7.3 IDI boggling problems?
 

I have a 91 Ford f-250 4x4 with a 7.3 IDI non turbo.
recently bought it as it is my first diesel, took it to my mechanic, for a good lookover, and he recommended that I replace the injection pump.... so we did, no it almost seems like it has no top end speed whatsoever?.... the truck was idling at about 850 before replacing the Injector pump, and then about 700 afterwards, its now blowing quiet a bit of white smoke on start up, (meaning it is burning rich I think) until it gets warmed up pretty good, then the smoke goes away quite a bit. however it seemed the truck was just " falling flat" so I had another acquaintance (who is a diesel mechanic) adjust he idle up via the injector pump....
my problem now is that the truck just doesn't have the power it should, or had before we replaced the injector pump....
for example, climbing a hill, I went from 65mph and 5th gear at the bottom of a hill, to 35, and 3rd gear at the top, it just fell flat on its face.

any suggestions?

Did you have the timing checked after the new IP was installed?

no sir, i assumed they would do that at this shop? when at idling speed, this thing is a massive monster, but at higher speeds (so far) it just falls flat on its face. Would the timing have an effect on this diesel with the white smoke (cold start this morning just to see what it would do, and the white smoke definately poured on out). being new at this diesel thing, i wasnt for sure if timing would effect how the fuel was burning, if it would burn it rich or lean?

---AutoMerged DoublePost---

talked to mechanic today, he did not put a timing gun on the truck afterwards, however he said he checked the timing via glowplugs, and it looked petty good.
the truck started blowing some great black smoke this afternoon when the temperatures were around 50 degrees, and ran like a strong bull after some pooonahnee, however tonight going up the dreade hill again, it fell flat once again. was blowing white smoke, almost seems like it is losing compression ability at higher speeds..... it is literally the STRONGEST motor I have ever seen in first, second and third gears, and it starts losig alittle in fourth? but after that it feels like a blown up old 4 cylinder. never seen nothing like this??

is this oncoming signs of cavitational problems?:argh:

timing, get it checked and done by someone that knows what their doing. Go from there.

Why did he suggest replacing the IP to begin with? Did the truck run ok before it was replaced?

Does your mechanic have an actual timing tool for one of these motors? Most shops will just time them by ear which a seasoned IDI mechanic may be capable of, but some of the younger guys only speak electrical and not mechanical. A lot of times these guys will mark the IP and put the new pump in the old position. The stronger pump can change the injection time as can new injectors. A new IP can also wear out old injectors much quicker as well. It's usually a good idea to change the injectors and IP together although it's not necessary. It is also entirely possible you just got a bad IP, you would not be the first to suffer that fate.

It is necessary to replace injectors at the same time as the pump, as you do not know the condition of them. You want to put an even load on the new IP that just costed $500+ otherwise, you will cause it to become worn out. I would just line up the center marks on the pump housing, and the center mark on the filler neck cover, adjust a dimes thickness accordingly.

---AutoMerged DoublePost---

But unless your truck was in dire need of a new ip, I would have stuck with my old one, what is the condition of it? How was it running before

the mechanic checked the injectors, we put on new fuel lines to everything at the same time, but the mechanic said the injectors looked good and open, we changed the IP because it would drive just fine and dandy, but immediately cut out with no response at times, sit for alittle bit, and do just fine and dandy for a few hours, then just cut out altogether again. the mechanic checked the fuel pressure coming out of the pump, and he said it was not running consistent, however fuel pressure was great to it, and a couple of other reasons, (rough idle, fuel leak, etc.) when i took the old pump back to get the core charge off of it, the salesman took a look at the old pump and said he could see where it was not functioning properly, being new at this diesel stuff, i didnt doubt him as he is an old seasoned diesel mechanic himself. I'm going to go ahead and take it to another shop and have them check the timing, if thats not it, i am not sure what it is...

Someone else told me though over the weekend that these IDI diesels with the non-turbo version aren't going to get much higher end speed than what i am getting out of it. I am serious when i say this thing is a MONSTER in the lower gears, (i know its a no-no, but i had to try it out, but i pulled off about a 60 ft long classic roasting burnout in it, and it wanted more) but when i hit the highway, 70-75 is just all she wants to do, and it makes it hard to be in normal traffic in my region, cause we have hills galore.
ANd yes syncostang, we did go through the "getting a bad Injector pump" scenario, had to get two pumps to get a good one to even begin with. got a lifetime warranty IP though, spent alittle bit on it, but got a decent chunk back with the core, plus i know the salesguy i bought it from, so he helped me out on it a bit.

any possiblity that this thing just isnt used to the absolute fridgid winter weather we have had this year?

