Injection pump help

['94IDITurbo7.3]

i would like a straight answer to my question. does the timing on the injection pump on my '94 7.3L idi Factory turbo change as the pump ages and wears? I replaced all of my injectors about a month ago and ever since i changed them my MPG is non-existent. Now when i start the truck it idles kind of rough for a few seconds and smokes white smoke then goes away no matter what engine temp or how long the truck has been sitting. from what i have read on this froum when you replace the injectors you should have the injection pump timing checked and adjusted. to me that makes sense. my engine has 200,000 miles on it.

I am 3rd owner of truck so i have no history on injection pump. is there any way to tell if it is original or reman?

i have been to my local ford dealer and they said that the IP does not need to be re-timed unless i get a new IP. i went to a local auto service shop and they said that the pumps really don't were out and the timing doesn't change. i told the auto shop that i have seen posts on this forum saying that if you get 100,000-150,000 mile aout of an IP you are doing good, and he said that he sees IP all the time w/ 250,000-300,000 miles and still going strong.

Sorry for such a long post but just want get a straight answer and want to explain myself.

Thanks

 

[Black dawg]

injection pump wear retards timing with age.

there is also an advance mechanism that functions differently with age.

 

[jonathan]

its time for a new one

 

[bigblue85]

you will definatly have to advance the timing as she wears. plus them new injectors arent use to the old injection pump so they are going to want more fuel as to where the old injectors might have not had a spray pattern that these new ones have due to carbon buildup.

 

[TWeatherford]

Its not necessarily time for a new one. If your pump has 200k on it, then yes its time. But he has no history on the truck.

What they're telling you about pumps lasting 250,000-300,000 or more is probably in reference to other types of pumps. The pumps that came on the cummins engines, Mercedes engines, and lots others are cooled and lubed by engine oil and are significantly larger (and more expensive) than our pumps. An IDI pump, from what I have gathered here, is on borrowed time much after 100k.

 

[bigblue85]

good point stanadyne pumps are alot more simpler because of its distributor style caused to be timed with the cam and crank. great build great design...

 

[icanfixall]

Ok.... With a pump of unkown mileage, Then installing new injectors... Your timing will be retarded some. Heres why. Lets use a new pump and injectors from the begining. The pump is timed properly. Now as these wear the injection pump pressure drops as does the injector pressure. You and I can't feel this degrading because its so suttle. Now throw in some new injectors that pop at the normal pressures. I'm betting your old injectors opened at around 1700 lbs or lower. Now a new set opens at say 1850... So you see the pump must work harder to push fuel to the injectors that are poping open at a higher pressure. That retards the timing. Same thing is all the injectors open at 2100 but one is opening at 1700. That low injector will be really advanced because of the lower pop pressure. So to close my feeling... Based on facts learned here and other places... Changing the injectors is cause to time the engine.... Any injection pump that has many miles on it needs to be checked ocasionally too. The do not last 250,000 to 350,000 miles thats a known fact. Now you will have some members post that they went 200,000 miles on a pump because they bought the rig new and are the only owners. That can happen but its no way the norm around these forum.

 

[typ4]

If your pump is painted and matches the engine color it is most likely original.

And you dont want that auto shop working on your IDI.

 

[OLDBULL8]

To elaborate on ican's synopsis on IP timing,. These IDI engines are timed at 2000 RPM and set at 8.5 to 9.5 degrees BTDC depending wether you have a turbo or NA. At 8.5* BTDC the piston is only approx. 0.086 from TDC and at 2000 RPM the IP has only 23 thousands of a second to inject the fuel BTDC. Retarded timing will result in incomplete combustion producing White smoke and rough running, too advanced timing and too much fuel will result in engine knock, combustion starts too soon causing the knock at lower engine RPM. It is a recommedation that when installing new/rebuilt full set of injectors that the IP also be new/rebuilt and timed. A new/rebuilt IP is capable of achieving 5000+ PSI that is why it can inject fuel in such a short period of time and overcome the set popping pressure (1850 PSI).

 

['94IDITurbo7.3]

Thanks for all the insightful replies

What ican said totaly makes sense. when parts wear tolerances change. now i just wish i could find a shop around me that does not think that the IP is invincible. My current IP is probably the original b/c the guy that i bought the truck form just kind of drove it and didn't really work on it much. I will have to look later today when i get home from school if my IP is painted or not.

Thanks again. this is probably the most helpful forum i have been looking at.

 

['94IDITurbo7.3]

If my IP is original then i am going to get a new one. does anybody know of a good place to get one from? i have read about mixed feelings for Pensicola Diesel. so not sure about them.

 

[Agnem]

Your not going to find a commercial establishment that has knowledge as complete as what your going to find here, with the possible exception of Hypermax. Very few Ford dealers have mechanics working at them that are old enough to know the IDI, and if they do, most have forgotten what they knew. If it wasn't necessary to re-time IP's due to age and wear, then I wouldn't be timing dozens of trucks a year at events.

 

[jonathan]

pm agnem

 

[icanfixall]

Mel's posting above is so true and thats why we work so hard here helping others to learn about these engines. This is very old engineering on these engines and it really doesn't make a dealership any money to stay current with it. Now this forum has many members that have a collective knowledge base that far excedes any dealership with one or two mechanics that know anything about this engine. They can look stuff up in books.... If they can read. I feel we have more than what they have and our passion is to help others.... Not make a dolar off someone that knows nothing about whats wrong. Ever take a car or truck to the dealer and they tell you its going to be $80.00 plus just to tell you something is wrong..... Well, didn't you know something was wrong when you drove in the dealership... Sure nuff... they sometimes take that amount off the total cost if they do the repair but really.... You knew something was wrong when you drove it in... This forum offers the diagnosis for free and the repair s too. Sometimes we even offer to fix things for you or show you how to do it...Teach a man to fish and he wont be hungry for life....

 

['94IDITurbo7.3]

i looked at my IP today and it appears that it is leaking fuel so i am going to get a new IP. that tin pan thing on top of the engine also is all wet.

i think i am going to get this IP seems like a good deal.
http://cgi.ebay.com/ebaymotors/Ford-IH-7-3-7-3L-turbo-injection-injector-pump-

Would a bad IP give a false TPS signal? Just curious.