got the car back from honda... did the cat work, and cleaned the emission system out again.. a bunch of black liquid came spurting out of the exhaust.. im guessing is carbon build up? they check the codes afterwards.. only misfiring in cylinder number 2 only!!! we're almost there!
The mechanic at Honda finally figured out why my car has been misfiring and why the spark plugs are always black when he pulls it out. When he starts my car up in the cold, he noticed a strong gas smell. He said the car is not burning the gas efficiently which is leaving carbon build up throughout the emission system. He has already cleaned the emission system for me again, including ports and valve again. He suggested I drive the car hard to burn the remaining carbon build up. Is there any reason why my car is not able to burn gas the way it suppose to? Is there a way to fix this problem?
didn't charge me for the work but still can't figure out why my car is not burning the fuel the way it is suppose to. I fill up 93 octane.. should I try to fill 89 octane which is less rich to see if it will burn it more efficiently?
no. Cheap gas will just make you get spark knock. (aka pinging aka predetonation) The only thing I can figure if you car isn't combusting fuel efficiently is something ignition related. (coil, dizzy, wires, plugs, ECU) We've been through all of that already though. Maybe your primary o2 sensor is bad, causing your car to run fat. But if that were the case, you'd think there would be a code for it. I'm still stumped.
__________________ WWW.OHPOC.ORG--The Ohio Honda Prelude Owners Community
The mechanic at Honda finally figured out why my car has been misfiring and why the spark plugs are always black when he pulls it out. When he starts my car up in the cold, he noticed a strong gas smell. He said the car is not burning the gas efficiently which is leaving carbon build up throughout the emission system. He has already cleaned the emission system for me again, including ports and valve again. He suggested I drive the car hard to burn the remaining carbon build up. Is there any reason why my car is not able to burn gas the way it suppose to? Is there a way to fix this problem?
What brand of plugs are you using?
For anyone reading along, you should only run NGKs in the stock heat range. Make sure they are gapped correctly also (can't remember the spec, Helms has it). Don't run Bosch +4s, those are a problem on 100% of all cars that have tried it.
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The correct plug gap for Preludes is 0.044. NGK plugs for the Prelude come pre-gapped.
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1988 Prelude S - victim of an 80mph backflip
1991 Prelude Si - sold
1989 Accord DX - impounded
1998 Prelude SH - bolt-ons dynoing @ 173whp&140tq
2006 CRF150F - sold
2006 YZ250F
I used to use NGK irdiums with NGK plugs.. when the misfiring codes first showed up, Honda suggested I only use factory plugs and wires, which I already changed. I am running on all honda factory tune up items right now which includes plugs, wires, pcv, cap, and rotor. I also changed the entire distributor unit with EGR valves and ports.
Is there anything that I missed? My check engine light came back on saturday when I was idling. However, it went off today when I started my car.... My emission inspection is due at the end of the month and I won't be able to pass with that light coming on and off as it pleases.
I used to use NGK irdiums with NGK plugs.. when the misfiring codes first showed up, Honda suggested I only use factory plugs and wires, which I already changed. I am running on all honda factory tune up items right now which includes plugs, wires, pcv, cap, and rotor. I also changed the entire distributor unit with EGR valves and ports.
Honda should be using NGK platinums. They do at my dealership. They may say Honda on them or something, but NGK makes them.
Anyway, I know this is gonna sound so rediculous, but maybe you need a new gas cap. Just the fact that you said you had a CEL and it went away on its own made me think of that. The gas cap not screwed in all the way\leaking is one of the only times you will get a CEL and it will go away after you fix the problem without you having to actually clear it. CEL's don't just go away on their own. Except that one. Maybe you burned the CEL out from it being on for so long. LOL Good Luck.
__________________ WWW.OHPOC.ORG--The Ohio Honda Prelude Owners Community
Honda should be using NGK platinums. They do at my dealership. They may say Honda on them or something, but NGK makes them.
Anyway, I know this is gonna sound so rediculous, but maybe you need a new gas cap. Just the fact that you said you had a CEL and it went away on its own made me think of that. The gas cap not screwed in all the way\leaking is one of the only times you will get a CEL and it will go away after you fix the problem without you having to actually clear it. CEL's don't just go away on their own. Except that one. Maybe you burned the CEL out from it being on for so long. LOL Good Luck.
