I need to work on my 1994 Aerostar 4.0 L engine. My van is the extra long version with 2 AC's. Can anyone tell me what parts have to be removed, if any, to access the fuel pressure regulator schrader valve to hook up a pressure gauge for a test? As you know there's not a lot of room with the hood raised and there are hoses, the steel oil filler pipe and heavy wiring harnesses all in the way and it appears no room to even slide in a hand. If the front wheel is removed will that allow access up through the wheel well opening? Also, I may need to remove and replace the pressure regulator itself. Any tips or advice? Surely the engineers had sense enough to know that one might have to replace the fuel pressure regulator one day and would not want to practically remove the engine to do it! Thanks for any advice or instructions.

 

To access that valve, you will probably have to remove the intake snorkel, and maybe the plastic shroud around the throttle cable. It's located near the front-right of the fuel rail. Some fuel pressure gauges don't have a pin to push in the spring loaded stem in the valve, so you may have to remove the stem. Most auto parts stores sell these metal valve caps that have the two-prong tool on the outer end that you can use to remove the stem.

If all you want to do is check the static pressure, you can just key on/off the ignition switch a couple times to pressurize the fuel system. If you want to check running pressure, and see how it's affected by the vacuum line on the regulator, you will have to assemble the snorkel and run the engine.

 

Thanks for your reply. The air intake duct is not in the way. I removed the plastic shroud and it helped a little. It's the rest of the stuff that's in the way. Has anyone out there actually removed and replaced the pressure regulator on a 4.0, 1994 Aerostar?

 

I have removed it to inspect it. It is plugged into the fuel rail and secured with two small bolts with 10mm heads. It does have some parts surrounding it, making access difficult, like a lot of things on this van.

 

Thanks for your effort, but "Making access difficult" is an understatement in my opinion. Standing in front of the vehicle, access to remove the regulator is completely blocked.

 

After disconnecting the large double wiring harness blocking a lot of the access I was finally able to use a fingertip to loosen and remove the valve cap and then snake a pressure gauge hose around all the other hose and pipe obstructions and use a fingertip to tighten the hose connection and get a reading. When the key is turned on the gauge goes straight to 62 pounds. Then when the engine cranks and is running the pressure sometimes briefly varies between 62 to 64 with a flicker of the needle but does not go lower than 62 and does not change if the engine is revved up. Then when the key is turned off and the engine stops running the pressure goes to 70 and remains there for about an hour or so and then slowly drops to 40 and finally to zero after a few more hours. Because of all the obstructions in the way I can't get my hand on the regulator's vacuum hose to disconnect it to see there's any gas present or to see if the pressure would go up with the engine running at idle but why do that if the gauge reads 62 pounds?

The issue I've been having is when the engine has been run to operating temp and the van driven for at least a few miles and then allowed to idle, the engine will idle for about 5 minutes and then suddenly slow down, shudder and quit running. I guess at slow idle speed, the high fuel pressure must be causing the engine to flood and die, although I don't see any black smoke coming out of the exhaust pipe. I had previously run a vacuum test and the reading remained steady as a rock at 20 at idle. So no vacuum leaks.

What do you guys think? Thanks.

 

"What do you guys think? Thanks."

Well it's been about 2 weeks and no reply so I guess you guys must not think anything. 'Doesn't matter. I replaced the fuel pressure regulator and all is well. The engine was flooding at idle.

For those who may be interested, the following was necessary to gain reasonable access to the fuel pressure regulator:

Drain the coolant down.
Remove the air intake duct. Be careful, they're old and brittle.
Remove the plastic shroud that's over the throttle cable.
Remove the upper radiator hose.
Disconnect one heater hose that's obviously in the way.
Disconnect the two, large wiring harness connectors that hang in the way. Be careful, the connectors are old plastic. Once disconnected, don't manhandle the wiring harnesses, move them over just a little, just enough.

I see no easier way to do this unless maybe if you have hands and arms like a small child but still have the strength of an adult.

 

Thank you for that info. I just returmed to this site or I woulda answered that fuel pressure WAS too high. Seems to me like 38 is sufficient, but that's just from memory, which at 69 yrs old ain't great. Thanks again for this info.

 

Somehow I did not see your last post, but glad you fixed it.

Yes, the high fuel pressure does indicate the regulator is not doing its job.

It seems that working on a lot of cars requires really high strength in very small limbs that can bend 360 degrees.