No fuel reaching the carb - suggestions please.

[IanMc]

Morning all,

Last weekend I tried to start the old girl - nothing, so just left it thinking it might need some more fuel as it was showing in the red on the gauge.

Last night I picked up 3 gallons of fuel and this morning I have put about half of that it in. Now the gauge is showing between red and 1/4 of a tank - still no start. Upon investigation I find that no fuel is reaching my in-line filter which is between the inner wing and the fuel pump in the engine bay.

Following that I poured a bit of fuel directly into the carb and it ran well for a fuel seconds before stopping. My thinking was that the engine cycle might pull and air trapped in the ful lines through and get things back to normal. But no, even after a few times of adding fuel directly into the carb the in-line filter is still bone dry...

After crawling underneath the car I can see no signs of any leaks along the length of the fuel lines, so I'm a bit stumped really. I did think about raising the back of the car in an attempt to force the fuel down to the front, but that should of course happen naturally with the pressure above the fuel in the tank - I think anyway...

Any suggestions please?  

[hoobby]

Fuel pump? Try cranking it with the pipe that attachés to the carb in a jar see if you get any joy.the other thing the float may have jammed keeping the valve needle closed or possibly corroded.i take it all as it was when it started last?.

Edited May 25, 2019 by hoobby
Float needle

[IanMc]

7 minutes ago, hoobby said:

Fuel pump? Try cranking it with the pipe that attachés to the carb in a jar see if you get any joy.the other thing the float may have jammed keeping the valve needle closed or possibly corroded.

Hi Graeme,

I hope you are well?

I did think about the pump, but would that stop fuel being pulled down to the filter that is about a foot before it? In other words, does the pump pull fuel down from the tank, then pump it on up to the carb?

Thanks for your help matey.

Sorry, I forgot to mention - the pump was replaced not long after I got the car, so its probably only run for 10-15 minutes in its entire life.

[hoobby]

Hi Ian I take it this is the mechanical type will suck then blow the fuel and air along the  line.could run a feed and return from a jar of petrol from the pump just to check its still working wouldn't be the first time I've bought new things that break or don't even work.think fuel has to be pulled from tank will not flow on its own.do you have a large syringe or something to suck the fuel along the hose attached pre fuel pump?.

Edited May 25, 2019 by hoobby

[IanMc]

15 minutes ago, hoobby said:

Hi Ian I take it this is the mechanical type will suck then blow the fuel and air along the  line.could run a feed and return from a jar of petrol from the pump just to check its still working wouldn't be the first time I've bought new things that break or don't even work.think fuel has to be pulled from tank will not flow on its own.do you have a large syringe or something to suck the fuel along the hose attached pre fuel pump?.

Hi mate,

Yes it is the mechanical type pump. 

I like the idea of trying to draw the fuel down to it - I will have a look around the garage and see if I can cobble something together.

Thinking about it, perhaps the diaphragm is stuck or gummed up... I might take the pump off and see what happens when I move the actuator arm.

Edited May 25, 2019 by IanMc

[hoobby]

I have just the thing here would only take a few minutes to drop it round don't be freaked out but " I know where you live"

[IanMc]

3 minutes ago, hoobby said:

I have just the thing here would only take a few minutes to drop it round don't be freaked out but " I know where you live"

OK mate, sounds good - we are off out shortly though.

Let me have a little tinker again later and if that fails I will drop you a line  

[1200bandit]

When you remove the pump fit fuel pipes to the inlet and outlet place the fuel line that sucks in fuel and move the arm on the pump in/ out and see if pumps fuel though 

[IanMc]

Just before we went out I disconnected the fuel hose to the in-line filter, then connected my vacuum pump. 

No amount of pumping could encourage any fuel forward. I will try Wayne’s idea with the pump, but I’m now inclined to think that the problem might be a blocked fuel line further back.

The investigation goes on lol

Thanks for all your helpful comments guys!

[H-400]

Hi Ian, had several times problems as you with classic-cars that were not used a lot. Was something like slime in the feul, blocked everything and had always to change the feul filter and clean the feul lines with air pressure. Had also some injection engines and they needed new electrical pumps... Sometimes it is so bad I had to build the feul tank out to clean it. The benefit of a Manta/Cavalier is that is not hard to do. Had once a BMW E30 that needed to clean the tank and had to rebuild the whole car to get it out... 

Grts, Herman

[IanMc]

Thanks Herman, helpful comments as always. I was thinking of disconnecting at the tank end and getting my compressor on fuel line.

That wont take long to do and it is at least one thing to take off the list.

[IanMc]

OK guys, so a little more to report here:

1) I disconnected the fuel line to the in-line filter and blew the fuel line backwards to wards the tank. I did this 4-5 times after the second time I could here the air escaping/bubbling back up into the tank in the boot. After I took the air nozzle away, fuel flowed freely back out - result!

2) Next I disconnected the rigid line between the pump and the carb - bone dry. I took the opportunity to blow that line through as well was I was there - no debris was seen.

3) Then I took off both rubber lines to the pump. The pump inlet and outlet stubs were both deformed by the tightening of the jubilee clips. I didn't take a photo of these, but I would estimate that the stubs were perhaps 'crushed' by approx 1/3 of their diameter. As bad as this is, it still doesn't explain why no fuel at all was getting through the pump body - at least not in my opinion anyway...

So at this stage I am thinking dodgy pump, but that doesn't feel entirely right at the moment. What do you guys think?

[IanMc]

Just remembered that I still had the old fuel pump in the garage. Luckily I have found it and the inlet and outlet stubs are much stronger.

