Author Topic: Inj pump taking on air, but no visible fuel leak (Read 1930 times)

erikandelman · « **on:** February 15, 2008, 10:11:26 am »

Hi all,

I have a 1985 rabbit 1.6 non-turbo diesel.

My injector pump is taking on air overnight, but there is no visible fuel leak. I can crack the injectors, bleed it out, and get it running, but would like a better solution!

I can only assume that fuel must be leaking out somewhere and air coming in. I have a clear line between the filter block and the pump, and the air is visible from the filter out and down the line several inches. Since the filter block is at the top of the system, and there is no visible fuel leak, I believe it is impossible that the filter is the source of this air.

Is it possible that the pump is leaking fuel and taking on air through a seal that is not visible? If so, what might be the likely location and culprit, and possible solutions?

Thanks so much,
Erik

KTZed · « **Reply #1 on:** February 15, 2008, 10:23:18 am »

Check the connection between the pump and supply line and tighten up the clamp. Tighten up all the connections while your at it. The fuel system is under vacuum before the pump so it is possible to take on air without leaking fuel. Mine was doing this.

jtanguay · « **Reply #2 on:** February 15, 2008, 11:22:03 am »

the other day my car wouldn't start... wondered wtf as i saw that my fuel return line was near full of bubbles! after cranking i could see the fuel flowing through the line... but not enough juice to crank for 1-2 minutes to re-prime the pump enough. turns out it was the little rubber line from the pre-heater return... i just cut it off because it was on there pretty good. it was all cracked on the inside! put a new piece of hose and clamped it down good... and she started after about 10 seconds of starting. i'll need to change some other hoses too though as she's starting and idling a bit weird now.. hopefully not from the air in the pump? but it was the return line... a little air leak can be a PITA! look for signs of diesel leakage. my fuel filter had a small puddle on it :wink:

KTZed · « **Reply #3 on:** February 15, 2008, 12:03:15 pm »

Ya I was poking around the pump the other day and pushed up against one of the little injector return lines and noticed a "phffff" sucking sound. Looked a little closer to see they were all cracked and just a little bump cause them to suck air. I bought some 1/8"ID clear polyurethane hose and will be replacing them over the weekend. I'll beat these bubbles yet :roll: