Hello All!
I've recently ran into the same kind of hesitation and sudden drop in engine power while at cruse speeds that I have seen before.  I replaced the fuel filter in the tank with no change.  I'm thinking about replacing the in-tank fuel pump again.  I replaced it (the in tank fuel pump) about 1 1/2 years ago after moving to Arizona.  It was having the same kind of problem.  I used a stock replacement from a local parts store.  That fixed the problem. 

Somewhere I remember a comment or two about using a 84 or 85 model year AC Delco pump.  I saw that after I had replaced and solved the problem.  Now, with everything pointing to a failing fuel pump, I think I'll go that route.  I seem to remember that the newer model pump puts out a higher pressure and that the 82 CFI system is very sensitive to fuel pressure.  The original (so I seem to remember) was a lower pressure or fuel flow. 

Any thoughts.  I really enjoy working on my baby now that the garage is complete. 

Thanks for the help.
Keith

The 82 and 84 pumps put out about 12 PSI and that pressure is "adequate" for the throttle bodies unless the pump has degraded and dropped lower.  The 85 fuel pump outputs about 45 PSI, much more than the throttle bodies need.  The drivers side throttle body has a built in pressure regulator that was factory set at about 11 PSI and will prevent the excess pressure from getting to the injectors, the overpressure will simply return to the tank via the return line.  If you install the 85 pump I recommend that you rebuild your throttle bodies.  This is really a simple task using a kit readily available for less than $100.  The reason I recommend this is if the original 30 year old diaphrams are in place the added pressure may cause a problem.  If your 82 pump is weak you should notice an immediate difference in the stumbling problem when you change pumps but to reap the full benefits of the 85 pump you will need to modify your drivers side throttle body to make the fuel pressure regulator adjustable.  I modified my pressure regulator and adjusted it to 14 psi and it made a huge difference.  Ive done this mod twice and there was a very noticeable difference on both vettes.  If you decide to make the fuel pressure mod, let me know.  I have some info that will be beneficial to you. You have a PM.Crossfire19822011-06-13 04:52:45

Great information Chip.  Thanks for the detailed PM.  That looks like something I can do.  I also noticed the fuel pressure rig that fits under the air cleaner.  I'll get one of those assy from DCS.  Any thoughts on using AC Delco as opposed to any other brand.  Generally, are there brands to stay away from?

Thanks for the help.
Keith

Thanks again Chip.  I'll give DCS a call after 9am.  Their web site shows the pressure assy "out of stock".  They may just whip those up as ordered.  I can't see them being huge demand item since 82 are a sub-set of the corvettes out there and the 84-85s are different.  Did you have to adjust the bends in the pipes any when installing?  I know the assy should stay in place and clear the air cleaner.

Thanks,
Keith

No bending required.  The fittings allow some adjustment of the gauge but the tubing is bent precisely and fits perfectly.  The only problem is removal of the original crossover line, they are very difficult to remove in one piece.  I ended up heating / bending / grinding an open end wrench to hold the fittings on the throttle bodies themselves while I removed the fittings of the original crossover line.

Ok, I get the picture.  I had experience with oil lines going to the generators on the F-15s.  I've talked with Jim at DCS and the pressure assys are two weeks out.  So, I'll start PB Blasting the fittings to free them up a bit.  I have an ok from the wife to get a grinder "When you need to" since she insisted we give away my old one when we moved from Mass.

I'm just now getting all my tools divided into like groups.... wrenchy things... ratachie things and so on....  not really doing the metric/ English separation yet.  We really purged the stuff when we moved - mostly my stuff....

Keith

Hey Keith, even if you just put in a '85 pump without doing anything else you wil  see a difference.  The '85 pump will deliver a higher volume of fuel and you won't get any starvation at higher RPMs.

Thanks Dave.  I found an ACDelco 85 pump in stock at a parts store downtown Tucson.  The counter guy looked up the specs on both the 85 and 82 pump.  The 82 was rated at 15 lbs and the 85 is rated at 50 lbs.

It was a little too hot for me to do anything this afternoon so I'll replace it on Wed early AM and see what happens. These days I don't drive anywhere with out 5 or 6 bottles of water in the car.  You really don't want to get stranded in the desert this time of year with out some H2O.

Thanks for all the help.
Keith

85 pump and a pressure gage works great.  Do you have the special tool to adjust your fuel pressure?  That thing cost a little bit.