7.3L Power Stroke Engine and DrivetrainDiscussion of the 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
This is my first turbo diesel and I'm still learning a lot about these things.
I've had Ford do the full diagnostic scan on it about 5000 miles ago and found a FPR that needed to be changed...everything else including the injectors were good. They did the FPR and fuel filter. I've also changed the alternator, GPR, and CPS.
The truck runs great. I've used maybe 1/2 quart of oil in over 5000 miles and I get 16-17 MPG all the time.
The only thing is when I really get on it, sometimes it honestly just doesn't pull. The engine doesn't quiet down when the boost comes in, like it does under light throttle and it just doesn't sound happy.
Just the other day I pulled away from a light and in about 3rd really got on it....something more than 75% throttle. It was blowing a little smoke, really loud and wasn't pulling as hard as I feel it should. Then I kept squeezing on the throttle until I just about got to WOT when it aggressively took off.
This doesn't seem right. I know sometimes when I floor it, it'll quiet down and really take off. Then sometimes it's like this, loud and not smooth.
I have no idea where to start. I am going to install a set of gauges soon. Also I'm thinking about getting the auto ingenuity PC scan tool.
Ford looked at it not long ago and it was running just how it is now when they did all their tests. They say everything is good.
Anyway, just thought I was get some ideas on what's up.
Thanks,
Steve
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Early 99 7.3 F250 4x4 6-speed 160,000 miles
DIY intake, MBRP 4" single exit, Isspro EGT and boost, DP Tuner 80 econo flash, Carbotech Bobcat front brake pads
Re: Engine runs great until more than 75% throttle...
[ QUOTE ]
Maybe that's when the torque converter locked?
How fast were you going when it kicked it?
[/ QUOTE ]Read his sig. I think 6-speed probably refers to the manual transmission rather than a new exotic Allison tranny he bolted on. I suspect turbo lag with a manual and the turbo is finally building boost.
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2002 F350 Lariat CC 4x4 Auto 4.10 DRW, DP-Tuner F5 live tuned stock, quiet, 40dd, 40, 60, 80 tow, 80e and 120r, B&W GN, BrakeSmart, 'pooned tank, tank and pre-pump mods, 2µ Dahl 100 filter, regulated return, BTS dual HPOP, AC singles with EDM 34 lpm nozzles, AIS, H2e, Spearco 6.0 IC, Hypermax 3.5" dp--> MBRP 4" 304SS exhaust, BTS tranny, 203º T-stat, Chevron ELC, coolant filter, Oilguard bypass with Schaeffer 9000, WranglerNW 200 amp alternator & Optima group 31 batteries, Nippon-Denso starter, SPA gauges, SteveRacer mods, Hella 80/100W 9007s, Hella Micro DE foglights, 1000FF driving lights, 220W backup lights, Stancor contactor, Michelin XPS Traction tires, X-Springs, Bilstein shox, custom bumpers but otherwise stock. Nov 30 '99 build engine with 16 K miles, Fluidampr, Comp Cam 910 springs, Melling LPOP and ARP headstuds. Alien-Patrol Customer Service Sucks!
Re: Engine runs great until more than 75% throttle...
[ QUOTE ]
[ QUOTE ]
Maybe that's when the torque converter locked?
How fast were you going when it kicked it?
[/ QUOTE ]Read his sig. I think 6-speed probably refers to the manual transmission rather than a new exotic Allison tranny he bolted on. I suspect turbo lag with a manual and the turbo is finally building boost.
[/ QUOTE ]
Whoops!!! [img]/ubbthreads/images/graemlins/blush.gif[/img] did'nt look at the sig....
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Big E and family of Three
2002 F250 4X4 CREW CAB PSD 4" LIFT
4" turbo back exhaust*custom tymar*DP tunes*Polished ATS housing*6.0 intercooler*Chromed intercooler pipes*H/O chromed Alternator*Dieselsite boots*203 thermostat*40K Trucool*FTVB*Manual TC lock-up*EBPV brake*AIH delete*boost Annihilator*Custom CCV*ITP/KCM (HPX)*Coolant filter*08 diff cover*DI fuel shim kit .055 @68 psi*engine mounted fuel gauge*custom engine cover*triple gauge*((XM))
297Hp dyno 2/11/07 (I need more power Scotty!!)
Waiting for install
pre-pump mod
2004 Keystone Sprinter 297fwbhs 5th wheel
with most of the goodies
Re: Engine runs great until more than 75% throttle...
Pulling "stronger" below 3/4 (or even half) throttle...than a 100% throttle can be indicative of a weak high pressure oil pump (or IPR, inj O-rings, etc)...
