7.3 hard start (fuel)
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Elder User
Joined: Sep 2004
Posts: 577
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From: Peoria IL
7.3 hard start (fuel)
I thought I had my 7.3 starting good after I got the glowplug system finally fixed. The glowplugs are all good and cycle fine but it takes me 2 or 3 cranks about 5 or so seconds long to get it to fire.
I have a newer IP, new lift pump, new fuel lines, new injectors, and I cant see any leaks in the fuel line that would let air in. Its been about 30 F around here and it should start right off with the gps cycling.
It has slow throttle response for about 5 minutes until it warms up. The engine wont respond to the pedal for about a second and a half.
The engine only has 200,000 miles on er and runs great with no blue smoke so I assume the compression should be good.
It seems like the lift pump might be bad but I just replaced it and dont want to go through that fun again.
I have a newer IP, new lift pump, new fuel lines, new injectors, and I cant see any leaks in the fuel line that would let air in. Its been about 30 F around here and it should start right off with the gps cycling.
It has slow throttle response for about 5 minutes until it warms up. The engine wont respond to the pedal for about a second and a half.
The engine only has 200,000 miles on er and runs great with no blue smoke so I assume the compression should be good.
It seems like the lift pump might be bad but I just replaced it and dont want to go through that fun again.
Thread Starter
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Elder User
Joined: Sep 2004
Posts: 577
Likes: 0
From: Peoria IL
The batteries have a good charge and seem to be cranking at full speed. It doesnt to crank slow until about 10 F. Do you guys hold your foot all the way to the floor when starting? I try this but it doesnt seem to make a difference as long as its more than 1/ 2 throttle.
Would turning up the fuel help some? Right now it doesnt blow any black smoke at all even under heavy load. My lawn mower blows more smoke than it. I turned my pump up one flat and it didnt even make a difference in smoke. I think its too lean. Whats the cost of a timing advance?
Would turning up the fuel help some? Right now it doesnt blow any black smoke at all even under heavy load. My lawn mower blows more smoke than it. I turned my pump up one flat and it didnt even make a difference in smoke. I think its too lean. Whats the cost of a timing advance?
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
Try a lift pump test.......
Do pressure and flow test on the fuel at the Schrader valve on the filter(FSS- fuel shutoff switch disconnected). Remove the tire valve core and hook a hose and pressure guage on it should see 4-6 psi when cranking. Then do a fuel quantity test same place, should see 1/3 pint in 10 seconds of engine cranking, route fuel to a suitable container with a hose.
If there is a problem with the lift pump and you are changing it, ensure the new pump comes with instructions as to correct installation proceedure if it is the newer model pump with the almost straight arm.
Do pressure and flow test on the fuel at the Schrader valve on the filter(FSS- fuel shutoff switch disconnected). Remove the tire valve core and hook a hose and pressure guage on it should see 4-6 psi when cranking. Then do a fuel quantity test same place, should see 1/3 pint in 10 seconds of engine cranking, route fuel to a suitable container with a hose.
If there is a problem with the lift pump and you are changing it, ensure the new pump comes with instructions as to correct installation proceedure if it is the newer model pump with the almost straight arm.
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Elder User
Joined: Sep 2004
Posts: 577
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From: Peoria IL
The pump I put on had a straight arm and came with instructions on how to get it placed on the camshaft. If it was on wrong i would imagine it would cause some damage inside the block and it wouldnt pump right.
I fired it up this morning and it fired right off at 20F. I guess I will go back to mashing my foot to the floor during startup like your supposed to do. any other diesel I have started needs lots of fuel on a cold day to combust.
I fired it up this morning and it fired right off at 20F. I guess I will go back to mashing my foot to the floor during startup like your supposed to do. any other diesel I have started needs lots of fuel on a cold day to combust.