Are you running larger tires, how about your gear ratio? Are you blowing any black smoke? What kind of EGT's are you seeing?

Just throwing this out there...Do you use diesel additive like your supposed to?

not sure on the Exhaust gas temp range, it is blowing some black smoke, but it also is blowing some white smoke on start-ups only,
and since I just bought the truck, I have been putting in diesel additives in the fuel.
Not sure on the gear ratio, pretty sure it's stock on the axle and tranny, tires are stock 31" or 32" tires....
how would the EGT effect losing speed and power at higher end speeds? being new at this diesel stuff... I'm just trying to learn, sorry if I ask a silly or seemingly stupid question, and the gear ratio would have nothing to do with the loss of power if I had established an already high speed, but lose it over time? correct?
is it in the 7.3 IDI's to just lose some ass when maintaining speeds up hills?

bad egts will kill your engine, and means that you're just puking fuel into the cylinders so you won't gain any speed

If you have the pedal to the floor and you are losing speed while blowing smoke, your exhaust temps are probably getting pretty high which could cause serious engine damage. I would invest in a pyrometer, could prevent you from turning the truck into a lawn ornament.

I was curious about your tires/gears because if you had been running oversized tires with a tall gear ratio that would really kill you on hills.

The N/A motors aren't going to thrill you on the hills, that is for sure. I don't know how steep your hills are and most of the hills I travel on are really curvy with low speeds so I have never had an issue holding 35-45mph in a turbo or N/A truck.

Does your tachometer work?

how do you fix bad EGT readings?

Been driving the truck every day just to get used to it, and see what other kinks may arise, nothing else motor wise, seems to run fantastically, it loves drinking fuel though, and it is blowing some white smoke on startups, and chillier days until it warms up now. almost seems like I am dumping fuel into it, (white smoke means burning rich, correct?)
at the rate it is using fuel, with the white smoke, I am thinking new injectors are in my future..... would this effect the EGT? (I'm thinking if I am burning fuel at a higher rate than engineered for, my exhaust temp is probably running higher than normal as well?
am I thinking right?

---AutoMerged DoublePost---

I do have a tach, it mases out at 4300, I never let the truck go over 3100 rpms, it is climbing the dreaded hill better lately with the warmer temperatures, when running this particular hill, I am usually running around 70 at the bottom, in 5th, which is just basically overdrive, at around 2 grand to 22 hundred rpm, I"ll let the truck get down to between 1500 and 1400 before I down shift, (I use this truck for hauling water (approx. 4000 lb per load) and it doesn't make a difference if I have the water tank with me or not, it runs the same with or without the extra 4000 pounds of water, so compression and power doesn't seem to be a concern) I am beginning to think I am overloading with fuel, since I have not changed the injectors, or adjusted them, since installing the new IP.
any other suggestions?

If your exhaust temps are getting you high(which a pyrometer will tell you) then the only thing you can really do is back off the throttle. You can turn down the fuel screw in the IP as well and make sure you have a clean air filter and unrestricted air flow.

White smoke on a cold start is normal, you should get a puff or maybe even a few seconds of white smoke on a dead cold start. My truck smokes a lot(15-30 seconds) when it's cold due to some underperforming glow plugs and larger injectors. How old are your injectors? If they have a lot of miles on them, the spray pattern could have deteriorated resulting in your poor mileage.

come to the conclusion that I need to replace the injectors...
any suggestions on some good ones? or should I just go to my local parts store and get the ones off the shelf? any particular rate, gap, flow, pattern better than the others? and for what reasons??
Actually planning on turning this thing into a local eyegrabber with future modifications, so I might as well start with the fuel system...

If you're going for power down the road, might as well get a set of moose misters now, also, when you pull your old ones out, get them tested to see what they were doing to your engine. I did mine in the shop last week. NOT a single one sprayed, it was a stream lol :s:

Run a gallon of ATF in your tank and run the hell out of it ... i run mine to 3400 then shift ... YOUR NOT running it to 4300 Rpm's .... mine is built and i woul never dream of doin that .. 4K and it wouldnt be good .... you need stiffer Valve springs and pump work to go that far up ...

Runnin mine 5 years now ... ( before i needed HG's ) loves atf and a bit of good filtered waste oil ( filtered to 5 micron) ... I have a build thread on the IDI section .... it was clean as a whistle in side ...

Movin and will be gettin it running before snow fly's again .

through it all .. sounds like either a lack of ( either fuel or IP pressure ) , or timing is messed up ...

Have you p[layed with the fuel screw in the IP ??