Hard to start Hot

[timc930]

The engine dying really does sound like a fuel deficit situation. Poor venting is only one cause for a fuel deficit like this. The other cause is a blockage upstream from the fuel pump(s).

Which electric fuel pump do you have? There are filter elements that can get clogged up in the stock Facet fuel pumps that came on 109 wagons:



Re-check the strainer screen on the bottom of the fuel pickup tube in the tank. Every time that my rover exhibits the exact same symptoms you describe, the strainer is plugged up with new debris from my increasingly rusty fuel tank. I generally scrub it with an old toothbrush then blow it out by putting my the nozzle of my blower into the uplift tube hole and gently (at first) blowing OUTWARD, clearing the screen completely.


As for the backfiring...I think that's a different issue. Backfiring out of the EXHAUST is often a leakage issue with the exhaust manifold or downpipe, combined with unburned fuel in the exhaust stream. Backfiring out of the CARB is often an issue with a hot spot somewhere in a cylinder or poor ignition timing or poor valve timing.

What do your spark plugs look like?

Hi Mark,

No blockages what so ever. I can blow thru all the lines all the way to the carb. The FP is a NAPA Facet type pump. Approx $65 and puts out 4-6lbs. Just purchased it and installed TG week. Pulled the tank line and there is no strainer screen, just a long pipe with open end that sticks down into the tank, unless the pipe slides into a strainer screen. I'll double check that.

I do have an exhaust manifold leak, as there is a broken manifold bolt and I hear a significant exhaust leak when driving.

[timc930]

Backfire usually indicates timing is off. If it were me I'd stop throwing love at that carb and order up a new one.

Yeah I've got a Weber 2bbl and manifold that came with the truck, I amy try that....

tim

[SafeAirOne]

No blockages what so ever. I can blow thru all the lines all the way to the carb.

With the absence of a strainer on the pickup end of the uplift tube in the tank, you've got to wonder where all that junk that's being sucked up is ending up.

The way this problem works is that you would be able to blow all the way through. It's not necessarily that a fuel passage doesn't exist at all, but rather that a large enough passage doesn't exist.

That's why you can run the truck at idle all day long, but soon as you start giving the engine some revs and it starts demanding more fuel, you start to develop a "deficit" of supplied fuel. It starts off slight at first and the fuel pumps can overcome the developing deficit, but sooner or later, the pull of the pumps is not enough to overcome the vacuum between the blockage and the pump to supply the engine with all the fuel it demands.

This is evidenced by the fact that the engine RPM slowly drops off until, finally, either there is NO fuel flow to the engine and it dies or it operates only up to a level where the available fuel supply to the carb is sufficient, such as at idle.

Imagine sucking soda through a McDonald's straw with a piece of ice blocking the bottom. You can get some soda through the straw, but if you really suck on it, a real vacuum develops and the straw collapses, leaving you thirsty.

I'm not saying that this is definitely your issue, but if it were me and I was certain that it's a fuel supply issue and not an ignition issue, I'd probably swing down to my local auto parts store and buy a length of fuel hose and the fittings to bypass the existing fuel line from the tank to the fuel pump and then figure out how to clean the crud off the inside of the fuel uplift tube and hook it up and test that out for a while to see if the problem goes away.

Speaking of ice, did you check for carb icing when it conks out on you? I doubt this is possible with the carb sitting right over the exhaust manifold, but you never know unless you check.

[timc930]

With the absence of a strainer on the pickup end of the uplift tube in the tank, you've got to wonder where all that junk that's being sucked up is ending up.

The way this problem works is that you would be able to blow all the way through. It's not necessarily that a fuel passage doesn't exist at all, but rather that a large enough passage doesn't exist.

That's why you can run the truck at idle all day long, but soon as you start giving the engine some revs and it starts demanding more fuel, you start to develop a "deficit" of supplied fuel. It starts off slight at first and the fuel pumps can overcome the developing deficit, but sooner or later, the pull of the pumps is not enough to overcome the vacuum between the blockage and the pump to supply the engine with all the fuel it demands.

This is evidenced by the fact that the engine RPM slowly drops off until, finally, either there is NO fuel flow to the engine and it dies or it operates only up to a level where the available fuel supply to the carb is sufficient, such as at idle.

Imagine sucking soda through a McDonald's straw with a piece of ice blocking the bottom. You can get some soda through the straw, but if you really suck on it, a real vacuum develops and the straw collapses, leaving you thirsty.

I'm not saying that this is definitely your issue, but if it were me and I was certain that it's a fuel supply issue and not an ignition issue, I'd probably swing down to my local auto parts store and buy a length of fuel hose and the fittings to bypass the existing fuel line from the tank to the fuel pump and then figure out how to clean the crud off the inside of the fuel uplift tube and hook it up and test that out for a while to see if the problem goes away.

Speaking of ice, did you check for carb icing when it conks out on you? I doubt this is possible with the carb sitting right over the exhaust manifold, but you never know unless you check.

