My daughter drives my 2002 Accord SE 4cyl. A few months ago she had a problem with rough idle at start-up, didn't specify whether warm or cold. She carried it to a highly recommended independent mechanic that works exclusively on Hondas. There was a code about a misfire on a cylinder but he couldn't replicate the problem. He suggested some injector cleaner and a tank of 89 octane every now and then. She did as directed and it hadn't happened regularly until now, several months later.

First start-up in the morning is fine. She drives 4 miles to day care to drop off her son. When she comes out it acts like its flooded. Its starts but runs very rough. She can rev it up to 3k and it smoothes out. She carried it back to the mechanic and he said there were no codes and he couldn't find a thing wrong. He did replicate the problem but could not find the culprit. He called a colleague at the Honda Dealership who told him that they had seen that problem of late on that model 4 cyl. They had not diagnosed the problem directly either. They both concur that it appears that a cylinder seems to be getting some raw gas in it after shut down, thus the problem resembling flooding of a cylinder. The mechanic suggested the 89 octane and come back if you just can't stand it any longer. He did not charge her for his attempts. Everyone I've spoken with about him says he's a good mechanic, knows his stuff and is honest.

To appease the son-in-law we changed plugs with new NGK. Problem still remains. Any help is greatly appreciated.

 

It has appearance of a leaking injector, which is what I think your mechanic suspects. Gas dribbles from injector into engine when hot and if engine is started w/i a short time, perhaps 1-2 hrs, you have a hard start to flush all the excess gas. If you leave overnight the gas will evaporate and start will be normal or near normal. An relatively easy check is to check fuel pressure after a hot shutdown. If it declines steadily, going to zero in < 10 minutes, a leaky injector seems likely. Fuel pressure monitor for a Honda requires special fittings to fit the fuel rail fitting.

good luck

good luck

 

Thanks Tex. How much trouble is it to replace an injector. I sit a major or minor repair $$ wise. I'm sure that this isn't exactly great for the engine but will it cause any additional damage I need to worry about?

 

I have seen a few bad TW sensors ( coolant temp ) act like this,, what it does is,, it tells the computer that engine is still cold thus the ecm will richen the mixture like as if it was a cold start,, thus too much raw gas will make it harder for the plugs to burn all the fuel , engine acts like it is flooded,, you rev it up to clear it and it runs ok the rest of the day till you park it and try to restart it a short while later ..

 

Thanks Deserthonda. Which should I persue first, the TW sensor replacement or the leaking fuel injector? Sounds like the TW sensor may be an easily switchable part. Is that correct?

 

Easy to switch, also easy to check. Helm book has a small table of electrical resistance vs. temperature, so you can use an ohm-meter &thermometer to check it out.

 

I agree w/ DesertHonda to check TW sensor first.

However if that proves negative, you should also have someone check the fuel pressure bleed down rate before replacing any injectors. It will be difficult to figure out which injector is leaking unless you have a miss indication from the ECU code suggesting one particular cyclinder. A fuel pressure bleed down test will only tell that an injector or ijnectors are leaking, but not which one/s.

good luck

 

In fact, by testing the fuel pressure bleed-down, it can't really tell the difference between a leaky injector vs. fuelpump check-valve or an FPR that doesn't close tightly.

 

test your fuel pressure regulator as well. there are own cases of this failing (mostly V6 cars) and lack of fuel pressure until the pump is able to pressurize the system