Kahuna6719

No codes,have been driving with fuel pressure gauge on for several days, plenty of pressure. New air filter, fuel filter less than a year old, connectors, wires looked good on and to pump. No problems with new pump or fuel pressure. Traced Vac. lines can't find any cracks or blemishes.

List of parts replaced that have not corrected the stalling problem.
Delphi Fuel pump, fuel filter, fuel relay, plugs, cap, rotor, wires, air filter, ignition control module, crank sensor, coil, coolant sensor, cats and oxygen sensors, ground straps frame to block, fuel pump to frame, Cam sensor. Thoroughly checked wiring at all sensors and connectors for cracks where wire could short. What's left?

cleveland63b

at the moment I have no other ideas honestly without being there to see and touch, I don't remember for sure but are those the sending unit assemblies that have the almost see through hose that goes to the pump itself? I have ran into holes in those that would suck air from time to time.

nkh34

we Put one in my truck and that hose from the pump to the sending unit came off and it did pretty much what yours is doing. Had to pull it to figure it out it had everybody stumped

nkh34

when you did the fuel pump did you just do the pump or the whole sending unit too? the reson i ask i just had my brother with me he says its common for people to crack the tubes on the sending unit and apparently it acts very alike to your situaion.

GM Fixer

what about fuel pump relay?

Kahuna6719

I changed fuel pump several weeks ago. I don't have a problem with the fuel pressure
60 lbs. at start up 58-59 lbs. while running.
I put new sending unit and pump about 8 months ago and read a lot of people having problems with aftermarket pumps so a week and a half ago just for the heck of it I put in a new Delphi to see if it would fix the problem. I was careful with the lines during removal of old pump and installation of the new. Baffling huh ?

Kahuna6719

GM Fixer I replaced fuel relay and I don't think that would cause me to stall while driving over 1500 rpm and 35 mph.

nkh34

Maybe she just needs the timing adjusted you might just have a dead spot in your throtle

Kahuna6719

That crossed my mind also nkh34 along with maybe the chain skipping a tooth. If it did that though I would think I would have backfiring and loss of power. I have a timing light but I can't see how you can get a reading. Have you ever checked the timing with a light on your 97. I can't seem to find a tab on the block. It kind of looks like a mark or tab if you look to the right side of the water pump there is an opening where you can see the harmonic balancer.

nkh34

I personally have not but looking into it i found this and it seemed like the best directions i hope this helps.

You need a scanner to set the timing on a 97 vortec 5.7 and 4.3 liter but they don't call it timing. It's called 'cam retard'.
On the scanner there's a pid that says cam retard and will show the timing in degrees. The spec is 0 degrees +/- 2 degrees.
The distributor is not adjustable from the factory so if the cam retard IS out you simply make it adjustable.
Remove the hold down clamp bolt and slip/slightly pry the hold down clamp off the distributor without disturbing or removing the distributor.
Take the hold down clamp to a grinder and grind off some material on the insides off both fingers sorta wallowing it out.
Re-install the clamp and bolt on the clamp. I like to barely snug it so the distributor still moves by hand.
Start it up.
Read the cam retard and see where it's at. When you move the distributor at idle, the carm retard pid will not change. You MUST rev the engine over 1500 rpm OR cycle the igniton key to update the cam retard pid to the current degree setting. If it's still out, move it a little more and rev it over 1500 rpm's and you'll see the cam retard pid change to it's new setting.
Just do this until it's at 0 degrees plus or minus 2 degrees.
Tighten the hold down clamp all the way and revf it over 1500 rpm's one more time just to make sure it didnt move when tightening the clamp.

I've done it many, many times at work. The reason it can come out of spec is simply from high mileage vehicles that have a slightly stretched timing chain and slightly worn distributor gear from normal wear and tear.
Not only does it change the spark timing but also the injector timing so if you see it at like 8 or 10 degrees out of spec, setting it back to 0 makes a huge difference in power.