Hey all,
We've had a problem with our 96 accord since December(?). To put it bluntly, it hesitates/stumbles after a stop, acting like the engine isn't getting fuel, but only if it has about 1/2 tank of fuel or less. There are no CELS or other symptoms.

This happened shortly after I replaced the fuel filter, fuel pump, fuel pump sock, fuel lines and brake lines due to severe external rust. I only changed the pump as a proactive measure because I had to drop the tank anyways. The lines pretty much crumbled in my hands, so I figure it was a wise choice.

Being that I finished up the car in the early AM, I was tired and swapped the charcoal canister line with the return line by mistake (even though I labeled them). The car ran like this for about a day (fuel tank made some fun gurgling noises), then started spewing fuel out of the charcoal canister. Once I realized my mistake, I swapped the lines back and the car ran OK, and no more fuel spewing out, but this problem surfaced.

Could hooking up these lines backwards, even for only a day, have caused this problem? I've heard that clogged charcoal canisters or vacuum lines can cause strange things...

Thanks for the help,
Ben

 

anyone?

 

The canister is used for storing fuel vapor to later be burned in the combustion process. The Purge Control Solenoid opens which then allows engine vacuum to suck the vapor from the canister into the intake. Considering that the PCM has a set duration that the injectors are open at a set condition, if there is additional fuel entering the cylinders that could most definitely cause problems. If this happened 7 months ago I would think that fuel would have been consumed by now. I'm also questioning the fact that it only does it only at or below a 1/2 tank, that seems very strange. I would try pulling off the canister and making sure there is no more fuel inside. That would be a preliminary check.

 

Thanks for the reply--

I pulled off the canister, and it was light-weight and had no evidence of fuel still in it.
Could something else have gotten messed up by me reversing the lines for two days? Maybe a valve or something? FPR?

My final thought was that maybe hooking those lines up backwards caused a lot of dirt to stir up in the tank. The problem is that I REALLY don't want to drop the fuel tank again. That wasn't fun at all. I still dont understand why the car runs completely fine until its at around 1/4 to 1/2 tank. Any suggestions of things I should do before resorting to that would be welcome...

Oh, and I also ruled out the fuel gauge being the problem-- it is still reading properly.

 

have you tested the fuel pressure regulater. also use an air compressor on the return line that goes from the fpr back to the tank

 

Why did you replace the fuel pump? How many miles do you think you drove with the lines crossed? Have you looked at your fuel tank to see if it has collapsed? With the purge control solenoid sucking on the tank for a length of time, it may have pulled a vacuum on it causing it to collapse. If the tank is collapsed that may explain why it only acts up at a 1/2 tank and below. Imagine sucking on a soda bottle, and the way it would collapse. The same concept applies to the fuel tank but on a larger scale. Look to see if the bottom of the tank has an indention in it.

 

Well, I doubt the tank collapsed, but I'll have a look to see if its dented in tomorrow. By looking at how far it is to my wife's work, I'd say it was only driven 10 miles before realizing the mistake-- it didn't take long for fuel to make it to the charcoal canister and start leaking out.

The car has 216,000 miles and the maintenance records from the PO go back to 130k with no mention of replacing the pump. I only changed it because I had the fuel tank out to replace the lines, the car ran perfectly. They were rusted beyond me splicing on new ones, so I had to drop the tank anyways to replace the complete lines. I figured I would make sure I never had to do it again, so I replaced the pump and strainer while I had it out. I assembled the sending unit with the new pump the same way that the old one was assembled. I still have the old pump too, as it worked fine.

Been pretty busy today, so tomorrow I'll check some of the things mentioned so far (dented fuel tank, FPR...). I figure I'll also take a borescope to look at the top of the tank and make sure all the lines still look ok.

 

Keep me posted, I'm curious as to what the problem is.

 

Oh, just another quick bit of info, the car also displays the same symptoms if you put the front at a sharp downward angle when below 1/2 tank, such as when parking on a hill with the front facing downhill. The car tries to die, then will begin to slightly surge, just up to idle, then back to nearly stalling.

Also, when the A/C is on, the extra load combined with this problem can cause the car to actually stall.

 

This also sounds like you have a clogged "idle air control valve" screen. The only difference is that it would show up at all fuel level conditions. The PCM tries to idle the car up under a load but can't because the screen that the air passes through is clogged with carbon and other deposits. Just as a pre-caution I would also pull off the IAC valve and make sure it's not clogged causing additional idle problems. That may not fix all of your problems but it could be of some help with your idle.

 

If it did stir up the fuel tank it may have clogged up the fuel filter. I would swap that one more time just to be on the safe side since it's only a 15 dollar part.

 

Well, nothing conclusive yet, however, I did repair a vacuum line and replaced a clamp on the return fuel line that was MIA...

Fuel just dipped below 1/2 tank, so if/when it starts doing this again, I can do some real troubleshooting. I also took a borescope to look down above the fuel tank and everything looks normal there.

 

More details...

Tank finally got low enough to really look into the symptoms.

Firstly, I parked the car on a hill with it having 5.6 gallons remaining in the tank. The engine began to stumble badly. If you hit the gas it would nearly stall-- car was starving for fuel. Pulled it onto a level surface and it smoothed out perfectly. I listened to the fuel pump in both positions. When on a hill, the pump started making some slight knocking sounds and would speed up and slow down-- the pump was sucking air.

I think I've pretty much confirmed that I'll have to pull the tank. A friend suggested that it sounds like a bad baffle in the tank-- since the baffle is supposed to hold fuel around the pump in the case of being on a hill/inertia when stopping/etc. Maybe I was too rough with it when re-installing it (I do remember having a tough time with it--perhaps I flexed it a little or something).

So that's what I'm going with for now. I really don't feel like pulling the tank anytime soon, so I'll update this thread if/when I get to it.