Reader Question

I have a 1987 Jeep Cherokee with the 4.0 Liter I-6 engine. I
have started having troubles with the electrical system. The
car starts just fine but as soon as I turn any electrical
accessory on such as lights or heater/ac, etc…

The enginehesitates and dies. I am thinking it is the alternator, but I
checked the votage at the battery when the car is running with
nothing electrical on and it reads 14.6 volts as does the dash
mounted volt meter. Could the alternator still be bad..not
putting out enough amps? or could it be something else? Please
help me!
Thanks,

Corey

Hey Corey

Yes, I think you probably have a bad alternator or a bad voltage
regulator…which should be inside your alternator (some models
had an external voltage regulator). I would get a rebuilt
alternator from your local auto parts store or have yours rebuilt
by a local alternator rebuilder shop.

Blessings,

Austin Davis

Hello again Austin

I took my alternator into my local Schucks store and they put in on their machine and it passed all of their tests. I put the alternator back in and it started and i turned on the lights and it did not hesitate or stall.

But after driving for about 15 mins with the lights on it started to choke itself and it died. I turned the lights off and it started back up, but i heard a hissing and discoverd the vacuum line for the MAP sensor to the throttle body had popped out of the throttle body.

I put it back in and when i turned the lights off and it started to hesitate I could hear it pop back out again. Whats going on! Please help.

Thanks,
Corey

Hello again Corey,

I have seen a lot of really strange things, but this is going to take the cake. You really need to get the alternator checked ON the vehicle, that is the correct way to check the charging system. Can you get a mechanic to run an electrical test on the vehicle for you?

I am not sure what is going on with your vacuum hose…is it oily feeling, if so it might need to be replaced so it fits tighter. Oil and rubber do not mix, and it causes the rubber to swell and work its way loose. there might be an oil leak that is dripping onto the vacuum hose??

Blessings,

Austin Davis

Reader Question

Dear Austin,

I have an older (1994) Jeep Grand Cherokee 5.2L V8.

The engine temperature-gauge rises dramatically when climbing long, steep hills.

Normal city and highway driving or small hills are never a problem.

My local radiator shop quickly diagnosed a ‘plugged rad’ and offered replacement to the tune of $500.

I’m a little skeptical and would like an experienced second opinion: Could it possibly be something else?

Faulty thermostat? Fan clutch?

Would a cooling system pressure-test help determine the cause?

- Wayne

Howdy Wayne,

I think I would concur with the radiator shop….a plugged up radiator is probably the problem here. The pressure test is the first place to start with overheating problems…you are correct, but I don’t think you have a coolant leak since the overheating only occurs under a heavy load.

These radiators are hard to look inside and inspect, but you can sometimes run your hand along the center part of the radiator when the engine is at normal operating temperature and see if there is a considerable temperature difference between the top and bottom of the radiator. If there is, you have a restriction in the radiator.

I would also check to make sure the radiator is FULL of coolant, since low coolant levels can cause this AND if this model is equipped with a distributor I would make sure the base timing is not set too high. If the ignition timing is “advanced” too much it can cause engine pinging noise/clatter noise like bad gas and cause the engine to over heat under a heavy load.

Advancing the ignition timing is a quick way to add a little more power to the engine…which is normally fine to do unless there is a secondary problem like pinging or overheating.

A restriction in the exhaust system like a clogged up catalytic converter or muffler will not allow the hot exhaust gases to escape…thus over heating the engine. Usually if this is the case, a check engine light is illuminated and engine performance is not what it used to be due to the restriction.

I would not be surprised to see a restricted radiator with a 14 year old vehicle, and it is usually standard practice to replace the thermostat and radiator cap when replacing the radiator.

Blessings,

Austin Davis

Reader Question

Hello Austin ,
I have a 2002 Jeep Wrangler Sport with 40,000 miles on it. It has always been very reliable until this past week when our temperature has been around and over 100 degrees everyday. I noticed that when I parked my car in the sun, the fog lights would turn on and stay on all by themselves.

I had to wiggle the control knob to get them to shut off, but they would come back on again. Now that has lead to my battery dying and when I try to jump start the vehicle, it will not staying running by itself. Do you have any idea what is happening with my Jeep?

Hello there

OK you got me on this one, I have never heard of this happening before. The fog light problem sounds like a bad switch, since you CAN get them to shut off if you wiggle the switch around. The other issue could just be a bad battery that will no longer hold a charge OR something has happened to your alternator and it is not charging the battery.

I would get an electrical system test to see what is or is not happening. This should include a battery “load test”, a drain test to see if something is draining the battery besides the fog lights being left on, and an alternator output test to see if the alternator is charging properly. If this battery is more than4 years old I would replace it regardless.

Does anyone have a suggestion for this visitor?

Blessings,

Austin Davis

Reader Question

Hi Austin, Just wanted to know your opinion on a problem I’m having. I currently own a ’94 Jeep Grand Cherokee Laredo and its been a worthy on and off-road vehicle. Lately I’ve been noticing the Jeep “lugging” when I turn the wheel 3/4 to a full turn.

Its usually more evident when I’m coming into my driveway or pulling into a parking stall. When backing out of a space, I don’t notice the lugging. Could this be a problem with my front axle?

Hope to here from you soon,
Jon

Howdy Jon,

I think what I would first do would be to clean your throttle body. This should be part of your routine maintenance anyway, and a dirty throttle body causes all kinds of low speed/idle complaints.

It’s pretty simple and fast to do and any fast lube place should be able to do it for you while you wait. We charge $80 in my shop. If nothing else, you should notice a much smoother idle and faster starts.

Here is more info on the throttle body

Dirty Throttle Body

Blessings,

Austin Davis

Reader Question I need help with 2002 Jeep Wrangler, will start sometimes, sometimes not. Changed starter,,no help, battery checks good, inition switch seems to be working. Can start with screwdriver to starter???? help???
Thanks SOOO much,

-linda

Hi There Linda,

When you turn the key to start and the headlights and other accessories go OUT then you have a bad battery cable connection. If the lights dim low, you could either have a bad battery or a bad starter motor…or a problem with the wiring to the starter, although that is rare.

If the headlights stay nice and bright AS you crank the key to the start position, you might have a bad neutral safety switch on the transmission or you could have an alarm problem or ignition switch or wiring problem.

I always start this diagnosis with cleaning the battery cables, making sure they are TIGHT, you should not be able to move them on the battery with your bare hands. Then I do an standard electrical test

1. Load test battery
2. Check starter voltage draw
3. Check powers and grounds to starter motor

Here is more on the subject
Why Wont My Car Start

Hope this helps,

Blessings,

Austin Davis