95 Astro fuel problem

my 1995 Astro died on the expressway the other night. Cruising at 55 mph, the engine cutout. Had it towed home.

Here is what I have so far, the fuel pump works (replaced in 2004). I can hear it cylce with key on, also hear it when I bypass direct to battery positive. I have fuel at the schraeder valve, but I don't know how much pressure yet. (key on, press valve and fuel flows out). I have to get an adapter for my fuel pressure tester. If I pour gas in thru the intake/air cleaner tube, the engine starts and runs. But as soon as that gas is gone, the engine dies. Could the CMFI unit in the intake have gone bad?

Any suggestions??

Welcome to the forum.

You have already determined the problem is with fuel delivery, you need to know what the fuel pressure is before going any further. Post the results when you have them. Here are some guidelines for checking fuel pressure:

Fuel pressure is not monitored by the On Board Diagnostic (OBD) system and therefore cannot set a Diagnostic Trouble Code (DTC), or illuminate the Service Engine Soon (SES) light.

Fuel pump operation:
The fuel pump circuits are designed to energize the fuel pump through a relay continuously any time the key is in the START position. When the key is in the RUN position the fuel pump will operate provided the engine is running. If the engine stalls, or is not running for any reason, the PCM/VCM will shut off the fuel pump approximately 2 to 3 seconds after the key is turned to the RUN position.

Fuel pressure test:
Install the fuel pressure gauge to the test port near the distributor. Turn the key to the RUN position but do not start the engine. While the fuel pump is running, fuel pressure must be 60-66psi. After approximately 2 to 3 seconds, the fuel pump will shut off. Fuel pressure must remain between 55-60psi for several minutes. A drop in pressure below 55psi indicates excessive leak down. The most likely place is the fuel pressure regulator, the lines under the upper intake manifold, or an injector.

Here is a link to an inexpensive yet ample fuel pressure tester: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=92699

Thanks for the response.

I bought a fuel pressure tester on my way home from work. I connected it to the pressure port (schraeder valve) near the distributor. The best reading I can get is 14 psi!! I replaced the fuel filter to eliminate the possibility of a plugged filter. Still only 14 psi. I then pinched the return line per the Chilton's manual. 14 psi!!

I am assuming that my fuel pump has gone bad again.:banghead:

Fully restricting the return line allows the pump to build full pressure, (approximately 75psi). Applying full pressure to the fuel pressure regulator can damage it if applied longer than momentarily for testing purposes. When you replace the fuel pump, check the connector at the module very closely for burned or corroded terminals, (common problem). Auto parts stores sell the pigtail. If it needs replacement, solder it on and use heat shrink tubing. Using a volt/ohm meter, check the resistance of the ground wire in the connector to ground. Should be less than 3 ohms. If more than 3 ohms, trace the ground wire back and clean/repair the ground connection to the chassis. High resistance in either of the wires, (grey is HOT and black is ground) will cause premature fuel pump failure. Be sure to double check the connections in the new module, they must be clean and tight also. After fuel pump replacement, recheck fuel pressure and leakdown as outlined in post #2.

Last night (Friday), I pulled the gas tank on the van. I had a real problem with 2 of the strap bolts. They were rusted badly. It took a while, and a lot of rustbuster, but I got the tank out!
I am going to replace the pump today. Thanks for the info about the wiring. I did not check with an ohmmeter the last time I replaced the pump. I have had electrical problems with this van in the past (weather pack). I will definitely check the wiring this time.

Thanks again!:)

Removing the tank can be a problem sometimes. Glad to hear you got it out. Post back your fuel pressure results when you've got the new pump in.

Thanks for all your help with this one.

I inspected the wiring and checked the ground terminal with an ohmmeter -- it was 1.4 ohms. Not taking any chances, I followed the wire to the chassis, removed it, sanded to bare metal, and reinstalled. Then I sprayed paint over the area.

My fuel pressure with the new pump is 62 psi. It holds at 58 psi for several minutes after. So I assume I don't have a leak-down issue. I replaced the strainer while I was in there also.

She fires right up!!:grinyes:

You are going to like this one.

If you remember, I had to have the van towed home. It was a flatbed. Well apparently the tow truck driver put a chain over the rear axle, because I am now leaking brake fluid in my driveway!!!:banghead:

It looks like it crushed/split the line! Soooo, tomorrow it goes back into my garage.

I might be posting a brake line replacement question next.:disappoin

What's that saying........."If it wasn't for bad luck,.......

Brake line replacement is not a big deal... IF you can break the bleeder screws loose at the wheel cylinders, yes, both of them. Cut the steel line right at the fittings with a chisel and use a 6 point socket to remove the line nuts. Spray some penetrating oil on the bleeders, (not WD40) and use a 6 point socket to break them loose. Replace the entire steel line from the junction to the wheel cylinder, don't splice it. Gravity bleed one side at a time, then have an assistant start the vehicle, (hydraboost) and bleed one side at a time.

Okay, I'm going to try it tomorrow, assuming I can get a brake line from Murray's or Advance Auto...............

Wasn't the brake line like I thought. It was the rear wheel brake cylinder. The seal was blown out. I replaced it with a new one for $11, and I'm back on the road.....:) :)

Rear Drum Brakes That Use #514 Shoes

GM has used this brake system on various models since 1978. There have been very few modifications made to the system over the years. Originally the drums were cast iron. Aluminum was used for a short time to conserve on weight, but the aluminum corroded rapidly so then they went back to using cast iron drums. Clips were used to fasten the wheel cylinders to the backing plates for a short time but they rusted out rather quickly and the cylinder would become loose. Now they use bolts to fasten them in place. It is a very reliable brake system if maintained correctly. There are two areas that are commonly overlooked while servicing it though. Occasionally the pistons in the wheel cylinders will seize in the bore. When the pistons seize, the wheel cylinder can no longer push the shoe out to contact the drum and braking ability decreases. Regularly flushing the brake fluid will prevent the pistons from seizing. Secondly, the 6 lands on the backing plates, (area that the shoes rest on) wear if they are not lubricated regularly. If the lands wear, it will allow the shoes to move inboard. The shoe itself is approximately 3/16" thick where it contacts the wheel cylinder piston. The contact area on the piston is about 3/8" in diameter. The point where the shoe contacts the piston should be centered on the end of the piston. If the wear to the lands is excessive, the shoes will lose contact with the pistons. Immediately upon applying the brakes, the shoes will slip off of the pistons, and the pistons will exit the wheel cylinder. This causes a major fluid leak, a loss of hydraulic pressure, the dash brake light will illuminate and a total loss of rear brakes will occur. Many times when a blown wheel cylinder is found, only the cylinder is replaced. If worn lands are the root cause and the backing plate is not replaced, the new wheel cylinder will do the same thing again.

I will pull the wheel and inspect the backing plate. Thanks for the advice. You have been a great help.:)