It Won't Start-Not Getting Fuel

[thamlin000]

My first post on the 912 Board!

My beautiful 67 912 has been running great since I bought it last March. It has a Harry Pellow-rebuilt engine. I drive it several times a week and the only work I've done is have the Weber 40s tuned/adjusted by a Porsche specialist. Unfortunatly, since last week it has decided not to start.

I've checked, and it has spark.

The clear fuel filter has no gas in it. I pulled the mechanical fuel pump and manually pumped it, and it seemed to have some suction (when pressed against my finger). I disassembled it and there was buildup and rust particles inside the pump, but I cleaned it out and reinstalled the pump and a new filter. Still, I am not getting any fuel to it.

I have a 1/4 tank of gas and the car ran fine several days prior to this........what could be the problem? I'd guess it's the pump, but I'd hate order a new one and have it not solve the problem.

Any advice is appreciated.

Here it is.

[Duke]

Beautiful car! I would pull the hose from the fuel pump to the carb, crank the engine & see if you get fuel from the hose. You can get a rebuild kit for the fuel pump if that is your problem. Pull the sender from the gas tank & shine a flashlight down in there & check the sock filter to see if it is clogged. Rust particles indicate your gas tank needs to be cleaned out & resealed. Good luck!

[Duke]

Another thought: The fuel pump has two check valves, they allow fuel to flow only one way. You can test these by blowing air into the inlet & outlet sides of the fuel pump. I had one of these go bad several years ago & had to replace the fuel pump.

[thamlin000]

Thanks, for the help.

I'll look at it again this weekend and see what I come up with.

[Peter T.]

Please post some more of your baby pics on the 912 Pics thread!

[GSpreeman]

I have a similar situation. How easy is it to pull apart the fuel pump just to clean it out? Are there springs and things that are going to fly all across my garage...and make me have to pay someone to rebuild it?

[WFBowen]

If you're just going to remove the filter screen, it's pretty easy (can be done on the car.) If you're going deeper into the pump (diaphragm, plungers, etc.) you'll need to separate the body which is held on by the six small screws. It's done on a workbench and that's when you get into the springs, etc. Not too difficult, but one of those jobs that requires you methodically lay everything out as it's removed.
Here are some pics/instructions from a manual:



Good luck,
Bill.

[GSpreeman]

Thanks for the post Bill. Here's how I made out.

I took apart the fuel pump and cleaned it out. Not a lot of gunk in there (actually, none at all). Put it back together. I looked down the carbs when I move the throttle and can see 1 jet dribbling fuel into the carb, the other 3...nada! I pulled the jets, cleaned them with carb cleaner and then shot them with compressed air. Still nothing.

So, I took out one of the idle jets and moved the throttle back and forth at least expecting to see some fuel dripping somewhere...nothing! Dang! What next?

[WFBowen]

Is the fuel on that one throat dirbbling from the accelerator pump (i.e. the tiny tube which sprays fuel directly down the carb throat from above?) Sounds like it's time to pull at least that carb and really clean/regasket it - Solex or Weber, they're very easy to work on. Just my ballpark guess, but I'd look at the accelerator pump circuits - especially checkvalves.

[GSpreeman]

That's where it's dribbling. I just ordered a carb book. This should be fun.

[69-912-swt]

Have you tried a little gas down both carbs, just to see if if fires up, Sometimes it just takes prime to get the carbs filled up, cranking with the starter just doesn't make it.

Just a idea before you start this

Bill

[GSpreeman]

Yeah, I've blown in enough ether I'm lucky my garage is still standing.

[djdsc]

Isolate the pump to check it. Buy some fuel line, run the intake end into a gas can and the out to a can or jar. Crank the motor and see if the pump is working. Verify it is working right off the pump not through the carbs. The carbs are a whole other system to test, later.

Was your clear filter filling with any rust type particles?

How does the inside of your gas tank look? There is a brass screen filter inside the gas tank over the fitting where the fuel line comes out of the tank. The fitting and the screen will unscrew from the tank. If there is crud in the tank this can get blocked.

