Ignition-related misfire at light/medium load and low rpm's possible?
03-19-2018, 10:24 AM
#1
Honda-Tech Member
Thread Starter
Ignition-related misfire at light/medium load and low rpm's possible?
I have pretty much exhausted all other options for what could be going on in my CRX, which feels like a shudder or shaking only under certain loads at certain lower rpm's (like 2000-3000). It clears up once the rpms increase. I am a newb at ignition systems but am wondering is it even possible for an ignition-related misfire to present itself in this manner? And if so, where do I start looking for signs about what could be happening? Would prefer not throwing more parts at it, but if there is some quick and easy stuff I can replace I will try it.
It has NGK bkr7e-11's gapped around .020, running e85, and everything else in the ignition is OEM as far as I can tell. Tuned on Hondata S300, the tables look clean. I've checked some datalogs and nothing presents itself, no weird sensor readings or anything. The car idles, cruises, and accelerates at WOT perfectly. It's only when I start getting on the throttle during normal driving, usually after 2nd and 3rd gear shifts that it'll studder.
Would a video help to diagnose? Been fighting with this, asking for opinions, had mechanics drive the car, etc for over a year now.
Here is the background info/why I am now considering an ignition problem:
- I've already replaced everything in the drive train. Tranny, clutch, flywheel, axles, mid shaft. It has new wheels, balanced tires, ball joints are good, everything feels solid.
- I've already checked out the fuel system for any issues. Checked pressure while driving, cleaned injectors, new filter.
- Engine mounts are all good. They are solid rubber inserts, no cracks and I've had them all apart already.
It has NGK bkr7e-11's gapped around .020, running e85, and everything else in the ignition is OEM as far as I can tell. Tuned on Hondata S300, the tables look clean. I've checked some datalogs and nothing presents itself, no weird sensor readings or anything. The car idles, cruises, and accelerates at WOT perfectly. It's only when I start getting on the throttle during normal driving, usually after 2nd and 3rd gear shifts that it'll studder.
Would a video help to diagnose? Been fighting with this, asking for opinions, had mechanics drive the car, etc for over a year now.
Here is the background info/why I am now considering an ignition problem:
- I've already replaced everything in the drive train. Tranny, clutch, flywheel, axles, mid shaft. It has new wheels, balanced tires, ball joints are good, everything feels solid.
- I've already checked out the fuel system for any issues. Checked pressure while driving, cleaned injectors, new filter.
- Engine mounts are all good. They are solid rubber inserts, no cracks and I've had them all apart already.
03-23-2018, 09:02 PM
#2
Re: Ignition-related misfire at light/medium load and low rpm's possible?
Have you logged batt voltage at all?
Start at the battery and compare with what your voltage is at igp1 and 2 at the ecu
Start at the battery and compare with what your voltage is at igp1 and 2 at the ecu
03-24-2018, 03:25 AM
#3
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Re: Ignition-related misfire at light/medium load and low rpm's possible?
I had the same issue with my ek d16zc it was like when it got to that certain RPM at random times not every time, that it was like it wasn't getting any fuel until I increased the rpms and the car would jerk. But mine is stock
03-24-2018, 07:05 AM
#4
Honda-Tech Member
Thread Starter
Re: Ignition-related misfire at light/medium load and low rpm's possible?
I will start getting some datalogs to see if anything weird is going on when the issue manifests. I haven’t looked at what my ignition timing, voltage, etc is doing yet because I’ve been to focused on thinking it was a mechanical issue, not a tuning or misfiring issue up until recently.
I know my battery voltage reading stays up around 13.5 to 14v and my AFR stays good the whole time. But hopefully datalogging and looking at timing and sensor readings will give me some clues.
I know my battery voltage reading stays up around 13.5 to 14v and my AFR stays good the whole time. But hopefully datalogging and looking at timing and sensor readings will give me some clues.
04-10-2018, 09:05 AM
#5
Re: Ignition-related misfire at light/medium load and low rpm's possible?
Hey there. A few options for you
see if you can swap a known good distributor. Known issues are the igniter and the internal wiring in the distributor. If you have it off also check for play in the bearings etc
gap up your plugs to .030 and see if it corrects the issue. Gap down only if you have spark blowout at high boost
i had a similar issue. Turned out to be a bad tps. I found it by data logging. Hold the throttle steady as possible and wait for a stutter to occur. Then check for signal dropouts on tps map etc. Found it after totally rebuilding the ignition system lol
others others have had issues with grounding cause this. Make sure your grounds are in place and clean
chay
see if you can swap a known good distributor. Known issues are the igniter and the internal wiring in the distributor. If you have it off also check for play in the bearings etc
gap up your plugs to .030 and see if it corrects the issue. Gap down only if you have spark blowout at high boost
i had a similar issue. Turned out to be a bad tps. I found it by data logging. Hold the throttle steady as possible and wait for a stutter to occur. Then check for signal dropouts on tps map etc. Found it after totally rebuilding the ignition system lol
others others have had issues with grounding cause this. Make sure your grounds are in place and clean
chay
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