I’m thinking that I might refit that and see what happens. I only changed it because I had a similar issue soon after I got the car running again, well over a year ago. I’m now wondering if that wasn’t a pump issue at all, but some restriction in the fuel line, like the one it seems I have just shifted.

At the end of the day, all I have to lose is a bit of time, so might as well give it a try.

[Ems]

As already stated it sounds like a blockage or fuel pump problem.  I'm sure my old mk1 Cavalier used to have a filter inside the pump housing that you could take out and clean.  Another thing worth checking is the carb as a lot of them have a small in-built fuel filter, also check the carb diaphragm for a split.  

Edited May 25, 2019 by Ems

[®evo03]

You could remove feed line from up close to carb and place it in a jar, crank the engine a few times, at least you will then know its the pump or fuel line blockage, i rhink i replaced one, and had similar issue, of course i had pipes wrongly connected. 

[IanMc]

12 minutes ago, Ems said:

As already stated it sounds like a blockage or fuel pump problem.  I'm sure my old mk1 Cavalier used to have a filter inside the pump housing that you could take out and clean.  Another thing worth checking is the carb as a lot of them have a small in-built fuel filter, also check the carb diaphragm for a split.  

Thanks for the input matey, appreciated.

I have checked the carb filter - all good there.

3 minutes ago, ®evo03 said:

You could remove feed line from up close to carb and place it in a jar, crank the engine a few times, at least you will then know its the pump or fuel line blockage, i rhink i replaced one, and had similar issue, of course i had pipes wrongly connected. 

Yes I did try that evo - nothing from that pipe at all. 

The first thing I did was to check the inlet and outlet were the right way around - they were lol

[®evo03]

Wonder if there is a gauze on the pump, or on the fuel sender in tank.

Time to get the airline out.

To block a line, its handy to have a metal bar, or bolt to clamp into open pipe with a jubli clip. 

[IanMc]

11 minutes ago, ®evo03 said:

Wonder if there is a gauze on the pump, or on the fuel sender in tank.

Time to get the airline out.

To block a line, its handy to have a metal bar, or bolt to clamp into open pipe with a jubli clip. 

No gauze filter on my pump mate.

I do have two line clamps that I use in fuel lines, brake flexi pipes etc

[IanMc]

(As suggested above), this morning I set up a little bench test for the old mechanical pump. This consisted of the pump held in the vice, a couple of lengths pf hose connected to the inlet and outlet stubs, a funnel and a 'catch tank' ( a plastic milk bottle  ).

I am pleased to report that the old pump works just fine when operating the pump shaft. 

Now I wish that I had done this test before condemning this pump and replacing it with the one that has stubs made from chocolate - and that's just the bits I can see... Oh well, you live and learn.

I'm off out to Old Trafford today with my Son to watch Man Utd Legends v Bayern Munich Legends in the 20th Anniversary celebration of Utd's Treble win. Really looking forward to that  

This all means that the fuel pump switch will have to wait until tomorrow I'm afraid.

[cam.in.head]

Hi ian it sounds like your sorting it anyway but I’d thought I’d add my thoughts.

ive never had a coupe so can only guess the tank is very very similar to a saloon tank which has a stub at the bottom to exit the fuel. I cannot remember wether this stub is removable or part of the tank .and I don’t think it has any sort of mesh on the inside like the pipe on a hatch tank would have. If you have experienced the first situation where no fuel ran out but did after you had blown it then it does sound like something blocking it in the tank or front to back line. 

If it were me and considering it’s only 4 bolts I would remove the tank .remove the sender from the side and have a good look inside if you can. You don’t want a bit of gunge floating about inside making the car unreliable if that’s what it is.

Eliminate the tank as being fine 100% and refit.

the fuel line is plastic so should theoretically last forever,check for damage/ squash / blow through with compressor.

pump wise it’s like most other parts these days.i would keep the original gm pump if it’s working ok rather than any other aftermarket type.they last a long time and seem to fail by letting oil out of the timing case before the diaphragm goes so if it’s nice and dry and working ok I would refit it.

The fuel system is very simple on our cars so there’s not much to go wrong . If you found no fuel reaching the carb then it’s pretty much NOT a fault inside the carb so I’d not do anything there.

get the fuel running from the back and you can hear bubbles when you blow and connect all back up and we should be good to go .

[IanMc]

Cheers Chris, much appreciated.

[1200bandit]

You can get a fuel stabiliser which prevents fuel degradation when the car is stored 

l have used Forte advance fuel treatment (on my 1200 bandit after it had been stored for two years)

it takes its time to clean out the carbs (about 250 miles) but it works

if you have a air line remove the fuel line seal the fuel filter neck with a rag and blow out any bits out of the fuel system 

[®evo03]

Yeh got mixed up hatch is feed from sender, coupe is lower centre, still think there is a wire mesh inside. 

You have tank breathers, romoving fuel cap should eleminate these, if blocked. 

[IanMc]

And..... all sorted!

This morning I refitted the old pump and the now car starts easily and idles.

Here you can see the inlet and outlet stubs of the replacement pump. You can clearly see the deformation caused by the hose clips and I never over tighten those too much - had too many (fake) jubilee clips fail in the past for that. By the way, these were after I had see how soft they were and tried to make them rounder again with a small pair of long nose mole grips. If I had even used medium pressure with the grips, I could easily have closed those right up.

 

 

Anyway, as I say all sorted now.

[cam.in.head]

Hi Ian.what was the actual issue then? . Did you find why there was a blockage ? . Or do you think you had tightened up the clips so tight that they actually closed up the stubs ? .?