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Was going to pick up a Christmas tree yesterday after church.. Haven't driven the truck (1990 7.3L) for a couple of weeks.
Got in, waited for the "wait to start" light to go out, after a few cranks it clattered to life for about 2 seconds then died. After that it never seemed to fire again. I thought perhaps the cool temperature (mid 30's) was the problem and put a 1500W heater aimed at the fuel filter on it for about an hour, but still nothing.
At that point the batteries seem to be mostly down, so I put it on the charger for several hours and then tried starting with some starter fluid, and still got nothing, though the battery still seemed weak.
Is mid 30's cold enough that it would cause fuel problems anyway?
Spin off the fuel filter and see where the level is, If it is not full you have air intrusion problems. Starting and then dying is usually a sign of air getting into your system. You will have to crank alot to get your system bled so charge those batteries up! Check for fuel leaks around the injector caps and return lines. My fuel is fine at 15-20* F so your fuel should be good at 30+.
Did not see any sign of fuel leaks. Just had the high pressure pump, and lines replaced about a month ago. If the fuel filter is not full, do I just need to continue cranking until it starts, or is there something I can do to speed up the bleeding process (like fill the filter?).
I tried briefly to start it on Ether, but I think the battery was pretty low by the time I tried that. Plus the 7.3L I'm sure takes quite a bit more starting fluid than my chainsaw!
Does the 1990 have a block heater? If so where would I look for the plug?
I'm going to put it back on the charger when I get home, and try again... plan b is hook up my other car, and use the jumper cables. Hopefully the alternator on my Cadillac can keep up with the truck starter!
A fuel filter that is not full means you have air intrusion and possible a fuel leak, look over all your injector caps(plastic) and check for fuel leaks.
block heater goes in on the passenger side block, trace that wire to its plug.
Thanks for the suggestions. Will my 1990 certainly have a block heater, or were they not standard?
Truck ran great a couple of weeks ago (I think last time I drove it was 3rd week in November), how would an air intrusion occur just from sitting? I will check it out. I did check the injector caps for indication of fuel leak and did not see anything.
There doesn't need to be visible signs of fuel leakage for air to intrude. I would back off from using the ether unless you disable those glow plugs or you will break a ring or worse. Block heaters are standard on all these motors
As mentioned, check the fuel filter and see if it's full. If not you can top it up with diesel, or a fuel treatment (such as dieselkleen) to reduce cranking.
I recently had one of mine start and die, filled the filter, same thing, checked the filter and it was almost empty. Turned out the mechanical lift pump had let go while the truck had been sitting for a while.
I will check the filter and see what it looks like. How big a deal is the low pressure "lift" pump to replace? Is there an easy way to check it without a pressure gage?
I will check the filter and see what it looks like. How big a deal is the low pressure "lift" pump to replace? Is there an easy way to check it without a pressure gage?
If the lift pump diaphragm is ruptured the crankcase will have fuel in it. Check the dipstick to see if the oil level is higher than normal. Its rare that these things break but it's possible. One way to check is to disconnect the feed to the IP and have an assistant crank the engine while you watch for fuel being pumped
If the lift pump diaphragm is ruptured the crankcase will have fuel in it. Check the dipstick to see if the oil level is higher than normal. Its rare that these things break but it's possible. One way to check is to disconnect the feed to the IP and have an assistant crank the engine while you watch for fuel being pumped
This is probably confusing to our fellow here. The lift pump doesn't do that when its not working. That is a different thing. The seals CAN rupture, that is not a way to determine if it is bad though.
Thanks for the clarification! I saw something mentioned in another thread about bleeding through a valve at the fuel filter... how does one go about doing that?
And where else to look for air infiltration? The lines and caps for the injectors are all new, about a month ago.
You can bleed it at the schrader valve, and then if needed at the injectors themselves.
Air intrusion is not always visible with any moisture and always occurs when sitting with the motor not running.
Air intrusion that occurs with the motor running is between the tank and fuel pump and causes the motor to run erratic at speeds.
Most of these came with a block heater, but not all of them, if it has one it will be located in the block above the starter.
30 degrees should not cause any fuel problems, even with summer blend.
Batteries should be completely charged, and it is better to hook your jumper cables to the passenger side battery, These need all the juice they can get to start, so make sure your cables are clean.
If you are using either, disable your gp's or their is a real possibility of damage, and it doesn't take much either.