stumble, bog, stall, recover
 

Good morning. My question regards a 1993 Civic LX 1.5 liter, 5-speed manual. ~120,000 miles. Timing belt changed at ~80,000.

Firstly, let me say that I did look in the “already solved, FAQ” section and did see what I thought would be a relevant posting to my problem, but I did not see the definitive fix included in the string.

My Civic bogged down yesterday, when giving it any throttle over just a touch. That is, at a very light acceleration it ran fine, but giving it any more than that would result in a severe bogging down. It stumbled and actually stalled a couple of times, but restarted. The ambient temp yesterday was 96º F with the heat index at 104º. I had just exited the freeway and made a turn when the bogging started. I made it to a gas station, removed the fuel filler cap, heard the requisite whoosh, and then filled up the tank. It was at about ¼ capacity before the fill up. The car recovered, and has not exhibited a problem since yesterday. I also added a bottle of Techron Fuel Injector cleaner with the tank of gas. No check engine light illuminated.

I believe that this problem will be back soon, and possibly will not recover allowing my to get to a destination. Therefore, I am looking for any similar stories, problems found and fixes.

Ed Fisher
Dallas, Texas

RE: stumble, bog, stall, recover
 

i would check the timing on the car...... my old car was stumbling and then picked up fine and it was the timing... when i swaped the belt i had the one or two tooths off the timing belt.... fixed it and then reset the timing to correct and it ran like a champ...

RE: bog, stumble, stall, recover
 

Addiction2Bass:

Thank you for the response, I will check the timing. My posting title may have been a little misleading though, it should have read, "bog, stumble, stall, recover". It was immediately after exiting a freeway, stopping at a light, and then taking off from a stop. If the timing had jumped, as in from missing teeth on the belt, I cannot imagine it recovering after a brief stop. It would seem that the cam/crank being off-synch would stay off. It certainly is worth a look though, and I do thank you for your response.

There is a posting with my exact symptoms on Wikipedia, so there may be a documented fix that shows up there. If so, I will post my findings here.

It almost seems as though there is a switching valve, or similarly actuated sensor, that is open/closed at freeway speeds, that didn’t like the sudden stop from those speeds/vacuums/signals, and then asked to move into a off-freeway state. A lazy slide on a valve? Perhaps carboned up on a 1993 with 125,000 miles? A vacuum line that collapsed just a little in this high-temp and demanding scenario? There has to be a logical explanation, and I am pouring over the manual now trying to understand the diagnostics a little better.

Thanks again for the posting, and any and all help from others is certainly appreciated.

RE: bog, stumble, stall, recover
 

And what is that documented fix? Or is there only a question with no responses yet?

RE: bog, stumble, stall, recover
 

"And what is that documented fix? Or is there only a question with no responses yet?"

It is simply a question with no responses yet. When I do find the root cause problem I will certainly post it to this list. Actually, I had hoped that someone here would have seen this/fixed it, but apparently it is not as common as I originally thought.

RE: bog, stumble, stall, recover
 

Making the exit ramp and sharp turn might have led to pulling a slug of water out of the gas tank. Purely a guess.

The controls are very simple. There aren't many valves, etc. to go wrong. Just a few sensors and a computer. There isn't any part specificially dedicated to high speeds versus low speed.

RE: bog, stumble, stall, recover
 

Rare intermittent problems are typically the most difficult to solve, leaving you to consider common causes for the symptoms. Low fuel pressure would fit into this category. When was the fuel filter last replaced? If it's been a while, this is a relatively straightforward maintenance item that would be worth doing and may even prevent the problem in the future.

RE: bog, stumble, stall, recover
 

Ron J wrote: "Rare intermittent problems are typically the most difficult to solve, leaving you to consider common causes for the symptoms. Low fuel pressure would fit into this category. When was the fuel filter last replaced? If it's been a while, this is a relatively straightforward maintenance item that would be worth doing and may even prevent the problem in the future."

I agree with intermittent problems being the hardest to pin down, and also with the fuel filter replacement being a smart move. I was just looking at the diagram for the fuel pump and it says (loosely quoted) 'if the fuel is obstructed on the discharge side, the relief valve will open to prevent over-pressure'. A intermittent clog inthefuel filter would certainly cause that condition, whereby the relief valve prevents full fuel pressure resulting in a starving/bogging condition.

mk378 wrote: "Making the exit ramp and sharp turn might have led to pulling a slug of water out of the gas tank. Purely a guess.

The controls are very simple. There aren't many valves, etc. to go wrong. Just a few sensors and a computer. There isn't any part specificially dedicated to high speeds versus low speed."

This is a good guess, since water and fuel can certainly separate. I was thinking of something like the fuel pressure regulator, perhaps getting an indication that the manifold pressure and the fuel pressure differed by enought to open the diaphram and feed the excess fuel back through the return line. Not likely I admit, but just a thought.

I really appreciate the comments and thoughts that I am receiving. Thanks for taking the time.

Ed

RE: bog, stumble, stall, recover
 

Fuel filter has been replaced, and the problem started to replicate when the fuel tank reached the 1/4 mark. This is the same symptom as last time, that is, exit freeway, come to a stop, car bogs way down with acceleration, recovers when the accelerator is released, stumbles, and tries to stall. This time, I filled the tank right away and the problem has not duplicated, again. Before the hard failure I notice that when shifting into 3rd gear there is a stumble, which may or may not be related. Any other ideas? Incidentally, the idle is going very low when the ambient temp is 90+ and the AC is on. Will cleaning the IACV screen remedy this?

Thanks,

Ed Fisher

RE: bog, stumble, stall, recover
 

I think cleaning the EACV/IACV is a good idea.

The main relay that controls power to the fuel pump is well known to fail in hot temperatures, so you might also consider soldering it:

http://techauto.awardspace.com/mainrelay.html

RE: bog, stumble, stall, recover
 

EACV cleaned this weekend, and the PCV valve verified to be working/sliding. The PCV hose is a little compromised, i.e., doesn't exactly snap back into position after pinching, but I think it is operational. Will report back after I get the tank low again. The ambient temperature shouldn't go down now until late September or so...

Thanks for the tips and responses Ron. The main relay site was very interesting.

Ed

RE: bog, stumble, stall, recover
 

Update:

I can say with relative certainty now that the bog, stumble, stall, recover is a function of getting below 1/2 tank and nearing the 1/4 tank of fuel capacity only. The problem replicated this morning when the ambient temperature is only 78º F right now. It does seem to get worse as the gauge drops below 1/2 level. Also, it appears to worsen a little after a turn. For instance, on the freeway at a constant speed, level ground, there are no hiccups. When shifting, as in sloshing the fuel a little, there is a distinct stutter. Would this point to the fuel pump, as in pickup screen or tube fell off?

As a recap I replaced fuel filter no help. Cleaned EACV no help. Cleaned and verified PCV no help.
Again, any help is greatly appreciated.

Ed Fisher
Dallas, Tx

RE: bog, stumble, stall, recover
 

You can inspect the fuel pump in the gas tank (see diagrams).

However, is it possible that the fuel gauge or sending unit has become inaccurate and that, when you have the problem, you are actually beginning to run out of gas?

Attachment 26609

Attachment 26610

RE: bog, stumble, stall, recover
 

Yeah when you're "1/4 full," how much gas can you pump in before it will take no more?

It's easy to take the pump out and inspect it, the tank should be mostly empty first though. Have a new tank filter on hand and just install it whether it seems to need it or not.

RE: bog, stumble, stall, recover
 

Good thoughts on the gauge being inaccurate, I should have posted that the amount of fuel pumped in is commensurate with the gauge reading; ¼ tank remaining on gauge is roughly 7 gallons or so. My tank is completely full right now so I’ll take out the pump when the level gets sufficiently low. Another thought; could the pump be overheating when the level gets low and becoming intermittent at that level?

Thanks for the pictures on the fuel pump, I appreciate the effort. I have found the online service manual but it is nice to know that I am looking at the same pump as you. Please keep all ideas/theories coming. I will replace the tank filter, after a thorough inspection, thanks for that tip.

