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Hey all. So my civic wont go over 3000 rpm/30mph it just shudders when I hit that… its in limp mode I suppose. It started when I heard and exhaust pressure sounding leak like a loud salt/pepper shaker coming from around the exhaust manifold to the downpipe area/cat…the engine runs very sluggish. So I took the pipes apart, took the cat out and looked through with light and I could see the light on the other end, everything looked intact with the cat as I thought that was the problem possibly being clogged. I bought a new flex exhaust donut gasket where the downpipe meets the cat and that stopped the loud leak finally. But now the car doesnt go over the 3000rpm/30mph. Before I got the new gasket and sealed the leak in the exhaust the car would go above 3000+rpm and 60mph like normal but the car would be very sluggish. I do have a CEL light on and I got the codes using the paperclip method. The codes are 41 and 65….now my primary o2 sensor wire I noticed has been dragging on the axle and has worn wire and frayed it open so I dont know if this would be causing the limp mode or what. I hooked up a vacuum gauge and the car does have great vacuum. I have installed NGK disbributor wires and spark plugs about 5 months ago also. Car has 214k miles by the way. (never have replaced o2’s) Anyone ever have this problem? Where do I go from here. I really need to get this fixed as it is my only daily driving car. Thanks!
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from what you are saying it does seem that you have a problem with the exhaust.. it might be plugged somewhere..
just to make sure thats not the problem, can you install a pressure gauge in the place of the O2 sensor and see if there is any pressure.. it should be something as close as 0..for the O2 sensor, the car should be able to run without but you will have fuel efficiency problems and might be running rich as the engine will regulate it but you will still be able to achive high mph and high rpm.. just have the wires fixed and check if its working on or not with an obd2 scanner..
you can also check for fuel pressure to make sure you’re getting enough fuel to the engine..
Based on your description you may have a restricted exhaust since that seems to have effected performance. You can test this theory by disconnecting the exhaust as close to the engine as possible and taking it for a drive, if the performance returns then it’s likely you have a restricted exhaust. People suspect catalytic converters for this often however I’ve seen more than one occasion where the muffler was filled with enough rust to cause restriction so don’t rule that out.
The Code 41 and 65 are for the O2 sensor so that fits. The wires are shielded so you really should replace the sensor instead of trying to repair it. BTW if the heater wires are shorted out it can effect the operation of the ECU and this may be the source of the problem also.
Thanks all for responding. Forgot to add that I did take the catalytic converter off and I did drive down the block with it off and the car ran just as horrible and sluggish. I have disconnected the exhaust manifold from the downpipe and have shined a flashlight all in it and havent found any stoppages in those parts. Also I did shine a flashlight in my straight through “sport” exhaust I can see all the way through in the rear until the pipes start to curve all with no cloggs or anything. I have a multimeter but I havent really got hands on with the electrical part yet so where exactly would I start looking/probing as far as the heater wires/ecu? Also I dont have a backpressure gauge handy..been on the list to get though.( I had called a mechanic, im supposed to take my car to him on thursday he said he charge $65 to tell me what the problem is. Then I can fix it myself. Unless I can get this thing running before then tomorrow as I dont really have alot of time during the week what with kids and work and I need this fixed asap.. before I take it to him. Oh also I did unplug the primary o2 sensor and drive it. Which car still runs bad.
Thanks again for the responses.I’d suggest checking the mechanical timing of the engine. If you’re off a tooth or 2 it can cause that issue.
I found the problem! It is the cat converter. I had read where you posted a reply on someone elses thread Eric about removing the o2 sensor and taking it for a test drive. Well I did just that and the car drives great, I went over 60mph w/ ease. The opened o2 hole was allowing the pressure to escape since the cat is going out. I dont know why though when I said that I took the cat completely off a couple months ago and the car drove bad. Maybe something having to do w/ the exhaust waves/backpressure..I dont really know for sure but im glad I was able to figure it out and didnt have to take it to the shop. Thanks all for the help I appreciate it. BTW I forgot to add also Eric that I check the valve timing and it was perfect. (I did the timing belt myself a few months ago because the mech that I took it too left out a bolt on the upper mount drivers side bracket and the other was loose half way out! So I ordered another bolt from honda and now its tight so I figured while I was in there replace the belt and tensioner.)
So here is my choice a Magnaflow direct fit cat….
Part number 22630 is the standard cat with less exhaust converting inards or 51093 for higher mileage vehicles and more of the exhaust converting inards. Should I go with standard 22630 or the better 51093?Good job diagnosing the issue.
I would stick with a OEM cat as aftermarket ones seem to be problematic.
Thanks thanks. I will update this later. Also forgot to add that I had started a thread a couple weeks ago about my civic stalling when I came to a stop and RPMs dropping down to zero then slowly going up to normal idling..well now that I relieved the exhaust pressure building up my car no longer stalls out when coming to a stop, which is also another good thing as I didnt know why it was doing that now I do. Kinda like when u stop up the end of the tailpipe and it stalls the engine out..except in this case it was the cat that was doing it…
Hi all just giving a little update…so i went ahead and bought the magnaflow 51093 “higher end” oem cat. The fitment was great no problems. Car runs good now. Everthing is free flowing. Still have a CEL though and had it scanned and said a circuit malfuntion in both sensors…so I went ahead and ordered both o2 sensors Denso brand yesterday. Car has 215,000 miles, Ive never replaced them. So I will update when I get them installed when I get them in a few days. 🙂
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