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95 Ford Contour, 150k. 2.0L I4, Auto 4 speed.
Sitting at idle in park, if you activate any power windows, climate control, turn on the headlights, flip on the wipers, even depress the brake, anything at all that uses electricity, it slightly shakes and the engine tone gets deeper, as if its got too much stress on it. Doesn’t have a tach but I estimate it’s idling at a normal speed, and if you ever so slightly give it some gas, usage of electrical things doesn’t affect it. Putting all 4 windows down at one time with the lights on makes it sound like its going to stall. When it’s cold, it sounds like a diesel idling, tap tap tap tap.
It also has a light shake when a gear is engaged, so I’m pretty sure the trans mounts are bad. But that shouldn’t be related to the electrical problem.
Car is valued at $500 by kbb, so it’s hardly worth fixing, I’m honestly just curious what you all think. If it’s something simple and cheap it might get done though. Weak battery? Excessive alternator friction? Or just an old, weak engine that’s dying?
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I would first start by checking your battery connections, then onto your grounds. If the vehicle is from the rust belt, you may have a grounding issue.
I would also be checking the output of your alternator.
I live in Pennsylvania and the car has been here it’s entire life… so yes, it’s got some rust on it. Thanks for the suggestion, I’ll try to run the alternator test soon but I don’t even know if there’s a voltmeter around here anywhere. Neither I or any family members ever do electrical work lol.
Sitting at idle in park, if you activate any power windows, climate control, turn on the headlights, flip on the wipers, even depress the brake, anything at all that uses electricity, it slightly shakes and the engine tone gets deeper, as if its got too much stress on it
that my friend, is your alternator bogging down your engine because it is probably putting out close to max. voltage. the magnetic field created inside the alternator is very powerful and places a heavy mechanical load on the engine.
That was my thought. Which is why I wondered if the engine is just so old and weak that it can’t handle the strain, due to a valvetrain problem or something else that could cause the tapping.
I wouldn’t blame the engine first thing as all of those systems were designed to work with the car and provided years of trouble free service up to this point I suspect. That said do the checks on the battery and charging system as shown in the above videos for starters. You might also check the ground connections as with something old and rusty those connections can get old and get to a point where they no longer function. Remember the ground side of the circuit is just as important as the power feed.
Well not exactly. It’s been like this for a long time, as with the engine’s strange sound. I didn’t think we’d be keeping it for much longer so I never posted about it or tried to fix it. However it’s increasingly likely that this car might have to last a few more years, so I’m curious. This car is routinely driven less than 10 miles a day, but about a year ago it was driven 100 miles a day for almost 3 months and soon after, these problems all began to occur. I don’t know which happened first, as I never drove it back then.
The idea is not to make assumptions and gather evidence and work with that evidence. As for how the car was driven I can say that letting a car sit is WAY worse than driving the heck out of it. When a vehicle sits all the systems are effected as rust and dry rot set in. As for the cause of the problem I would still suggest looking at the electrical system as it’s operation is critical to every other system on a modern vehicle.
New symptom: Vents blow air that smells like exhaust. The car did this a few years ago for a short period but it stopped on it’s own, and now it appears to be back. No idea how long it’s been going on as I don’t drive it often and it hasn’t been cold enough to use the heat. Exhaust smell only comes through panel vents, not the defroster vents…? I didn’t think that was even possible.
Normally when I run into that it’s oil leaking onto the exhaust and the fumes go up through the HVAC inlet near the wipers.
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