TPIMonteLS

iTrader: (1)

Ok, on my 350 TPI motor I finally swapped in an adjustable fuel pressure regulator that I had laying around. Car was a 305 then a few years back swapped to a 350. At the same time had a custom PROM burnt by a reputable member here, rarely throws a code although just recently it shows one for the o2 sensor. Car has Ford pink top 24# injectors for the 350. Car sat for quite some time in the past year between moves and winter storage, so it was running with about 10 month old gas for awhile . Got a fresh tank in and played with the regulator. Now my question is I'm not sure how to set it, with the vac line off from the regulator or connected? With it off I have 43-44psi, with it on down to about 36-37psi.

Also for vacuum, I'm taking the reading from the back port on the plenum. At idle it has a pretty steady 15 inches.....but if I give it a WOT quick it backs down to about 0 then back up. Is that normal or a sign of a bad vacuum leak? When driving it does have a bog if I go WOT from a stop. From a roll it pulls pretty well.

A few other issues the car has as well as hard starting and it doesn't want to keep an idle when cold but I want to get the pressure and vacuum figured out to begin with.

Ward

iTrader: (1)

Your fuel pressures look good, those are stock pressures. You may actually want to lower the pressure a little, 24# injectors are a little too large for a stock 350. I'm betting that it's throwing a rich o2 sensor code because of that. You'll want to adjust the pressure with the vacuum line off, that way you're not fighting with vacuum for fuel pressure control. Also, the vacuum sounds fine, it's supposed to go down as RPM increases (as the throttle blades open). I would first try setting the IAC and TPS, that could explain the idle and bogging issues. Check here for directions:

https://www.thirdgen.org/tpimod2

For dialing in the fuel pressure, it will be kind of trial-and-error, unless you have some way to monitor it. You can do it fairly easily using a laptop, an ALDL to serial cable, and WinALDL. Assuming your O2 sensor is working well, you can watch what the computer is doing to adjust fuel. If it's running rich, you will see the computer pulling fuel to compensate, if it's lean you'll see it adding fuel. There's also the low-tech "smell the exhaust" trick, to see if it's rich. For now, I would try bumping it down a couple PSI at a time, until the SES light goes away.

TPIMonteLS

iTrader: (1)

Thanks for the tips. I re-set the IAC, didn't seem to do much. Still working on the TPS, its had some issues for awhile with its readings, at WOT it doesn't get close to the 4.0 volts, its closer to 2....trying to remember how my multimeter was set to read the voltage.

Car starts after a few cranks now, maybe not perfect but much more tolerable. Still can't hold an idle when cold though.

One thing to mention is that when I swapped in the 350, the cold start was removed. I used a 90+ runner set and plenum I had but am using the 87' TB...would this potentially cause any issues?