Ok here is the issue,
i picked up a 89 f350 4wd auto with the 7.3l about a week and a half ago. when i bought it i knew it had these issues. so was not a surprise.
So when i go out, weather it be 32° or even 70° it takes two tries to get it fired. once started for the first time, you can shut it off and fire it back up first try.
today i did a compression test, the engine has 136k miles.

5 pumps: max press:
1: 340 385
2: 350 400
3: 325 380
4: couldnt get to with my compression tester
5: 380 440
6: 330 385
7: 340 380
8: 360 420


Im thinking its injector issue, but cant be certain. i did notice that it has BB code injectors in it. and not sure on the pump condition.

the other odd thing is there is NO smoke coming out of the exhaust and VERY minimal blow by. i get a small puff of black on start up, and if im going up a hill ill get black.

any opinions????
was thinking of replacing injectors
Thanks
Rob

btw the compression tester was pretty dang old. it was the local ford dealers that has seen a lot of use, so i dont know if i should take these numbers at 100% accurate. the quick connect on it was not real tight and at one time blew off ha ha ha

 

Sounds to me youre getting some air in the lines after sitting, slow like. So once you get it fired the air is purged and it will start up again fine. No smoke when cranking is a good indicator of it. Those numbers dont seem horrible, has it been sitting for a while?

 

umm i think the PO said around 6 months or so,
he bought a newer dodge and this old truck was sitting in his yard so he finally decided to sell it. no smoke when cranking either, just once it fires you get a small puff of black.

btw you can hear a random light "pop" in the exhaust when sitting at idle. once you rev it to 1200-1500 the engine smooths right out.

Rob

btw i have maybe put on 150 miles since i got it.

 

mine does the same thing when idling.. and im not real sure what it would be.. maybe a leaky injector. The sitting might make your compression test look less than ideal. After a good long hard drive might test it again and ill bet you see better numbers.

something to do if you havent, get some power service and fill the fuel filter with it, let it run for a few minutes to get it in the IP and lines and shut her down and leave it for a day or two, surprisingly, it did wonders for mine.

 

Opinions are like @$$#0!35, but I would do the same thing, only with Seafoam.

-Matt

 

my 88 will loose a cylinder if left idling for more than 15-20 minutes. once you rev it up it comes back to all 8.
i am just too lazy to put injectors in it again.
the ones in it now have around 140k miles on them.

 

Well changed out one set of injector o rings that were leaking, helped the rough idle some.
gonna pull all the injectors this weekend and pop test them, the local for dealer loaned us their pop tester.
while i have them out i have new injector o rings for all of the injectors.

also my DD is having some issues so will be driving the truck in to work tomorrow. lets hope it goes smooth
Rob