Car question (Rick help me) engine dies while driving

Factual Questions
1

Here we go again. I really need a new car, but as we’re nearing the end of the 1998 ford escort 142k miles on it era, here goes…

While driving, occasionally the car engine dies, especially when it hits bumps in the road. Sometimes it just dies randomly, but 90% of the time it happens while driving over a pothole, or uneven road thing. This leads me to believe that there is a loose electrical connection somewhere… Only the engine dies and it is easily restarted. Lights don’t go out, radio doesn’t cut off, etc.

I’m not sure what to make of this. Rick?

2

OK somebody cue up the Mission Impossible theme music.

Yes I agree that it is almost for sure an electrical issue. Complaints like this one are what give me gray hair. I know it is electrical but where and which circuit?
Does the car have a tach? If so the next time it happens look quickly at the tach. Does it drop like a stone, or coast down to zero slowly? If it drops like a stone it is an ignition issue.

Other stuff to try (In no particular order)
Is the battery secured in place with a hold down? A shorting battery can cause stalling (and fires) Just because it is heavy does not mean it will stay in one place. Look at the underside of the hood above the positive cable. Burn marks?
Are the battery cables clean and tight? Any fuzzy white, green or black stuff needs to be cleaned off with either a baking soda solution, or a commercial cleaner.

Are there any strange sounds from the engine before / when this happens?

With the engine running try the following:
Wiggle the key in the ignition lock, both up and down, and clockwise / counterclockwise slightly. Ignition switches do wear out, and sometimes the weight of the keys on your ring can give problems.

Go under the hood, and find the various wiring harness, garb them tug and wiggle them to try and reproduce the fault. Do not grab the spark plug wires. Or you will look like this -> :eek:

Find the fuse box, do any of the fuses have corrosion on them? get a small wire brush and clean. Replace any fuse that is listed as being for ignition, EFI computer, EEC or fuel pump. (sometimes fuses blow part way, and vibration can make them go bad, and then come back)

find the ignition coil. With the engine off examine the small wires attached to the coil. Tug on them, are they snug?

Does the car have an aftermarket alarm system installed?

Has the car ever been wrecked?

let me know what you find.

3

IANAMechanic, but a scan tool would be helpful. Buy or borrow one if you can. Almost anything that causes the car to die instantly, should bring up a trouble code. Any one of several sensors (or the wires connecting them to the computer), can give a signal out of the normal range and cause the car to die. You’ll have a hard time tracking the problem down without one.

4

This is a commonly held, but incorrect belief. Let’s say just for the sake of argument that the ignition switch is bad and goes open circuit causing the car to die.
The onboard computer(s) cannot tell the difference between the driver turning the key off, and a bad switch. This is just one example, there are many others.
I did not mention using a scan tool, as the OP did not mention a check engine light.
If the check engine light is on, then maybe the code will lead you in the correct direction. Or it could be the code is a result of another problem, and not the cause.

5

Sorry, I didn’t mean to imply that the scan tool would solve any problem. I wasn’t sure about the check engine light. I’ve had cars that had codes stored without the light coming on. I just mentioned the tool because I know the frustration of trying to find intermittent problems and thought that checking the codes might steer the op in the right direction.

6

A big collection of keys danging from the ignition?

7

No 'blem :slight_smile:

The Librarian Possible. It has been known to happen this way.

8

note to self: Learn to Type.‘dangling’?

9

Don’t sweat it, with my poor spelling skills, I read it as dangling. :stuck_out_tongue:

10

All spelling issues aside, zuma tell us about your keys.:slight_smile:

11

I had a car doing that for a couple months. I found the problem when I did a tune up replacing spark plugs and wires. It was a spark plug wire that was cracked to the core, but you only saw a good intact wire with a visual under the hood. A bump or other movement allowed the crack to open slightly and short to the manifold until the wire moved back. I only could see the crack when holding the wire after removing and bending it. Lot’s of luck.

