Hello everyone,

I have a '91 E350 with 7.5L gas engine which has charging system trouble. Basically the battery doesn't charge when in the van. I still don't know if it's the battery or the alternator or anything else. I'm going to get the battery tested in the next couple of days (I don't have a charger or a tester), but if the battery is OK, I'm going to take the alternator out and get it tested.

I can see the alternator and the belt, but I can't get to it. The air cleaner housing (?) is in the way. My questions are,

1. Is taking the air cleaner housing off the easiest way to get to the alternator?

2. How do I get it off? Get those two small hoses on the front and the two hoses on the right off, then take the lid off, take the filter off and look around for a way to get bottom of the air filter housing off so I can access the belt? I'm a noobynoobynoob and I don't want to break anything .

Here are the images ImageShack Album - 6 images

3. This is not that important, but I'm just curious. What's that cylinder like thing in the last photo? It's in the front inside under the hood, driver's side.

Here's the image ImageShack Album - 1 images

Thanks.

 

The cylinder type can you see and question is a vacuum reservoir.
All you need to do is remove the two sheet metal screws that hold the air cleaner box to the cowl, then loosen the hose clamps for the two large intake hoses that go to the throttle body,then disconnect the remaining small hose(s) and remove the air cleaner assembly. (The air filter is inside that box)
Disconnect the battery negative (ground) cable and loosen the belt then start removing the alternator itself.
Before you go through all that trouble, why not invest in a cheap voltmeter and when you connect the meter to the battery, engine off, it should read approx 12.4-12.6 volts.
Then start the vehicle and turn on the headlights, heater blower on high setting and raise the engine RPM . If the voltage reading drops below 12 volts, alt is in need of replacement..
Otherwise, with all accessories off and engine RPM up some, the voltmeter should read at least 14 volts. If not, alt is no good. Let us know how you make out.

 

I turned everything off and connected a voltmeter to the battery. It read 11.7 V.

Because my battery is dead, I couldn't crank the engine with it. I have a small portable jump starter battery that can barely crank this engine. Connected it and started the engine. Disconnected the jump starter and checked voltage. But the engine was at idle. Did not raise engine rpm. Read about 12.5 V. There is a battery charging gauge on the instrument panel. It didn't read charging or discharging. Turned the headlights on and the engine died in about 30 seconds as the battery died. Jump started again and tried to drive, but the engine died after about 300 feet with headlights on. Had to jump start it again to get back.

The jump starter battery was getting used up, and with the dead vehicle battery connected to it, it couldn't crank the engine. So I disconnected the vehicle battery, connected the jump starter battery, and checked the open circuit voltage. 13.2 V. Started engine, checked voltage at idle. 13.7 V. Looked at the charging gauge, and it showed a very slight charging.

I did all of the above before posting here.

I can raise the engine rpm and check the voltage again, but I'm waiting for the jump starter to recharge. It'll be ready for another go tonight. But I'm going to try to get the battery tested and recharged from somewhere before that.

 

Oh, and also, I pried the battery covers off and looked inside. The plates looked bent (wavy when looked from above), if that means anything.

 

If the plates were not covered with electrolyte, there is a good chance the battery should be replaced. I have seen them come back after adding water to the cells and recharging,but not too often. Even after you replace the battery you should see 14.2 volts with the RPM up slightly . If so the alt is probably OK.

 

The plates were all covered. Got it tested and charged. They said the battery is OK.

Came back, reconnected battery and tried starting. Engine cranked without a problem and started. Did the alternator test again. I don't have a tachometer, so in the description below, judging by sound, 'low rpm' means about twice the idle rpm and 'high rpm' means about three times idle rpm. The voltage kept fluctuating sometimes, and the +/- error accounts for that.

Open circuit voltage before test 12.50 V.

Idle: 12.7 +/- 0.2 V without anything on, 11.4 +/- 0.2 V with headlights and cabin heater on full.

Low rpm: 12.4 +/- 0.5 V without anything on, 11.4 +/- 0.5 V with headlights and cabin heater on full.

High rpm: 12.2 +/- 0.2 V without anything on, 11.4 +/- 0.5 V with headlights and cabin heater on full.

Open circuit voltage after test 12.10 V.


So I disconnected the negative from the battery and started getting the air cleaner housing off. Here are some questions I have.

1. What are these two big hoses going to the right? Because they go in to the engine, I guess they are the engine air intakes? Here are the images. ImageShack(TM) slideshow

2. What are these two smaller hoses at the front? Images here. ImageShack(TM) slideshow

3. There is a small line at the right bottom. What is that? There was something like a square sponge, which I guess is a filter of some sort, where it starts, but it was not rigidly connected to the line. I don't know if I or someone else broke it. Are the square thing and the line supposed to be in two pieces or one? Images here. The line is in the center of the last picture. ImageShack(TM) slideshow

4. There is also a small line at left top. What is that? Here are the images. ImageShack(TM) slideshow

5. And finally there is a big line coming in from the bottom to the left edge of the air filter housing. I guess this is the air intake to the filter? Does this line just go to bottom of the vehicle or is there something before the air filter? Images here ImageShack(TM) slideshow

6. Finally got to the alternator. As far as I can see, there are two belts. There is a tensioner for the other belt, but there isn't one for the belt turning the alternator. How do I get the tension off the belt to get the alternator off? Here are the images. ImageShack(TM) slideshow

I thought I might be able to slip the alternator off without loosening the belt, and started taking the bolts off. But the second bolt seems to be too tight for my socket wrench which is only about 8" long. Maybe it's because of corrosion. Tried WD-40, but didn't work. Trying to find a steel pipe or something that I can use to extend the length of the socket wrench so I can get more leverage.

 

Good photos!
The two large hoses go to the throttle body that's for the air intake for the engine.
The twin hoses in the front of the air cleaner housing are for the air pump that cleans up the air going to the exhaust manifolds and the converter. The hose that connects to what you described as the square thing is the PCV filter that's the PCV fresh air intake, there should be a horseshoe type clip to keep the filter stable, usually comes with the new filter. The small hose at the top of the plastic housing closest to the intake hose is from the air pump to muffle the air pump noise.
Hope I covered all your questions.
Loosen the belt with the tensioner as directed in the diagram. Then you can move it out of your way. Penetrating oil does help to get corroded bolts loose, but you gotta let them soak awhile. I usually put a little grease in the bolts when reinstalling them so they come off easier next time. While you are at it consider replacing the belt while everything is off.

 

I forgot to reply to your post.

Replaced alternator, and it works fine now.

Thanks a lot!