6.5 TD with mechanical injection system

[Eric Selinger]

I am looking at replacement engines for my 94 6.5TD and was wondering what it would take to convert to a mechanically injected 6.5 and still use the turbo set-up? Has anyone done this? Any problems? Ideas?
Thanks!

Eric

[Bobbie Martin]

I did the conversion to a DB2 pump. If you have a manual trans, its pretty easy. If you have an automatic, its a bit more involved. In addition to the mechanical pump, you need the throttle linkage & cable. You also need new fuel injection lines, ($175 to 250 depending on where you get them) as the lines you have don't fit a DB2. If you have a single thermostat, the linkage is easy, dual stats it takes a bit of fabrication. Fitting the pump & related items is pretty straightforward, but it took me a weekend to do. There is a bit of rewiring for the injection pump, but not too much.
The real trick is the control of the auto transmission. I'll just say there are several ways to do this. I'm working on an article for the DP detailing the way I did it. It is completely different to anything you have seen here. Hopefully it will be ready soon.
I recommend the DB2 swap. You can get 200-300 HP reliably with the DB2. You know, regardless of what you do, the DS4 is going to fail sooner or later. Sure you can come up with some contraption that will postpone the inevitable failure of the PMD but that is all it will do, postpone the inevitable. Not to mention the optical sensor. With the DB2, if you have fuel & air, it will run and runs pretty smoothly. If I seem down on the DS4, its for good reason. I had one for over 7 years. Even with FSD coolers, fuel treatment, etc., we went through 4 or 5 pumps (I lost count). Our old DB2 equipped 6.2 Suburban never had a pump failure.
The turbo is no problem. Use a Turbo Master and you can remove the vacuum pump and related boost control. Just make sure you get a 4911 DB2 pump or equal.

[rjschoolcraft]

Bobbie, I'm sure the experience that you had would sour me too. However, I'm on my second pump. This one was installed at 76,000 miles by the dealer under warranty. The truck now has over 183,000 miles on it, so over 100,000 on pump. The FSD is still mounted in the factory location and has never been touched. My horsepower has to be somewhere in the mid 200's. Kennedy's DS4 equipped truck outpulled the Project Truck in last years Pull Off. I'm not ready to give up on the DS4. In my opinion, there is nothing wrong with you or anyone else converting to mechanical injection; however, I don't think you should push other people so hard to do it. I think it should be presented as an option with all of the pros and cons and let thinking people decide. Some of us are being successful while retaining the electronics.

[Eric Selinger]

I have had only one pump replacement under warranty at about 70,000 miles, When I turned my 6.5 off for the final time on Sunday it had 195,962 miles on it (also has the original injectors and glow plugs). I love my truck, it got me home eventhough it wwas real sick.

I have more problems with lift pumps and OPS than the pump and it's other components, it's just that I'm fixing to spend a bunch on a new engine, and just know that the pump is the weakest link, why not get a mechanical system that I know will run.I plan on keeping my truck till the wheels fall off, or I get a good price for it. I can do the fabrication and work myself, but my concern remains in how to get the 4L80E trans to work right.

Are there any detailed requirements and procedures available from someone who's already donw this?

Have a lot of people done this? Have people who've done this been happy?

Thanks to all.

Eric

[rjschoolcraft]

Yes, there are folks who've done this. In fact, there was an article in the DP earlier this year about a Suburban...I can't remember who did it. Bobbie Martin has done it, and as he said, is writing an article. Those folks would be better to comment on it than me, but it is doable.

Folks have had to come up with some ingenious ways to hook up the accelerator pedal brackets and cables while still keeping the electronic accelerator pedal position device functioning for the transmission and computer.

My advice would be to fix the engine, then think about whether you really need or want to do the electronic to mechanical conversion. I won't tell you not to do it, but I think you should really think it through first. At this moment, I can say that I doubt that I will ever consider it, and I intend to drive this thing for a long time still.

The reason that I mentioned Kennedy's truck is that it has commonly been assumed that you cannot get high end performance with the DS4 pump. Kennedy's truck is proof that you can. My personal opinion (with not much to back it up) is that more could be had beyond what Kennedy achieved: but then I'm always an optimist about such things. Right now, Kennedy's truck is the lead dog as far as 6.5's go that I'm aware of. I drove it and it really is impressive. The Project Truck is right there with it and is mechanically injected. There is probably more in it too with turbo upgrades and the like. I don't think anyone has really found the limit yet.

