rev limiter on 4.0 sohc

[sina220]

ok, ive searched aroudn for info on this and didnt find anything that completely answered my question so i figured id make a new post...i have a 99 x w\the 4.0 sohc engine and heres my beef...if im at a standstill on flat pavement and floor it, itll go all the way to about 52-5400 rpm or so and shift which is normal from what ive read...but if im going say 20 mph and floor it itll go to 3000 rpm and hesitate there for several seconds before it begins to gradually get to about 3500 rpm n then take off as normal...another example is theres a hill by my house, the speed limit is 30, if im doing 30 at the bottom of the hill and floor it all the way up the hill i usually hit about 53 mph...if i stop half way up the hil because im behind someone whos turning, then floor it once theyve turned i can hit about 55 mph, in half the distance...all because from a stop the car revs up into 5200, and when going 30 it wont go above 3000 rpm...is this some kind of limiter, or is there just something wrong?

 

[sina220]

also, i know at 30mph itll be in higher gear and wont have all the power, but even still...it wont rev above 3000 rpm...i notice this everywhere not just this hill, that it hesitates around 3000 rpm for a few seconds...n then continues its normal rpm acceleration...itll stay steady and constant until 3000, hesitate...then be steady and constant til whatever the next shift point is...and it does this no matter what my speed, unless im starting froma standstill

 

[Nate1]

Sounds more like you don't like the shift patterns on our cars, stock isnt for very agressive drivers. If you get dual program diablo chip from apten, people say that the shift patterns alone are worth it. You can also try getting a shift kit. The motor revs, I'm pretty sure that what you want is more aggressive downshifting.
-----Nate

 

[Majisto]

)My Explorer must seriosuly be a freak because mine will constantly rev upto 6K and shift whenever I floor it (Or I don't even need to floor it all the time). Many times you just don't have aggresive enough gears to get the engine revved up high enough, especially when going up hills and loading your engine down.

The 5R, like most Ford trannies is a bit quirky, and follows a really odd shift pattern due to its 5 "speeds". I have noticed that when the O/D engages and the torque converter locks that I can press the accelerator in a lot before it finally shifts out of it to accelerate.

My trick is to fully let off the throttle, and then press it down again. This un-locks the TC and lets you accelerate quicker and not have to press it down enough to un-lock it. It also helps to prevent the transmission shudder in the Taurus when the TC locks up in 3rd gear and then shifts into overdrive (Stupid Ford! )

 

[SWLathrop]

There's a TSB out for delayed engagement/shifts. This may be your problem. I'll see if I can pull the TSB today and post tonight.

 

[jackrod]

I have a 99XLT 4.0 SOHC. I had a simular shifting pattern as sina220. The highway to work has a slow rising incline where I get on. When there is traffic, I had to floor it to get up to speed so I can merge in. My X would only climb to 3600 rpm, and would continue to upshift until it was in overdrive. I used to push the button to turnoff the overdrive, but the rpm's still stayed around 3600 in 4th gear. Oh, and I have a slight lag between pressing the peddle and the engine responding, (.5~1 second?).

After I found this website, I bought a K&N drop-in filter and reset the computer. On the same onramp, when I floor it (wot), the engine reaches 5500 rpm before shifting (with or w/o overdrive on), but still has the time lag after flooring the peddle.

PS - since joining this website, I find myself trying to deside which mods I want to do first.

 

[Majisto]

Originally posted by jackrod
I have a 99XLT 4.0 SOHC. I had a simular shifting pattern as sina220. The highway to work has a slow rising incline where I get on. When there is traffic, I had to floor it to get up to speed so I can merge in. My X would only climb to 3600 rpm, and would continue to upshift until it was in overdrive. I used to push the button to turnoff the overdrive, but the rpm's still stayed around 3600 in 4th gear. Oh, and I have a slight lag between pressing the peddle and the engine responding, (.5~1 second?).

After I found this website, I bought a K&N drop-in filter and reset the computer. On the same onramp, when I floor it (wot), the engine reaches 5500 rpm before shifting (with or w/o overdrive on), but still has the time lag after flooring the peddle.

PS - since joining this website, I find myself trying to deside which mods I want to do first.

The delay is normal it seems because of the somewhat slow computer, and its in-deciseveness. My SOHC has a lag time between gas pedal depression and response but I have gotten used to it. *Shrugs* If you're running at 3,500 RPMs in 4th, then it hasn't gone into O/D yet...remember the tranny in our SOHCs is a 5-speed.

 

[Robert]

My cure for the long lag time when downshifting was to install my SuperChip. Now it shifts instantly rather than the .5 - 1 second that the stock programming has. Mine has never had a problem accelerating to 6000 RPM and beyond (with Superchip) any time I hold the throttle down long enough.

 

[jackrod]

Sina220, I forgot to mention the mod for the throttle cable. It helps to reach the wide throttle open position when you press the gas peddle to the floor - if your cable has slack in it.

You can find all the information by going to: Throttle Cable Mod- How To, in the List of Useful Threads section.

Robert, I'm going to get an Apten Chip in the near future.

 

[SWLathrop]

TSB 02-13-8: Transmission - 4R44E - 4R55E- 5R44E- 5R55E- LOW LOINE PRESSURE READING AT WIDE OPEN THROTTLE (WOT) - SLIPPING SHIFTS AND/OR DELAYED ENGAGEMENTS - POSSIBLE DIAGNOSTIC TROUBLE CODES P0732, P0733, P1762 SWT - VEHICLES BUILT BEFORE 12/1/2001

FORD: 1995-2001 EXPLORER
1995-2002 RANGER
1996-1997 AEROSTAR
1999-2002 EXPLORER SPORT
2001-2002 EXPLORER SPORT TRAC

MERCURY: 1997-2001 MOUNTAINEER

Some vehicles built prior to 12/1/2001 may exhibit the following shift and engagement conditions:

1. Low line pressure readings while in DRIVE at WOT
2. No 2nd gear
3. No 3rd gear
4. No engine braking in manual 1st
5. Slipping shifts and/or delayed engagments
6. DTCs P0732, P0733 or P1762 may be present


Hope this may help somebody.

 

[mbryda]

What's the fix? Is it the valve body gasket?

 

[Nate1]

Im guessing this is not a free fix like 00M12? Is it a GEM reflash or a valve body, or some, other piece of hardware?

 

[TPLYNCH]

I think Ford has been fixing these as they come in for tranny service. At least they did with mine, cause I had no engine braking before I had them change the tranny filter @60K, and since that service I've had engine braking. Vaguely remember seeing something about valves listed on the invoice at N/C, but didn't think anything of it. In fact, the service writer insisted that there was no such thing as engine braking in 1, only if you had it in 4low. I knew he was wrong, but before I could bring it to another dealer, I found the problem was fixed.

 

[Nate1]

Just called the dealership, they said it would be $87.95 to diagnose it. I guess that would be okay if they would also diagnose my engine's bucking and my A/C rattling.
Haha there is always one more thing to fix
-----Nate

 

[SWLathrop]

"nweibley",

Don't know about your other issues, but your bucking problem could be a bad TPS. Have run into that one a few times. But then again, I could be wrong.