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Hi everybody
well I been trying to put my car back in shape again by doing some repairs and adjustments.
there is this particular problem that’s been bugging me for some time.-94 Honda accord coupe EX F22B1 MT-
the car runs rich, i didn’t find any help on Google or YouTube so far so I’m posting here.
the symptoms are: exhaust smells like unburnt fuel.
the car feels heavy when accelerating.
the spark plugs have the air fuel ratio ring (i read it somewhere) very very black. the intake has carbon deposits even though I clean them quite often.the car does 22-23 MPG on Shell Super city highway combined and I read on various forums that I should be getting close to 28 MPG.
the car has 131000 miles original engine. it’s serviced regularly and very well kept after.
where should I start? what should I check? and what are the factors that make it run rich?
thank you very much
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car running rich- check for vacuum leaks.when was the last tune
up? cap,rotor plugs,wires.Hondas run best with honda parts.
cap and rotor Honda wires NGK plugs NGK check engine light on?college man, thank you very much for your reply.
I watched all of ETCG videos, big fan and learned a lot. I posted this comment because I couldn’t figure it out from the videos or from the internet.
vacuum leaks: I did the check like Eric does in the video. I couldn’t find any easy or visible leak. I used carb cleaner. emptied almost the entire can all around the engine and didn’t find anything.
Last Tune up:
I do the maintenance work on the car periodically according to the Honda manual I have. I do the changes and inspections sometimes even before it’s stated.
Oil and filters last week both engine and gear box. brake and clutch fluids including abs did it on mid 2012.Plugs: I changed them every 24000miles. the ones I have where changed 10000miles ago so I believe they are good. I use OEM NGK, always.
wires: not OEM but good aftermarket (so they told me) and they have aprox 33600miles and put them in 2008.
cap and rotor are the original ones so they have 131000 miles. I did find like white corrosion on the back of the cap on each metal contact, cleaned it and did no change.
Hopefully this week this parts arrive because I ordered them oem new.no check engine light. sometimes I get code 12 EGR lift sensor (did the EGR port cleaning, don’t know how often should I do this)
I have a stainless steel exhaust manifold, that has the lower down pipe crushed like 1/3 of the diameter, before the o2 sensor. (sensor is relatively new, changed it in 2010.) nevertheless this problem comes from before I had the new manifold installed.
these are the previous plugs.
and the actual distributor cap.
I didn’t take a picture of the rotor, but the metal tip on it is a bit black.thank you very much for your time
ok.Post back when you install the new cap and rotor.
That may be the issue.The contact points are pretty far
back.that means the spark has to jump farther to transfer.
keep us posted. 😉ok I will. Thank you!
could the cap and rotor be the cause of the problem?
I posted another topic describing something odd about my car.
sometimes it runs perfectly and sometimes it doesn’t. fuel trim is pretty much stable but as I read it’s a bit out of spec.
what sensor o what factor could cause the car to run fine sometimes and like crap the other times?
I read about MAP sensor and 02 sensor causing this, running rich will causes what i describe; lack of responsiveness and performance but not always.
as soon as I’m able to swap cap and rotor for fresh new ones I’ll post back.
the spark plugs should not be like that right?
correct me if I’m wrong
thank you very much!
Look at it like this.We spray fuel in the combustion chamber.
we need to light that fuel off and burn it. if that spark is
weak we are not burning all the fuel we just put in. I’m not
saying this cap and rotor will fix the issue.But it can’t hurt.
Honda parts are good.But not 130k good for a cap and rotor. 🙂Your car being a 94 doesnt monitor EGR flow, just the lift of the valve. Your car has a vacuum controlled EGR valve. You could have a problem with the solenoid, vacuum line or the actual valve. Typically with a stuck open EGR valve(big vacuum leak) your car would run very poorly all the time.
Your car uses a MAP sensor to detect manifold pressure, this is the first point for fuel metering. Again with a failing MAP sensor your car would probably run like crap. If you were to backprobe your MAP sensor to read its voltage, it should read under 1.0v, usually .8-.9v at hot idle with all loads off. If if were higher or lower that could indicate internal engine problems or mechanical timing being off.
The second point for fuel metering is your primary 02 sensor. You said your car has an aftermarket down pipe right? I remember an ETCG video where eric had an aftermarket pipe where the 02 didnt sit far enough into the exhaust stream to read correctly. Did you replace your 02 sensor with a factory unit? I would stick with OEM or a Denso product myself.
Your plugs are definately on the dark side but I have seen far worse. Start with the cap and rotor as those are the cheapest but we may have another issue going on here. My accord is similar vintage and i get between 29-32mpg on the highway so yours is definately on the lower range
As soon as I get the parts I’ll swap them and see what happens.
I did check timing, but i believe it would’t hurt me to check it again so I will.
Thank you!
Ridingred24: thank you very much for your reply, I’ll try and check the egr system to see if i can spot a vacuum leak or anything odd.
I never got a CEL from the MAP or the o2 sensor, but could the map be “tired” and read with error?
I will test it to see the voltage.I do have an aftermarket manifold and downpipe. when I did the install I did check that the O2 sensor would sit in a similar position to the oem part. But I already had this problem before installing it.
I have the one I bought at the dealership, don’t remember the brand but its OEMAnother possibility would be your engine coolant temperature sensor. That is located under the distributor. I will try to get a reading of mine at operating temp so you can compare yours to mine. That is another big player in the air/fuel ration game
fortunately the car doesn’t have problems with temperature.
on 2011 I replaced both the coolant temperature sensor and the sending unit just in case, with oem parts. No matter how hard I punish the car, the needle always stays in that spot around 1/4 towards the “C” on the temp gauge.
the coolant was also changed. and the thermostat too.should I check it anyway?
I don’t recommend you mess with the timing. It’s not likely to be out unless someone has removed the distributor.
Given that you’ve covered most of the bases you might want to check the operation of the coolant temp sensor. If it fails it can cause the mixture to be off. A quick check is to unplug it (it’s under the distributor) and take it for a drive. If the symptoms change you might want to change the sensor and recheck. Also, it’s very important that there is no air in the cooling system. If there is it can fool the sensor and cause a bad fuel mixture as well as idle issues.
The engine coolant temp sensor sends it info to the ecu for air/fuel ratio corrections. The temp guage has its own sensor. If you replaced it with an aftermarket then that could be an issue.
hello everybody. thank you very much for all the answers.
well it’s been some time and i tested the car. new map sensor, new distributor cap and rotor and it still runs rich.
I can smell it out the back too.
when you accelerate you get like a struggle until it passes the 3000rpm line then it accelerates.
it feels like something holds it back and then it goes.
I’ve checked the temp sensor. its all okay. the previous one was working well but I changed it for a new one sometime ago and it’s running fine.something I’ve noticed and maybe it helps to figure this out.
i have a stainless steel exhaust manifold and downpipe the downpipe has a dent (medium size) just passing the curve under the oil pan.
can this cause some problem with the 02 sensor? and make it run richer?The dented downpipe could effect the scavenging of the engine.
http://en.wikipedia.org/wiki/Scavenging_(automotive)Have you checked fuel pressure and when was the last time you had your car smogged?
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