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Injection Pump Swap

6.5L

6.5L

Old Iron Runner
Messages
1,177
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433
Location
Northwest Wyoming
So I got to thinking today. I always hear about people wanting to swap to a DB-2 from a DS-4. Yet, if the DS-4 was more power-capable and easier to tune, why don't I hear about people swapping from a DB-2 to a DS-4 system. It seems with PMD relocation and all that, that the DS-4 can be reliable and make a bit more power than the mechanical injected trucks like mine. Not that I don't like the DB-2. I was just wondering. I also got to thinking, the 7.3L IDI also used a DB-2 injection pump. Wouldn't it be possible to convert a 7.3L IDI to electronic injection if you swapped all the wires and harness and maybe had a custom chip made for it. I am not very familiar with the electronic injection so I don't know. I think it would be kind of cool to have a turbocharged 7.3L IDI with a electronic pump that was chipped. Has anybody heard of somebody doing this or know if it's possible?
 
The 7.3 pump spins the opposite way. You can flip the cam ring ,but the advance piston not sure. The housing or input shaft will not bolt up either.
 
I guess a more accurate way to put it is a db2 is cheaper to adjust and a DB4 is able to do finer adjustments.

Easier to tune depends on what you're looking for.

DB2 - a little bit of wrench work and you can turn the fueling up and down. But it's one adjustment across the entire range AFAIK. Simple mechanical injection so no electronic parts to fail.

DB4 - needs software to reflash ($$$$) but fuel and timing can be adjusted all across the range vice the turn of a screw on a db2. Electronic components can fail, but so can anything electronic. I just accept it for more control over the injection than mechanical can offer.

DB4 is also supposed to be able to put out more total fuel than a DB2 although I've never been bothered engouh to actually go look up the stats.

Cheers
 
Likely because you are new... :hihi:

I have converted a 6.2 engine from a DB2 to a DS4 to use in my 1995 Suburban.

The DB2 will put out more fuel than the 6.5 can burn. So unless you add lots of upgrades the difference becomes irrelevant in total fuel.

The DS4 is a DB2 gone electronic. This means you get the mechanical issues on top of electronic issues. Double the failure points. The PMD and optical sensor are failure prone parts. Different fuels also cause trouble with the optical sensor as well as low fuel.

Many get tired of the electronics, poorly designed PMD, stranding them. This is why there is a love for the more reliable DB2.

In my experience the DS4 starts easier than the DB2 and has better idle control. But I have already spent more on it for tunes and PMD parts. Start a DB2 and it will run till it is out of fuel or you shut it off. A DS4 will run till the PMD dies...
 
I have only had my 6.5L for about a year and a half now so I am still learning about them. I use to not like them but the more and more I drive my truck and tweak it, the more I have come to love it. I try reading something new about a 6.5L everyday. I know it sounds kind of obsessive but I like to know everything I can about my vehicles. The more knowledge the better. I check the forum about 20 times a day looking for new content that peaks my interest haha plus sometimes it's a nice break from my Cellular and Molecular Biology homework. Damn college sucks haha
 
I have had a 6.5 Diesel Suburban for almost 16 years and a 6.2 Sub before that for 4 years. The first 9 years with the 6.5 it had a DS4, the last 7 a DB2. After having both, I would never go back to a DS4. The reliability factor of the DB2 is so much better than the DS4. With a good pump and injectors, it starts immediately and runs smoothly. Really I think it would be hard for anyone to tell the difference in a DS4 and a DB2 by driving them back to back. Well, maybe one difference, you could drive the DB2 back, you might be walking if you had a DS4. :hihi:
 
Ive also converted a few. The problem for most was controlling the trans if auto. I sell the OptiShift now, for less than $600 its not worth fooling with a factory TCM, ESS......
 
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