ROFL! that's what I was thinking too.. maybe the light blew out! lol but unfortunely no.. I noticed when I am standing idle, the car is fine... when it is on a uphill slant, the car will start to vibrate a bit and my check engine light would come on...
I ran seafoam and replaced my o2 sensors and i still cant get the light to go away! (full tune up has been done already) p0304 missfire in cylinder #4, im getting a valve lash on tues hopefully this will solve the problem.
I ran seafoam and replaced my o2 sensors and i still cant get the light to go away! (full tune up has been done already) p0304 missfire in cylinder #4, im getting a valve lash on tues hopefully this will solve the problem.
Are you having the same problem as I am? rough idle at uphill slant? Seems like both of us have done the same maintenance on both our cars... -_- aren't we the lucky lude owners
Same with me but i only noticed it more recently when i was stuck in traffic and i was on a uphill slant and my car started to idle roughly... The guys at Honda told me theres another guy with a Type SH that is having the same problem as us. Hope this makes u feel better LOL
Clogged fuel filter? Weak fuel pump? Sounds like a "not enough fuel getting to the engine" issue. The gravity is fighting against the flow of the fuel. I suppose it could still be a bad gas cap, as the fuel pump would be sucking air with the fuel. I'd (re-) start with a new gas cap fo' sho'. FO' SHO'!!!!!!!! And a fuel filter. Those are both pretty cheap.
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Clogged fuel filter? Weak fuel pump? Sounds like a "not enough fuel getting to the engine" issue. The gravity is fighting against the flow of the fuel. I suppose it could still be a bad gas cap, as the fuel pump would be sucking air with the fuel. I'd (re-) start with a new gas cap fo' sho'. FO' SHO'!!!!!!!! And a fuel filter. Those are both pretty cheap.
Changed the fuel filter already and gas cap is on the way...
full tune.... spark plugs, wires, cap and rotor, both o2 sensor, fuel filter, pvc valve, i got a valve lash adjustment, checked fuel injectors, ran sea foam, and did an oil change. My next move will be to get a compression test and like i said im expecting the worse!! this sucks the car only has 103k miles
Changed the fuel filter already and gas cap is on the way...
Nice. Let us know if that's it. Like I said, I kinda doubt it, but at this point, you've already tried nearly everything else, so it can't really hurt. Just the fact that your CEL went away on it's own made me think it could be a gas cap issue. Also I think somebody told Speck on PreludePower that they had a cracked vacuum cap on the throttle body that was barely visible (the crack) but let in just enough air to have a vacuum leak and cause a misfire.
Also Speck, have you done the EGR port cleaning yet? It is alot easier to do than the write-up makes it sound. Once you get into it, it's a piece of cake.
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well i spent about an hour and a half looking for any possible air leaks and also removed egr valve to clean. It was really dirty but for some reason i think my idle got worse after i cleaned the egr??
well i spent about an hour and a half looking for any possible air leaks and also removed egr valve to clean. It was really dirty but for some reason i think my idle got worse after i cleaned the egr??
You have to remove the EGR port plugs and clean the ports themselves. I had cleaned my EGR valve multiple times with no change. Then I cleaned the EGR ports, and no more CEL. My code was for a P0301 (cylinder 1 random misfire) And yeah, the car will idle a little rough at first until all the carb cleaner or whatever you used to clean the EGR gets burned off. Maybe 10-15 minutes. EGR port cleaning
That's a pretty good write-up on how to do it, except that instead of using a modified shop vac, I used compressed air and a blower nozzle. And instead of a gun cleaning kit, I got a set of like 10 nylon-bristled brushes from my local tool store for like $5. If you are going to use compressed air to clean the ports, cover your fenders with a towel so that you don't get the carb cleaner and carbon all over the paint. Also, I don't think it is totally necessary to punch a divot in the plug before drilling into them. They are paper thin and drill very easily as long as your bit is pretty sharp. Just be sure to put grease on the bit to catch any metal shavings. Here's all you need:
Nylon-bristled brushes--$5
1 or 2 cans of carb cleaner\brake cleaner\carbon remover--$4-8
Cheapo slide hammer ( get the cheapest one you can find, like a 2 lb. hammer or whatever. It doesn't take much force to pop those plugs out.)--$5-10
EGR Port plugs from honda there are 6 of them--$3.60 ish for 6
Blow gun for air compressor--$3
So you can see that you can do it for about $20-30 and even cheaper if you know somebody that owns a slide hammer, like I did. Good luck. Hope this helps. And sorry for the mini-threadjack, ItzRoyal.