One other side note, the car coughed yesterday when leaving church with a full tank and shifting out of 2nd gear. Even my grandson noticed it, so I know it wasn't paranoia. Could I be getting closer to a hard fail of some sort?

RE: bog, stumble, stall, recover
 

Do you have the D15Z1 engine? If so, you might want to inspect the EGR system.

Regarding the possibility of a faulty fuel pump, you could measure the fuel pressure.

Other items worth consideration:

-Clogged air filter
-Ignition timing out of spec (check with timing gun)

RE: bog, stumble, stall, recover
 

Engine is a D16. I'll check the timing, but the car seems fine except when low on fuel..

RE: bog, stumble, stall, recover
 

Your most recent experience seems to suggest that the problem may also occur when the gas tank is full.

RE: bog, stumble, stall, recover
 

Agreed, the cough with a full tank may be related. It has not replicated since though, and the car will darned near not run at all when the fuel level is low. This makes me think that it was a one-time occurence but I have been wrong plenty of times and this could be no different. I will give it a good check-out as soon as the tank gets a little lower.

I will be out of state for a week or so, and therefore my response time may be a little delayed, but I will get to the bottom of this and post the root cause. Thanks Ron, for sticking with me.

Ed Fisher

RE: bog, stumble, stall, recover
 

I understand your continued focus on the fuel system.

If you would characterize the problem as rough running/misfiring, then the Fuel System Troubleshooting Chart below suggests that you consider: (1) problems with the fuel injectors (Seafoam treatment?), (2) contaminated fuel in the tank (drain and discard remaining fuel when problem occurs at 1/4 tank?), and (3) problems with the fuel pressure regulator.

Attachment 26535

RE: bog, stumble, stall, recover
 

Ron: (and anyone else still reading this saga)

I would consider it a rough running/misfire, almost to the point of not running at all. It is a serious bogging, stutter, close to stall, shaking type of misfire. The last time it was running so poorly, I swung around with a U-turn, let it set a second to compose itself from the turn, and slowly went back to a near gas station (Shell). I had actually wondered about bad fuel that does not show itself until the tank is low. The theory being that the good fuel sinks to the bottom and is picked up by the pump, while the contaminated fuel separates and floats on the top only to show itself as the good fuel is used up. The only hesitation that I have with this theory is that I judiciously buy from the same two stations, both top tier gasoline, Chevron and Shell. Of course, anyone can get a bad delivery though in their underground tanks. It almost acts as a floating diesel fuel. I will definitely investigate this thoroughly. I hope I can get the tank sufficiently low this time before trying to siphon all of that out.

I also should have mentioned that I ran a bottle of Techron Fuel Injector cleaner in the tank as soon as the problem first appeared. No help there, and I have had very good luck with this brand of cleaner in the past (contaminated flutes on the intake valve(s) of a Toyota Camry cleared right up).

Do you have an idea what the fuel pressure regulator may be seeing on a low tank? I read the manual and it seemed that the regulator opened when there was a disparity between fuel pressure and manifold pressure, but I can’t tie that into the lower fuel in the tank correlation, especially since the tank seems pressurized as evidenced by the “whoosh” when removing the filler cap.

This will be interesting. Thanks again Ron, your approach is both logical and intelligent, and I appreciate both.

Ed Fisher
Dallas, Tx

RE: bog, stumble, stall, recover
 

Yeah, I guess the best fit is contaminated fuel, particularly fuel contaminated with water (or some aqueous solution) as earlier suggested by mk. I think that gas and diesel fuel would be fully miscible, so this would not fit as well. In the former case, water is more dense than gas and therefore would be at the bottom of the tank.

Here's a possible scenario:
When the tank is full of gas, the fuel pump draws only gas, which is in vast excess over the small amount of water at the bottom of the tank. As the gas level falls in the tank to 1/4 full, there is a much smaller amount of gas mixed with the same amount of contaminant water and, in addition, the lower total fluid level permits more sloshing and mixing of the two fluids, allowing uptake of water by the fuel pump and causing engine bogging.

