have an extra dont you since you got an extra intake and fuel cross over.

 

All I did was take it out of the old fuel rail and put it in the new one. I guess after 100,000 miles it didn't like getting messed with. No, I didn't get the regulator. Those suckers are exspensive too, $92 at the dealer which was the cheapest price I could find on short notice. The aftermarket ones are $135.

Remember I said something about the truck being hard to start well the problem was that the regulator isn't holding any pressure when you turn the truck off. So each time you start the truck you have to crank it to get pressure in the rail first.

The regulator will be in tomorrow so hopefully it will take care of my problems.

 

BTW, if any of you ever need a new regulator it's part number 17113678 . It's called a regulator kit that comes with all the o-rings, the little filter and the regulator cartridge. I just checked SDPC and they have it listed for $64. Too bad I needed it like right now.

 

So I guess we won't be meeting at the track tomorrow?

 

PM sent

 

Man, I feel like a idiot. The only problem with the old regulator was that the little o-ring that goes over the fuel restriction tube didn't come out of the old fuel rail. As soon as I got the new one outta the bag I saw that little black ring and was thinking to myself "Hmmm...I don't remember that being on the old one, I BET it's still in the fuel rail " It was. Oh well, I put the new one on anyway and it works great. Fuel pressure at idle is 50psi and raises to 59psi with the reference off.

Now I just need to get my PE table(using stock) dialed in. The initial run after getting the injector flow rate set for good idle and cruising trims resulted in a 10:1 AFR on the wideband from 3000-6000rpm. BTW, that was equal to .990-1.000mv on the stock O2's.

These 42# SVO's drive real nice at idle and cruise. I just put in the same data that I had in my car with these injectors and it works great now that the fuel pressure is back to normal. If anyone wants to switch over to these in the future I can definately help with the tuning. They should be good to close to 600rwhp depending on how lean you want to tune and how hard you push the duty cycle.

John

 

that is some high 02 voltage. if i remember right i was seeing .96 or so for richer than 10-1 ratio, either you are richer than 10-1 or this is a good example of why you can't really tune by using the stock 02 voltage. the fjo set up maxes out at 10-1 so could you be way richer?

 

Yeah, that's up there isn't it. The last time I saw voltages close to that I saw 10.4:1 on the wideband if I remember right so it's probably pretty close. I think if you matched your individual O2's to a wideband then you could use them but, not someone elses. I've never really seen any other comparisons though so I don't know.

I don't know what the useful range is with the techedge unit but, it seems to be good down that low. I'll have to write them since I didn't see the info on the website.

The first PE change resulted in 12:1 down low going to 11.6 by 4000rpm then gradually rising back to 12.1 by 6000rpm. I'm going to tweak this just a bit more to get it around 11.5:1 for this weekends project.

The tuning for the big injectors has also KILLED my timing. I'm only seeing around 17 degrees at WOT which is a definate SOTP loss in performance from the 22-24 I had dialed in. I guess I'll have to kill some more anyway so I just left if alone.

 

Fuel pressure at idle is 50psi and raises to 59psi with the reference off.
What do you mean by "the reference off"?
My fuel press. stays at about 50 whether I am idling or getting on it. I don't have the FMU on anymore, and my fuel press stays the same all the time.In PE, my 02's run from about 945 min. to about 975 max. No wideband results yet.