Don’t jump right in and suspect the carbs. Most carb problems are not.

If your clear filter is after the pump move it to before the pump, it is easy to watch it fill or not.

[912UK]

Originally posted by Duke
Beautiful car! I would pull the hose from the fuel pump to the carb, crank the engine & see if you get fuel from the hose. You can get a rebuild kit for the fuel pump if that is your problem. Pull the sender from the gas tank & shine a flashlight down in there & check the sock filter to see if it is clogged. Rust particles indicate your gas tank needs to be cleaned out & resealed. Good luck!

I agree with this as a check as most of the tanks I see have glazed filters in there.. get it out and clean it up ... be careful they are delicate buggers..

[Green 912]

dose it run at all when you put gas in the carbs?

[GSpreeman]

When I spray some ether down them I get it to fire up for a few seconds but, I'm not sure it's not just dieseling. I picked up some replacements for the idle jets from CbPerformance and dropped them in. The thing is, when I move the throttle, I still don't see any fuel squirting into the carbs even though the fuel line is full going to the carbs. I'll have some time tomorrow so I am going to try to troubleshoot everything from the ground up.

[Mao_Junior]

Hello, all!

Been reading these forums for years, and love them. Was in a wheelchair for two years related to a sports injury...was told I prolly wouldn't walk again. Also lost most of strength in arms. Prior to injury owned a 928 and 944. Always wanted an early 911 or 912. I didn't drive for nearly five years. Happily I tell you that I purchased a '69 912, and am able to walk and drive albeit with some pain. Who cares about the pain, right?? OK, enough about that.

I recently had new Weber carbs put in as my fuel tank was sending tons of rust particles out. We also finally located a new gas tank, and I had that replaced. Car was running beautifully as it has since my mechanic changed carbs. However, there was the distinct smell of gas like when the attendant puts the cap on incorrectly. Also, car needs to go back as fuel gauge not moving. I put a full tank of gas in, and started driving as normal. Well, this morning took it out for about 20minutes. Stopped and started car 3 or 4 times. When back at home car will not start now, but only cranks with nary a sound of turning. I'm not capable as a mechanic. Any ideas? Sucks that can't use car over this weekend after just getting it back after two weeks or so.

I really enjoy this forum...thanks!

-mao_junior-

[JT912]

If you aren't able to get the fuel filter to fill by priming the line (mity-vac or other method) then the screen filter at the fuel tank might be clogged. The fuel pump is a pretty easy do-it-yourself rebuild part, but unless I am missing something, it doesn't sound like you are getting fuel to the engine area from the front of the car.

[Christopher E]

Sounds like a blockage way earlier than the carbs. You should easily be able to check i t by first opening the tank filler cap and introducing some air pressure into the fuel line at the left of your engine bay. That should pop any sediments or debris back into the tank and get fuel through. Still all that gunk/rustflakes or whatever is trapped in your tank and WILL eventually block the flow again - so if thats the case the tank has to be cleaned out. My car has an additional electric fuel pump in the smugglers box and POwner fitted a not visible in-line fuel filter at the tank exit - under the steering mechanism protective plate underneath. This filter clogged up with sediment and flakes and gave the same symptoms as you have - I was clueless until I found the hidden filter.

You might even get away with draining the gas tank from underneath the car and not even taking it out. You can inspect the insides of the tank if you remove the fuelgauge-sender. ( DO not use a match!!! but rather a sealed flaslight - with a strap around your wrist as well - as you DONT want to drop anything down there).

Good luck! / Chris

[Mao_Junior]

thanks for the quick replies! After sitting for the remainder of the day, she started up again around 8 hours later. When my mechanic removed the filters he stuck in I couldn't believe the amount of sediment that was in there. Reminded me of when people sift for gold and come up with a net full of fine powdery rock. I have forwarded him your replies. (He is a close family friend, and his dad worked on almost nothing but old 911s back in italy when he was younger.) I, agree, there prolly is considerable debris still. But why such a strong smell of gas still? She goes in Tuesday in the a.m., so I will report back.

Thank you so much! This is an amazing forum.

-mao-