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Discussion Starter #1
OK guys so I have been fighting this truck for the last two years and I have replaced injectors high-pressure oil pump injection control prefer sensor injection pressure regulator fuel pressure regulator Exhaust back pressure sensor and tube exhaust manifolds full 4 inch exhaust New turbo Garrett with billet wheel and mechanical wastegate New up pipes with donuts has a PHP hydra chip also has brand new air filter 6637 fresh 10W-30 Motorcraft diesel oil since it?s becoming cold in winter here in Michigan has a new fuel filter. For some reason it has no power until around 2600 rpm then the boost is around 8psi or so and climbs rather quick but once in over drive and when approaching a hill I?ll push the pedal and high pressure oil will rise no speed gain then it will downshift and go this all happens at 60mph when it starts losing speed going up hill. This is all happening on the 80hp setting, if truck is in stock it constantly downshifts even on flat ground, fuel pressure is at 72psi and barley drops under a load. So my question is I have no flashing on my overdrive light can this still be torque converter or trans related. Also while watching the torque converter on a monitor locked it will read 0.6rpm then jump to 32.0rpm then to 3.3rpm then to 60rpm is this normal? Or what could be the issue?
 

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Sounds like a boost leak. Google boost leak tester 7.3. They are cheap to build.
 

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Discussion Starter #3
I made I boost leak tester and found 1 plenum was leaking on the driver side, I resealed it and all is well, so then I rechecked it and it with soapy water and nothing bubbled this time but I do hear a air leak almost like it?s in the engine? Driving down the road there is a howl on the driver side like the up pipe is leaking there is just no visible soot and the gaskets I?ve changed 4 times now and they were new pipes as of last year. Another thing this truck never smokes and only a light haze of black on 120 race mode. I just kinda wonder sometime about fuel delivery but everything from the tank up is all new as of 4 months ago. Max boost 24psi and that?s really trying hard.
 

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Discussion Starter #4
She does have 228,000 miles on a all stock transmission and torque converter just has no codes or flashing on the stick but still makes me wonder, plus almost every gear kicks and if you stand on it hard you gotta let of to shift and this is still happening with my upgraded valve body as of 2 months ago. Truck won?t pull anything hangs at 3000rpm and losses speed slowly. If you brake torque it the truck will start building boost then start smoking a light blue and stall out but will start right back up? What is the deal with this damn truck. I?ve even taken it to 4 shops and always leave them clueless they never have a answer.
 

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A computer controlled transmission will only do what its told to do by the computer, I would suspect the tps (app sensor) is either out of adjustment or simply bad, its what tells the pcm how far you are stepping on the pedal, and one of the inputs the pcm uses to schedule shifting and line pressure for the transmission. With your sensitive downshifts and having to let up on the pedal to get it to shift under hard accel I believe its the tps. Its on your accelerator pedal under the dash, I've never had to change one myself, but should only be two or three bolts holding it on. It also affects fuel delivery so that may solve the power issue as well.

Those converter numbers are fine, you don't need to worry about what the scanners interpret as tcc slip until it starts staying above 100rpm or so, and normally won't throw a code until the slip goes above 200rpm.
 

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Discussion Starter #6
Transfixer, I appreciate your info a lot since I?ve been fighting this forever. It is the old style TPS that you can replace without buying the whole pedal, which I had actually adjusted it to read .95v at idle and 4.0v WOT before WOT was only 3.76V, could this sensor still be bad without throwing a code?
 

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Discussion Starter #7
I greatly appreciate the info though and I will replace that throttle position sensor on Monday I know it?s the original one from 99 hopefully it?s the answer I?m running out of parts to replace.
 

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Transfixer, I appreciate your info a lot since I?ve been fighting this forever. It is the old style TPS that you can replace without buying the whole pedal, which I had actually adjusted it to read .95v at idle and 4.0v WOT before WOT was only 3.76V, could this sensor still be bad without throwing a code?
Yes, they can be bad without throwing a code, its basically a rheostat, and the portion of the sensor that it runs in most of the time, like part throttle at cruising speed, can get worn, or show signs of arcing/wear in the spot it stays the most. I didn't think those were adjustable ? But you can probably tweak the bracket enough to change the readings , Ideally most throttle position sensors are set around .5 volt at idle to around 4.5volt at full throttle, you might see if you can tweak things to get closer to those numbers ? basically spreading out the voltage change over a wider range,
 

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Discussion Starter #9
Yeah it was not adjustable I had to drill out the bushings then Oblong out the holes and watch the computer and set it, but that?s the best adjustment I could get from it. .5 volt idle would bring me at 3.46 WOT which I?m guessing is the sensor being bad or worn like you said.
 

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I didn't see this mentioned in your original post, but if you haven't changed the cam position sensor ? Then I would change that also, I installed the dark blue sensor in mine ( early 99 F350 ) and it made a difference , both in faster starts and smoothness of idle, and smoother acceleration also. I also have an IH one as a spare, and another new ford one for a spare as well.
 

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So you have a few problems. Transfixer sound spot on with the tps. But it stalling out is something different. Your going to want to check your icp and ipr numbers while driving at wot. You can use the torque app for this. I would also check your fuel pressure. You could have a plugged up pickup in the tank. It needs to be above 45 at wot. Idle psi mean nothing really. But at idle it should be around 55. Also at wot check your boost and ebp
 

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Discussion Starter #12
EBP at WOT is 52psi max boost on 120 race is 25psi without the boost fooler so it defuels. Fuel pressure is 72 psi and Wot drops to 70psi, ICP at idle warm is between 492 and 505 and crusing at 60 mph it?s at like 1500psi if I touch the throttle just a little it will ramp up to 2450psi but no gain in speed from the truck injectors just get loud. IPR at idle warm is 11% and at 60mph it?s at 23% Wot it hits 46% and ICP WOT hits 3024 psi. Fuel tank has a brand new fuel sending unit with the filters as of 4 months ago and new fuel pump a long with dark blue CPS and I have a gray for a spare. Something I did forget to note is sometimes if I run it kinda hard it will knock at idle it?s really inconsistent and random but the more it idles it starts to fade away and it?s loudest on the passenger side which always knocks. Truck uses no oil ever and fuel filter has been changed 5 times in 2 months it?s always super clean, truck is just kicking my ass I just want to be able to pull with her again.
 

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Discussion Starter #13
She about almost stalls going from drive to park rpms will shoot up about 700 to 800 rpms then back to 750rpm but it will sit there and surge for a minute and sometimes it won?t, then sometimes it won?t stop kinda strange.
 

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Just for grins. Pull the chip and see how it runs.
 

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Discussion Starter #15
I tried that too already, I have a TS6 chip also with PHP custom tunes for the early 99 and it was still the same. Only thing I have not tried is a flash programmer and I guess swapping the TPS, those are my last things before I swap the trans I guess. It fired up this morning 19 outside not plugged in smoked less then a minute and cleared up, should I start wondering about compression? I had a shop check it realative and they said it was great but never did give me the numbers.
 
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