98 Honda Civic with Old Gas?

[NCLaker]

Looking for some help a problem with my daughter's 1998 Honda Civic LX. It had been sitting in a garage since the end of Dec. She left it with about a gallon of gas in it and did not put any stablizer in the tank. She just got back home to uses it, and put a can of Seafoam and filled the tank.

Car runs fine except when engine warms up. If the car is idling (when sitting at a stop or shifting out of gear & coasting) the rpms dip so low that the engine dies - otherwise it is running great. She said it did not do this before this before she put it in storage.

Does the low idle need to be be adjusted, or is this possibly a gas/fuel system issue? Any recommendations on the fix? I am hoping I can just put a fuel system cleaner to fix it (not sure if the Sea Foam she put in it will do the trick or not).

Thanks.

[Scott K]

I would run the gas out of the tank, then refill and see if it got better, if not then look into it, if it doesnt do it any more then its fixed!

[Shack]

What you guys did to the gas should work fine. I would say the gas is not that old (I have seen veh.'s start with gas 3-5 times as old) and is what I would do to only 1 gallon of old gas.

Any check eng. light on? I would think a code scan would be a first start and then fuel or idle air control would a possible next step.

Good thing to check while waiting for the import king Airjer to chime in is to look in the air filter area for a mouse nest. Any funny smells?

P.S.,

No low manual idle adjust screw on this eng.

[NCLaker]

Thanks for the quick feedback. No check engine light. Just idles real low and then kills.

Good point on the mouse thing. I noticed some some pieces of rubber insullation under the car when we pulled it out - thought it might be a mouse so I scanned the engine and saw no evidence, or any mouse droppings so assumed it was okay. I will check again more thoroughly.

Thanks for the tip on the no low idle screw ... saved me from messing with it.

[theoilman]

My educated guess would be you have some water in the gas - likely condensation from leaving the tank so low over temperature changes through the winter and into spring. I would recommend trying a can of 'dry gas' - any brand. Then run the current tank of gas out, refill and see if it clears. From what you have done I doubt if it is a problem with old/stake gas either. A small amount in the tank mixed with a fill up of fresh will definitely solve the old gas problem.

[Shack]

Good point T.O.M.!

Water could be the cause!

[Capt. Don*]

"Rubber insulation under the car"? Possibly vacuum hose? Sounds like a vacuum leak, can you hear any hissing around the engine?

[Jeremy airjer W]

Condinsation is a possibility but unlikely the cause!

My first thought like the Capt. is a vacuum leak. Every once and a while we will see them leaking in between the intake and the head. You can CAREFULLY spray the area with carb spray (it is flameable and extreme caution should be used when doing this) if the rpms change when a specific area is sprayed you have found the problem.

Norm25 seems to have the Hondas under control and I'm sure he'll chime in as well!!

[norm25]

Definitely check for vacuum leaks, possibly a Idle Air Control Valve? How much have you driven it while doing this? Have you re-filled the fuel tank?

[NCLaker]

Thanks all for the suggestions on what to check.

I have driven it ~50 miles, mostly highway. Coming out of storage the tank had about a gallon it, so put in a can of Seafoam and filled it up with ~9 gallons. Is the Idle control valve, the same as the item airjet refered to between the intake and the head? I thought about about trying the carb spray test (as suggested by airjet), but I am not sure I am comfortable with doing this - especially since I am not sure how to find the engine location descibed.

Also, I tried listening for a hiss in from the engine and could not detect the sound (per Capt's suggestion)

[Jeremy airjer W]

AIRJE"R" not airjet

The area that I am talking about is where the intake plenum bolts to the head. The fuel injectors are monted right in this area. Occassional we will see the gasket in between the intake plenum and the head fail and cause a simular if not identical symptom.

Carb spray should not be a problem unless the ignition wires are leaking or the engine is really hot. The problem is likely there when the car is cold but is not noticeable at that time. I have not had an IAC go bad on one of these and the fact that it runs fine when cold would lead me to believe it is a mechanical failure of some sort rather than an electrical components failure.

[norm25]

Forgot to mention this earlier but low coolant level can cause the idle air control valve to not function properly as well.

Good luck.

[NCLaker]

Coolant is something I can handle - looked full in the radiator but the resevoir was empty so added up to the max line. Hopefully does the trick.

Airjer - sorry about the typo. If the coolant trick does not do the trick, I might have to stop by Woodbury Autocare - I work a couple miles from there. What hours & days of week are you there so I could have you take a look (on the clock of course).

Thanks!

[Jeremy airjer W]

No problem for some reason the t gets substituted a lot!

Bring it on over, I'm there everyday from 3-10. This Saturday 8-4. I will be off today and Monday.

[NCLaker]

I tried Norm's suggestion on the coolant level. Since filling the coolant reservoir the idling seems much better (not sure if this is coincidence or due to just driving more since pulling from storage).

Now it looks to be idle at ~400-500 RPM range. Is that the level it should be at?