Need some help on fuel issues with 96 bonny SSE.

Finally got around to working on my bonneville today, replaced fuel pump and strainer and fuel filter but still have problem.

Car will randomly stall out while idling, could be a few minutes or car could run for about 30-45 mins its intermitant.

I figured it was the fuel pump because I put a fuel pressure gauge on the rail it would be fine, but then drop a ton, then I would give it some gas and it would stall out.

I am thinking it could be a VATS problem or some kind of fuel pump wiring harness problem. Is there anyway I can test the VATs and also does anyone have any tips for maybe checking for an electrical short in the fuel pump wiring?

What would cause fuel pressure to drop to almost nothing?

On the gauge it would be fine and then randomly drop to almost nothing, only enough to let hte car idle, giving it any throttle would stall the car....

any help appreciated.

usuaully if its a VATS problem the "Security" light will be on, and most of the time the car wont start to begin with.

my first impulse is a clogged catalytic converter on that one...especially since you changed out the pump and whatnot, hows the flow coming out of the tailpipe when it does run?

Pull the vacuum line off the fuel pressure regulator while it'* running. Any fuel in the line? If so, it'* bad. Replace the FPR.

There are a couple of good VATs threads from yesterday. Vats would disable you for about 3 minutes and the security light would tell the whole story.

It'* not too likely that its a VATS problem seeing as how he said the car can run for a few minutes or for 45 minutes before stalling. If VATS fails while the engine is running it will not shut off the car.

It is smart enough to realize that durring a particular ignition cycle, if the code was valid at start up and latter goes bad that it means the vehicle obviously wasn't stollen and a fault has occured, so it will illuminate the security light and allow the engine to remain running for the remainder of that ignition cycle.

casey38boost, if you are loosing fuel pressure with the car just sitting at idle but you have already replaced the pump and other goodies, well I would have to say you are loosing power or ground to the pump.

Start by checking terminal tention at the fuse and the relay but do it carefully, if you go jamming something too big in the terminal you will stretch it yourself and cause problems. A regular size paperclip bent straight is about the right size. Also look for green or white corrosion at the terminals. Also try swapping the fuel pump relay with a different relay on the car, the part numbers are on the relays so just be sure you switch it with the right number.

If that turns up nothing, you can determine the condition of the power and ground circuits that supply the pump by using an amp meter. If amperage falls off while this problem happens, it means that somewhere in the circuit something stopped flowing electricity. Wether it is the pump or the wirring it will not determine, but beings your pump is new it would most likely be wirring.

If it is wirring, the next logical place to look is at the fuel pump connector. Again look for damaged or corroded terminals. If you find nothing, you will need to look at the wirring itself.

Here'* about the easiest way for you to do this. Hook up a sealed beam headamp to the circuit at the tank end, then remove the fuel pump relay and jump the circuit. This will simulate power and ground to the headlamp and light the lamp.

Now with the lamp lit you will need to start manipulating the wirring of the fuel pump circuit untill the light flikers. Once you isolate a section of wirring that makes the light flicker, you have found the short/open.

BTW, it must be a headlamp bulb because it needs to be something that consumes a fair amount of amperage. A small amperage bulb will not work as well.

I ran a new ground today for the fuel pump.

I cut the black wire from the fuel pump harness and ran a ground right to the frame. It ran for about 25 min with nothing going wrong with it.

I am going to test it out tomorrow and see whats going on with it.

Thanks everyone for the help, I'll keep posted on what happens.

Thanks,

Casey

Thats the spirit! It is actually the easiest way to eliminate a wirring problem...just run a new wire. I can not do this though on account that at my work place I'm working on other peoples vehicles, not mine.

But if it'* your own vehicle and you run the new wire in such a way that it is not in danger of being pinched, snagged, rubbed through or corroded away then it is an acceptable fix for a do-it-yourselfer.

I personally would just fix the fault on my own vehicle but it is much easier for me to find the fault than it is for most folks. <<<<< I know that sounds like bragging, but I'm not trying to, I'm just being honest. I have been in this field for some time now.