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Hello everybody. I am new to these forums, so if I am doing something wrong please let me know
I have a 1996 Civic HX and I have been having some misfiring problems with the engine. When the engine is cold it runs great, but after it heats up the engine starts misfiring under low throttle and/or between 1700 and 2000 RPM. If the engine starts misfiring (flashing engine light and jerking in high gears) it can be corrected by giving the engine more gas.
OBD codes:
P0301 (Cylinder 1 Misfire)
P0303 (Cylinder 2 Misfire)
P0304 (Cylinder 3 Misfire)
P1300 (I think this is a random misfire code, but maybe someone here can shed some light on that)
The engine has no smoke coming out the tailpipe, seems to have good compression (based on the OBD tool I have), starts up pretty easily, and runs great when cold.
In the pursuit of fixing this problem I have replaced:
Spark plugs
Spark plug wires
Distributor cap
Distributor rotor
Fuel filter
Fuel injectors
EGR valve
IAC valve
Air/Fuel ratio sensor
O2 sensor
I have tested the MAP sensor and the ignition coil and they still seem to be performing correctly.
If anyone needs more information I would be happy to provide it!
Thank you for any help!
EDIT: forgot to mention the entire car is stock
Last edited by davidkollmar; 05-31-2019 at 03:09 PM.
The front oxygen sensor for the HX is extremely expensive
That being said first try burping the cooling system
Originally Posted by EE_Chris
I've never seen an OBD2 D-series with a bleeder bolt. If anything, old school GS-R's were the ones to have the bleeder bolt on the upper radiator hose fitting.
The OEM thermostat for the OBD2 D-series engine begins to open at ~180* and is fully open by ~195*. The radiator fan kicks on ~205*. Water boils at 212*.
Make sure you have the heater control set to full hot (so that coolant can circulate through the heater core) but make sure the fan is OFF (so that it's not trying to cool the coolant you're waiting around on to get hot).
Leave the radiator cap off. Helms says to "leave it loose". I can only guess this is to prevent coolant from spilling out while air bubbles are being purged. I just leave the funnel sticking out of the radiator neck.
Fill the system with coolant, start the car and refill as needed. Stand around and wait for the cooling fan to at least come on once. I've NEVER waited a second time. If after the cooling fan kicks on once and you still see air bubbles, then wait some more. But in general, you really don't even need to wait till the cooling fan kicks on. By that time, you're assured that the thermostat has fully opened - or was suppose to.
Believe it or not, there are people out there that will drain what they can from the system, refill it and then tighten the radiator cap up and call it "finished". It's those massive air bubbles that were never purged that cause problems with the hunting idle.
I just did the timing belt on my 00 Ex this past weekend, so the procedure is fresh in my mind.
Is it possible your timing could have jumped a tooth or two? When did this start? Any event leading up to this or completely random?
Wouldn't that cause all the cylinders to misfire all the time?
It started a couple months ago. I don't believe there was any event that started it, one day, out of the blue, it just began bucking really bad in 5th gear.
If I get some time I might have to take off the timing belt cover and double check the belt.
Wouldn't that cause all the cylinders to misfire all the time?
It started a couple months ago. I don't believe there was any event that started it, one day, out of the blue, it just began bucking really bad in 5th gear.
If I get some time I might have to take off the timing belt cover and double check the belt.
Just to make sure
The Hx takes a different cap and rotor than all of the other d-series
The hx manual trans takes a 5 wire front oxygen sensor
The hx also has a few minor tweaks.
Can you post a picture of the engine bay. Lets make sure your firing order is correct on the distributor cap first
Wouldn't that cause all the cylinders to misfire all the time?
It started a couple months ago. I don't believe there was any event that started it, one day, out of the blue, it just began bucking really bad in 5th gear.
If I get some time I might have to take off the timing belt cover and double check the belt.
Your getting 3 out of the 4 on cylinder misfire codes, close enough. I would check mechanical timing to rule it out.
Could also be a CAT going, mine did some weird stuff when it was going bad. May want to peak your head under there when the car gets hot to see if its giving of excessive heat.