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Last edited by Lude Acts : 04-10-2009 at 10:22 AM.
i had the same problem for almost a year. same codes and rough idle sometimes.
the cause:
i had accually sucked water in the intake from a large puddle and hydro locked the motor. i spent a hole day pumping water out the cylinders. when i finally got it to run i had a bad cylinder but ater a few days of driving it like that it kinda clered up. (my prelude is the self healing kind)lol. compression check showed one of the cyilders running 30 psi lower than the rest. a leakdown test showed a small leak through an exhaust valve. so i still drove it cause the idle wasnt too bad. kinda felt like i had a cam.
fix:
well i had done many oil changes on this car and because of the mileage 130k i alway used 10w30. and its staring to get hot down here in the desert. so i decided to try a thicker oil, 20w50. and once i started the engine i immeditely noticed the engine was running smoother. i drove it for 2 days and the light went out. 2 weeks later the light hasnt come on. everyonce in a while i get a little rough idle but not as bad as it was.
ok so after cleaning the egr valve (a lot of carbon build up!) and sparying some cleaner down into the manifold and driving the car one whole day idleing is smoother and back to normal best of all no CEL! well at least it hasnt came back on. I just ordered the egr port plugs and will clean the ports once they come in, this might be the solution
ok so after cleaning the egr valve (a lot of carbon build up!) and sparying some cleaner down into the manifold and driving the car one whole day idleing is smoother and back to normal best of all no CEL! well at least it hasnt came back on. I just ordered the egr port plugs and will clean the ports once they come in, this might be the solution
I've done all that... =T
Still came on for me... hope it works out for the better for you... I did just change my gas cap tho and driven it for about 3 days now.... about 60 miles combine and so far so good...
So it looks like I may have been right on both cars. (knock on wood) I will sh*t if I helped both of you guys fix your CEL's. Not so much with Speck, because I'm pretty sure that is the EGR ports judging by the fact that spraying cleaner into the IM helped. But ItzRoyal's car has had me stumped for months, and if your code is gone, I'm gonna be happy. And think of it this way, even though you guys have done all that work on your cars, you needed all that stuff eventually anyway. Good luck guys and LMK the outcomes.
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yea well my light came back on! im still waiting on the plugs to get here so i can clean the ports. Ill also be changing my gas cap since is pretty cheap
my CEL came back on too.. and yes is OEM gas cap... everything i've changed so far has all been OEM items. Fuel pump will be next... what kind of fuel pump would you recommend
?
my CEL came back on too.. and yes is OEM gas cap... everything i've changed so far has all been OEM items. Fuel pump will be next... what kind of fuel pump would you recommend
?
Damnit, ItzRoyal. You had me all excited. Back to square one. Have you checked the fuel pressure? How many psi is it at? Your fuel pressure regulator could be bad, although I've never heard of one crapping out. On the other hand, I've never seen a misfire as elusive as yours.
And Speck, the CEL will keep coming on until you thouroughly clean those ports. The fact that it stayed off for a little while after you sprayed cleaner in the IM is kinda promising though. Make sure you clean them very well, so you don't have to do it twice.
I'm getting frustrated trying to help you figure this out, ItzRoyal. You must be pulling your hair out by this point.
__________________ WWW.OHPOC.ORG--The Ohio Honda Prelude Owners Community
So far, everything under my hood is back to stock. I've even changed my aftermarket intake back to the stock one... If my rings are wearing out, should I try to use 10w 40? instead of the 30?
let me know how that fuel pump goes, When ever im at a stand still and tap lightly on the gas the idle comes back down fast almost stalling the car! how can you test for fuel pressure?
speck, when i first changed my fuel filter, the mechanic told me that the filter was not even dripping at all. Normally, when you take the fuel filter out, it should drip out... but in my case, it wasn't even dripping so he knew the filter was clogged. This can also be due to the fuel pump, not pumping the fuel effectively. As Lude Act also suggested, it can be the fuel pump also so I am gonna tackle that first. I've been pretty busy lately so I won't be able to take the car into Honda to change it. I will however, post the result afterwards.
Kaygnarly, I changed both my o2 sensor already with a new cat converter also.
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