Slow response when letting off throttle (keeps revving)

[GCncsuHD]

I have had an issue with my 2000 F250 7.3 6 speed ever since I installed the PHP 6 pos. chip. When I am in either the 80DD or 140Extreme modes and at moderate to WOT if I let off to shift the engine will rev another 2-300 RPM. Even if I roll into it in gear then let off quickly there is a ~1 second delay before the truck slows down. Same if I rev in neutral, it will jump RPMs higher after I let off. The 40 tow tune does not seem to do this at all, as soon as I let off, it lets off. The issue is more noticeable in the 140 tune than the 80. The truck is otherwise stock other than exhaust/intake.

I have driven my brother's 7.3s in the past, both an auto with banks 6gun, and a 6 speed with a TS. Neither of them did this on their highest settings that I can remember. I also asked a friend of mine with a 7.3 6speed and a TS, his does not do this either.

I signed up and asked this question on PHP's forum, and this is the response I got:

Yes, it's due to the injection pressure regulator's response time (not that there's anything wrong with it). The amount of injection pressure required and the high pressure oil pump's lack of ability to keep up with the demand causes the pressure regulator to close a lot....thus causing the delay in injection pressure drop when releasing the accelerator pedal.

I asked if there was any potential remedy to the issue, and I got nothing.

It seems to me there should be some way around it if these other trucks do not appear to have this issue on similar power levels. Any suggestions or am I stuck either waiting a second or so to shift, or looking like I missed a gear every time I do shift? If this was normal, I would assume I would have read about it somewhere, but in all my searching I have never seen it mentioned once.

 

[Arisley]

I would talk to Bill about it. It should bot do that.

 

[GCncsuHD]

I would talk to Bill about it. It should bot do that.

Thanks, I bumped my thread on their support forum as well to see if I get any answers this time. Other than this issue I have been very happy with their tuning, although after driving with their tunes for about 5 months, I have noticed which tunes I use more than others, and will probably change up my tune selection anyway, but if they have no solution to the issue I will probably try tunes from elsewhere.

If I remember I will try to datalog throttle % vs RPM.

 

[golfer]

stock injectors?

I've seen this with my personal 6 speed with some of our larger injectors, until I got the tuning sorted out...I had to lower the values in the MFD table...I think...

 

[vanderchevy18]

I've seen this twice on trucks that I have put chips in. Its definitely the tuning. I had one do it on a 6.0.

 

[GCncsuHD]

stock injectors?

I've seen this with my personal 6 speed with some of our larger injectors, until I got the tuning sorted out...I had to lower the values in the MFD table...I think...

Yes, stock injectors, the truck is all stock with the exception of chip, intake, and exhaust with 182k mi, up until 173k it was a delivery truck for Airgas/National Welders, bone stock dealer serviced work truck with all service records. Injectors were never touched in the records I have.

 

[golfer]

interesting...I assume it doesn't do it on alllllll the settings (or at least not on the stock setting, if equipped?)?


do you have any method of monitoring the engine parameters while driving?

(such as you could with auto enginuity?)

it's (the chip) is either holding too much ICP pressure...or it's requesting too much injector pulse width...or a combination of the two.

 

[Charles]

99% chance the MFD just needs to be pulled down at low pedal AD counts in the rpm range where it hangs and below.

1% chance the ICP desired table needs to be dropped in these same areas instead.


Truck should snap up, and snap right back down if you stab the pedal. It's just a little quirk that got missed. Happens all the time. I just did it YESTERDAY, lol.

 

[GCncsuHD]

interesting...I assume it doesn't do it on alllllll the settings (or at least not on the stock setting, if equipped?)?


do you have any method of monitoring the engine parameters while driving?

(such as you could with auto enginuity?)

it's (the chip) is either holding too much ICP pressure...or it's requesting too much injector pulse width...or a combination of the two.

I don't have a stock setting, I figured if I needed that I would yank the chip.

Doesn't do it on 40tow setting at all, 80DD setting only does it on WOT, but not as severe as on 140Extreme setting. 140Extreme does it anywhere above say 75% throttle (guessing).

I don't have auto enginuity, I do have Torque for Android, I know it reads throttle position, rpm, I haven't programmed or really gone through the more advanced PIDs. I'll see what is available for me to log.

 

[jaybuller]

Thanks, I bumped my thread on their support forum as well to see if I get any answers this time. Other than this issue I have been very happy with their tuning, although after driving with their tunes for about 5 months, I have noticed which tunes I use more than others, and will probably change up my tune selection anyway, but if they have no solution to the issue I will probably try tunes from elsewhere.

If I remember I will try to datalog throttle % vs RPM.

i would deffinatly call and ask to talk to Bill, don't dick around and talk to anyone else there. They didn't write the tunes and will get you pretty much nowhere. They'll probly tell you they will relay the message to Bill like they did me, and guess what nothing was ever done until I actually talked to Bill. what your descriing is deffinatly not right. I have the same truck as you with a 6 speed and there is absolutely no delay and what your describing could actually be dangerous in the wrong situation

 

[GCncsuHD]

i would deffinatly call and ask to talk to Bill, don't dick around and talk to anyone else there. They didn't write the tunes and will get you pretty much nowhere. They'll probly tell you they will relay the message to Bill like they did me, and guess what nothing was ever done until I actually talked to Bill. what your descriing is deffinatly not right. I have the same truck as you with a 6 speed and there is absolutely no delay and what your describing could actually be dangerous in the wrong situation

I agree, it very well could be dangerous in the wrong situation, I have relegated it to the 80DD tune and stayed out of WOT and it has been fine, but it's no fun having a setting that is useless. I'll probably try to call on Friday after my lunch hour, will probably be my first chance to call.

 

[jaybuller]

just a thought but is there anyway your intercooler could be full of oil and when you get the boost built up (like in the higher tunes) it pushes the oil up enough to keep the engine running? I doubt it is the problem but just something you could check out while you wait to call PHP

 

[Arisley]

That would have to be a lot of oil.

 

[PDT1081]

I don't have a stock setting, I figured if I needed that I would yank the chip.

Doesn't do it on 40tow setting at all, 80DD setting only does it on WOT, but not as severe as on 140Extreme setting. 140Extreme does it anywhere above say 75% throttle (guessing).

I don't have auto enginuity, I do have Torque for Android, I know it reads throttle position, rpm, I haven't programmed or really gone through the more advanced PIDs. I'll see what is available for me to log.

I'm not sure Torque will read throttle position accurately. It didn't on mine last time I tried. There have been quite a few updates lately so it may work now. HPOP pressure and duty cycle works, RPMs, Boost, and voltage are what mine is currently setup to read. It's been awhile since I've tried any of the other PIDs so they may work now too.

 

[powerSmokin]

I just had the same issue but not with Bill, was my own tuning and a buddy tuning. It was mass fuel desired issues and when it was changed it went away.

 

[Chvyrkr]

That would have to be a lot of oil.

Yeah... I pinched my CCV road draft tube once after messing with a turbo, and didn't know I had.

The truck seemed to be running way better, then it blew an IC boot on the third or fourth WOT run, and I noticed a crap load of oil in the IC tubes when I put it back on that led me to the CCV tube. Turbo might have been on the way out lol.

Truck had no throttle hang though, even though I was injesting enough oil to feel the difference SOP.