The Hx takes a different cap and rotor than all of the other d-series
The hx manual trans takes a 5 wire front oxygen sensor
The hx also has a few minor tweaks.
Can you post a picture of the engine bay. Lets make sure your firing order is correct on the distributor cap first
Here is the engine bay (I hope it is clear enough...), I labeled all the wires before removing them from the old distributor cap so I'm pretty sure they are in the right order, but feel free to check.
I do have the 5-wire oxygen sensor on the top of the exhaust manifold. I believe I got the correct distributor cap and rotor, they fit on as expected, but didn't change the way the car ran (for better or worse).
Originally Posted by civichxtreme2
Your getting 3 out of the 4 on cylinder misfire codes, close enough. I would check mechanical timing to rule it out.
Could also be a CAT going, mine did some weird stuff when it was going bad. May want to peak your head under there when the car gets hot to see if its giving of excessive heat.
hmmm ok, is there any way to check the timing without removing the valve cover and timing belt cover? Currently I have a gas leak between one of the injectors and the fuel rail, so the car is out of order for a few days. How would I tell if the CAT is going bad? How hot would it get?
Small update here if it helps anyone solve this...
The car is now seemingly misfiring all the time, after the engine heats up it shakes a ton when it idles and you can hear the bad idle out the tailpipe.
I swapped the ECU with another one I got on ebay and that did not change the problem at all...
I also clamped each of the vacuum hoses (save the PCV hose) and none of them affected how the engine idled.
I have been idling the engine for several hours now and the coolant level in the overflow tank doesn't seem to have gone down. The coolant temperature also registers at about 209F when the fan comes on, so I doubt there is an air bubble blocking the temperature sensors.
I still have yet to check the timing belt for slippage but I will likely end up doing that in the not-so-distant future.
Any suggestions are greatly appreciated! Thank you to the people who have helped out so far!
Don't forget it's a D16Y5 with an EGR system, which is a very common and well known source of misfire codes.
Egr valve malfunction would illuminate the check engine light. The egr valve would respond to the ecu commands and the manifold pressure sensor would detect its operation
Egr valve malfunction would illuminate the check engine light. The egr valve would respond to the ecu commands and the manifold pressure sensor would detect its operation
In theory, you are correct.
In practice, a clogged EGR chamber often does not throw an EGR code.
In practice, a clogged EGR chamber often does not throw an EGR code.
I saw the process flow for p1300 and it seems to be true for v6 accord models, but I dont think its a valid flow for the y5 from my experience
For the engine to run properly it needs air, fuel, spark, and compression. We must verify all of these are working correctly to find the system that isnt working correctly
If his ignition coil tests good, and the icm tests good, I would then suggest a compression test.
Did you use proper ngk copper plugs? Did you gap them correctly? Have we verified firing order to the cap? Have we replaced the cap and rotor? Is there any contamination in the distributor from oil or water? Are all ground from the thermostat housing amd engine clean and in good condition? Does the car have any exhaust leaks? Does the car run better with the front oxygen sensor unplugged?
What is fuel pressure? When was the fuel filter replaced? Are the fuel injector o-rings in good condition.?
After all of those it could be a bad headgasket and you would want to do a compression test
There was a guy who had an HX and swore up and down that there was no CEL for the EGR. He finally took it in to get clean and low and behold it was clogged to *****. He showed a video of the mechanic using some sort or steamer or high pressure steamer to clean out the ports as well as the port on the head. He came back to respond he was happy. The End.
Thank you very much for your help and suggestions everyone! I am happy to report that after scraping and pulling the gunk out of the EGR ports (3 out of 4 of which were completely plugged) and brushing out the EGR chamber, the problem seems to be solved! The car is now no longer getting any misfire codes and it drives much better (shocking).
So, to anyone in the future who may be having the same problem and comes across this thread: CHECK YOUR EGR PORTS! It only took me a few hours to clean them out and it would have saved me a lot of headache if I had done it sooner!!!
04-29-2019, 01:04 PM
1996 Honda Civic HX misfire problem [SOLVED]
