1998 Chevy 1500 Stalling on Left Turns

[Bschmi17]

Hey was looking for some advice I have a 1998 chevy 1500 that first stalled on me back in august and I've been tinkering with it when I can. But it stalls on left turns almost every time it does seem to help if your giving it gas when your turning verses coasting or braking. But you can turn right all day long. It will even stall most the time if your driving straight and at higher speeds and you just jerk the wheel to the left for a little bit. Everything stays on like all electronics when it kills. Usually starts back up good after you put it in park and turn the key back. I've pulled and tapped on wires and sensors did not change or kill it. I've replaced the ICV, EGR because it had a code for that, cam sensor, ignition module, MAP sensor, cleaned throttle body, talked to people and sat online trying to figure it out. I did try and bring it in to the local chevy dealership to have them try to diagnose it which all they said was it loses fuel pressure when it cuts out. it idles fine doesnt kill in reverse when I turn left. A couple times did stutter when i was just braking coming up to a stop and a few times was a little harder to start, but normally its just left turns that stalls it and normally it fires right back up. I have replaced the fuel pump to i did that back in 2017 so I wouldn't think that would already be bad? Hopefully you can have some insight for me!

[Jsdirt]

If indeed the pump stops running during a left turn, then you've got a chaffed power or bad ground wire somewhere along the harness for the fuel pump power. I'd be focusing my attention there, especially on the right side of that harness. On a '98, anywhere north of the Mason-Dixon, I'd bet on it.

[Bschmi17]

1 hour ago, Jsdirt said:

If indeed the pump stops running during a left turn, then you've got a chaffed power or bad ground wire somewhere along the harness for the fuel pump power. I'd be focusing my attention there, especially on the right side of that harness. On a '98, anywhere north of the Mason-Dixon, I'd bet on it.

The only thing is that I had my mechanic do a fuel pump in 2017 trying to solve a problem back then. And I know that the new pumps usually come with a new wire harness and I asked him and he said that he usually replaces them with the new pump so he thinks he would have. I'll see what I can find on that when I get a chance. 

[Jsdirt]

Some come with a pigtail, but not the entire harness.

[Doug_Scott]

 The first thing you need to do is nail it down to be either a fuel or ignition problem.  This should be relatively easy to do. 

 

There should be a port on the fuel rail that you can connect a fuel pressure gauge to, and then you could run the fuel pressure line and gauge out the back of the hood and then pass it under the wiper arm/blade.  It's best to have your passenger watch the gauge. If the fuel pressure drops, causing the engine to quit, then you know where to look. Something I have noticed is that you have not tried to restart the engine while still moving.  Perhaps you were not aware that if you put the shifter into neutral, then turn the key to start to see if the truck restarts. When the truck starts to stumble, before it quits, watch the fuel pressure.  If the fuel pressure is starting to drop gradually until the engine quits, and then does not go back up right away, you will need to look at power going to the pump.

 

The whole point here is to figure out which of the two major areas the issue is in, then focus your efforts on that area.