gozapper

Does the 1st gens have the sock strainer in the fuel tank?
I'm fighting a engine surge at idle. New filter installed recently.

Thanks, Tom


92 350, stock.

Trebor

No, it has a large strainer basket.

gozapper

Thank you,

Tom

wannadiesel

Does the truck start easily after sitting overnight?

gozapper

Yes it always starts on 1st hit on the key.
problems started when I stop with it in gear and foot on the brake, it would grunt and grunt idle. put it in park and it would smooth out.
The rest of the story; I have been blending biodiesel, wvo and some wmo.
I am suspect that the fuel might a heavier viscosity and the vane pump in the IP is not pulling the fuel up through the filter and might be starving under load.
275 K on the original pump maybe? New filter month ago.
I have an old solenoid type pump and bypassed the engine pump. It showed
3 psi after the filter. It starts right up, but it is doing the same.
I centrifuge the wvo and wmo for hours and run it through a 20 micron filter.
But I am suspect that the new filter could be restricting the flow.
Tomorrow I will blow back through the line from the tank, change the filter. If that don't fix it. Then I will pump pure diesel from a can.
I will report back the results.
I would like to install the upgrade piston pump if I could find one for a good price. I just think it would be a waste to put a stock lift pump back on .

Thanks for the response.
Tom

wannadiesel

Sounds like trouble with the idle spring or the governor. Did the trouble start with the filter change?

gozapper

The problem started when cold weather began. At the time I thought it was the filter or the wmo,wvo was getting thick. I changed the filter, then I had a leak from the wif sensor. I changed to a non wif sensor type filter. I didn't to play with it today. Had to move rnd bales of hay for neighbor all afternoon.The lift pump would not pump at all. I am going to put a standard lift pump on it tomorrow. I need to start hauling cars to the shredder quick while they are paying over $140 per ton.
I'll report back tomorrow. Thanks,
Tom

gozapper

I put a new lift pump on today. Bled the lines, it started right up, is still doing the loping thing.
After it warmed up,the idle smoothed out. When I put in gear with my foot on the brake, it lopes.
It runs down the road very good, plenty of power.
When I stop it wants to die, but it will stay running rough. I could turn the idle up. But I'm afraid that it might want to creep hard.
What, where is the idle spring?
thanks, tom
If it might be the govenor, what needs to be fixed?

wannadiesel

The idle spring and the governor are inside the pump. The idle spring provides fine speed control at idle to prevent surging, if it's broken (or somebody forgets to put it back in when installing a 3200 RPM governor spring) the idle will surge. Worn parts in the governor will also cause surge.

Make triple sure you have no fuel leaks before you condemn the injection pump.

gozapper

What is the procedure to check for leak in the fuel line?
I did a search and didn't find anything.
I could run a line from the lift pump direct to a gallon jug of clean fuel, then if it still does it, the problem would be from the lift pump through the filter. if that was the case, then how to find the leak?
When I push the pedal to increase the idle, it smooths out. Would an air leak let it smooth out?

Thanks, tom

wannadiesel

A small amount of pressure in the fuel tank will show leaks in the lines.

Running it off a jug of fuel is a good method of eliminating the suction side as a trouble area.

Added RPM often masks a problem with air.

BAR

My truck was doing the same thing, turns out I forgot to put the idle spring back in after I had the top of the pump off. Got a new spring and put it in and fixed the problem. But if you haven't had the pump apart I doubt that is the problem, I don't know if they wear out over time or not?

wannadiesel

They can break...

But again, I would not tear into the pump until you are triple sure there is no air getting in the fuel.