Recently bought 1986 with a 7.3 idi and it is hard to start always (hot or cold).

[mecjr22]

Bought a 1986 F250 a few months ago and it has been giving me a headache. The truck has a 7.3idi with ats turbo. When I bought the truck all the glow plugs were bad so I replaced the glow plugs but it was very hard to start because the glow plug light would not come on because it has been warm here. I put in a manual glow plug switch and it now starts after turning the engine over several cycles (pushing the glow plugs for 10 seconds or so and then turning the engine over for about 10 seconds again of using the glow plugs and turning over the engine). I have replaced the return line caps, o rings and lines. I have put in a electric fuel pump because the mechanical pump started leaking through the seep hole. I thought the electric pump would have helped but it didn't help.

I replaced both batteries because they were going bad but the engine still turns over slower than I think it should. The more cycles of turning the engine over the faster it turns over. Would my hard starting problems be related to a weak starter. Once I get it started it runs great. But once I turn it off, even for 30 seconds it won't fire back up without glow plugs and at least two times of glow plug attempts and a few cycles of turning the engine over. Is fuel leaking back to the tank after it turns off? I'm stuck and need some suggestions. Thanks

 

[Kevin 007]

The first two things that come to mind are a worn injection pump giving you a "heat soak" issue when you restart it hot and its a pain to re-fire.
And the engines must turn over as fast as possible to generate enought heat to quickly start any diesel. So even if your pump and the rest of the engine are in great shape, you still need to get er turning quick for a fast start; especially when cold.

So...me thinks, starter and possibly injection pump. You mentioned that you have replaced all caps and orings so im going to assume there are no leaks elsewhere in the fuel system to be giving you grief. Have you confirmed that by checking for air at the fuel filter?

 

[wildman7798]

A starter that is tired or worse, can draw too many amps when cranking and cause a serious slow to crank scenario. It will often mask itself as weak or tired batteries. Most of the auto parts stores can do an inductive crank test on your primary lead or battery to see how many amps the starter is drawing so you can at least rule out or deal with that part of it. This isn't going to solve the bigger problem you are experiencing but might help with sorting out the cranking.

 

[Still Strokin]

I second the weak starter issue... Our 300,000 mile 1994 7.3 was getting hard to start warm or cold... There were no air or fuel leaks and the injection pump had been recently rebuilt.... After listening to other 7.3's start I realized how slow ours was turning over... Replaced both batteries & positive cable and still cranked slow.... Put a new starter on it from napa and wah lah... Starts on the first try every time and spins over fast like a brand new truck. Not saying this is your issue but its possible...

 

[icanfixall]

WEll it sure sounds like a bad starter. If you have trouble starting it I bet the other owner did too. Go to ebay and get a DB gear reduction starter. They spin the engine so fast you can't count the rpm at cranking. You do know that engine is not the original engine for that truck. No 7.3 with turbos came in the 6.9 trucks like yours. But thats not a problem. All 6.9 and 7.3 engines swap easily because they are drilled the same. Any part on a 7.3 will bolt directly to a 6.9.

 

[dirtbiker]

I have heard several good comments about DB Electric starters. No need for ebay, though. They sell them in their web site for less money than on ebay, and ship for free. It is dbelectrical.com.

 

[mecjr22]

Well after testing the amp draw on the starter while cranking the engine I realized it was drawing to many amps. Ordered a gear reduction starter as suggested from DB electric off ebay and installed this morning. To my amazement it was turning over very fast compared to the old starter and it fired right up after a few seconds of the glow plugs. Thanks everyone for the suggestions and help.

 

[wildman7798]

Nice ...gotta like those success stories

 

[icanfixall]

The gear reduction starters do the job very well conpared to the sluggish direct drive oem units. The faster the engine cranks the hotter the air is so thats a better starting engine. Compress air fast and it heats up. Diesel requires 942 degrees to ignite. Goggle it if you feel this is waving the BS flag...