Anony_V

Hey Everyone, here is the deal:

I have a 97 Civic hatch with a B20B4 block, B18C1 Head and Transmission.

Bought the car in December from a friend of mine, had no serious issues at the time of purchase. Timing belt snapped on me, had to replace a couple exhaust valves, had the head re-machined, new head gasket, timing belt and a secondary timing belt tensioner from Vibrant (too much slack in stock belt, kept slipping off cam gears). Main issue here is the intermittent jerking, although the car has another symptom as well, not sure if it is related.

First, the jerking:

Been doing it for a while now, maybe two months. This is after I got the head back from the shop and put it back on. The jerking only happens between 2.5K-3.8K RPMs, but is not restricted to one specific gear and does not happen during acceleration. Usually occurs during highway driving at between 60 and 70mph, just cruising down the road. If I take the engine to 4K or above and cruise, jerking ceases. But seeing as the speed limit is 60 around here, and 4K RPMs is over 70, I try not to do this very often

Best way to describe the jerks; it feels like I stomped on the clutch and released it really fast. It is pretty sporadic, although sometimes it comes in bursts. Sometimes it lasts for an eighth of a second, like a quick pop of the clutch, and a few times recently it has dragged out for a little longer, maybe a full quarter of a second of loss of power, then power resumes as normal.


My best guess for this issue is the fuel system, be it the pump, filter, or injectors. But I could and do welcome any other opinions on possibilities here.

Second symptom, may be related, may be not. This one happened before I had to do the head work, but happens way more frequently now.

Car will stick at certain RPMs. What I mean by stick is, lets say I put the car in second, go to 4K RPMs, then pop the clutch and move to neutral. While in neutral, the car will stick at around 2K-3K RPM. This symptom, just like the above issue, is not gear dependent, although it seems to happen less in 4th than any other. Maybe just coincidence. Also, if i just tap the gas and take it to around 4K RPMs while in neutral, idle resumes normally around 1K RPMs. Another solution when I roll to a stop is to put the car in 1st and just ease off the clutch a little, forcing the RPMs down to 1K. The issue corrects itself there. This doesn't really bother me, although it does make some of my shifts very jerky and makes me look like an *** on the road, like I've never driven stick before .

My best guess for this one is either the Cam Pos Sensor, the Crank Pos Sensor, or the Throttle Pos Sensor.

Thanks is advance to anyone that has any info for me, I really appreciate it!

-Travis

Fliptard

check the voltage at your TPS, adjust if needed or replace it if you cannot get the correct CLOSED throttle voltage

tony_2018

If you tensioned it properly there should be no slack on the belt, and since you replaced the belt did you get a gates belt at least?


Motor mounts? Did you adjust idle, and check the tps while your at it? Truthfully it shouldn't really matter where your engines rpms are, you should still be able to disengage/engage, go into any gear at cruising speeds without any issues.

Nave43

Im having a similar problem with my 93 del sol si. It has a d16a Vtec engine swap that was done by the previous owner. It usually only happens in second gear sometimes in first (couldn't imagine it happening at speed), and wont stop till i push the clutch and let back off. Although i dont know how long it would do it for being as i never let it happen for more than a second or two. Also it only happens during acceleration but more like burst of power. Its rather rare but still a problem because like previously stated it make me look like an ****.

Anony_V

Checked the voltage, TPS reads normal voltage range, right around .5V at closed and around 5V At Full open.

Anony_V

There is slack because the head was milled, secondary is neccesary, and yes, it's a Gates OEM replacement. Not sure what motor mounts have to do with this issue, but they are Innovative Poly mounts. Idle is adjusted properly. The tranny goes into gear just fine, but the engine sits at around 3K RPMs in neutral occasionally between gears. And the idle issue isn't really my main concern here, I'm more focused on the jerking. I had a co-worker ride with me last night, and he thought possibly the coil pack. Going to hook the coil up to the ohm meter tonight and see what the results are there. One of the things I forgot to mention earlier in the post is this only happens after the car has warmed up and gone down the road about five or six miles.