Performance 6.5 Injectors

[DmaxMaverick]

I am sorry if this has been answered before, however I have a 93 6.5 td an I was looking at the turbo, it is a GM-3 and there does not seem to be a wastegate on it. it looks like a rod with a spring holds a butterfly valve closed when the exhaust pressure gets enough it forces the valve open.
If that is correct How could you increase the boost?

Welcome to the Forums!

That thing you described is the wastegate. It's just mechanically controlled. Increase the boost by increasing the spring tension. By whatever means. Be careful, there is a point of no return (meltdown). I would not recommend adjusting it w/o gages. EGT, at least to keep from getting too hot, and a boost gage to see the results of adjustment.

[93GMCSierra]

Welcome to the Forums!

That thing you described is the wastegate. It's just mechanically controlled. Increase the boost by increasing the spring tension. By whatever means. Be careful, there is a point of no return (meltdown). I would not recommend adjusting it w/o gages. EGT, at least to keep from getting too hot, and a boost gage to see the results of adjustment.

Thank you, yes I am going to get some gauges, I have been looking into that, besides boost and EGT what other gauges are recommended.
I have had this truck for about a year, however I have only just started looking into how to modify it. I pull a heavy 3 car gooseneck but only on occasion an I like the power to buck the wind an climb hills but when not hauling I want very decent mileage as well.

[TurboDiverArt]

Thank you, yes I am going to get some gauges, I have been looking into that, besides boost and EGT what other gauges are recommended.
I have had this truck for about a year, however I have only just started looking into how to modify it. I pull a heavy 3 car gooseneck but only on occasion an I like the power to buck the wind an climb hills but when not hauling I want very decent mileage as well.

Transmission temp.

Art.

[93GMCSierra]

Transmission temp.

Art.

Even on a manual transmission?

[TurboDiverArt]

Even on a manual transmission?

Oh, sorry about that. Didn't read closely enough!

Art.

[More Power]

I talked to a fellow member yesterday about an ongoing problem he's been having with his DB2 6.5. He told me he ordered and installed a "marine" fuel injection pump and matching injectors from a non-marine vendor some time ago. The engine ran horribly. Some time later he installed a freshly rebuilt on-road DB2, which helped, but the engine still ran rough.

Then, he ordered a set of stock injectors from another vendor (who doesn't advertise here). These were installed, but the two of the eight leaked fuel at the joint where the two halves of the injector meet. There were no markings on the injector bodies - anywhere. No manufacturer name, no model identification, nothing... Sounds like China to me.

The Robert Bosch injector I have sitting on my desk has "Robert Bosch" and "Made in USA" imprinted on the injector body...

So, he replaced these leaking injectors with two original injectors he'd saved that had 150,000 miles on them. The engine ran a lot smoother and they didn't leak. Now, he's thinking about replacing all eight injectors with new ones. I recommended he deal with a certified fuel injection shop that sells name brand parts.

The glow plugs.... He was recently sold a set of eight glow plugs... that did not have any identifying markings on them. The vendor claimed they were as good as or better than the AC-60G.

His low-compression 6.5 struggled greatly to start when cold, even after modifying the glow controller to produce a 15-second first glow.

While one of the injectors was out, he watched the tip of the glow plug while someone turned the ignition key to run. The glow plug tip didn't turn orange, it didn't turn red, it didn't glow any color... The truck owner could feel a little heat when sticking his finger down the hole (just short of touching the glow plug tip).

So, he's installed a fresh set of 8 ACDelco AC-60G plugs, which allow quick and smoke-free cold starts.

Jim

[alteredspeed]

I have a 6.2 which i will be adding a banks sidewinder to soon. I have The DB-2 pump that has just been rebuilt and the fuel turned up a bit. My question is should I have the stock injectors rebuilt or buy new ones. And if the answer is new, where and what source should I get them from. Also I due have a good Diesel fuel injection shop close.

[Robyn]

I personally would have yours rebuilt by a reputable shop and have them set to the top of the POP spec. Also request that they pay a little extra attention to detail and get them all as close to each other as possible.
This will make your engine run smoother all the way across the RPM spectrum.

IMHO this also stops some of the harmonic vibes that can lead to issues.
If the injector pop pressure is all over the map from one to the next it can vary timing a bit which will not help the cause any.


Good luck

Robyn

[More Power]

I have a 6.2 which i will be adding a banks sidewinder to soon. I have The DB-2 pump that has just been rebuilt and the fuel turned up a bit. My question is should I have the stock injectors rebuilt or buy new ones. And if the answer is new, where and what source should I get them from. Also I due have a good Diesel fuel injection shop close.

www.usdieselparts.com is a supporter of this site and has been in the diesel fuel injection business for 60 some years. They are an authorized reman/retail center for Stanadyne, Bosch, Delphi and others.

