JDGPULLER

I think my 99 is defueling at 2400-2600 RPM, we have run it on the dyno many different ways and it always defuels at 2400 RPM.

we have changed-- new VP$$, new TPS, new boost sensor, new IAT sensor, have tried a different ECM, a different drag comp, a new edge wireing harness, a haisley defueling plug, a red line box (which HP & LB graphs almost the same as the drag comp except the engine winds out to 4000RPM). new turbo, new head and heilex3 cam (lots more power but still defuels at 2400RPM).

What the heck am I over looking??????

any help greatly appreciated, Thanks Mark

nitrousn

What is your boost pressure?? What is your fuel pressure??

JDGPULLER

my boost pressure is 48PSI and starts to drop at 2400RPM, the fuel pump pressure is maxed out on a 15 PSI guage and might drop to around 15 but no less than 14PSI. I will try to post a dyno sheet with a boost pressure graph.

JDGPULLER

Here is my dyno sheet-
Blue line is Edge comp only.
Red line is Redline box.

JDGPULLER

no one has heared of or seen this before?

JDGPULLER

I guess I got everybody stumped this time?

Bob Wagner

who's vp44 did you buy?

JDGPULLER

Performance Diesel Warehouse $1089.00 + 400.00 core which I kept since both pumps made the same power.

paulb

I don't have any answers for you, but I have to say the whole graph looks strange to me, not just from 2400 rpm. On my truck the torque curve normally peaks at about 1800 rpm, and then slowly drop from there. My horse power curve normally climbs until it peaks at 3400 rpm, and then drops suddenly (defuel). I guess what I am saying is that I would expect your peak torque to be about 600 rpm sooner, and of course your hp to continue climbing to redline.

The drag comps that you are using. Are they for a 99? Even though the later boxes will plug in, they have different programming. What turbo are you using? It appears that it either spools fairly late, or there is a lack of fuel down low as well. When you used the Redline box, did you still use the Comp for timing? When you hit the 2400rpm did EGT's drop as well as boost?

Paul

JDGPULLER

The drag comp was ordered for this truck and it use to lay down a graph like you described. The torque is probably different because It has a Helix 3 cam. It has a sledpuller 66 turbo. I think the comp was off on that run but it did the same thing with it on. the EGT's never get hot maybe 1400 at the most.

did you notice the boost graph?

Thanks for any input.

JDGPULLER

Paul what kind of numbers does yours put down?

I am in the process of buying a 02 3500 6spd 4x4.

paulb

I did notice the boost graph, but it doesn't strike me as being odd for a large single. It looks like it opened the wastegate at about 48psi, and then as drive pressure increased it caused the wastegate to slowly drop boost by about 6psi.

What injectors do you have?

paulb

Last dyno was 638hp and 1283ftlbs torque. #2 only.

JDGPULLER

nice #'s.

I have a boost ell to the waste gate and it is shut all the way. It has F1 220's and clears all the smoke at 2400 also.

Ph4tty

Humidity?? Look at the difference humidity makes in the upper rpms on these pulls. These are from the f-1 page- probably Doug S's truck which is set up close to yours:
http://www.f1diesel.com/mach7runs.html
http://www.f1diesel.com/mach8runs.html