72 911e - Wont Start

tiwebber · 06-08-2014, 09:27 AM

Hi folks. My fuel pumped started leaking so I sent it away for rebuilding. Before I sent it away my car was running fine - just a bit leaky! I installed the rebuilt fuel pump and it started up right away. Then I took it out for a drive and it made it about 300 yards and the engine died. My first thought was that it was not getting gas (ie still fuel pump...). However, when I turn the key on, it engages the fuel pump so I am suspect that the issue not the new fuel pump - specially since it worked for a short while (started and went 300 yards).

When I try and start the car it turns over and it sounds as if it almost wants to start then make a put-put-put noise. Almost like a car out of an old cartoon. Because the fuel pump is new/rebuilt its "obvious" to suspect it. However, the pump "sounds" fine. Not sure if there is enough information here to help diagnose but I thought I'd give it a try!

Thanks!

ischmitz · ischmitz's Garage

Not enough information. Sound won't tell you if you have fuel pressure. I am with you on suspecting that changing the pump is more likely than not what causes your issue.

Maybe something got dislodged and went through the fuel line and now clogs is up downstream from the pump?``

tiwebber · 06-08-2014, 10:23 AM

thanks Ishmitz. Unless there was "something" in the rebuilt fuel pump I cant see how there would be anything in the lines. When I removed the fuel pump, I "corked" the three lines.

Its pretty easy to access the fuel filter gas lines. Maybe I should remove one of them, turn on ignition to engage fuel pump and see if gas is coming out of the line. Not exactly sure which line on fuel pump is "input" and which is "output" ( and there's a third - return I assume).

tiwebber · 06-08-2014, 10:51 AM

Here's a picture of the fuel filter. I am not sure which lines are which but i've labelled the lines according to what I think is right.

Key piece of information here is that fuel is coming out of the "IN" from fuel pump when i turn the ignition key to engage fuel pump. NO fuel comes out of the other lines when I do that. Could the filter be clogged or??

tiwebber · 06-08-2014, 03:40 PM

I found another fuel line below the fuel filter. After reading a few threads I think this is the line that goes from filter to MFI. When I turn on ignition and engage the pump no fuel passes through this line either. I am going to replace the fuel filter.

I am happy to buy them here (pelican parts) but in the interest of time...are these carried by local distributors or is this a specialty part that is harder to find?

Porboynz · Porboynz's Garage

Check your fuel line connections to the pump, its not intuitive the way they connect.

tiwebber · 06-08-2014, 08:53 PM

Thx Porboynz. I'll do that. But why would a strong flow of gas come from the "fuel line IN" in my pic above if the connections to the pump were incorrect? I guess maybe the "strong" flow is not strong enough to push through the filter?

Hil911 · Hil911's Garage

Hi From Canberra

I apologise if this is insulting but here is the diagram from the Haynes manual. It shows the flow directions pretty well.

I was a bit unsure about what you meant when you referred to the fuel pump. There is a fuel pump and an injection pump. Both need to be working!

One thing that kills the pump pretty fast is the cut-out solenoid. My 2.4S stopped dead when it lost the connection!

And my double-dumb question: I assume that you haven't lost the drive belt (or its timing) on the injection pump?

Hil

Porboynz · Porboynz's Garage

Red alert Hil911, that's the notorious Haynes diagram with the inlet and outlet for the MFI swapped at the filter console.

Here is the correct layout.

Porboynz · Porboynz's Garage

Tim, look at the above routing of the fuel lines and make sure you have your fuel pump connected as shown, in particular the output from the electric pump. Your labelled photo is wrong, that centre line from the fuel filter is the fuel return. You have labelled the cold start fuel line as "return from the injector" This line is not a return, quite the opposite.

Hil911 · Hil911's Garage

Ha ha! Well at least it makes it clear what NOT to do! To be honest I never used it: always label everything as you take it apart and put it back the same.