My Suburban performs so much better now that I can't believe it. The tinkerer in me keeps wanting more, but it really is impressive. I can now pull with late 90's Powersmoke and Cummins equipped trucks (stock trim). Mine is still the stock compression ratio too. The thing that I can't figure out is why GM didn't do some of this stuff from the factory because the heat management problems have been solved and could have been in original equipment.

Boy, I kind of rambled off the subject a bit. Sorry.

[cruzer]

Eric, I think the info you are looking for is in the 1998 & 1999 Feature Article books. Click on books at the top of the page. The 1999 book helped me alot on converting to late model cooling also. Ther's alot of other useful info in these books.

I did not have to convert, but I would, after reading all the problems on the electronics. Seems to me there are problems that just won't go away. I am amazed at he persistence & patience
of these GM owners. Hats off to you all!!!!

As for the 4l80E, FYI 92-93 6.5td had these trans also, so there is a computer available if yours does not work. A junk yard maybe an option. Just a thought.

Here's another benefit to mech inj. On my way down into KY my alt died. I was able to drive 70 miles to Lex. and exchange for another. It was satisfing to know my bat was not driving a computer to make the engine run.

I was in the same boat as you, when my motor went.
I knew heat took out my engine so I corrected the problem. I also knew if I was going to rebiuld, I was going to have more power. My injection system had 125K miles on it also, so everything needed to be replaced. My power is awsome now. It's not he same truck as b4. Someone suggested the 300 hp pump, I thought about that, but after talking to John Kennedy I opted for a stk 4911 and turned it up. Alot of TDP advertisers tried to sell me the big pump. IMHO John was right. He said alot of people have the big pump and have to turn them down.

I did a lot of research and decided what I needed/wanted to build power b4 spending money on parts. I did all mods at the same time, except for exh and gauges. It works flawlessly.

[ 11-18-2003, 07:55 AM: Message edited by: cruzer ]

[Bobbie Martin]

Ronniejoe, I'm not trying to push anyone to do the swap. I don't think there are very many 6.5 owners that will claim the FSD is reliable. I'm sure the number of DS4's that have over 100,000 trouble free miles are in the minority. Also, I was not claiming you can't make HP with a DS4. Obviously it can. I'm sure if someone would do the dyno work there is a bunch of HP in these engines (keeping it all together is another topic!). I wouldn't mind a bit more HP, but the only reason I did the swap was for reliability.


Folks have had to come up with some ingenious ways to hook up the accelerator pedal brackets and cables while still keeping the electronic accelerator pedal position device functioning for the transmission and computer.
As far as the swap goes, keeping the APP, in my opinion, is NOT the way to go. The way I did it is so simple I'm surprised others haven't done it. It took me hours of research and there are some very specific details that take a lot to explain, which is why I'm doing the article. I can tell you my 4L80E shifts perfectly and uses factory GM components that are relatively cheap & easy to obtain. In fact, if you drove my Sub you would never know it has mechanical injection. Everything operates just like it should, even the SES light works.


Have a lot of people done this? Have people who've done this been happy?
I would guess that relatively few with automatics have done the swap, because they are worried the transmission will not shift properly. If you keep the APP, it probably won't. Yes, I'm happy I did it.


As for the 4l80E, FYI 92-93 6.5td had these trans also, so there is a computer available if yours does not work. In 1994 GM changed valve bodies in the 4L80E. So the 92-93 4L80E trans computers are not compatible with 94 and later transmissions. But you are on the right track.

[MikeC]

Ok guys, while we are talking about swapping to DB2 pumps, I have some questions.

I just spoke with Jamie Avant today about repowering my 96 with one of their 18:1 engines with all of the goodies and even putting the 300HP marine pump and hi flow marine injectors in it. I would have them do the install as I don't have the equipment and expertise.

Is it worth the swap?

What kind of headaches am I going to create?

And for those who have done it or have looked into it, would YOU do it?

Looking for any and all advice.

Thanks in advance!!

Mike

Oh yea, If I do this anyone want a nice running 6.5 with 100K on it, 65K on the pump and which hasn't taken my 9500# camper into the mountains as I don't want to hurt it.

[Tough Guy]

There is a DS4 mechanical IP available from Peninsular. The conversion is fairly technical with a 4L80E, it has been done I have seen and riden in a converted Suburban.

Reliability is the real issue.

The project truck at the half way point was at 52mph and still accelerating, but the EGT's were at 1400+ :eek:
I do think the turbo John had on his truck would have solved my heat problem... or not... :D

Cheers