12

I know this is a really long shot, but I’ve seen happen (albeit on a forklift, with no real shock absorbing ability). On our forklift we had the same problem, hit a bump and the engine died. Turned out, one of the bolts that holds the head to the block had come out or broke off or something. When we’d hit a bump with it, the head would rise up enough to let air into the cylinder and kill the engine.
Like a said, it’s a long shot, but it’s worth taking a look at as long as your under the hood.

13

Thanks everyone for your replies… Anyway, on to answering your questions

It does not have a tach, but the speedometer drops like a stone. That was very noticable and I’d have mentioned it if I thought it meant something.

I haven’t had a chance to check this, but last time I was under the hood, the terminals were pristine and I’m pretty sure there was a tie-down. Battery and cables are both relatively new.

No strange sounds.

I tried this, and wiggling the keys did not induce the problem.

Haven’t tried this yet.

or this.

I’ll try this tomorrow, once I figure out what an ignition coil is :slight_smile:

No and no.

14

The check engine light does not come on.

And the spark plugs and spark plug wires are both brand new (well, 6 months old).

15

A CLUE!
Now we have something to work with. The reason the speedo drops like a stone is that it is electrical, and it either losing power or ground. Most likely it is the same fault that is causing the engine to stall. While it could be either power or ground, I would bet power as the engine and speedo have most likely have separate grounds.
Looking around the net, I can’t find a complete wiring diagram for you car, but the ignition hot leads out of the ignition switch are the blue and black/red wires.
If you are feeling ambitious take the covers off below the column and find those two wires. verify they have voltage with the engine running. Then tap the ignition switch with a screwdriver handle and see if you get a failure. You could have the electrical portion of the switch failing.
To recap:
Finish the tests I listed before
Pay particular attention to the battery cables., and examine the fuse box carefully.
If all of that checks out, I would start to look very seriously at the electrical portion of the ignition switch.
Maybe Gary T will stop by and just maybe he has access to a wiring diagram for your car, and can give more specific ideas.

16

I am a car retard. I think you are saying I can disassemble the steering column and look at ignition wires. How do I verify they have voltage? Are you within 200 miles of San Jose?

17

Hehe if you can walk me through this mess, Rick, you are a true genius. You pretty much nailed my last car problem.

18

Bumping my car thread.

It turned out to be a loose battery cable. I’d like to know how a loose battery cable could kill the engine but still leave the lights and other accessories alone, though.

19

Not bad, it only took you five months to follow the advice I gave you in my first post

:smiley: :smiley: :smiley:
I’m glad you found it.
A couple of things can happen here. First off if you take the battery out of the circuit, the alternator can go wild and produce some crazy voltages spikes (I have heard 100V mentioned, but let’s just say >50 Volts) The computer is set to shut down at about 18 Volts to protect itself against over voltage.
So you hit a bump the battery cable goes loose, for just a second, the computer detects a disturbance in the force, and the engine dies. The lights being, well stupid, keep shining.

20

A related question. Several months ago, the 1995 Camry I was driving at the time behaved similarly to the OP’s situation. I’ve since sold the car to a friend; roommate, actually, which means it’s a tough topic to ignore. Among the problems I encountered around that time was a complete meltdown of the battery, which leaked all over the harness and destroyed the associated cabling.
Naturally, this happened during an 8 hour drive from West Virginia while stuck in a 3 hour long traffic jam, much to the chagrin of the motorists behind me. :mad: I was able to restart the car using a jumper pack, and the car would restart and run for a few minutes. Once traffic cleared up, I made the rest of the trip (all highway) without incident. Since it was night, I couldn’t see that the battery had leaked all over the place and caused death and destruction everywhere in its path.
The friendly neighborhood mechanic replaced the battery, harness, and cabling and said that, surprisingly, the alternator was fine. Now, however, roomie’s been experiencing the same thing (albeit only once every week or so). Is it likely that something else (like, maybe, the alternator isn’t as fine as the mech thought?) was affected?