Hard Starting 7.3 diesel


Rottweiler482
10-31-2005, 02:11 PM
I have a 91 f250 w/ the 7.3L diesel. I have had a new engine put in it, but the Ford place that did it didnt' know what they were doing I had to bring it to another ford dealer where they fixed most of the problems that i was having with it.
Now it's running good but when I leave it for 12 hrs or more it has a terrible time starting, and now that the weather is getting colder it's getting even worse.
I'm just trying to find out if it could be a fuel leak or bad glow plugs.
Anyone have any idea on hard starting in warm weather and now it's really hard starting since it's colder out side.

Hope for any type of help.

Thanx

unclebubbles
11-01-2005, 01:45 PM
I have a 91 f250 w/ the 7.3L diesel. I have had a new engine put in it, but the Ford place that did it didnt' know what they were doing I had to bring it to another ford dealer where they fixed most of the problems that i was having with it.
Now it's running good but when I leave it for 12 hrs or more it has a terrible time starting, and now that the weather is getting colder it's getting even worse.
I'm just trying to find out if it could be a fuel leak or bad glow plugs.
Anyone have any idea on hard starting in warm weather and now it's really hard starting since it's colder out side.

Hope for any type of help.

Thanx
You can test the glow plugs yourself. If you have an ohmeter, disconnect the plug form each one , and test from the tip where the wire snapped on, to the base or a good ground. If theyre good, you should get a reading of around .5_1 ohm( looks almost like a dead short, which it really is, its a heating element). If its bad, youll get no reading, like an open circuit. Theres usually no middle ground here, they work , or they dont. You can also test them with a powered test light. After theyre checked, and or fixed, test your batteries, and check your cables, and connections to be sure theyre clean and tight. A bad battery , or connection , can cause the engine to turn slower than it should, which can cause starting problems. A weak starter can also. You mentioned that you had problems after a rebuild. You might take it to the place that got your problems fixed, and have them check the injector pump timing. This is more critical to proper starting on a diesel, than on a gas burner. AS far as a fuel leak, these engines have a block mounted transfer pump, that pumps fuel to the injector pump. The check valves can go bad allowing fuel to leak back, and cause problems. If everything else checks out, and you still have problems, have this pump ckecked for proper output. Good luck
Later
Ed

BULLITTR6
11-02-2005, 03:16 AM
a block mounted transfer pump, that pumps fuel to the injector pump. The check valves can go bad allowing fuel to leak back, and cause problems.


Does the lift pump have a check valve in it? Sometimes, for no understandable reason, my engine will spin and spin but not catch fire. Most times, though, it will fire up within 2 seconds. Maybe my fuel is leaking back, like you say.

Recently with high 40 degree mornings, I have to cycle the plugs twice to get her to go. You could possibly have a small air leak in the fuel system, too.

Rottweiler482
11-02-2005, 08:21 AM
When i go to start it up, It will start right up for about 2 seconds then it will die out and it takes around a minute or so to start back up, but only seems to do it when it sits for a while. At least 6 hrs or so, then it will spit and spuder for a while before clearing up. After that it runs really good.
I have had the timing checked and a new fuel pump but i'm thinking now that it may be a faulty one. Any ideas
I thank everyone for the help

Take Care and Stay Safe

unclebubbles
11-02-2005, 09:21 AM
When i go to start it up, It will start right up for about 2 seconds then it will die out and it takes around a minute or so to start back up, but only seems to do it when it sits for a while. At least 6 hrs or so, then it will spit and spuder for a while before clearing up. After that it runs really good.
I have had the timing checked and a new fuel pump but i'm thinking now that it may be a faulty one. Any ideas
I thank everyone for the help

Take Care and Stay Safe
Yes, the lift pump has 2 check valves in it. One on the suction side, and one on the discharge side. It is made just like mechanical pumps for gas engines. I havent had one apart in a long time, but i guess theyre still made like they used too. The injector pump doesent have enough suction to draw the fuel from the tank, so this pump can cause alot of problems. You are correct , a leaky line , sucking air can have the same symptom, as a bad pump The spitting and sputtering is an indication that it could be getting air in the system. Check all your hoses and fittings, and make sure you have all the air purged from the system. The nexttime it does it , check for air and fuel at the schraeder valve on the filter housing . If youre repeatedly getting air here, you have a leak some where. Be sure to check the feed line for the lift pump. Not to insult your intelligence, but those trucks have a block heater that will help considerably, especially in New York! Most people here in Fla. never use them, and dont even know they got em. I have one on my gas burner, its kinda nice to have warm air when you star up. Good luck
Later
Ed

ripfish
01-09-2006, 01:06 AM
Rotweiller482,

Did you get your problem fixed. I have the same exact senario. 89 F-350 7.3 IDI. Starts for a couple seconds running really rough. Then stalls and is hard to start after that. Once and awhile it fires right up no problems. I think those fuel check valves may be my problem also? Please let me know what you discovered.

Add your comment to this topic!