Hello guys, this is the first time i have ever posted anything, anywhere.

I am having a hard time getting my '92 Aerostar going.
I was driving down the highway and it just cut out on me and wouldn't start back up. I couldn't hear the fuel pump working. I checked the fuse, the relay switch under the hood and the fuel safety swith on the inside passenger kick panel, they all had current. I then assumed it was the fuel pump and after i got the tank dropped we ran current to the old pump and it worked. So i thought i would take the pump back for a refund and talk to the guys up at the parts store.
The parts store said, "Its still the pump, just because it ran when you hooked up a power line to it doesn't mean it works fine."

On top of that my father-in-law was telling me that if the fuel filter is clogged enough it would not allow electric power to the fuel pump either.

Does anyone have any idea of what my next step should be? Should i drop the tank again and replace the pump? Are there any other electrical parts (relays, fuses, anything) i need to check?

Please give me some advice. I really need to get this thing moving and back on the road, its my Covered Truck!

 

Ok, here's the test that most accurately tells the story of whats going on. If you get a fuel pressure guage, you can actually measure that pump under load. Connect the guage to the port on the fuel rail. Start the engine and see what kind of readins you gett with it idling, and then again when you open the throttle. If it is lower than specs, suspect the fuel filter first, and then, if a new filter does not improve it, suspect the pump or the regulator. If the regulator reading change, it is probably good. The regualtor is a little time consuming to replace, but really not very expensive. It is probably working correctly though. The fuel pressure guage is the most accurate way to diagnose fuel problems.

 

The van wont run or start at all, It stopped running while i was on the highway and hasn't started since.
Even when you turn the ingnition to "on" you cant hear the fuel pump begin.

 

Have you checked for voltage at the connector right at the fuel tank?
Since the pump did operate on the bench yet doesnt operate when installed would lead me to believe that the pump is okay and that there is a power supply issue.

 

There are three relays near the battery. I think one of them is for the pump. Test them, and make sure they are working. You can check them with a multimeter, or with a pair of test clips and a 12 volt battery. They are pretty cheap. 2 or the relays are nearly the same, and there is a replacement part that can replace both of them. The OEMs are keyed so that they don't interchange. I don't know why they do that, since they are both identical.

 

Stacker,

When you turn the key to the "Run" position, the fuel pump relay receives power from the EEC computer power relay. The pump should run for about 2 seonds to pressurize the fuel rail, then cut off. If the fuel pump is not running at all you need to check for power to the fuel pump relay.

The fuel pump relay on my 92 3.0L aerostar is the third relay from the firewall on the driver's side wheel well. First is "Accessory relay", second is the "WOT relay" (Wide Open Throttle relay - controls the A/C compressor by cutting power when the engine needs it as in passing), third is the fuel pump relay, and fourth is the EEC computer power relay. Disconnect the fuel pump relay electrical connector and using a volt/ohm meter check for power to the "Red" wire (i.e. red wire to ground) with the key in the "Run" position.

If you have power, then your EEC power relay is probably good. To further check the fuel pump circuit, take a short piece of wire and short across the "Yellow" and "Dark Green/Yellow" wires at the connector. If you hear the fuel pump run, then the inertia cut-off switch, fuel pump and related circuitry is good. You probably have a bad fuel pump relay. (Note: the Yellow wire provides power all the time from Fuse Link E for both the fuel pump relay output and the EEC power relay output..so if you lose power to the yellow wire it might appear that the EEC power relay is bad when it isn't)

Try this and let us know what you found.

Ron

 

Stacker:

Pop the distributor cap and see if the rotor is turning when you crank the engine.
Check to see if you have any fire making it to the Spark Plugs?
You could have a bad coil, more likely a bad TIF-IV Ignition Module.

Jay

 

Well, as I said, test the fuel pressure, and that will tell you if any fuel is reaching the injectors or not. To test you ignition, remove a plug, and hold it with a very good insulator up against a good ground. Crank the engine, and see if it sparks. If it sparks at all, then you should get some fireing. If it is not a bright blue spark, then something is wrong with it, but at least the engine would run. Jus check the ignition system and make sure it is running.

 

Stacker,

Come back...What have you found?

Ron

 

I don't mean to steal this thread, but my problem is so simlar that I thought I would ask here. The van died suddenly yesterday while driving. Cranks fine, fuel pump cycles, everything else seems good, but no start. Could it be the inertia switch, if so where is it and how do you reset it? What are the other possible problems. Check rotor as suggest above? Any thing else?

Thanks.

 

As with any no start situation, the first thing to do is determine whether the problem is electrical (no spark) or fuel related.
Start with electrical since it's easiest to check.

 

Sorry for the ignorance, but how do I check for no spark?

 

You remove a spark plug. Touch the out shield of the plug to a good ground, and crank the engine. Make sure that whatever you use to hold the plug wire is not conductive. Tools with longer plastic or wooden handles are ideal. The fuel shutoff switch is something I forgot about. You will probably have to check with your owners manual for it's location. Most of the time, it is on the firewall, inside the passenger compartment, on the passenger side. You should probably try to reset it.

 

A quick way is to pull off a plug wire at the plug end, insert a screwdriver into the boot so that it makes contact with the metal clip while holding only the insulated handle of the screwdriver. Next, bring the metal shaft of the screwdriver to within half an inch of a metal ground (i.e. cylinder head etc.) Then have someone crank the motor over, if you get an arc from the screwdriver to the metal ground source, you have spark. If you are unfamilliar or unsure of this procedure, find someone who is, and you can be the guy turning the motor over.

 

jmcgardner,

If you can hear the fuel pump cycle, then the inertia shut-off switch is good and has not tripped. The inertia switch is there to cut power to the fuel pump to lessen the chance of fire in accidents.

Still, hearing the fuel piump cycle is no guarantee that the fuel rail is remaining charged. Get a fuel pressure guage and connect it to the fuel rail.

Test 1 - fuel pressure regulator. Turn the key to "Run" and let the fuel pump cycle. Check for fuel pressure, it should be 35-45 psi and very slowly drop once the fuel pump stops. If the pressure immediately drops to zero, then you probably have a bad fuel regulator.

Test 2 - Injector control. If the fuel pressure remains at 35-45 psi or very slowly drops, you can check to see if the fuel injectors are being energized by the computer. Again, with the fuel pressure guage attached to the fuel rail and pressure holding, disconnect the inertia shut-off switch (located behind the passenger kick panel). This will kill power to the fuel pump while not effecting the EEC computer's control of the injectors. Next, crank the engine for about 5 seconds. If the pressure drops more than 5 psi while cranking, then the fuel injectors are opening and your problem is more than likely related to ignition spark. Remember to reconnect the inertia shut-off switch.

Next is to check the ignition system. Now you may get a spark, but if it is not strong enough it might not start the engine. The spark should be bluish in color. It has been my experience that once you have limited the problem to the ignition system, it is probably time to change your plugs and plug wires and even possibly the rotor and distributor cap (if applicable).

Just my 2cents. Let us know what you find.

Ron

BTW, do you have a check engine light?