Engine/Transmission (1998.5 - 2002) No Top End/HP

[Tom C]

this post is for a frient who was a die hard Ford driver. This is his first Dodge. He just bought a new 2002 cab-chassis with a flat bed. (4x4, 5spd, 3. 54 gears) when he first got it he said it would run right up to red line in 5th gear and would pull hard the whole time. Now he has 1200 miles on it and says it will hardly pass 80MPH and took its sweet time getting to that. has anyone else had this symptom? He says he has babied it the last tank full or two to see what his best fuel milage is. Hes been getting 15-16 MPG.



Any Suggestions?



Tom

 

[fj40charles]

Hey Tommy,



Did he have the ecm flashed at the dealer? Lift pump good?



Charles

 

[Tom C]

Hi Charles, I beleave its 110% stock. Is there a reflash for that model? They flatbed people disconnected the batteries to weld on the flat bed. could that reset a ECM?



on another note: Have you started with the mods on the fj40? My frame is still in the shop :{ . Do you know anyone who does acid dipping on auto bodies?



Tom

 

[F-15I Ra'am]

Disconnecting the batteries might have thrown the the calibration off on the APS. Might need to recalibrate it.

 

[tarussell]

Mine is doing the same thing. I started looking into what was wrong and I found I had a bad lift pump, so I replaced it and it helped somewhat. I started reading the Service Manual to look for reasons of poor performance and saw where the flow return control valve could be stuck or not working correctly. I replaced it thinking that the fuel was not flowing fast enough and heating up causing the lack of performance. The truck still runs the same way with the new valve and I tested the old one and it was working fine according to the pressure readings. There are no codes in the ECM so I am getting stumped as to what to do. I guess my next step is take it to a professional diesel tech. I could use the warranty but my general opinion is that my local dealers service dept. fowls up more than they fix , so that will be my very last option. Thomas

 

[LSMITH]

Any time you have a low power complaint on a diesel engine the FIRST thing you do is change the fuel filter/s. If the complaint is in the upper RPM the case is even stronger to change the filter.



Change the filter and get back to us.



EDIT: it doesn't matter if you only have 500 miles on a fresh filter, CHANGE IT. You can get horribly dirty fuel, and it only takes a little to clog a filter.

 

[tarussell]

That is interesting. I did notice a slight increase in power the last time I changed the filter, but I was on a failing lift pump and did not know it. I have been changing the fuel filter every 6,000 miles ( every other oil change ) and it's do for another change this week. I thought I was getting my fuel at a good ( high volume ) station; filters always look gray in color every time. Does excessive amounts of fuel additive clog filters? I have been using Red Line 85 Plus ( 12 oz. ) in every tank since new.

I have not had a filter change since the new lift pump so I will see if it helps. Thanks , Thomas

 

[LSMITH]

Your additives should not hurt the filter a bit. You can get a load of garbage in the fuel even at a high volume truck stop, all it takes is fueling while the truck is dumping a fresh load of fuel in the tank and stirring up all the crap on the bottom. Even fueling right after the truck leaves can do it. It happens to all of us eventually.



I think you are throwing money away by changing the filter at 6K miles. You should (IMO) change the filter based on restriction. I change mine at 4 PSI of restriction. You can put in full time pre and post filter gauges, or you can just check the restriction with temporary gauges every couple thousand miles or if it feels a little sick. I have had filters last as long as 22K miles, and as little as 1500 miles. One thing I know, I don't change a filter that doesn't need changed and I do change them when needed. No guessing either way.



You can also use pre and post gauges to see if your filter needs changed when you have a low power situation. If you don't have a guage to hook up you have to throw a $15 filter at it and see if it helps.

 

[Tom C]

Can Cummins recalibrate the APS? or is that something that the butcher (dealer) has to do. Changing filters is a good place to start.



Thanks



Tom

 

[Lsfarm]

AeroDynamics?

Did the truck run good prior to the bed installation? then after the bed was installed not want to go past 80mph?



There is a member in Hawaii who has a large flat front on this flatbed, and can barely get over 80 mph.



This may be the problem: he had a 'Drag Chute' installed as the front headboard of the flatbed.



Just a thought,



Greg L. the Noise Nazi

 

[tarussell]

LSMITH - I got up way early this morning and changed the filter before the day got started . It helped, but there is still a power problem. I did notice a fuel pressure increase. Usually on the second half of the tank the pressure is a pound or two lower at idle, and now it reads 14 PSI at idle on the low side of the tank when it usually reads 12 or maybe 13 PSI .

To make sure that I am not crazy I got a co worker to drive my truck (he has a 99 CTD 5-speed) and I drove his and we both felt that mine was down on power. He has driven my truck when it was new and said it is no where near as strong as it was- and I agree ... ... Now my truck will still run circles around a 215 HP automatic CTD but it does not feel any stronger than a standard 235 HP 5-speed truck that is similarly equiped.

