hi,

need some help here, I'm driving a 94 model Accord with a H22A engine and manual gearbox. The problem I'm having is whenever I start the car when the engine is still cold (overnight or after long stop), it will idle as if it's running with 3 pistons only, quite rough and the engine is vibrating.

After driving for over 20 minutes, then this problem doesnot occur anymore, smooth idling.

I've checked the vacuum hoses, service the injectors, replaced the distributor, spark plugs and plug cable but the problem does not go away.

Is there any other thing that can cause this?

 

Have you cleaned out your carbon deposits recently? Air filter is clean?

 

No, haven't done that for over 2 years. Air filter is using HKS SPF, changed recently.

Can you please explain on why carbon deposits can cause such problem. Thanks.

 

I don't have time to delve into it, but basically think about how much excess carbon particulate your engine generates and how little of it actually gets out of the engine. That stuff has the potential to clog up stuff inside your engine. The first time I ever cleaned them out was just recently, at 160k...barely any carbon came out of the exhausts, but the idle is noticeable smoother. Either way, it can't hurt to do it...grab a bottle of seafoam and slowly suck 1/3 of a bottle into your engine through a vacuum line (PCV or brake booster work).

 

As far as to much carbon, what about the cataltic converter? Mine has 200,000 on it and I did a h22a swap recently, I feel that it might be clogged. My exhaust tips before my swap were all black on the ends, and I cleaned it up some but its hard to get off. Is my cat junked up? If so whats the best way to solve that? I do not have to have one where I live, should I cut it out? Get a hi flow cat?


Thanks

 

Well if your cat is gunked up you'd notice awful MPG and a loss of power...the exhaust tips of all cars turn black. High flow cats are a good way to fail emissions tests. Honda has very free flowing cats compared to other companies...an OEM one is your best bet.

Listen, pour some seafoam in and see if it still has the same problem. If it does, it might be the cat. But I can't believe that you wouldn't get a CEL.

 

Whats seafoam? And where should I put it? Sometimes my Cel does come on when its cold and I pull it up high in R's ...sometimes it turns on and then it turns off. Once in awhile I see it come on but its not a constent thing. I don't know what to think about the CEL coming on once in awhile. I mean its got a whole different brain motor tranny then what the accord had before

 

Seafoam cleans carbon deposits out of your engine...you can get it at NAPA, advance auto, and most independant auto parts stores. Do a search, there should be specific instructions on how to use it here or on the net. 1/3 into your vacuum tube, 1/3 into your crankcase, 1/3 into your gas tank to clean it out good.

 

I'll try to get this Seafoam thingy but I doubt I can find it here in my country. Alternatively, I've enquired a local speedshop on carbon cleaning services. A whole job of injectors cleaning, motor flushing and carbon cleaning will cost me around USD$60.00 only. Will do it soon and let you all know if there's an improvement.

Thanks 98CoupeV6 for your advise.