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fuel starvation
ditchlewis - 22/7/07 at 03:26 PM

i have a pinto with a mechanical fuel pump. the car was running well just needing a carb tune up, untill i moved the fuel filter. then the car stopped running.

if you put fuel unto the carbs it runs until the fule runs fuel.

took the pump off and it seems to be operating well, tightened all the clips and replaced a kinked pipe.

the so~~~ng thing still wont pull fuel so wont start.

Arrrrrgggh just want to set fire to the thing now

ditch


rusty nuts - 22/7/07 at 03:39 PM

Are you sure you have no air leaks into fuel feed pipe between tank and pump? A porous hose could cause your symptoms . Try just putting a piece of pipe onto inlet of pump and other end submerged in fuel . Also check for blockage and air leaks in main fuel line . Try taking fuel cap off if tank is not vented . If all this fails it may be that pump is faulty. Also check that the fuel pump push rod and operating cam has not worn.


bilbo - 22/7/07 at 04:03 PM

Where did you move the filter from and to?


zetec7 - 22/7/07 at 07:21 PM

They're right - either the line is plugged (possibly at the filter, since that's all that's changed) or, more likely, there's a tiny air leak - probably at the filter connection. Remember, mechanical pumps usually work on suction through the line, not pressure...and air moves through the line easier than fuel, so the tiniest air leak will stop it dead. Try bypassing the filter with a piece of hose and see if that cures the problem...


bobster - 22/7/07 at 08:20 PM

possibly a real stupid answer but you have installed the fuel filter the right way round?


ditchlewis - 23/7/07 at 11:29 AM

thanks for the suggestions. i will try these.

i was at a party last night and it occured to me that i had the boot box out last weekend and i recal it used to foul the fuel pipe. when i put the box back in it did not want to return easily, and i think that i might have moved the fuel pipe in some way and thus i have kinked the pipe with the boot box, at the back out of sight. the car started last weekend but i may have just been using the fuel in the pipe. it would explain why there was fuel above the pump, but none in the pipe before the pump.

tonight i will remove the boot box and have a look.

the fuel pump is new and so i was at a loss as to why it should fail.

thanks lads i will keep you posted.

ditch


DarrenW - 23/7/07 at 11:37 AM

I guess the quick way to determine if it a fuel delivery problem from tank to pump is to rig up a fuel can with pipe to the pump. If it runs OK like this then the issue is further back.

Im not sure if there are safety implications running from a fuel can. Ive seen plenty of people do it.

I kinked pipe sounds feasible. I had a filter problem in April when i serviced the car. Filter inlet was blocked with swarfe from tank, it only got starved at high revs though and usually ran ok. I could hardly blow through the filter as well. This leads me to think the pipe will almost need to be blocked to stop it running well at tickover.


ditchlewis - 23/7/07 at 01:23 PM

i have filters at both ends. one at the front 12" from the fule pump and another at the rear 12" from the tank. the one at the back is already looking filthy with just 100 miles of use.

the pipe from the top of the tank pushed up the flexable pipe along way and this was pushing against the boot box. i'm sure that this pipe has become kinked and is the one causing the problem.

well fingers crossed that it is this.

will keep you posted.

ditch