Zino

Ok Here is the scoop. I have a 1994 Suburban with the 6.5 Turbo Diesel. Chip, injectors, open exhaust. Blew up the 4l80E and put a NV4500 in it. Great rig and runs like a bear. But I know I know, Cummins. So I finally break down and shelve out the dough for a 2001 2500 HO 6Sp. After a couple of days, I come to realize its a dog. My Suburban would hammer it in the 1/4. So I rip out the muffler and resonator and fit in a straight section of pipe. Sounds absolutely divine, but no performance gain at all. So I buy a TST powermax with the adjustable settings (0-9). Even on setting 9, it does absolutely jack until about 2,000 or 2,100 RPM then it does hit pretty hard and comes up to 3,000 RPM in no time. Truck is definately faster now, but I still think it sucks from idle to 2,000 RPM. I didnt buy a Cummins to have a 1,000 RPM useful powerband.
Checked the lift pump pressure, sure enough 1 to 2 psi with the pump on, 0 Psi with the engine idling. Install a new lift pump, 14 Psi idleing, great, but no performance gain at all. I am NOT a fan of K&N or any type of aftermarket filter, so just for a test, I take the inlet hose totally off of the turbo and go for a test ride. No help. But I do notice that at some point in the trucks previous life something went through the turbo, as the compressor wheel is nicked up a bit.
I cant make even a hint of smoke with this rig, and I am only getting 28 PSi of boot on setting 9 and full accelerator pedal ( its not a throttle ya know) . My dilema is that I dont know whether its the chicken or the egg deal.... Is the turbo shot and taking too long to spool up and so the computer is waiting to see more boost until it adds more fuel... oor is something wrong with the fuel system and its not adding enough fuel to make the power and thus the boost??? Leaning toward the latter right now... Lookin for some thoughts here.... Thinking about a stage three BD injector set

Thanks
Zino

BigBlue

The HO's repsond better to injectors than they do boxes. Also, I don't know much about the TST box, but if it's like the COMP, did you hook up the wire to the injection pump? On my 01 SO auto with straight pipe and a BHAF and a COMP setup like an EZ(no pump wire), I can let a nice bit of smoke out from a dead stop. Turbo lag is almost none. I've got 13 psi at WOT. What kind of FP do you have at WOT? When I get a new lift pump from Dodge, it had 13 psi at idle but only 6 at WOT. > A set of stage 3 injectors would help you out a lot but I don't think your clutch will hold the TST AND the injectors.

Hired Gun

Did you install the boost elbow? Seems to me that that might help you spool better. It comes with the TST. Also, for low end pick up, try stacking the edge ez with the TST. It made a world of difference in my 99. Hook up the pump wire. You will get smoke then.

Zino

Yep installed the elbow and did hook up the pump wire. I have heard the same thing about stacking the EZ with the TST. But for that cash, I think want the injectors. The fact that it doesnt smoke at all tells me either I have a fuel system problem, or the tuning of that TST box is just waiting for more boost to add more fuel. The fact that the TST box has a CARB EO number tells me it is conservative in terms of adding fuel before boost is up. THe injectors should add the fuel RIGHT NOW correct???

FMF MX

Zino -<br><br>Put a set of DD 2's or rv275's, and I guarantee you'll feel it..Nothing bigger unless you want to change turbos..

98rammer

i've never been in atruck with one, but yes, the fact at that TST runs off of boost signal would be my guess. a comp box will add more low-end fuel (smoke-which isn't necessarily good).<br><br>Tom

PapaSmurf

I have a truck like yours HO with 6 speed. I have DDIIs and a EZ box on it. My truck runs pretty strong. I bought a TST PM 3 just because. I too learned that the HO don't get much from a fueling box. I gained roughly 5 mph in the 1/4 when I run the box on.<br> We also have a 99 3500. The plan is after we beef up the trans is transfer the PM 3 into my wife's truck along with a set of DDIIs.<br> When I talk to fellow HO owners I recommend a phone call to Peter at South bend Clutch and then Edge EZ and a set of DDIIs. IMO forget about a fueling box for the HO. I am very happy with the way my truck pulls. I ran 16.5 in the 1/4 <br>Hope this helps.<br>See Ya<br>Chris

Zino

Yep, I have heard all of this. I did read somewhere that the HO actually has SMALLER injectors?? Is this true? If that is the case, then for sure it explains why the HO's dont respond so well to the boxes but really come alive with the injectors. I think I am gonna go for the BD III's. I can allways turn the PowerMax Box down, and it would be tons of fun to smoke out some yuppie idiot in a Lexus or some * teenager in a 'souped up' ( havent seen one break 16's yet at the track) Honda Civic with a ridiculous wing and muffler..... Plus it would really **** off the evironmentalists, which is a bonus too....