Jim

[alteredspeed]

Have a injection pump question. Bought injection pump in the process of having it rebuilt. A guy i know said the pump # that i have is junk. He is a big mouth and a Ford Guy, (not that that is bad)LOL. Are all DB-2 pumps created equally? Or should i have the diesel guy stop rebuilding this one, a little worried scence i payed 100.00 for the pump and some where between 550.00 and 650.00 dollars to have it rebuilt, he said depending on if the cam ring is worn and a couple of other things. Is that price range fair? Buy the way the pump # is DB-2829-4267. My reserch showed it was 84-85 military pump. Pleas help I really dont want to waste money. (who does with diesel being 3.37 in VA)

[More Power]

Among the Stanadyne fuel injection pumps, they were more or less created equal. In part, the model number reflects its fuel calibration and any factory upgrades that may have been added through the years. That's why the model numbers change over time.

For example, if the seal composition or a governor ring assembly is changed, the model number will change. This allows the industry to know what the build and upgrade level is for a given pump.

Jim

[alteredspeed]

Is the pump mentioned in my last post a good one or should i keep looking.

[More Power]

If you are running (or think you might eventually run) a turbocharger, the DB2-4911 is one of the best choices for the 6.2/6.5 - along with matching injectors. I'm not a fan of mixing and matching pumps and injectors. When we got to the fuel injection system in our 6.5 Project truck back in late 1998, I acquired a marine DB2 and matching marine injectors from Peninsular.

Otherwise, any 6.2 DB2 pump built since the mid 90's will be just fine for a 6.2. The various seals in the 6.2 DB2 were made from Viton beginning in 1983, which works fine with the ULSD. The quality of the pump depends on the quality of the rebuild. Not all moving components are replaced during a typical rebuild. The head & rotor for example, are only replaced about every 3rd or 4th rebuild. Things like pumping plungers and rollers, most bearings and all gaskets & seals are replaced at every rebuild. Other parts are replaced during a rebuild only when they don't meet Stanadyne's specs. I was told once that a Stanadyne shop doesn't make any money or even loses a little when they have to replace the head & rotor. Most pumps with bad H&R's are scrapped as a result.

Jim

[Robyn]

If the pump is rebuilt back to MIL specs it will be a fine little pump for your oil rat.

Robyn

[More Power]

I received a call this morning from a very unhappy 6.5 owner. A number of upgrades and repairs were added to his '95 6.5, which resulted in losing about 8 miles per gallon. New cylinder heads, performance Prom, wastegate mods, FSD/PMD relocation kit, and last but not least - "40-horse" injectors were added.

To help isolate the problem, I asked the owner to re-install the factory Prom, then drive the vehicle long enough to clearly identify any fuel economy changes. If no help, I suggested he install genuine Bosch factory-spec 6.5 injectors. I asked that he provide followup, and I'll report here what he has to say when I learn more....

Jim

[ThreeQuarter]

Hey MP--Any news from the unhappy owner?

[Robyn]

The corelation between the gains in performance directly influence the weight of the right foot as in how it is applied to the loud pedal.
The more the turbo whines and the more the beast growls the heavier the foot becomes.

The lust for the adrenaline rush as the little diesel beast comes to life increases with every improvement along the power curve.

My opinion is that there is a great likelyhood that the fun factor is taking over and allowing the horse to drink heavily at the fueling pond (MPG) as in sluuurrrrp, YUM YUM.
Or more clearly the black smoke factor.

If I run my Dahooooley with a sane foot on the throttle the Town mileage will average about 15-16 and Hwy at 18-20

Now with the new chip and a few other things that were done the little pony loves to run and it feeeeeeels sooooooo good.
If Im romping it around and enjoying the power the town mileage will drop to about 12.

This very well could be the issue.

The only way to objectively acertain whether the power improvements are the culprit would be to have an objective 3rd party drive the truck very conservatively and see what happens.

My 94 Burb is bone stock with absolutely stock components including a KITTY.
The early prom is still in the ECM as is the 5068 IP still fitted to the engine.
This rig will consitently knock down 21=Hwy and 17 City.
Now as far as power goes, it would be pressed hard to yank a sick whore off a pot.

Bet me our friend here is not seeing a heavy right foot.

Power is heat and heat takes fuel.

Now there could be other issues that we have not heard about yet too.

Later and Best to all


Robyn

[More Power]

Hey MP--Any news from the unhappy owner?

Actually yes... I've heard from him a few times since my last post - as recently as yesterday. He's been running the factory EPROM for the past few months, and the mileage came back. He's planning to upgrade the cooling system now, with the upcoming summer towing season.

Jim

[Robyn]

This does not supprise me at all.
Most of the factory chips are very conservative when it comes to fuel flow.

If I remember correctly 68cc max is stock. The performance chips are in the neighborhood of 91.

Seems to me I was told that the DS4 is maxed out at 91cc

Along with some other changes that come with the chips this could certainly account for the changes in fuel economy.

Robyn

[93GMCSierra]

one question I have though, and this does depend on watching the foot that controls the pedal, if you upgrade for performance that means the motor works less at a given rpm, to maintain speed for example, thus in the long run you should see better fuel economy. is that completely false?