Can the mechanical pump in my 1993 6.5TD be turned up enough to require the use of marine injectors or will the stock ones flow more than the pump can put out?

I'm thinking I may need new injectors, mine smokes (fuel) a little on start up for a few seconds, I may have a bad glow or two, but it fires right up everytime when cold. I've only had the truck a short time and dont know if the injectors have been replaced in 194,000miles.

Whats wierd is my 1992 still has its original injectors in it and its got 340,000 miles on it and it hardly smokes at all on a cold startup, but I always tried to buy clean fuel at known good stations, and have good filters on our tanks at the shop, and it has had some form of fuel and oil additive ran in it over half its tanks and oil changes since new, but I think the injector pump is about to go (original).

My 1994 208,000 miles I've owned for a couple of years, I think may need injectors also, fuel smokes also at startup but not bad, I doubt I'll replace them its just a feed truck.

I didn't know it was recomended to replace the injectors every 100,000 miles, until I started reading this great forum a couple months ago, the 1992 truck has always ran so good.

Anway back on topic, do I need marine injectors witout an aftermarket injector pump or should I buy the stock ones? The 1993 truck is just a play toy really, going turn up the fuel, add a 4" or 5" exhaust, intercooler, and a bigger turbo, until it needs a rebuild then prolly going to 18:1 pistons, I just wanna see what a 6.5 can really do.

Thanks,

Marine injectors are all hype, the high flow types anyhow. The 6.5/6.2 IP is a positive displacement pump. You could have injectors with openings the size of a garbage can and wouldn't get any additional fuel!

Which would max out first, the stock pump or stock injectors?

Which would max out first, the stock pump or stock injectors?

You will never be able to max out the injectors, they have basically no effect on fuel volume.

so what is the point of all the different injectors? they're definately different between the turbo and non. what makes the difference.

Also interested in this as I will be starting a 6.5 build right after the holidaze. I was planning on 18-1 peninsular pistons and marine injectors with the marine IP. Is there a difference in the marine IP or is it just another DB2 4911? Was told by one source the marine injectors are made of stainless which accounts for their higher price, other than that no real difference. Any clarification?
I know the turbo injectors are short body to fit under the turbo plumbing, vs. the non turbo injectors, but not sure if that effects fuel delivery rate.

Late model 6.5 injectors have same tip turbo or non turbo. Turbo have slightly higher pressure. Mechanical marine pump is best for max output. They make a 250hp 2 plunger version (DB2833-4974) and a high output 4 plunger 310hp version (DB2831-5722). Marine injectors are not stainless. Stock injectors will flow more than the engine can burn.

Try to find this info anywhere on the net.

Basically 5 types if you ask me. Hi flow IMO offer no performance increase. Hi pops could possibly offer a finer spray, but i tend to think it is minimal to none. I have never seen any made of SUS, I would expect the origional OEMs to be hardened steel which would probably last longer.

1. 6.2 1700 PSI Pop
2. 6.5 1900 PSI Pop
3. 6.5 ~2200 PSI Pop (just guessing on the higher pop pressure, don't really know)
4. 6.2/6.5 Hi flow or Marine (worthless IMO)
5. 6.2/6.5 Hi flow and hi pop

I'd replace with standard OEM new injectors. If you want more fuel spend the money on a reflash or high volume pump.

I believe even the 300HP pumps are a variation of the 4911. Edit: this looks to be wrong according the DieselPro's post above.

The High output marine mechanical pump (5722) has 4-plungers instead of two. Quite unique and can be upped even more.

How much HP will the stock injectors support?

How much HP will the stock injectors support?

I think your misunderstanding how the injectors function. They have very little to no effect on HP. They could probably make 600HP if you wanted them to!

In common rail setups (ie DuraBux), the injectors have a pool of fuel behind them, so injector flow and rail pressure determine output. In the 6.5 the IP determines output in a positive dispacement pump type of setup.

Even if the injector discharge nozzle was the size of a pin head the fuel would be forced out. Or the injector line would burst, or maybe shear a pin in the IP!

For just about any 6.5 setup the OEM injectors are your best option.

so does this mean heaths high flow injectors are worthless? i installed a new 6.5 non turbo motor. motor was built in 2000 for a military hummer mechanical pump non turbo. i have reflashed computer but did not see a very noticable gain. i wondered if it was b/c of the injectors bheing non turbo. what do you think? sorry for the highjack.

IMO high flows offer no additional fuel or performance.

OK, thanks, thats what I wanted to know. I have seen a few direct injected engines on other applications where the fuel flow from the pump exceeded the injector nozzle flow, hydrolocked and destroyed the pump.