So I've been having this issue at least ever since I replaced the DOHC ZC that came in the car with another DOHC ZC off craigslist. I'm not sure what it could be...

So at partial throttle, normal driving conditions, pretty much right around 1500-1700RPM the engine feels like it misfires. Its just a "blip" so to speak, and then once it moves on up to 1800RPM and above it seems to run just fine.

I am having issues with my IAC valve, I'm getting a code for that but I have literally ALWAYS (both engines) had a code for that when the engine is cold. Once it warms up I can turn the key off then back on again while I'm driving and the CEL goes away. I'm not particularly worried about it but I'll be troubleshooting that shortly.

I don't think the problems are related, but I'm driving for MPGs right now and this is making it very annoying while trying to shift at lower RPMs. Anyone had this issue before?

Things I have replaced recently that I thought could be related:

Distributor cap 2k miles ago (couldn't get the rotor off but it looked fine, I cleaned it too)
Fuel filter about 10k miles ago

Aaaand thats it. I don't really know what else could cause it at only a very narrow range of RPM except for maybe TPS. I took a multimeter to it a while back and it seems smooth throughout the range of motion, but I'll double check it tomorrow sometime.

 

I'm Getting the same problem, about to tear it down and check the timing. I will let you know if it is the timing in my case. Are you on a PM6 ecu?

 

have you tired a different ecu or know of someone with a good dist you can test on your car?

 

I'm running a PM6, the correct ECU for the engine. I haven't tried a new confirmed dizzy, mine works fine except for that blip. I have suspected it though, they are sneaky.

 

PM6 Is not the actual ECU for the DOHC ZC. Since that ECU is based on a single cam motor that produces lower HP then the DOHC. The true potential will never be used with a PM6. I'm going to chip a PR4 with a PM7 base map and see if that solves any issues. The biggest problem I have right now is the Cam Position Sensor code which seems to get me only 20-25 MPG on my PM6.

I ran the PR4 ECU and it was constant black smoke from running too rich, but still seem to get that BLIP at around that rpm too. The only thing left is to look at the timing and make sure it is correct, because I bought this car from another guy who didn't know wtf he was doing.

 

I got my brother a zc civic http://ef-honda.com/main/viewtopic.p...076&highlight=
had some issues turned out to be just a faulty FPR.... wasted my time checking the timing 3 times, swapping dist, and different ecu...

we did end up finding a pm6 ecu with a pm7 chip, and defintly ran stronger for sure vs. the pr4 or pm6

 

Its not the FPR, since I replaced mine with a regular 12V relay and hacked up the old relay.

 

fpr is fuel pressure regulator not main relay

 

Ah ok my bad I have the PM7. I'll look into the FPR, its pretty damn cheap to just replace it, isn't it? I'm going turbo within the next year so maybe a decent adjustable FPR would be useful.


Do ya'll think its the FPR? Its weird that it only does it at a very narrow band of RPM. I actually watched it more closely in the last day or so, and I was mistaken about it being at 1500, its actually closer to 2100. So either my memory is bad or it has...moved? Hmm.

 

I had that happen on the d16 my car had originally, had a blip right before 2k then drove normal no codes. Friend had a spare dizzy, tried it worked great.

 

Interesting. I'll have to see if someone at the local meet will let me borrow one...assuming I can find someone with a OBD0 D-Series in their car, lol. I can't think of one off the top of my head.