RE: bog, stumble, stall, recover
 

I have found the definitive fix for the problem of bogging/stalling when the fuel level reaches below somewhere under ½ to ¼ of a tank-full of gasoline. The fuel pick-up screen, or in tank fuel filter had detached from the fuel pump. The slip fit of the plastic components would not adequately hold the filter in place, so I used an epoxy called ‘tank repair’, which is two-part, to adhere the plastic elbows/fittings used for the filter to pump pickup. The car now runs down to 1/32 of a tank with no problems.

My theory: air bubbles from sloshing and low fuel could get into the orifice for the fuel pick-up and cause the sputtering/bogging/stalling conditions. The bubbles are more pronounced and closer to the pickup when the fuel level is low. Even with the in-tank baffle in place and secure, the small bubbles in the fuel are picked up by the pump inlet. The fuel filter, with its very small mesh screen, acts as a sieve to keep the bubbles out of the pick-up tube and therefore out of the fuel circuit, which of course includes the injectors. Air bubbles are simply too big to make it past the screen.

Thanks for reading, and thanks to Ron J for sticking this out with me.

RE: bog, stumble, stall, recover
 

Nice fix. Congratulations. Did you happen to shoot any photographs of the filter/screen so that you could post them for others to see?

RE: bog, stumble, stall, recover
 

Ron:

I did not get any pictures, actually I never thought of it, but I will know better for next time. It is all pretty straightforward once you get the pump out. I fished out my filter from the bottom of the tank with a pair of forceps and when test fitting I could see that it was a loose fit. I believe my pump had been changed out by the previous owner, and just the motor was replaced which necessitated removing the screen and putting it on the new motor/pickup. This was probably where the problem originated. Anyone replacing the pump would be advised to epoxy the filter/screen to keep it in place.

Thanks again Ron.

Ed

This really should be a sticky post
 

Ed,

First, let me congratulate you on your fine detective work and perseverance in trying to isolate your issue. Ultimately this led you to your problem source and solution.

Second, others might have this issue in the future and I'd hate for them to have trouble finding your solution.

Third, would you be willing to start a new thread, copy some of your descriptions and then your solution you posted here at the end? that way, no one will have to look at 3 pages of posts b/4 seeing the solution. Perhaps, label the subject as Problem Solved:...

Lastly, would the mod be willing to post this as a sticky or under the "Look here first" section?

Thanks.

RE: This really should be a sticky post
 

I would be willing to start the thread, and post it as a 'lessons learned', or 'solved', of something as such. I don't know about a sticky, as this seems to be a rather isolated occurence, but I will let others decide about that line of reasoning.

I will also add that a 'problem solved' section is a good idea. After a search, I read pages and pages of someone chasing a stumbling/bogging problem and the fix/solution was never posted, not even at the end of those several pages. It was, admittedly, very frustrating.

Thank you for the kind words.

Thanks for posting all your info, Ed.

I am having the same issue with my 99 Civic EX. It will bog down, jerk, and come close to stalling while I try to accellerate while under 1/2 tank of gas. I had it at a Honda specialistist for diagnosis/repair yesterday. So far I believe plugs, distributor wires, and some other electrical things have been changed out, to no avail. I have a return diagnosis appt. Monday and will be taking a copy of your fix and problems for them to look over. I Techron'd last night as well as filled up, so maybe my problem won't duplicate until I get under 1/2 tank again.

I think you likely have the solution though and again, thanks for posting.

Thanks for the post. I have a similar problem but is very intermittent but never really paid attention to the gas tank level when it happens. It happened last night and my tank was at 1/3 full. However, it may have been full at one time but not really sure because I wasn't paying attention to it. I started a thread but didn't update it because problem is very intermittent. In fact I went through two gas tanks and didn't really sputter to bad, just a little unresponsive to 1st or 2nd gear acceleration a couple times.

Regarding the new posts on the stumble, stall, recover. If you remove the rear seat of your car and lift the cover on the tank you can easily see the screws holding the fuel pump to the tank. Seriously, the hardest part of this was removing the rear seat as I didn't know there was a hidden screw. All in all, 30 minutes should reveal whether your pickup tube/screen has become detached from the pump. In my case, the pump had been replaced by the previous owner. Replacement pumps are motor only, which means the pickup tube from the original pump must be used on the replacement. It is a loose fit when re-used. Best of luck.