Stalling when fuel below 1/4 tank

[enslow]

My wife tells me her 97 Lesabre stalls occasionally when she's over the 400km mark. I don't believe she's running out of gas, otherwise her fuel economy should be much worse than on my 99 Lesabre. I forget how much fuel I put in the last time, but it wasn't so much that the tank would have been empty.

I'm planning on checking the following:
1) Replace the fuel filter.
2) Add a bottle of Techron into a 1/3 full tank to help clean any gunk.
3) Check grounds underneath the coil packs (an idea I got from another stalling thread).

Would a liter of methanol in a 1/4 tank of fuel be harmful to the fuel system/engine to help remove any water in the tank?

I would have thought that a clogged fuel filter would cause stalling whether the tank were full or near empty. I would also have expected that poor grounds would cause stalling on full and near empty tanks. That leaves contamination in the tank. Am I on the right track or have I forgotten something?

[2000Silverbullet]

Take a fuel pressure reading.
Shouldn't let the tank regularly get below 1/4.
Clean the tank before you change the filter or get two filters.

[enslow]

Take a fuel pressure reading.
Shouldn't let the tank regularly get below 1/4.
Clean the tank before you change the filter or get two filters.

Cleaning the tank sounds like a big job. Are you suggesting that contamination in the tank is likely given the symptoms? Or would the Techron treatment be enough for cleaning the tank.

I agree that it shouldn't get below 1/4 tank. And before I tell my wife she shouldn't let it go below 1/4, I'd better start remembering to keep my tank above 1/4 also.

[2000Silverbullet]

I meant cleaning the tank with the techron.
I'm a big believer in the effectiveness of using techron.

It will remove a lot of crap so you should change the filter again after a few tank fulls.

[enslow]

Thanks a lot! I knew it was good stuff, but to hear that I'll have to change the fuel filter again after a few weeks suggests that it works even better than I thought. I'll see about getting the Techron going this weekend.

[enslow]

I was looking for a write up on changing the fuel filter, other than my FSM which has simple drawings, and not the most clear. I finally found it, but it was under this thread:
http://www.pontiacbonnevilleclub.com/fo ... 6&p=206708

This looks like a really good write up on changing the fuel filter, along with good pictures. How easy would this be to put into a tech thread? For now I'll be saving the thread in my favourites until I get the job done. It seems easy enough, but the procedure is much easier to follow than the FSM.

My thoughts on the procedure:
1) fuel pressure relief: I will try pulling the fuel pump relay and running the engine until it stops. This is the trick used in the Ford Service Manual and works well with no mess in the engine bay.

2) Can I install a vehicle lift like the one shown in the link for under $100 and in a morning? Man, that is luxury.

[swiles]

that was a problem for me i found that the fuel pump was going i would look into changinf it if pressure and filters are good

[enslow]

Oh great. I hope it lasts until the summer then when I'm off work. I don't have a fuel pressure guage, but maybe it's time to get one. However, the car does have 200000km on what's probably the original fuel filter. The fuel out here is not so bad except that it has quite a bit of ethanol in it now as regulated by the government.

Is it common to replace fuel pumps on cars several times in a 20 year or 400000km lifetime?

[2000Silverbullet]

the car does have 200000km on what's probably the original fuel filter.

LOL that's the funniest quote I've heard in a while!

[00Beast]

the car does have 200000km on what's probably the original fuel filter.

LOL that's the funniest quote I've heard in a while!

Yeah, I'd change that ASAP. I change our fuel filters on the Bonnevilles yearly.

[enslow]

the car does have 200000km on what's probably the original fuel filter.

LOL that's the funniest quote I've heard in a while!

Hey, don't blame me.... I got the car last summer with 197000km. I suppose the fuel filter is one of the first things I could have done, but it was more important to do a tranny fluid change, plugs, wires, oil change, and then winter set in.

Once I'm over this darnned cold I'll get a fuel filter in.

FWIW, I only changed the fuel filter on my Grand Marquis once every 100000km. I think the fuel in Vancouver is probably cleaner than other places. It also has a lot of ethanol in it which causes its own drivability issues. I've never had any drivability, fuel economy, or emissions issues related to fuel filters, but I usually change them once every few years.

From what others have said, it seems as if the gasoline is pretty bad in places. Some people claim their fuel economy drops drastically, others do talk about clogged fuel filters. This car came from the interior of BC and may very well have had bad gas.

[enslow]

Besides, it's only the wife's car..... don't tell her any of this, she'll kill me!

