Split-second engine stall and/or clutch disengagement

ANTHONY HARMON

MEMBER
1999 HONDA CIVIC
4 CYL
FWD
MANUAL
195,000 MILES

I have had three different things happen, all of which I suspect are related to each other:

1. Usually at highway speeds in fifth gear (though it has happened a couple times at lower speeds in third gear), the car momentarily seizes and jerks, feels like it might feel if I were to push the clutch pedal down and quickly release it. At the same time, the dash lights come on momentarily (or at least the battery light) like the engine has stalled. But this is only for a split-second and then everything is normal again. Like the engine stalls for a split-second then restarts. This has happened many times now over the last six to nine months or so (though I believe never more than once in a trip), and, like I said, almost always on the highway in fifth gear, though a couple of times on back roads in third gear.

2. The following has happened twice, both on back roads in fourth gear at speeds between thirty five and forty mph. I noticed that giving gas was not accelerating, and I looked down and saw that the engine had shut off, with rpm at zero (despite the fact that car was coasting at thirty five and forty mph, was in fourth gear, and I was not touching the clutch pedal) and I believe the dash lights were on. I pushed the clutch in and tried to restart the engine while moving, and it turned over fine but didn't catch. I pulled over, and tried several times more, but while it turned over fine, it did not start. However, after I let it sit for a few minutes, it started fine and ran fine for the rest of my trip.

3. The following only happened once so far. On the highway at about sixty five mph, in fifth gear, I noticed a loss of power (like in item two above), and looked down and saw my rpm was at zero, despite the car being in gear and my foot not touching the clutch (I cannot remember if the dash lights were on). I put it in neutral, and thankfully I was able to safely coast a few lanes over to the shoulder. But as I was slowing down, in neutral, I looked at the dash and saw that the engine had somehow restarted itself at some point since I had put it in neutral and started pulling over to the shoulder. So I put it back in gear and continued on my way with no more problems.

The engine starts and runs fine in general, and I have noticed no problems with clutch slippage (although I have been told the clutch probably will need to be replaced soon, because the pedal only needs a slight depression to disengage the clutch).

3 Replies

CARADIODOC

MECHANIC
33,873 POSTS

Everything you described could be caused by the crankshaft position sensor or the camshaft position sensor. The clue is the tachometer shows zero rpm even though the engine is still rotating and the ignition switch is on. The engine computer uses the signals from those sensors to calculate engine speed, then it tells it to the instrument cluster.

The best way to approach this is to connect a scanner with record capabilities, then go on a test drive. Press the "record" button when the problem occurs. That will record a few seconds of sensor data, and since that data goes through the scanner's memory, the recording actually starts a little before you pressed the button. That data can be replayed slowly, later, to see what changed.

If the problem becomes worse, a diagnostic fault code should be set to indicate which circuit needs further diagnosis. It is important to understand that fault codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. First we want to rule out wiring and connector terminal problems before narrowing it down to the sensor.