Have mercy on me. My daughter'* boyfriend has a 99 Bonneville with nearly 300,000 miles on it. In the last 12 months I have spent more time and money on it than on the 4 cars in my own family...

This morning he drove it to my house. It ran fine on the way here. He went to start it five hours later - no luck. It turns over but my feeling is it is not getting fuel. I pulled loose the duct work (whatever you call it) going from the airbox to the mass airflow sensor and sprayed starting fluid in there. It would start, run for 2 seconds and then die.

My guess is either the fuel filter is completely plugged or the fuel pump is shot. This car is a total heap so I'd really appreciate any input as to how to know what the real issue is before I spend any cash on it. I have not problem spending 20 bucks on a fuel filter. If it is a fuel pump inside the tank (not sure if that is where they are located) then this car is probably headed for the junk yard...

I would say to check fuel pressure with a guage. Its unlikely that the fuel filter clogged completly.

I don't have a fuel pressure gauge. Could I just disconnect the fuel line, turn the key to "on" and see how much fuel flows? Looking for a way that a DIY guy can check to see if it is the fuel pump Vs the filter.

That would show if the pump is working but not working properly. You can rent one from autozone. The pump could be working but not pumping enough for the engine to run.

I have rented the fuel pressure gauge from Autozone. It shows that I have 30 pounds of pressure. Given that I have fuel pressure, the guys at Autozone then sold me a Crankshaft position sensor. They were not sure how much effort it would take to replace it, but I have done some research and it looks like it is a bit of a pain to replace (not impossible, but time consuming for sure).

I'd like to do a sanity check before I do through the effort of replacing the crankshaft position sensor. Here'* what I know:
- The engine turns over, but will not fire or start
- I've confirmed it is getting spark buy spraying starting fluid in the mass airflow sensor area. When I do this, the car will start and run for a couple seconds - then dies.
- The fuel pressure gauge from Autozone shows about 30 or 35 pounds of fuel pressure at the shrader valve so I am getting fuel, but it is not being delivered through the injectors

Given what I have described above, does this sound like a bad crankshaft sensor?

Thanks,

Erik

I dont know the exact pressure soppose to be but that sounds low to me. One of the other members should be able to tell you what it is suppose to be exactly. I am not as fimilar with the bonnys as others but if the crank sensor is bad it might shut off the injectors on that vehicle. I think the fuel pressure is suppose to be like 50 or something.

On the S10 it is 50-60, I would guess it is in the same range for the Bonnie, 30 sounds way to low.

I think mine sits right around 42-44psi. Yea, 30 psi is too low for the engine to run. Considering that car does have 300,000 miles on it, I would say the fuel pump is worn out.

If your crankshaft position sensor had failed you would get fuel but no spark, which is not the case. The least expensive way to rule out the fuel filter is to change it. Most likely, you need to replace the fuel pump. On the 2000+ Bonnevilles there is an access panel in the trunk to get at the fuel pump, but I think on the 99'* you have to drop the tank. Someone with a 99 on the forum will have to confirm that.

Change the fuel filter.

Thanks everyone for the input.

I was told by the AutoZone guys that if the CrankShaft Position Sensor is bad, it WOULD still get spark (which the car has due to the fact that the car starts briefly via starter fluid).

It is only getting 30 - 35 pounds of fuel pressure. Does anyone have a feel for how much pressure I will gain by changing the fuel filter. My guess is it has not been changed for a very long time.