[00Beast]

Gas is *shoot* no matter how clean you think it is. Add to that an old rusty tank, and you have issues. Replace the filter ASAP.

[enslow]

I agree Beast. It just that in some places people talk about the gas being so bad that their filters clog up within a couple of years. That just doesn't seem to happen here. Certainly, the performance of my Grand Marquis never changed after changing the filter in the 14 years I've driven it. Yes, I did change that fuel filter about 3 times.
But yes, definitely, I will be changing that fuel filter ASAP. In fact, I'll be doing both the 97 and the 99. I'm just waiting for my $#@% cold to lift. On Saturday I when I stood up I almost fell over from dizziness!

[2000Silverbullet]

Since you don't know the complete history on those 197,000 kms I'd change the filter.
I think you have a plastic fuel tank but most fuel stations have metal tanks.

A fuel pressure check after the filter is changed is recommended to rule out a weak worn out pump.

[2000Silverbullet]

Oh Larry, we are spoiled with temps here in BC. It's warm compared to the rest of NA.

Get er done. 3C is not even glove weather!

[enslow]

Oh Larry, we are spoiled with temps here in BC. It's warm compared to the rest of NA.

Get er done. 3C is not even glove weather!

Silverbullet, I was talking about MY cold, not THE cold.

Now, my wife is probably because I'm probably whining too much about my cold, so I'll give you that.

[renchjeep]

I ALWAYS change my fuel filter every 20k miles, or less. (not sure what that works out to in km.) Cheap insurance for the fuel pump.

But, I did recently (about a year ago) replace my fuel pump with a new Carter unit from NAPA, with a new fuel strainer or "sock", and shortly afterward had a similar problem. Starving for gas at 1/4 tank, especially on hard turns. Turns out that my Carter fuel pump had decided to drop the "included in the box" fuel strainer! Bad fitment by me, bad part, knocked around a bit during installation? Bought a new AC Delco pump and strainer (twice the cost of the Carter!), and no problems so far! (10k plus miles)

I must mention that when I was experiencing the "fuel starvation" problem, I could actually HEAR the fuel pump becoming louder, and thought that maybe I had a broken baffle in the tank. I was looking into a new fuel tank, as I understood at the time that broken plastic baffles in the fuel tank can cause the same type of problem.

If you DO drop the tank, look for broken baffles, or a lot of sediment in the tank.

Good Luck.

[jonnevilleSSEi]

I noticed the other day that my low fuel lamp went on when I knew I'd had had 1/4 tank remaining. I was parked on a hill with the rear of the car higher than the front. I deducted that may be the cause and verified such when I started driving and the tank settled back to where it was. A close friend who buys and sells cars (and turned me into the Jonneville!) mentioned that a lot of GM fuel pumps are located in bad positions and that I shouldn't let the tank go beyond 1/4 full OR park on hills if it's anywhere near there. He's had GM cars of that era not start because of that alone.

[enslow]

Thanks to Beast's write up on changing the fuel filter, I managed to get both filters done on the 97 and the 99. Now, he was working on a nice new car, not an old rusty thing like mine (well, my wife's). I used a lot of Seafoam Deep Creep (I didn't have PB Blaster), a hand wire brush to loosen as much external rust as possible around the threads, then more Deep Creep. I also had to use a small hand file to clean off the rust from the shoulders of the 5/8ths nut. It is a really tight fit, but it will go on if the nut is clean.

If you set up the two wrenches, you can often loosen stuck nuts by squeezing the two wrenches together. Vice grips are just too bulky for this method to work. When it didn't work the first time, I sprayed more Deep Creep on, wire brushed off more external rust, then tried again. After an hour I got it off. I knew if I got impatient, I'd be spending another couple of hours getting a repair kit. It took me an hour to get the filter off my wife's car, about 15 minutes on mine. That time includes jacking the car up and getting tools out.

I got a fuel pressure guage, but I have yet to use it. It comes with quite an instruction manual. While I've got a pretty good idea of how to use it, I do believe in reading instructions first. I'll check the pressure later. Besides, I've got a ballast to change in the kid's bathroom now.

Thanks all for your suggestions. I have considered all of them. I'll try to wait until summer before looking into the fuel pump. This is a very friendly board, the reason I joined. I hope, if the admin here is open to it, to contribute to the tech section on some of the things I have, or will do. For example, I may consider writing a tech article on changing out the little bulbs for the door locks, or changing the drivers side mirror. I've done that twice now (not for me though!)