Hil

sballard · 06-09-2014, 04:14 AM

IIRC there is an error in the factory manual about the line routing to the fuel filter. I don't know if this applies to the Haynes as well. I recall Grady frequently pointing this out.

Porboynz · Porboynz's Garage

Last thing Tim, fyi the return/bypass fuel line from the electric fuel pump is the one nearest the electrical connector beside the little alloy hat shaped fuel bypass valve, the middle connection is the fuel output and the larger diameter of the 3 connections is the fuel input from the fuel tank.

Cork? Did you really jam something organic up the fuel lines while the pump was being serviced? I use a suitably sized bolt and seal it up tight with the hose clamp, anything else may leave fragments to block the line.

tiwebber · 06-09-2014, 12:50 PM

Perfect. Thx for that additional info on the fuel pump connectors. NO! Nothing organic. I plugged the hoses with the butt end of drill bits then clamped them up. That way I was not deflecting the hose too much (ie full clamping w/o something inside it).

tiwebber · 06-09-2014, 01:59 PM

Just off the phone with my mechanic (nice guy, encourages me to do my own work). His comment was that the car would not start at all in the first place if the hoses were not on the right connectors on the fuel pump (and as mentioned above, i did label them so I am pretty sure I reconnected them right -> really one is larger than the others so its 50/50 chance even if I didn't!!!

I told him about my "fuel filter" test...ie that i can see strong flow into the fuel filter (as per the corrected diagram above) but i get "NOTHING" out of the bottom fuel filter connector that goes to the MFI. He thinks a new fuel filter is next step based on this too.

I have ordered a fuel filter! I'll will update the thread when i know. Thx all.

Porboynz · Porboynz's Garage

Quote:

Originally Posted by tiwebber

Perfect. Thx for that additional info on the fuel pump connectors. NO! Nothing organic. I plugged the hoses with the butt end of drill bits then clamped them up. That way I was not deflecting the hose too much (ie full clamping w/o something inside it).

Hey that's a good idea, I have plenty of drill bits in the 'to be sharpened' draw, you could find an exact fit as well.

Porboynz · Porboynz's Garage

Quote:

Originally Posted by tiwebber

Just off the phone with my mechanic (nice guy, encourages me to do my own work). His comment was that the car would not start at all in the first place if the hoses were not on the right connectors on the fuel pump (and as mentioned above, i did label them so I am pretty sure I reconnected them right -> really one is larger than the others so its 50/50 chance even if I didn't!!!

I told him about my "fuel filter" test...ie that i can see strong flow into the fuel filter (as per the corrected diagram above) but i get "NOTHING" out of the bottom fuel filter connector that goes to the MFI. He thinks a new fuel filter is next step based on this too.

I have ordered a fuel filter! I'll will update the thread when i know. Thx all.

Well if the filter is blocked and the pump is good then all the fuel would exit the filter housing by the middle return hose. It strange though if you do not get any fuel out that bottom line at the base of the filter, I can not imagine how a filter would get so blocked it did not flow something. Puzzling.

Porboynz · Porboynz's Garage

Unless the bypass valve in the filter housing is jammed open, that might do it, the fuel would flow via the path of least resistance out the overflow. I would expect a dribble out the bottom hose though, just from the effect of gravity.

tiwebber · 06-09-2014, 10:47 PM

When I removed the connector at the bottom of the filter a bit of gas was there. Not alot though. What you say makes sense. I dont know how the fuel filter could go from working without issue before I had the fuel pump fixed to fully clogged after. That doesn't make sense to me. I hope the filter is all it is though.

tiwebber · 06-20-2014, 04:02 PM

I installed a new fuel filter. Sadly no luck. In the pic below i've highlighted where the gas comes in from the fuel pump. If I remove this line there is a strong flow of gas from the Pump through the line. However, even with the fuel filter off, no gas seems to be getting through the connector from the line in, into the filter/filter area itself. Is there some kind of gate between the line in and the fuel filter area than can close (ie one that should be opening but it not?)?