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DB2 Conversion thread

HighSierra86

HighSierra86

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Location
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IMG_4417.JPG My DS4 gave up again after 45k miles/10 years. Not a bad run I guess, but with dreams of never replacing another PMD I decided to go the mechanical route. I've had great luck with our DB2 6.2s and was never let down by their reliability.

Started amassing parts a few weeks back and finally have everything I need. I think. Read through Bobbie Martin's guide he graciously made available. Most of his listed part numbers are no longer available from GM or anywhere else for that matter. The throttle cable proved to be the toughest find so far.

Anyways I've completed the tear down and have finally started putting things back together. Found a lot more work for myself during the year down including alternator bearings, seeping water pump, and some oil leaks needing attention. Also found the source of my recently acquired excessive turbo lag!IMG_4416.JPG

Purchased a rebuilt DB2 4911 with full updates including the rotor head. I had priced brand new, but at $2000 I just couldn't justify it being that much better than a high quality rebuild. Sure looks small next to the DS4! Even though it would be perfect time to reach in and turn the screw, I'm leaving it in stock form for now to keep the warranty until the truck is up and running and all the bugs are worked out.

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Nick
 
Currently have the new pump mounted in the truck. Resealed the valve covers, new glow plugs, front main seal, fluidampr and pulley installed.

Trying to come up with a throttle bracket design that will work around the dual thermostat housing has proven to be a little bit of a challenge. I ordered a bracket from Peninsular that I was told would work with the dual housing. It does not. No big deal as I will probably use is as the basis for my custom bracket. Not much room in there with the upper hose outlet in the way...
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Nick
 
His compressor is on the drivers side so that should work for you if you turn the housing 180*. I think he said what radiator hose he used in his thread.
 
I had seen what Leroy did by rotating the housing, but then id have to re-route the upper hose (that i already purchased new) and possibly the upper intake. I ended up making my own bracket to utilize the upper hose and housing as-is.
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The three brackets pictured above are as follows from left; Peninsular, factory '93, and what I believe is from a Humvee? The pump it was removed from was a 831-5079 and had what I believed to be 24V electrical. None of these brackets worked in my application so I made my own.

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Just enough room in there for everything! My only hope is that my initial pump timing is close. Otherwise too much movement is going to mean some adjustments might be necessary.

-Nick
 

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Looks sharp! I will probably be doing something similar with my tahoe project so thanks for the pictures.
 
I had a hell of a time locating an OEM cable. New and aftermarket was not an option. I had even ordered a cable for a 6.2 out of desperation hoping to adapt it if needed. I don't usually consider myself a lucky person, but a stop at the pick and pull junkyard proved otherwise. Found a '93 6.5 truck that was kind enough to donate the throttle cable and bracket, fuel pedal, wire harness, and the cruise control box and cable (I have no intentions of hooking up cruise but it was there!)
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On the topic of cables. Here is the aftermarket ATP Y270 cable for the 6.2 compared to the 6.5 factory cable. Not really a close match at all. Im hoping to never break this cable as I don't know where the hell to find another!

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Anyone have any ideas for a bushing on the eyelet? The IP was already missing from the parts truck, so I'm assuming it went with it. Going to hit up the hardware or Home Depot to try and find a bushing that might work, but I'm drawing a blank for now....

-Nick
 
Got to spend a bit more time on the truck this morning. Installed the new water pump and cover, alternator, thermostats, and brand new IP hard lines from Leroy. I'm now onto my least favorite subject. Electrical. Anyone converted a OBDII truck have any pointers? Bobbie Martin's guide explains well for the OBDI, but I am unsure of what to do in regards to the glow plug circuit in this case.

I have traced back the engine harness and was able to completely remove one large section that contained all of the wires headed to the IP. Only one wire came from another harness behind the fuel filter housing. Any one have a wiring diagram that might shed some light on what this wire is for? and if i can possible re-use it for the new pump...Its a smaller 14ga? orange wire that eventually connects with the black wire at pin C on the PMD harness. See cut wire below..
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Any help in regards to hooking up wiring for the pump would be appreciated. Thank you.

-Nick
 
Good thread. I did flip my Tstat housing to clear cable bracket, but then that meant the hose had to run right were the upper intake is so I had to get a Peninsular upper. Works well, but Id like to make a bracket like yours or Nates.

What are you doing for trans control?
 
HighSierra86 said:
I had a hell of a time locating an OEM cable. New and aftermarket was not an option. I had even ordered a cable for a 6.2 out of desperation hoping to adapt it if needed. I don't usually consider myself a lucky person, but a stop at the pick and pull junkyard proved otherwise. Found a '93 6.5 truck that was kind enough to donate the throttle cable and bracket, fuel pedal, wire harness, and the cruise control box and cable (I have no intentions of hooking up cruise but it was there!)
View attachment 50561

On the topic of cables. Here is the aftermarket ATP Y270 cable for the 6.2 compared to the 6.5 factory cable. Not really a close match at all. Im hoping to never break this cable as I don't know where the hell to find another!

View attachment 50562
View attachment 50563
View attachment 50564

Anyone have any ideas for a bushing on the eyelet? The IP was already missing from the parts truck, so I'm assuming it went with it. Going to hit up the hardware or Home Depot to try and find a bushing that might work, but I'm drawing a blank for now....

-Nick
Click to expand...

Specific only to the bushing area at the IP: You have both a 1992 (on top) and 1993 throttle cable as far as I can tell. Maybe older as well as 1992? My 1992 doesn't have the bushing. My 1993 ate one as it fell apart. Regardless it's a plastic core with a rubber grommet around it. GM discontinued the throttle cables. I think the bushing only comes with new cables. NOS Ebay? The bushing reduces IP drive noise brought into the cab by the throttle cable esp. from sloppy chains...

I would strip that truck in the junkyard of the t-stat housing and other specific 6.5td parts and drop them on ebay. Even the single t-stat is in demand.
 
It's alive! Finished up everything yesterday and was even able to get out for a quick road test!

For the throttle cable bushing I ended up using a door pin bushing from a Ford truck that was almost the perfect size. Only had to slightly up-size the inside diameter.

The wiring was much easier than I had originally thought it was going to be. Only thing still in question is the relay I ended up using to power the pump and advance circuit. Anyone know how much amperage they actually draw? Seems the 30 amp relay I used was a bit warm after running the truck for a while. Just wondering if I should be using something heavier duty or at least split the load of the two circuits.

As far as the glow plug system goes, I left everything factory intact, and they work just as before. No need for any PCM harness modifications or re-wiring as needed with the OBDI trucks.

In reality the entire conversion was fairly simple with the manual trans truck. I am so far very happy with how much better the truck idles and runs smoother across the board. I've got a few small things to button up today and then I'll put it to work to have a better idea on overall performance and drive-ability.

-Nick
 
Welcome to the magic world of no pmd!

I cant remember what draw is for the solenoids. Just remember 1 circuit for fso and another that runs to the advance units
 
Sorry for bringing up an old thread, but I wanted to show the throttle bracket I've made. This is one of the top results when searching so I figured it might help some people.

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In this case it wasn't for a DS4 to DB2 conversion, but for a V-belt to (later model) serpentine swap with dual T-stat crossover.
 
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