Jon0249
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- Dallas, TX
Recent troubles with my 1990 M998-A0 (6.5NA) that I would appreciate advice on.
This summer, it ran fine here in the Texas heat. From the time I brought it home in March 2015, it had always started almost instantly. However, late this summer the crank to start time started going from near instantaneous to 3-5 seconds, to 8-10 seconds, occasionally even longer. I figured it was time to replace the fuel filter and water separator. So I did. Nothing really changed, with start times continuing to be 10+ seconds on cold start. Once started, it would restart immediately the rest of the day.
As the weather cooled, starting took even longer. Most recently, after a tough start, I was pulling a trailer up a long hill and the engine just died. I slipped it into N and it restarted on the fly without even stopping. That happened again, after I had floored the accelerator in a defensive driving maneuver. It also restarted on the fly before I came to a stop. A few days later, with cooler nights and days, it failed to start altogether and has sat for a couple weeks since.
My assessment:
A. With the cooler temps, the glow plugs became a necessity, and their failure caused the starting issues. That was confirmed today when I took #3 out and it was burnt. #2 is stuck, as are a few others I'm afraid. However, I just replaced them this past spring, so the reason they failed is the real mystery.
B. Fuel - I'm guessing the block mounted fuel pump has been going bad for a while and with cooler temps the diaphragm just couldn't handle it and cracked.
All other indicators are normal. GP light comes on for 6-10 seconds as it should. I installed a grounding cable in the spring, so electrically, it's sound. No other issues that come to mind.
Thoughts? Why did I burn the brand new glow plugs? Regarding the fuel, is it possible there is enough air in the system that would cause this kind of problem? I bled the fuel filter canister top bleed screw, so I have discounted that as a factor, but maybe I missed something? Cranking it today, with the bleed screw loose, fuel escaped there, as well as the petcock drain.
Thanks in advance for your expertise!
Jon
This summer, it ran fine here in the Texas heat. From the time I brought it home in March 2015, it had always started almost instantly. However, late this summer the crank to start time started going from near instantaneous to 3-5 seconds, to 8-10 seconds, occasionally even longer. I figured it was time to replace the fuel filter and water separator. So I did. Nothing really changed, with start times continuing to be 10+ seconds on cold start. Once started, it would restart immediately the rest of the day.
As the weather cooled, starting took even longer. Most recently, after a tough start, I was pulling a trailer up a long hill and the engine just died. I slipped it into N and it restarted on the fly without even stopping. That happened again, after I had floored the accelerator in a defensive driving maneuver. It also restarted on the fly before I came to a stop. A few days later, with cooler nights and days, it failed to start altogether and has sat for a couple weeks since.
My assessment:
A. With the cooler temps, the glow plugs became a necessity, and their failure caused the starting issues. That was confirmed today when I took #3 out and it was burnt. #2 is stuck, as are a few others I'm afraid. However, I just replaced them this past spring, so the reason they failed is the real mystery.
B. Fuel - I'm guessing the block mounted fuel pump has been going bad for a while and with cooler temps the diaphragm just couldn't handle it and cracked.
All other indicators are normal. GP light comes on for 6-10 seconds as it should. I installed a grounding cable in the spring, so electrically, it's sound. No other issues that come to mind.
Thoughts? Why did I burn the brand new glow plugs? Regarding the fuel, is it possible there is enough air in the system that would cause this kind of problem? I bled the fuel filter canister top bleed screw, so I have discounted that as a factor, but maybe I missed something? Cranking it today, with the bleed screw loose, fuel escaped there, as well as the petcock drain.
Thanks in advance for your expertise!
Jon
