I have a series of questions about this vehicle. I have the two books on the vehicle but I don't have enough mechanical experience to figure out a few things.

General question #1

I tested the alternator at idle by checking the volt? on the battery. The vehicle rough idles/low idles to stall. The voltage read out is erratic. Is this because the alternator is just trying to keep up to the idle differences?

Air Questions?

Air intake. There is an air box and filter to the throttle body. But for some reason, I think the guy who had it before replaced the radiator but was too lazy to replace the Engine Air Box Tube including the part that connects to the Air Box and the Tube Leading to the outside.

There is a hose that is supposed to go back into the Engine Air Box Tube and is just open to the air. I went to the junk yard to try to find this part and the closest I came was an 88? style F250 I think. I was wondering what that tube going back into the air box does. One goes into air box with the filter (which is attached) and one goes into the Airbox Tube connector. Ford Parts . Com has the diagram for the air intake.

Any hope of tracking down the actual parts? I tried to just sort of put it together but its not a perfect fit and I'm not sure how functional it is.

I'm wondering what sensors this vehicle has. I have a range of vehicles in the book and I know this year is on the cusp of change for Ford. Mainly I'm wondering about the difference between MAF and MAP. I'm pretty sure it doesn't have a MAP sensor based on my research.

I'm basically going to poke around and try to clean the air sensors to see if they will function or if I have to replace them.

Any feedback on these matters will be helpful.
Thank you in advance, if you are able to answer them.
Victor.

 

The voltage fluctuation could be from the low idle/ stall condition.

Your correct, you should not have a MAF sensor on this year. But you will have a MAP sensor. With out the MAP sensor, the engine will not start.

Here's a Link for the sensors you have for testing, and the sensor function.

If your having a problem with the idle, and running, check all the vacuum lines for cracks and breaks, a vacuum leak normally shows up as a fast idle, but a cracked line to a sensor can cause a low idle, or a no start. Also, check the egr valve, this could be causing a bad idle condition.

The tube your asking about, is it a small tube, like 1/2"? That could be the engine crankcase breather tube, that connects to the valve cover to the back side of the air filter box, on the clean side of the air filter. Should be a small filter there that connects the tube.

If it's any help, I might have some air box parts laying around from a '91 5.8 that you could use?

 

One tube (yes, about 1/2") goes to the clean air side. The other tube goes no where. But the digram shows it's supposed to go to what I would assume is the, "dirty air side?"

Thank you for the link. I will review it.