Hi,


I recently bought a 1993 F350 cab and chassis with a 7.3 IDI and e40d transmission. It has 107k miles on it and starts up every time no problem. My issue is that when it starts up and runs, the high idle is on and runs bad. its surging, missing, skipping and sounds awful. after it warms up, it runs good when the high idle is off. There is still a slight miss that is very faint every few seconds that's only noticeable on the lower rpms.


I put in new fuel tank pickups, new fuel filter, new fuel injectors, lift pump, orings, return lines and caps, return line check valve, and a new air filter. My last resort is to pull the injection pump off and put on a rebuilt one. The problem was there before I put in the new injectors and is still there after new Delphi injectors.


I checked compression today and here are the results. The truck was warmed up, and all glow plugs removed.


I don't know which cylinder is which but I'm going to say driver side is 1,3,5,7 and passenger side is 2,4,6,8. 7 and 8 being closest to the firewall.


1-400
3-360
5-300
7-320


2-380
4-360
6-375
8-300


My questions is, what is wrong with my engine and what do I do? Do I need a new injection pump or a new engine or both?


Thank You,
Jeff

 

I would have the timing checked, then if that doesn't fix it go for the injection pump. your should change it with the injectors.

 

Let it warm up, then pop the hood and push the lever on the driver's side of the injection pump in. Do things get worse or better or not change?
Chances are, it'll be worse. If so, I'd just loosen the injection pump and advance it a dime's width.
See this video for details:
And before anyone else says anything, yes, timing the vehicle 'properly' with a light and pulse sensor/luminosity probe is a good idea. But getting it 'close enough' isn't hard; especially if you're dealing with a seriously retarded engine. Just advance it a bit, and see how it feels.

 

hi,


I looked under the hood real quick and I didn't see a lever on the driver side of the IP. is it possibly the lever that controls the throttle on the passenger side? if so, should giving it throttle make it worse?


sorry, I'm new to all this.

from the video it looks like I have to loosen the pump up and turn it a certain way. I'm not sure but which way to turn it for advance or regard to make it run better. how would it get retarded if its never been touched?


I'll try turning the pump to fix timing tomorrow.


Does anyone think my compression numbers are erratic?


thank you
jeff

 

your numbers look like a run able engine to me,
As for your timing moving, it happens as the pump wears normally, changing your injectors can affect the timing. I check mine every oil change. you can get your timing close by ear witch you need to try for testing your problem, but in 2 degrees of timing you can gain or lose 3mpg. that is why everybody says to use a meter.

 

remember one degree at the pump is two at the crank, I recommend you get some help with this, as many have made it worse. your engine wants you to run it hard, babying carbons them up

 

Alright,a few points:
On the side opposite the throttle lever is a small lever that goes vertically down the pump. As you add more throttle, this lever moves on an aluminum cam and pushes in a small pin down near the bottom of the pump. If you push in on this lever at idle, the engine will get quieter/less clattery. It may also sound worse/start missing. This lever normally retards the engine a bit as RPM increases off of idle.

Pump timing adjustment:
You need to loosen the three 9/16" nuts holding the pump to the cover in front of it. One is right down the top of the pump, and then the other two are on the sides, near the bottom. You may need to take off the cold idle solenoid bracket(passenger's side of pump) to gain access to that nut.
Then, rotate slightly as follows: The top of the pump goes towards the passenger side to advance, drivers side to retard.

Now, why would you need to adjust this? As your IP wears with normal use, it's hydraulic advance mechanism wears as well, and basically, it doesn't advance as much as needed. Also, the injectors wear as well, which changes the timing somewhat. The upshot of it is though that after ~100K miles on an injector pump, it will be somewhat more retarded than it should be.

My thoughts on timing is that you advance it a dime's width, then take it out on the road. Does it feel better or worse? More or less power? Chances are, it will feel somewhat better, probably be a little louder and smoke less. Keep advancing it a little at a time until it sounds quite clattery and has less power than before, then retard it a bit and call it good.
Yes, you can get a timing tool and spend $100+ attempting to do it right... But really, when you have a worn injection pump, you won't get it to work as well as new, even with a tool.
If you have the money, a newly rebuilt injection pump and a set of good injectors will really help... But that's easily $1000, and chances are that's not something you want to invest in right now. If you did get a new injection pump and injectors, /then/ I would recommend getting it properly timed, because the timing would actually mean something. With a worn pump, my experience has been that the timing you settle on is a compromise between 'works great at the low end, clatters horribly at the top' and 'loads of top-end power, feels mushy and smokes at the low end' due to how the pump's advance curve has changed due to the wear.

Thing is, however, you can do a bit of tuneup and have a perfectly good vehicle that should easily get 14-16MPG, without spending any money for another 30K or so. It might not be as good as stock, but you have to decide whether it's worth the money now.