Author Topic: Losing power -- fuel related? (Read 4945 times)

Methanolab · « **on:** April 29, 2006, 09:44:15 am »

I've got an '83 quantum TD that I am working the bugs out of. I've put 1200 trouble free miles on it with everything running pretty good. Now I am cruising down the highway and am getting a loss of power. Then I press the peddle and nothing happens. The motor keeps idling then it clears up and I go on as normal. This kept happening yesterday. It happened worse again today and it stalled out and I couldn't get it to start again. I get a tow home and when I got here it started.
I just replaced the fuel filter and air filter the other day and noticed some air bubles in the line. Last night I checked the screen at the botom of the fuel pick up tube and it looks good but the clamp holding it to the shock boot was broken; I replaced it with a zip tie and filled up the tank. I am thinking I should check the fuel lines for clogs. Other than that is there any way I can test the fuel pump or know if it is the problem? Could this be caused by a problem with the EGR system? I also may have gotten a small amount of brake fluid into the fuel tank that was left in a funnel when I added some ATF to the tank, could that small amount be causing this? Thanks in advance.
--Chris

jtanguay · « **Reply #1 on:** April 29, 2006, 09:04:34 pm »

Hmmm.... Could this be an air-lock issue? I had a 1983 audi 5000 gas do what you are describing. It would drive for a bit, then lose power, and die. Wait for 10-20 mins, and she fired right back up! Turns out the gas cap was broken... wasn't letting air into the tank. So the car would suck the gas, until there was this large vacuum in the gas tank. Took a while for the tank to suck air back in and when it did all seemed fine.

I had to take off the gas cap to relieve the pressure every once in a while until I got a new one.

I hope this is your problem, because its such an EZ fix!

Methanolab · « **Reply #2 on:** April 29, 2006, 09:38:45 pm »

I don't think it is air-lock. I checked the gas cap and it is working well and the vent line is clear enough that it would relieve pressure. I recreated the condition by clamping the line and reving the engine till there was a power loss then it stalled. There was froth in the filter to pump line. I then road tested it (without the line clamped). I ran it up the highway till it lost power and stalled, then I pulled over quickly and saw that there was froth in the line again. So the problem seems to be from the filter back.
I took out the fuel sender unit and there was some crud in the cup in the bottom of the tank that it sits in. Not a ton but maybe enough to stop up the screen. I drained the tank and sucked out the crud. Tomorrow I am going to drain the fuel line and make sure it is not clogged and maybe even drop the tank to rinse it out although it looks pretty clean. Does anyone have any suggestions on improving the flow/function of the in-tank strainer? I am thinking of making it wider so it is harder to clog.

Methanolab · « **Reply #3 on:** May 03, 2006, 06:22:40 pm »

I think I've got it. The PO replaced the rotten steel fuel lines with rubber hose then proceeded to clamp the fuel lines between the tank and the underside of the vehicle; thusly squashing them and restricting flow. I dropped the tank and all lines and flushed them. Then reassembled, put the tank back up, then snaked the lines through where the steel lines went so they move freely. Seems like all is well. Thanks for the replies. The fuel sender is also dead so I put a 60 ohm resistor in line and the gauge reads just over half a tank now. Its good for the psychological factor.

jtanguay · « **Reply #4 on:** May 03, 2006, 07:22:21 pm »

Quote from: Methanolab

The fuel sender is also dead so I put a 60 ohm resistor in line and the gauge reads just over half a tank now. Its good for the psychological factor.

hehe!!! glad to hear your problem is fixed.

hillfolk'r · « **Reply #5 on:** May 07, 2006, 12:15:04 pm »

on one of my old rabbits once, i drove over a big rock,and smashed the fuellines flat,i had like no power,,,,i cut em outta there,all was well,besides the big dent in the floorpan!!!