6.9 and Early 7.3L Injection Pump interchangeability??

[Petri317]

DIS mistakenly sent me a 7.3L pump for an 89, when I have a March 1984 6.9L. I figured, no big deal, the two pumps are similar enough they will work. Is this true? Are the 6.9 and 7.3NA pumps interchangeable? I am still in the preocess of rebuilding the truck/engine, but this all came about when DIS called to REJECT the original 1984 IP I sent them. They said they do not deal with the earlier IPs!! It worked fine, so I'll try to get it back and get a 7.3 core to send them. Upon talking further with DIS, they said they don't recomend using the 7.3L pump on my 6.9. Should I keep the 7.3 Pump and use it, or send it back for a 6.9 unit?
Thanks in advance,
Peter


P.S. A little update on the project; the '84 chassis and body are no more. On a sour note, turns out the 5 speed I was to use from the 89 had a MAJOR crack in the bellhousing, so it looks like I'll be sticking with the trusty T19. Oh well.

 

[EvergreenRanch]

hey maybe we could work out a little deal...i wanna replace my IP and i have a 89 7.3.......maybe we trade plus i throw a little cash your way so you have you core? PM me and we'll figure something out. i could have my core out and to you in less than a week.

 

[towcat]

P.S. A little update on the project; the '84 chassis and body are no more. On a sour note, turns out the 5 speed I was to use from the 89 had a MAJOR crack in the bellhousing, so it looks like I'll be sticking with the trusty T19. Oh well.

so......what will you be doing with the broken ZF5? :Sly
I have a shelf full of core IP's too....

 

[Petri317]

EvergreenRanch: I wanna see if the 7.3 IP will work for me first, but if it won't we might be able to work something out.

Towcat:I have the broken ZF5 sitting around;not really sure what to do with it. Is there any(cheap) way to fix it? If not, you can have it, if that's what you're hinting at. :Sly

 

[82F100SWB]

I have a 91 7.3 IP on my 6.9. It will work, but, I believe the timing curve is different in the 7.3 pump. I can't say for sure. All I know is with the way I have it set up(7.3 pump/injectors) it drives more like my 460 than a 6.9....

 

[EvergreenRanch]

hahaha yeah ill be very happy to help just lemme know!

 

[The Warden]

this all came about when DIS called to REJECT the original 1984 IP I sent them. They said they do not deal with the earlier IPs!!

:***:

Since when?!?

I replaced the IP in my '84 in June 2002 with one from DIS, and it was a 6.9l pump and everything went quite well. My old core was accepted, and the new pump's been doing well (other than a sticking FSS)...

That said, I had always assumed that the 7.3l pump was identical to the 6.9l pump, except the return line being a hose nipple on the 7.3l instead of a threaded fitting for a metal line on the 6.9l. But, I don't know...maybe the fuel curve is different? If so, I wonder if it's better to use the 7.3l pump? ...OTOH, every indication is that a DPS pump can do wonders :Sly

 

[Agnem]

I don't see any problem using a 7.3 pump on a 6.9. I know the other way around works fine too.

 

[Petri317]

That's what I thought Mel. I was 99.9% convinced that the pumps are interchangeable, so it came as a shock when the folks at DIS said otherwise. I suppose they say that for liability concerns, or something? As for not accepting my 6.9 pump, I suppose they did that because they sent me a 7.3 Pump and wanted the same in return.

EvergreenRanch: Looks like I will be using the 7.3 pump. If I find something that might help with your truck, I'll let you know.

 

[TLBREWER]

That's what I thought Mel. I was 99.9% convinced that the pumps are interchangeable, so it came as a shock when the folks at DIS said otherwise. I suppose they say that for liability concerns, or something? As for not accepting my 6.9 pump, I suppose they did that because they sent me a 7.3 Pump and wanted the same in return.

EvergreenRanch: Looks like I will be using the 7.3 pump. If I find something that might help with your truck, I'll let you know.

I just got a pump from DIS last month. Course I had no problems because mine was 7.3 for 7.3. I just wanted to remind you not to drag your feet too much on satisfying their core requirements. You'll notice on the receipt that if they don't receive a suitable core from you within 30 days, they charge you a $500 core charge. I found that to be a little stiff since the new IP only cost me $426.

Tom

 

[typ4]

Might have to be a little forceful with them and ask why t hey sent you a 7.3. I know people that have swapped them around on used ones and all works ok. just a little more fuel on the 7.3 pump according to my pump shop.
mt 2 c. This is why I always have my unit rebuilt and just wait. Also a shop that isnt totally honest can say "your core wasnt rebuildable, so sorry" then whack you with a fat core charge when realistically they probably have many cores on the shelf they could sell you.
russ

 

[sle2115]

You'll notice on the receipt that if they don't receive a suitable core from you within 30 days, they charge you a $500 core charge. I found that to be a little stiff since the new IP only cost me $426.

Tom

OUCH!!!

 

[towcat]

Towcat:I have the broken ZF5 sitting around;not really sure what to do with it. Is there any(cheap) way to fix it? If not, you can have it, if that's what you're hinting at. :Sly

I don't think you read the post you did a few months back, but if you have a guy who knows his **** when it comes to aluminum welding, your case is repairable. Cheap? I have no clue. I have a couple of guys I barter with who does all my welding for me, so I really don't have a clue what real life $$$ are. If you can make the drive south, I can hook you up with the guys. If you can come up with a tag number on the IP, there's a very good chance that I have one on the shelf. but as far as running the 7.3 ip on a 6.9.....bolt it on and go.

 

[typ4]

I am going to pick up some pumps at the u pull it when I can, 15 bucks with a 5 core charge

 

[Diesel JD]

That's pretty gay that they wouldn't accept the core, the reasonis that the early(original 6.9) IPs had only 1 shaft seal and the newer ones have two seals. the result was that instead of weeping fuel out the weep hole like teh newer pumps do the early ones would fill your crankcase with diesel. I have a friend who had this very problem. I agree with Mel, the 6.9 and 7.3 pump are absolutely interchangeable, we have had a lot of members here and over at TDS who have used one with the other. You won't damage the engine. The 7.3 pump delivers more fuel earlier on in the RPM band. Timing is the same I think. You can have plenty of fuel with either pump to melt the engine together, so you will have to buy a pyrometer if you get into any mods, just as you would witha 6.9 pump, and you may have to turn the fuel down if you are seeing a lot of black smoke. It's totally wrong though that they would charge $500 for a core charge. Most places only give a $50 core credit...