If you don't have a chip in the truck, then I doubt the HPO Pressure is your problem...
go over the underside of the truck with a flashlight...inspect the exh manifolds and uppipes for (pre-turbo) sooty exh leaks, which could be limiting your boost...but exh leaks don't really "come & go"... [img]/ubbthreads/images/graemlins/shrug.gif[/img]
If you have a chip in the truck, and it pulls harder at 3/4 throttle...then it is likely that your HPOP is weak.
take care~
Dave
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Powering the Fastest (no drugs) Power Strokes @
Thunder in Muncie 2004
TS Performance All Diesel Challenge 2004 Indianapolis Diesel Nationals 2007
Scheid's Diesel Extravaganza 2007
Powering the top Ford pullers @ the Indianapolis Diesel Nationals 2006 Indianapolis Diesel Nationals 2007
Re: Engine runs great until more than 75% throttle...
mine will do that if I try to hold it in the lower gears for longer than I should without changing gears to a higher one, when I'm WOT. A kind of run out of POWER feeling?? Is this what your talking about???
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2k F250 XLT CC 6sp PSD, 3.73 LS axle, Superchip, W-D Turbo Brake, Memphis speakers & 5ch amp, WD-Pyro & Boost gauges, Rechargable MagLite, quick disconnect jumper cables, CAT batteries, ARE tonneau,
"unaable" on the tailgate!! New door actuators!!
T-304 Stainless exhaust turbo back, Southbend clutch
Re: Engine runs great until more than 75% throttle...
The truck is not chipped.
It doesn't pull harder a 3/4 throttle than 100%. I'll be slowly advancing the throttle and get past 50%. From about 50% to 75%, the power doesn't change much. The engine is making a racket and doesn't feel very happy. Then I'll keep going until I get to almost WOT and it'll all of a sudden come to life and start pulling, but it's still making a racket.
Now, usually when just tooling around you have your normal diesel engine noise. When you get on the throttle a little (maybe 1/4), the boost comes in and the engine noise quiets down and she takes off. Sometimes when I punch it, its still like this. The engine clatter quiets down, blows some smoke, and takes off. But then there are times like what I'm talking about here, where it's just very noisy and doesn't pull hard at all.
Very strange.
I've had this truck for about 5 months now and it's always done this. But like I said, if I don't romp on it too hard, I'd never know there was a problem.
I have another thread started where I'm trying to figure out an off throttle "jolt". I honestly feel that it's not the drivetrain. Basically when I am holding speed down the road and even fairly slowly let off the gas, I get this pretty hard jolt. Maybe these two things are related? It only jolts when the engine is fully up to temp and when at speeds less than about 70 MPH.
Is it possible that my exhaust backpressure valve is acting up? It seems to be working just fine, but I guess you never know.
Thanks for the help.
Steve
__________________
Early 99 7.3 F250 4x4 6-speed 160,000 miles
DIY intake, MBRP 4" single exit, Isspro EGT and boost, DP Tuner 80 econo flash, Carbotech Bobcat front brake pads
Re: Engine runs great until more than 75% throttle...
Also, if I am trying to shift at WOT, it'll stumble when I get back into the throttle before it takes off.
The last time it did it, I was WOT in 3rd, shifted at 4th and when I hit the gas again, it'll fall on it's face for a split second then take off.....and I don't mean turbo lag, I mean engine cut out. I know this isn't a sports car, but it still doesn't seem right. Maybe these two are related.
__________________
Early 99 7.3 F250 4x4 6-speed 160,000 miles
DIY intake, MBRP 4" single exit, Isspro EGT and boost, DP Tuner 80 econo flash, Carbotech Bobcat front brake pads
Re: Engine runs great until more than 75% throttle...
when you say "engine cut out" do you mean the engine stops running? Does your tach drop rpm's all the way down to none? not just dropping rpm's due to changing gears? Maybe try posting if there's anyone here that's near you with a 6speed that you can drive your truck over to so you-all can compare trucks???
Also this "making a racket" noise ??? Have you been able to listen to other Ford Powerstrokes 7.3s?? Some are louder than others but it's really difficult to say if yours is normal or not.
Re: Engine runs great until more than 75% throttle...
That's a good idea...getting a ride in someone else's truck.
The only thing is that my truck changes. Sometimes it feels and sounds great, sometimes not. That's what I'm going off of.
As far as the stumble when I shift, a stumble is the best I can describe. Like there is a 1 second delay. If you shift, don't get back into the throttle until 1 second after you would normally...that's what I feel. BUT like I said, this is only when I'm shifting from WOT to WOT as I grab another gear.
As far as the EBPV, I need to figure out how to test if it's sticking. I know it is closed when the truck is cold, and it opens up once it's up to temp, but as far as it acting up...who knows.
I know it's difficult to understand (even harder to explain). I appreciate the help.
Did this help at all? Any more ideas?
Steve
__________________
Early 99 7.3 F250 4x4 6-speed 160,000 miles
DIY intake, MBRP 4" single exit, Isspro EGT and boost, DP Tuner 80 econo flash, Carbotech Bobcat front brake pads
able" on the tailgate!! New door actuators!!
Linear Mode
