engine and drivetrain Fuel vapor-lock problem-need help.

[TobyB]

Holy Pants-

I wonder if the large filter, mostly full of air,

was acting like a resonator and reacting with the

fuel pump to prevent it from drawing?

That would be cool, in a PITA way...

t

[jgerock]

Glad you could solve your fuel problems.

Most folks with carb'd 2002s like to add one of those plastic see-thru filters as used on air cooled VWs. Many of these new ones are really substandard quality and the internal "orange" element can dissolve and clog up a carburetor. The VW-based ones are fine for a tiny single-barrel Solex, but probably don't have enough capacity for a twin-choke unit.

[Napes]

Jim; Maybe I've just been lucky, but I've been using the "see-thru" VW filters for the past 20 yrs. (or more) with no problem to date, and I run a 38/38 Weber on my car (though the car that's having this problem runs a 32/36).

It's looks like I spoke too soon in my post above, because similiar fuel starvation problems reared their ugly head again this afternoon. Got the car home by pouring fuel into the carb a few times to get it running, then limped home.

After allowing the engine to cool for 3½ hrs. w/ the hood up, and seeing the fuel filter now full of fuel, I finally decided to disconnect the fuel line at the carb and see what came out when turning the engine over. Absolutely nothing came out, so now I'm finally suspecting my brand new fuel pump may be the source of my car's erratic performance.

The car ran so good when it was running w/ the new pump I thought that could not be the problem. But I may have been wrong.

Tomorrow I'll remount the old pump and see where I'm at. This is becoming sort of like a telenovela on Mexican TV. Stay tuned.

Bob Napier

Re-installed the old, original Pierburg pump and the car has run flawlessly since. Apparently there is something not right in the new pump, and all this time I thouhgt it was a vapor lock problem. Should have looked more closely at the "last thing done" on the car - that was the pump. It just fooled me because sometimes it ran great, and other times, nada.

[Lippincott]

.

Edited March 30, 2014 by Lippincott

[hankeester]

On 8/18/2009 at 12:32 PM, Napes said:

Problem appears to be solved. I greatly appreciate all who offered their thoughts and suggestions. As with new problems ask yourself what was the last thing you did. I half did this - I installed a new fuel pump, which was working great. I didn't pay enough attention to the other thing I did.

I though I'd install a new filter as long as I was going to replace the pump. Went to PepBoys, WalMart, AutoZone, and, finally, Checker looking for the small fuel filter I've always used (the one that's about 1¼" in dia. and is used on air-cooled VW Bugs). I was unable to locate one so I went with the smallest I could find which looks to have about ½ cup volume.

I decided to try Barry Allen's suggestion of running a new fuel hose from the firewall to the pump. Went to my friend of 25 yrs. at CarQuest (don't know why I forgot to check there for a filter) for hose and while we were comparing the 1/4" and 5/16" i.d. hose to the stock 8mm he brought out a filter to check to see which was going to work best. I was looking at the hoses when my wife, who was standing next to me, said, "Look, isn't that the small filter you've been looking for?" Yep, it sure was.

I again checked with Rob Torres @ 2002 Haus and he still recommended placing the filter before the pump. The OEM Pierburg also puts out 3 psi as per J Swift's suggestion, and this proved to be insufficient to deal with larger volume filter.

So far the new small filter seems to have solved the vapor lock problem.

I hope my experience will help others in the future.

Bob Napier

 

 

Napes,

 

Funny thing on this, you might have just fixed my problem. I put a fuel filter on a couple weeks ago along with a ton of other tune up stuff including points, condenser, plugs/wires, etc.

The previous owner must have deleted the fuel filter so I just bought one that looked the same as what Pelican or Blunt sells from Lowes in the lawnmower section. I didn't think about the psi at the fuel pump and if an oversized filter would affect things. I just ordered BMW OEM filter and will see when I get it installed or initially just compare sizes to see if the OEM is a lot smaller. I've been chasing vapor lock only when engine is hot and on hot days for 2 weeks (doesn't happen in 70 degree weather). I also have a backup fuel pump in the trunk I'm going to replace too but after the filter is installed so I can see where the problem was...