Car died then came back to life

[saucy]

On my way home last night my 94 MTX suddenly lost all power, not electrically, it just would not go. I pulled off to the side of the berm and was able to drive at like 25mph but it would not rev up like it was not getting gas. I filled up last week and the tank was now all the way down to 1/8. After putting for about a minute it cleared it's self up and was running normal but then the check engine light came on. I was afraid I might have water in the tank so I headed for some gas. By the time I got to the station the check engine light was out and the car ran fine. When I removed the gas cap there was more pressure than I had ever really heard from any tank. Could my cap be screwed up, causing a pressure problem. Also my I noticed since I bought the car in November that the fuel pump whines really loud. I read on these forums that the filter is probably past due for a change. Any suggestions on what cuased this little episode.

 

[projectSHO89]

It definitely sounds like fuel starvation caused the almost-stall condition.

Since your CEL did come on, read your codes to see what the computer didn't like about the running condition of your engine. The code(s) may be helpful in getting a more accurate diagnosis.

Pressurized fuel tanks are very common and are not in themselves indicative of a problem.

The fuel filter idea is definately a good one. The part is relatively cheap although a bit of a PITA to replace due to location and raw gasoline.

Your stumbling symptom along with the whine could be a warning sign of impending fuel pump failure...or not.

Steve

 

[saucy]

I'll check the codes this weekend. I've been meaning to get to that filter, just can't catch a break in the weather here. There is alway a foot of snow on the ground. (Ohio)

 

[SHO--ripper]

IF you are going to replace the fuel filter you should replace the pump while inside the tank. Your problem sounds like you need a new pump. WHen you turn the car on does the pump make a loud noise? if so there is your problem. I would replace it asap because it will leave you stranded very soon. Hopefully your bolts won't be as rusty as mine where because i snapped the head off one and the other took hours to get out. SHOtime has a good how to on fuel pumps. Just to give you the heads up you will need a 1/2 drive with a 13mm socket and an extension. I suggest you put your car on ramps unless you have 2 sets of jacks and jackstants or even better a lift. You will also neet to depressurize you fuel system and you can do this with the schrader valve on the fuel rails. I think you need a 10mm socket also if i am not mistaken and a flat head screw drive. don't drop the tank too fast because you could risk snapping a fuel line. Hopefully this will be helpfull. one word liquid wrench .good luck.

 

[SLOSHO89]

I'm not saying that the fuel filter is your problem.


Any ways... The fuel filter is easy to get to and you don't have to drop the tank like SHO--ripper said.

 

[sdpatt]

The fuel filter is outside the tank and its replacement is not easily transferred into a new fuel pump installation. Two separate jobs.

 

[jelloslug]

BUT, if you do deside to change you fuel pump, you should go ahead and change the filter while you are under there. You might also want to cut an access hole under the back seat while you have the tank off so if you ever have to mess with the fuel pulp again you won't have to drop the tank. The extra 15 or 20 minuits it would take could save you a lot of time later on.

 

[saucy]

I think that I have dicovered the problem here guys. This was the second time the car was giving me problems and just like the first time the tank was almost empty 1/8 tank originally full. This time I couldn't get the thing to even idle. When I released the gas cap there was a huge sucking sound. I put it back on, tried to start it and volla! It started! My theory is that my cap is not venting and as my fuel level is dropping from full to almost empty it's creating a huge vacuum and my pump is not getting any gas to the engine. I filled the tank up and I'm going pick up another cap today. Let me know if anyone has experienced this too. BTW, I know that my gauge is working cuz I've driven the car a couple of times dead on Empty with the fuel light on and I didn't have this problem. Maybe with the freezing temps I broke the cap trying to get it loose from the tank?

 

[jelloslug]

That "woosh" sound was pressure from the gas vapor, not vacuume. Do you know if the pump has ever been changed? It sounds like it could stand to be changed.

<small>[ February 27, 2003, 09:31 AM: Message edited by: jelloslug ]</small>

 

[projectSHO89]

It might very well have been vacuum. Has it been pressure, fuel flow would not have been reduced.

As it now runs when the cap was removed, it would confirm that it was vaccum to my satisfaction. I saw this on my new boat the first time I ever opened it up. A faulty tank vent allowed the tank to pull a vacuum and the motor would fall flat on its face from fuel starvation. A 200 Merc can do that pretty fast at WOT

Rx: New gas cap. Make sure it's vented.

Steve

 

[sdpatt]

The fuel cap does not vent the fuel tank. In fact, the fuel cap is tested during the emissions inspection to verify that it adequately seals the opening. If you are having pump problems at low tank levels, it could be the signs of impending pump failure. The pump body wil heat up more when the fuel level is no longer covering the pump. This is not a problem with a healthy pump as they are designed for this situation. It is a sign that the pump is experiencing heat related problems from its age.

 

[projectSHO89]

The gas cap is pressure, not vacuum tested during emissions testing.

Air has to get into the tak to replace the volume of fuel used, otherwise there will be a huge buildup of vacuum.

Steve

 

[DougLee25]

Exactly! When they test the gas caps at emissions time, they pump up a cylinder in order to pressurize the gas cap, not put a vacuum on it.

Doug