2.25 petrol problem....

[SafeAirOne]

On my 109, there's a very fine mesh strainer on the bottom of the fuel pickup tube in the fuel tank. On 2 occasions, the strainer was sufficiently clogged with fine sediment so as to allow fuel supply at all RPMs initially, but after 10 minutes of driving would develop a suction because the engine required more fuel than would fit through the clogged strainer.

Eventually, I'd loose the high RPM range and shortly later, as the fuel defecit grew, I wouldn't even be able to keep the engine running at any RPM.

After letting it sit for a few hours the suction that developed in the fuel lines would eventually suck enough fuel in from the tank that the pressure in the lines would equalize.

Starting it up and running it was normal again for 10 minutes, then it would start all over again.

The "ah haa!" moment came when it died and I removed a fuel line in the engine bay and got a "sucking in air" sound. Pulled the fuel pickup tube and cleaned the strainer with a toothbrush and some diesel and fixed the problem.

EDIT: I would have posted this earlier, but I thought you already checked this. Re-reading the original posts, it looks like you went UP TO the tank but not inside it.

[albersj51]

I took Gudjeons advice and installed an electric fuel pump. I used this in conjunction with a bypass fuel filter and a return hose; no problems with it that I can tell. Terry Anne has some info about e-pumps as well. Here is what I used:

Filter: Napa Gold # 3054 Bypass fuel filter (purolator sells the same thing, give them the Napa number and they'll find it).

Pump: Napa # E8012S Electric fuel pump

I'll take some pics of the set up and post them up. It was a straight forward install. My tank already has a blank plate over an access hole. I drilled a hole in the blanking plate, tapped it, and installed a "nipple" to attach the return line to.

The e-pump is installed under the passenger seat (loud), at the same level as the tank (these pumps are good for pushing, not for pulling so keep it at or below tank level to allow gravity to help). I tied the power wire into the ignition switch so that it shuts off when I turn the key, and I grounded it to the chassis.

I hope this helps!

[fred98050]

EDIT: I would have posted this earlier, but I thought you already checked this. Re-reading the original posts, it looks like you went UP TO the tank but not inside it.

I even did not think about it

I'll check tonight.

Thanks

[fred98050]

I took Gudjeons advice and installed an electric fuel pump. I used this in conjunction with a bypass fuel filter and a return hose; no problems with it that I can tell. Terry Anne has some info about e-pumps as well. Here is what I used:

Filter: Napa Gold # 3054 Bypass fuel filter (purolator sells the same thing, give them the Napa number and they'll find it).

Pump: Napa # E8012S Electric fuel pump

I'll take some pics of the set up and post them up. It was a straight forward install. My tank already has a blank plate over an access hole. I drilled a hole in the blanking plate, tapped it, and installed a "nipple" to attach the return line to.

The e-pump is installed under the passenger seat (loud), at the same level as the tank (these pumps are good for pushing, not for pulling so keep it at or below tank level to allow gravity to help). I tied the power wire into the ignition switch so that it shuts off when I turn the key, and I grounded it to the chassis.

I hope this helps!

Great info. I'll check TerryAnne as well.

Thank you

[fred98050]

Just checked draw tube and it is all clear...

[SafeAirOne]

Just checked draw tube and it is all clear...

OK. If fuel supply is your problem and everything is clear of obstructions then I guess there's only one thing left.


I'm still trying to put together a plausible way that a bad mechanical fuel pump/diaphragm could present these symptoms...

I suppose that if it pumped at a reduced volume...say, just enough to keep the bowl filled at through 1500 RPM...it would do just fine for a while, but when the RPMs increase beyond 1500, the bowl would slowly empty till the sputtering would start. It makes sense that further pressing on the accelerator would exacerbate the stumbling because there's not enough fuel available in the bowl to be squirted into the carb by the accelerator pump.

Hmm...That sounds reasonable, doesn't it? Anyone ever have that happen to them?

I wonder if the symptoms would disappear again for another 5 minutes if you let the rover idle for 10 minutes after it stumbles (so that the bowl has a chance to refill at idle before being depleted by driving).


EDIT: Oops...I see that dunerunner explained this earlier (and in a much simpler way) when he referenced a clogged fuel line.

[fred98050]

OK. If fuel supply is your problem and everything is clear of obstructions then I guess there's only one thing left.


I'm still trying to put together a plausible way that a bad mechanical fuel pump/diaphragm could present these symptoms...

I suppose that if it pumped at a reduced volume...say, just enough to keep the bowl filled at through 1500 RPM...it would do just fine for a while, but when the RPMs increase beyond 1500, the bowl would slowly empty till the sputtering would start. It makes sense that further pressing on the accelerator would exacerbate the stumbling because there's not enough fuel available in the bowl to be squirted into the carb by the accelerator pump.

Hmm...That sounds reasonable, doesn't it? Anyone ever have that happen to them?

I wonder if the symptoms would disappear again for another 5 minutes if you let the rover idle for 10 minutes after it stumbles (so that the bowl has a chance to refill at idle before being depleted by driving).


EDIT: Oops...I see that dunerunner explained this earlier (and in a much simpler way) when he referenced a clogged fuel line.

Just took the truck for another test drive (for the last time today) and sure enough after experiencing the sputter I stopped, waited for about 4 to 5 minutes at idle. Back on the road, engine ran great for 5 minutes or so then it started again...

So I guess your explanation is more than reasonable. I also discovered the hand primer on the pump (). Played with it for 2 minutes and, absolutely nothing... No fuel going downstream, no noise, nothing...


I have a replacement pump that I'll install tomorrow and go from there... If this fixes the problem, I'll open the old pump and see what was going on.

Learned a lot but I am done for today.

Tired, smelling of gasoline and cold.




-Frederic

[SafeAirOne]

...after experiencing the sputter I stopped, waited for about 4 to 5 minutes at idle. Back on the road, engine ran great for 5 minutes or so then it started again...

So you can use the 109 for trips of 5 minutes or less and the 88 for trips longer than 5 minutes. Perfect!

BTW: A tidbit of additional info...a perfectly good fuel pump might not pump with the hand priming lever if the camshaft just happened to come to rest with the fuel pump arm on top of the fuel pump cam lobe when you shut it down, because the diaphragm is in the ...um...fully pumped...position already.

[fred98050]

Update 3.....

That's the kind of fuel flow I had before replacing fuel pump:




************************************************** *************
Today:

Replaced fuel pump:


Checked for leaks from tank to fuel pump line. I did not have any reason to believe that there was a leak but just in case....:




Here is fuel flow with new pump:



Took the truck for a test drive and all is fine now.....

I would like to thank everybody for all their help and suggestions in the past few days.

Cheers



Frederic