m35 starting problem

[mill1970]

hello im having problems starting my m35 multifuel running on petrol/diesel mix when engine starts she runs fine will start first thing in the morning on here own after a long time turning her over on the starter . but when she is warm she will not start without a bit of easystart can anybody help thanks

 

[m35tech]

Others may have a couple of questions or suggestions, from the group on the forum, whats the temperature in either Far, or Cel , and any other conditions that you have experienced as of late, sounds to me like your fuel pump and or a problem with a crack in a fuel line or a leak

 

[poppop]

A couple friends on mine bought three 817's and two of them had a problem like this. The rubber fuel line had a crack in it and was sucking air. If it starts cold and not hot them I suspect the fuel is warming up and making the crack bigger. Apply a little compressed air to the tank for a couple minutes and them check the lines for leaks.

 

[50shooter]

Howdy

I'm having similar problems. I just bought a 77 multi and drove it home. Ran like a top for 40 miles or so. I suspected fuel issues so drained and cleaned the tank. Replaced all filters and bleed the filters and injectors. Started up pretty quick with the 6th injector open still. It ran smooth and perfect for 2 minutes. I had a grin from ear to ear. Honked the horn at my 3 year old and she lit up.

About 10 seconds later it died so quick I didn't know what happend. No notice, no RPM shift nothing but instant death 3 times as fast as using the engine stop cable.

Any ideas? I wonder if some air was still in the system somewhere. Would this cause such a quick kill?

Thanks to all. This is the coolest website and bunch of guys in one place. I have only been a member for a couple weeks and am amazed at what I've learned already.

 

[joec]

Is the pump in the tank running?

Or is it just runnning enough to start the truck then heating up and stopping.

If you have a spare fuel cap. Take and drill and tap a valve stem for a tire to put in. or just get one that has a nut on it. Put a couple pounds of airr in the system and try it . if it stays working then it's the pump. O9r put a preesure gauge on the top of the fuel filter to see how much pressure you have.


Joe

 

[DDoyle]

If this were my truck I'd probably go through the following steps.

Turn on the master switch, get out of the truck and put my hand on the fuel tank to see if I can feel the slight vibration the in tank pump causes (the low air buzzer would keep me from hearing it run).

If its not, check the fuse under the cover on top of the fuel tank AFTER turning the master off.

If in tank pump is running, I'd open the bleeder screws on top of the fuel filters and see if I get a good spray of fuel.

We'll come back to this part in a bit.....

But if I did, I'd then remove the cutoff cover on the side of the injection pump (four screws) and taking care not to lose or damage the gasket make sure that the cut off lever inside moves VERY freely. If not, there are more steps, but read the TM or ask more advice before cutting the safety wire.

Back to the fuel, if you have fuel flow at the bleeder screws.....

I'd also be suspect that the primary fuel filter (located on the passenger's side frame rail beneath the alternator) is plugging. The in tank pump could charging the system and make fuel squirt from the bleeder, and fill the filters as if a reservoir. The running engine however is drawing fuel from the filter bodies, if the elements are clogged the in tank pump can't push the fuel through as fast as the engine sucks it out. The result is an engine shut down, until the filters refill - and the secondaries won't refill without the master on.


Not knowing the current climate where you fellows are - is there a possibility that the fuel is jelling?

Going beyond this and looking for needles in haystacks....andother problem I've run into is inside the tank.

The fuel pump itself is at the bottom of the fuel pump assembly. A rubber hose connects the pump to the outlet you see at the top of the tank. I had a truck that developed a hole in the top of that hose. If the fuel level was above that hole, the mechanical fuel pump in the IP could draw fuel and the truck run. If the fuel level got below that hole, either through usage or parking on a slope, no fuel would leave the tank.

Hope this helps,
David Doyle

 

[joec]

If this were my truck I'd probably go through the following steps.

Turn on the master switch, get out of the truck and put my hand on the fuel tank to see if I can feel the slight vibration the in tank pump causes (the low air buzzer would keep me from hearing it run).

If its not, check the fuse under the cover on top of the fuel tank AFTER turning the master off.

If in tank pump is running, I'd open the bleeder screws on top of the fuel filters and see if I get a good spray of fuel.

We'll come back to this part in a bit.....

But if I did, I'd then remove the cutoff cover on the side of the injection pump (four screws) and taking care not to lose or damage the gasket make sure that the cut off lever inside moves VERY freely. If not, there are more steps, but read the TM or ask more advice before cutting the safety wire.

Back to the fuel, if you have fuel flow at the bleeder screws.....

I'd also be suspect that the primary fuel filter (located on the passenger's side frame rail beneath the alternator) is plugging. The in tank pump could charging the system and make fuel squirt from the bleeder, and fill the filters as if a reservoir. The running engine however is drawing fuel from the filter bodies, if the elements are clogged the in tank pump can't push the fuel through as fast as the engine sucks it out. The result is an engine shut down, until the filters refill - and the secondaries won't refill without the master on.


Not knowing the current climate in the UK - is there a possibility that the fuel is jelling?

Going beyond this and looking for needles in haystacks....another problem I've run into is inside the tank.

The fuel pump itself is at the bottom of the fuel pump assembly. A rubber hose connects the pump to the outlet you see at the top of the tank. I had a truck that developed a hole in the top of that hose. If the fuel level was above that hole, the mechanical fuel pump in the IP could draw fuel and the truck run. If the fuel level got below that hole, either through usage or parking on a slope, no fuel would leave the tank.

Hope this helps,
David Doyle

Well said Dave...I'm just not that articulate with typing.

You are a man of wisdom...!

 

[JohnnyReb]

I would consider making Daves post a sticky. Excellent diagnostic approach to a series of fuel problems.