I've had enough of DB2 pumps and poor idle quality.

A little background, I've got an 86 Chevy 1/2 pickup with a 6.2L engine in it currently and a TH700R4 tranny. I've been through nothing but heck with this engine and have decided to replace it with a 599 casted 6.2 with 6.5 heads. So when this occurs I also want to ditch the "old-school" DB2 pump and replace it with a DS4 electronic injection pump. This engine will also be turbocharged from the first time it breathes life, with an ATS turbo.

Right now I'm in brain storming mode and I need a parts list of things to acquire to make the swap viable.

The parts I have access to:

-DS4 5288 Injection pump and associated injector lines
-6.5 N/A intake manifold
-6.5TD injectors
-94/95 HD computer (with automatic prom, need stick prom)
-Partial harness for engine stuff
-6.5 Timing cover and reluctor wheel
-6.5 Crank position sensor

Thats all I have now, some parts I know I need are:

-APP petal
-?

I don't have a clue how to wire this thing yet, and I don't have any diagrams from a OBD-1 truck. But this will be OBD-1 because I figure that this would be the easiest to convert to, but I could be wrong, suggestions welcome here.

The biggest problem with the conversion that I see thus far is getting the transmission to shift properly. I'm thinking of getting a longer cable made up (recomendation on sources welcome) and attach it to the APP inside the cab as compared to on the IP as it was before. I'll also have to contend with the TCC lockup that also rides on the IP, but maybe I can tap signal off the APP?

Thanks for the look

I'm not really worried about time on this project. As I've given up on the current engine and will be building the new engine soon. But, all in all, the truck is sitting parked permanently.

where r u located?

When you switch to EFI you'll have to put a '94+ timing cover on the block, ds-4 pump but what year '94 ECM means 5068 and '95 ECM could use a newer DS-4 pump, And to make it woth it, I'd put a 4L80E if you're going through all this trouble to retro fit it. You also will want to add an aldl and the dash if you're not equiped or you can't run diagnostics(check engine light) or look at timing.

Thanks good points thus far

-Needed 95+ ECM (I'll find out what the one I have is)
-ALDL, yeah I forgot about this one.

Still considering the 4L80E thing, I just figured it as going to end up being too complex to do them both.

Just a note, this will all be tested on an engine test stand, so I'll make sure this will all work before ever trying to get it to run in the vehicle.

Save yourself a kick in the rear later on and get a high quality rebuilt DB 4911 injection pump, keep your 6.5 mechanical. DB injection pumps are normally much more durable than the DS counter parts, but quality of rebuilding is key.:grd:

DB injection pumps are normally much more durable than the DS counter parts, but quality of rebuilding is key.
D Cam hit the nail in the head, send you pump up this way chevydiesel.

This topic is admirable, and I am personally a big DS pump fan, but making your DB2 setup work properly is so much simpler.

You could always trade vehicles here with someone who has enough of there DS4 pump!

Gee, where ever would you find someone like that... LOL

Hey chevydiesel, whats your problem with idle quality anyway?

TDG,

Hmm, quality rebuild.. Well perhaps I'm being a bit harsh on the ol DB2 system because mainly every engine I have one on is about worn out I suppose.

I've had the original IP rebuilt, new injectors, etc. still a crappy idle. Then I tried a brand new Military DB2 (actually for an 86 HD) and it did the same thing, still recovering from that little experiment.

I haven't been in a 6.2 truck that had what I would call a good idle, except an engine with the timing very retarded = no power.

The problem with the idle (I so obsess about this) is that when the truck is in gear sitting at a light I get the "shiver" or uneven combustion events. It basically shakes me, and the things sitting next to me in the seat next to me. Now, this isn't the shake you'll see the whole truck moving about. It's more the shiver you get in the cab thats uneven. Another example is when you're in gear and you just baraly have the break on and the truck "uuches" in time with the slight miss. All of my 6.2's do it, some more than others, granted the '86 is now a gonner due to the fact it eats lifters as a kid eats candy. And yes (I know you're thinking it) the engine, cab, tranny mounts have all been R&R'ed (I told you I obsess).

But, on the other hand, my 6.5TD even with a broken wrist pin (funny knock) still idles way better than any 6.2's I've been around, and its a 95 with a DS4. So thats why I'm considering this swap. I'm thinking that the computer actually compensates to create a better idle. I've also heard of someone else doing this very same thing, and for the VERY same reason, I'm still trying to track that person down.

I don't know about the 4911 thing, because I have a buddy that had a truck with this pump and it behaved the same way as the ol 6.2 did/does.

This could be some other problem. These pumps will idle smooth if everything else is right. I have an old '84 Suburban that has a Goodwrench replacement 6.2 with over 100 thou on it. It idles very smooth at all times. Never a problem of any kind. My '82 pickup has an old red 6.2 with 240 thou and idles just as you describe. In fact, I think it has a dead miss at times. That's just age and mileage. Slight loss of compression and slack in the timing chain. The pump is not the problem. I, too have tried changing pumps and settings. To no avail, it's just normal wear on mine. The pump's fine.

Not to Hi-Jack your thread, but my 98 will on occasion while stopped in gear (foot on brake) surge/miss/ it has done it 1/2 a dozen times in the past 3wks. no surging at any driving speed. Except for this problem the truck hauls a$$. Does this indicate a pump issue??
Nick

chevydiesel,
Timing chain slack can give you rough idle like that too, I don't know if you've done that...

Your right about the DS4, computer control allows the PCM to control advance and idle speed to compensate for different conditions, and the DB2 can't do that.

Also, rough idle is almost never a pump problem, first thought would be injectors, but you've done that, next valve train and timing chain.
nickg,

Broken Fuel Solenoid Armature sounds like.
Expect DTCs for long/short Closure Time and eventually Engine Overspeed.

Yeah, I've been down a few roads troubleshooting the poor ol thing, the only thing left is a top end job. The timing set is a gear set now.

I'm just stoked at the DB2 because I've never had any success getting a decent idle out of an engine equipped with one.

I'll start putting the new engine together soon, and I'll test it on a test stand with the DB2 first. The engine will be mounted on regular engine mounts and full suspended by rubber. So I'll see when it shivers and shakes. I plan on running the engine for very many hours before transplanting it into the truck.

I agree with TDG, the DS4 is the way to go, it has great drive-ability and mods available. FSD sucks, but there are fixes available. For your build I would look for a complete motor, if you're lucky with computer and 4L80-E, on ebay lots of pulled ones in unknown condition some with bad blocks or internals. You would probably save alot of money in the long run being able to transfer all the little components (IP, injectors and lines, exhaust manifolds, accessories) that would normally have you going back to the parts counter over and over again.

Why not do a compression test on one of your rough idling engines? I will bet that you will find one or more cylinders a little low on compression.;)