Zino

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Zino

Well after reading that, Gary, there is definately something wrong with my machine. With the TST on 9, its not even remotely close to being able to slip the stock clutch up at 2,600 RPM let alone below 2,000 and I dont see better than 20 Psi of boost until 2,500 RPM. What you describe is actually what I bought the Cummins for... Gut wrenching torque!! I just have to figure out whats wrong. I am really begining to suspect the turbo compressor wheel. I will try to take a picture of it and post it here for some opinions. Something definately went through it, a few blades have some decent (1/8&quot pieces missing from the tips, and there appears to be alot of clearance between the weel and the housing, which is also chewed up... Havent towed yet, but MPG is averaging 17.5 mixed driving. Thanks guys for all your help !!!!<br><br>Zino<br>

RacingD98

My truck got real sluggish for awhile until I checked out the MAP sensor. Replaced that and I was back in business. <br><br>...... just something else to look at ......

Bart Timothy

I suspect the problem may be a combination of something not working right and driving style. These trucks don't drive like gassers or 6.5s, and have only got about a 1500 to 1700 rpm power band. <br><br>You won't slip the clutch at 2600 rpm. The clutch will start to slip when the torque is comming on at 1600 or 1700 rpm. Keeping rpm above 2200 is one way to save your clutch. Addition of just a fueling box to an ETH is not enough to slip the clutch anyway. <br><br>Exhaust and intake mods are a waste of time and money until after 350 hp. <br><br>You, also, should be getting some smoke, and boost should be above 28 lbs if the altitude is below 4000 ft. If the turbo isn't working right, the smoke will still be there. Sounds like there no extra fuel being added. Maybe the box isn't working, or not hooked up properly.

Idaho CTD

What are your egt's like? If your turbo isn't somewhat up to snuff then your egt's will be through the roof with the PM3 box on anything above 3 or so. How about max boost on level 9? You should see boost in the low to mid 30's. One other thing that might be giving you problems could be a leak in the intercooler system. Typically that means a leaky intercooler boot. If you get a rubber pipe cap and attach a valve, guage, and air hose connection to it you can place it over the turbo inlet and pressurize the system to check for leaks. Dont forget a hose clamp or two to hold it on as well as physically holding it on with your hand. After about 10psi they like to pop off.

WTTD

I have somewhat limited experience with the TST comp. But the last one I messed with would smoke and bury the 1500 pyro on anything past level 6. I cant help but think you might have tapped the wrong pump wire. I know from experience that they (boxes) do not work if you tap the wrong wire. TST's will fuel plenty heavy even on an HO. Something is definitely wrong, the TST should help a lot.

Zino

Well you are correct, I would expect it to be more likely to slip the clutch at the lowers RPMs than up at 2,600, but the reason I mentioned that I couldnt even get it to do it at 2,600 RPM was that is the only place I have any decent toruqe!!!!! 1,500 to 1,800 is way lame. On the highway pulling a 3% grade, 6th gear, setting 9 about 2,500 RPM so about 85 MPH floored, it will hit 1,300° and I have to back off. Box is definately hooked up right, cuz when I put it on setting zero it REALLY is a pig. Max boost I have ever seen is 29 PSi for a millisecond, normal floored boost is about 25 Psi.. great idea on leak testing the system, Iwill do that right now. I could not agree more that intake and exhaust mods are a waste before 350 HP SO TRUE !!.. BUCK THE MARKETING LIES !!!! I just took the muffler off thinking it might have been sooted up or seomthing, plus I LOVE LOVE LOVE the sound of the straight pipe,,, ummmmm Love to drive in tunnels or under overpasses or next to the jersey barriers... I am gonna rebuild the turbo, then put 275 RV injectors in. Hopefully that will set me up. I am not looking for 400HP or 1,000 FT*lbs. All I really want is about 300HP at the wheels and 700 Ft*lbs. A 1,500 RPM powerband would be GREAT with what I have now. That would mean it ran strong from 1,500 to 3,000.... Now It only runs decent from 2,100 to 3,100....