Good point. I'll bypass the existing line and see what happens. Yeah no icing at all at the carb...

tim

[timc930]

So in the meantime, I just replaced the plugs (autolite with NGK) and drove for an hour or so today with zero problems. I have not yet bypassed the existing fuel line, but interesting that replacing the plugs gave this result....

itm

[SafeAirOne]

What did the old plugs tell you about what's going on?

[timc930]

What did the old plugs tell you about what's going on?

Most were rich, one was brown. Not sure how this would cause the truck to feel like it was loosing power, then eventually shut down, unless the plugs were just fowling out. Drove it for a while tonight with the new plugs and so far it's running fine, but I am sure I still have a problem.

[bugeye88]

To quote Alice "things are getting curiouser and curiouser"..... Might as well replace points and condenser while your at it. Maybe coil as well to give the whole ignition a kick in the pants. My money was on a fuel supply issue. Did you ever drain the tank to see any crud in the tank? screen on the fuel pick-up?

Cheers,
Rob
Bugeye88

[timc930]

To quote Alice "things are getting curiouser and curiouser"..... Might as well replace points and condenser while your at it. Maybe coil as well to give the whole ignition a kick in the pants. My money was on a fuel supply issue. Did you ever drain the tank to see any crud in the tank? screen on the fuel pick-up?

Cheers,
Rob
Bugeye88

So I replaced the Cap, Rotor, Points, Condensor, Wires several months ago but did not replace the plugs until the other day. All fuel lines are clean, and tank is spotless on inside. Fuel filters are also spotless. Truck has been running fine since I replaced the plugs, well so far....

edit: Just got back from another drive to the beach with the dogs and truck ran great. When I pulled the old plugs three were black, one was almost normal. I know the truck is running rich as the mpg is lower double upper single digits, so the only thing I can think of at this point is the truck was fouling out, just not sure why it was able to start after sitting....I am reaching at this point but still working on it...

tim

[bugeye88]

Tim,

Right, so it was either a bad plug, fowled plugs in general, plus a carb that is not jetted properly or other carby problems like clogged jets. Have you gone through the carb recently? Also carb air filter, especially if its the oil bath type should be cleaned. Keep plugging you're making ground.

Cheers
Rob

[timc930]

Tim,

Right, so it was either a bad plug, fowled plugs in general, plus a carb that is not jetted properly or other carby problems like clogged jets. Have you gone through the carb recently? Also carb air filter, especially if its the oil bath type should be cleaned. Keep plugging you're making ground.

Cheers
Rob

Yeah pulled the carb apart over TG week, soaked in carb cleaner and reassembled. Checked needle and seat as well. Could be wrong jets though as it appears to run very rich, but it has the stock weber 34 on it...

have not touched the oil bath yet....

tim

[SafeAirOne]

One final thought---on an occasion or two, I've had the cloth on the inside of the air intake hose between the air filter and the..well, it'd be the carb in your case...de-laminate and collapse into airstream, blocking the airflow to the engine. In my case, the power loss combined with the plume of black smoke out of the tailpipe were dead giveaways as to what was going on.

Chances it, this is not your problem, but it can be intermittent, causes a rich mixture and a power loss.

[timc930]

Backfire usually indicates timing is off. If it were me I'd stop throwing love at that carb and order up a new one.

So as I stated earlier, it's running 100% better, but I am still way rich. I moved the truck, then pulled the intake and exhaust manifolds off to replace bad exhaust gasket, and there was fuel pooled up in each of the intake ports on the head. Plugs are black again after driving less than 100 miles so I have ordered a new weber carb.

[bugeye88]

Tim,
Hope the new carb does the trick. Be sure to order it with the correct jets for you altitude. Most carb sales places will do that for you, and they are usually good. Since I remember you are running a dual inlet carb, I assume it is the Weber 35 DGV. I have run one of these on a Series 111 and it was quite good. But this is a lot of carb for these 2.25 engines and can run rich easily if the jets are off even a bit. The single inlet 34 ICT Webber I feel is a better carb for our applications, and is what I am running on my 68 Bugeye. It provides better intake velocity and is easier to set up and has good linear power curve. The other carb I like and have used is the Rochester GM carb. Again, a lot of carb for our engines but they are quite reliable and have linear power curve with a bit more top end power. The 34ICT has better low end characteristics. Let us know how it goes.



Cheers,

Rob
Bugeye88

[timc930]

Hi Rob, I was running a 34ICH, and just ordered a new one from our host, should be here tomorrow. I do have a progressive 2bbl Weber and matching intake manifold that came with the truck, but I just did not want to go to all the trouble of jetting it properly to run with the little 2.25, as I have no idea where to start, or what size engine the carb was jetted to work with. Years ago I had a 1.7 litre 914 and I installed one of the Weber progressive 2bbl carb's, but it came properly jetted. I am hopping that RN knows the proper jets to work with the 2.25 and as such the carb should come properly jetted.

Right now I just want it to run right, with decent mpg!

tim