My truck has taken to stalling if I start it after fully warmed up / before fully cooled down. Goes like this: It will start up, run 2- 3 seconds then stall. It will then restart after 5 - 10 seconds of cranking. It starts up OK when cold.

Also: It idles weak and rough when fully warmed up, often at lower than normal speed. Power seems a little low as well.

Both these conditions are worse when the truck has worked hard and heat - soaked - either towing, or driving on the highway at 60 MPH +.

It has the original injection pump and injectors as far as I know, at 105,000 miles. Could this be the injector pump dying? I've been keeping the tank topped up to max out fuel cooling just in case. Seems to help with easy driving. I'm running little or no biodiesel; B10 max.

Ideas? I'll be checking this Monday. Home computer is dead:rolleyes: .

Thanks!

John




I've been careful to keep the tank topped up

Did you verify fuel pressure on the filter at idle by opening the air bleed or drain T?

I will open the bleed valve, but don't have a way of checking pressure other than just looking for flow. Guess I'm more sense than science.

When you open the bleed, run it into a pop bottle or something clear or light colored to check for air bubbles. If you don't see any, and fuel appears to be under good pressure then your probably OK supply wise, need a gauge to be 100% sure though.

However, air in fuel normally causes faster idle, then stalling.

Low idle speed and stalling is either metering valve sticking or the governor needs attention, both mean you need injection pump overhaul.

Try just turning the L.I. adjusting screw in while the engine is idling, until it idles about 700 RPM, you can set the fast idle solenoid the same way, push it in with a screwdriver to engage the throttle lever, turn it until you get the cold fast idle you want.

Also, verify your cold advance/fast idle mechanisms are working.
If you remove the green wire on the top of the pump with the engine cool, you should hear the engine change tones, quieter, slower idle. If you don't hear a change, you probably have a bad temp sender in the head/crossover, common problem, easy to fix.

I have a 93 6.5 turbo, auto trans, 70k, with the same problem. I changed lift pump. It helped, but did not completly solve the problem. If I wait a minute I can fill the engine stumble, I can then go with no problems. It is almost like the IP runs out of fuel. I have a new fuel and air filters. Some other problems I am having. If I take off with a heavy foot The response is not smooth, if it was a gas engine I would say it was missing. I can hear the turbo run but I have no idea how much boost I am getting. I don't have a lot of black smoke. I am only getting about 10 MPG. My 94 gets around 15 MPG. One last problem, my temp. runs about 190 unless I around town, freeway, air, no air, but if I work the engine at all going up a steep hill climbs fast 210 and rising if I don't slow down < 50 without load, < 25 with load. After the hill The temp will go down just as fast. I remove the thermostat, the trunk is running about 150, I still have the same problem just takes longer to get to 210. The system can not remove the heat fast enough. I have a new radiator and coolant, with a external trans cooler. Not sure if everthing is related, but I wanted to list all the problems.

That stumble might be the Cold Advance disengaging.

It will have an exaggerated effect if housing pressure is higher than normal due to higher than normal return fuel, usually from a worn advance piston.

I suggest rebuilding the pump before you get hard start hot problems.

I put the a stock 195* tstat back in. I hope the tstat is the heat problem I need to pull my trailer about 200 miles this weekend. I have been reading post about heat problems and the fun clutch. Everything I read about car fans is they don't do much after 30 mph if everything is clean and you have good air flow. Inputs? Maybe I should start a new thread.