Rep Power: 0

I've already posted this to honda tech and 7thgenhonda with plenty of views but no replies, hoping someone can offer any input please.


I'm trying to figure this out and I'm new to troubleshooting Hondas (coming from owning only diesel vw, this is my sisters car). Its a 2004 civic dx automatic with 96k miles (156k kms non freedom units).

The car was running ok and one day when running errands I came to a stop sign it just died and would not start unless holding the throttle a little (not to the floor). There is now what sounds like a miss under around 3k rpm but when revving it out its smooth till redline / limiter.

Things done so far:
Replaced crank position sensor
replaced all 4 coils, spark plugs are fairly new
checked timing, marks line up on cam and on crank
removed and cleaned iac
cleaned throttle body

I checked the plug to the crank position sensor but only gets 3.74v on the one of the pins, I thought its supposed to be 5v not lower? Other pin is battery voltage dont recall what the 3rd pin should read

I have got it to idle briefly but when it did idle, it sounds like uneven puffs out the exhaust like a miss but more so out the exhaust than at the motor if that makes sense. When you start to rev it out it sounds about the same until the higher rpm range where its smooth.

The fuel pump is working as I can hear it prime (multiple primes does not help the no start issue). Once running it will continue to run but I have to constantly drop it into neutral to keep the revs up when coming to a stop.

Does anyone have any other tips for troubleshooting or anything else I can checkout? My next thought was to get a new IAC since that should be responsible to keep help idle. Briefly before this issue started on cold start the rpm would hunt a little (no vacuum leaks that I could find or hear).

Thanks in advance!

 
Rep Power: 225

I hope that crank position sensor was OEM and not an auto parts store special...

As for the idle I would start by cleaning the IACV. Here's a good thread with lots of idle info.

https://www.civicforums.com/forums/3...e-posting.html

 
Rep Power: 223

Check timing, clean all the intake sensors, that better be a oe sensor you put in.
no check engine light correct?

 
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Not autostore special but Standard Motor Products sensor from rockauto, ok fine so not OEM but still no change after swapping it out. Also took off the IACV and cleaned it, while it was dirty again no change after putting it back on. EGR make sense? I found a video from Eric O of south main auto (youtube) where he had the exact same situation and it turned out to be the EGR stuck open with a chunk of carbon. As I said I'm not super familiar with these motors and this would be my first time dealing with speed density. Everything else I've owned or worked on was maf based. It certainly smells rich when running it holding the throttle even when coolant is to temp after a few min. I'm going to check the EGR when I get to it this weekend but thank you for your input regardless. Ill follow up once I've removed and cleaned the EGR.

 
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No check engine even after running it to operating temp for a few min by holding the throttle. Checked timing it seems to be good, belt is also in good condition. No not OE but no change in behavior after either, I guess its possible its the sensor not being an OEM one. I did clean every sensor plug and pins I could in the bay with contact cleaner. As I replied above I found an almost identical issue posted on youtube by mechanic Eric O. of South Main Auto where the EGR was suck open and it was behaving the same as in this situation even down to the exhaust noise and sounding fine at higher revs. Speed density relying on manifold pressure is something I'm new too so I wouldn't have thought of it affecting fuel trim although it did come across my thoughts that it was getting too much fuel based on exhaust smell. I'm going to check the EGR valve in a few days and report back with my findings. Thanks again for your input I really appreciate it.

 
Rep Power: 368

hondas are notoriously finicky about the sensors

 
Rep Power: 225

Just realized the low mileage. Has the timing belt ever been replaced? Recommended service is like 7 years or 100k miles, it's well over due based on time.

I have never heard of that happening on these 7th gens but who knows.

You can take the IACV apart and spin it by hand, it should spin freely. I previously had a '03 Civic Si that would almost stall every time I pushed the clutch while slowing down, cleaned/replaced a filthy IACV and it ran perfect afterwards.

If you're not sure take some pics and post them. Here's a thread for checking engine timing.

https://www.civicforums.com/forums/1...ne-timing.html

 
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So good news, the car is fixed and running again. It turned out to be a small chunk of carbon lodged in the plunger of the egr preventing it from closing. Here is the link to the video I referenced Eric O. from the South Main Auto youtube channel:

 
Rep Power: 225

That's a first for me. Nice find!