One thing I might need to mention is when the truck was new it pulled very hard for a stock H. O. . I could get it to smoke a little out the tail pipe at will ( black smoke ). 4th / 5th and 6th gears felt real good under hard excelleration. I ran along side a 2WD 3500 Reg. Cab w/ a ETH several times and I always pulled ahead at the top of the power band. Now the same 3500 will stay right next to me or pull slightly ahead. The truck will no longer produce any smoke out of the tail pipe if gassed heavily at low boost.



Could there have been a learning mode in the ECM when it was new and I got use to power that I should not have had ? The truck is not slow but it definetly does not pull like it did. The motor still revs like it should and has good bottom end power. I normally drive like an old man ( easy going ) and all is well power wise, but when stretching the motor out it no longer has the same feel at all.

FWIW my clutch is in fine working order the tires are the same size as always and the truck has been empty every time I test it.



Got any ideas on where to look next ? If it is with in my grasp I would like to tackle this problem but I will spend the money where it counts ( professional ) if needed.



Thanks for any help or suggestions, Thomas



Tom C , sorry for kind of hi-jacking your post but I figured this is a good place to ask since you may have a similar problem and I did not want to duplicate this post.

 

[Tom C]

Tarussell, Your not hi-jacking at all. . I beleave my friend is in the same boat with you. We are looking for any and all info that may solve the puzzle Keep the suggestions coming. The more that is said, the more we learn. I'll find out if his truck lost the power after the weld job. Can or do the ecm's have a learning/memory program??



Thanks,



Tom

 

[LSMITH]

You could try re-calibrating the APPS (throttle position sensor), to do this unhook both batteries for a while and then reconnect them. Turn the key on without starting, slowly press the pedal to the floor and slowly let up. Turn key off and then start normally, take a spin and see if it helps.



You could also clean the MAP sensor and the AIT sensor. Some guys have reported good results from the cleanings.



On another note what type of weather have you been having where you live? Winterized fuel can cut your power pretty dramatically if it is an aggressive blend. If you live where it gets cold it could be as simple as winter fuel.



EDIT: I see one of you is in FL, winter fuel should not be a concern there. As far as the ECM learning goes, there is no proof either way that I know of. I do know this, if I grandpa my truck around for a few hundred miles it gets sluggish, and it takes a few hundred miles of aggressive throttle use to get back to normal. A hard tow or a long drive at high speed maintaining higher EGT will get it back to normal also.



The ECM only gives you the power it thinks you need at that particular moment, not like a 12V that will give you everything it has the moment you ask for it. Run it hard for a couple tanks of fuel.

 

[tarussell]

Thanks for the leads on what to do ! I'll clean the MAP & AIT sensor's and reset the APPS for starters, than start to drive it like it's stolen ... ... ... .



It does seem to have good power, for a few tanks , after a long pull sometimes. I think that you may have solved my problem.





Thanks for the effort on this problem , Thomas

 

[Tom C]

My friend has been driving the snot out of his the last tank full. He says it seems to have regained some power. So hes off for more full throttle action .



The power lost came after he added the 1K lb flat bed and babied the truck for fuel milage (flat bed head board does not block air). I drove the truck today and it drives real nice. just missing that ummpphh (power band and growl) that usually is there. It felt just like a '01 auto I had. all intercooler clamps look good and tight. will get him to try the above listed tricks and see how it works after that.



Does a EZ box fool the system all together. in other words... Say the ecm does have a memory map. would a EZ fool the map (over right the ecm commands) ??? another way to ask would be: does the EZ add info to the ecm or completly fool the ecm?



I had a power problem in a '01 I had (it was an auto). after several trips to the butcher (dealer) and getting reflashes to increase power in OD it still had low power. I added the EZ and zoom I was off to the races.



Thanks



Tom

 

[Big_Daddy_T]

I believe that there is no ecm fooling. They are piggyback. It alters the signal after the ecm. Like an amplifier in car audio. Makes it louder. Changes the parameters a bit. Amps can do this with a crossover. The ford is the one that has a plug in module ecm. I think those chips are called proms.

It is unlawful to change the ecm parameters too much. If I remember they can bump it up to 500 ft lbs legally. I asked for the rv reflash and its not approved. 25k fine or somin the like.

 

[LSMITH]

The EZ basically "asks" the ECM to add more fuel and to bump the timing a little, the VA tacks on a little signal to the one sent from the ECM.



The criminal activity of BOTH is known to the ECM and recorded in a couple parameters that can be found if someone looks.

 

[tarussell]

LSMITH - You are " The Man " ! Thanks for the insight on what to do. I started driving it harder and towed about 8500 lbs. for a few hundred miles, and it seems to be waking up .



I started thinking of the trucks ( CTD ) that I have driven and the ones that feel nice and strong are the ones that have been driven hard and are way over-loaded all of the time, and the few that have been babied all along are slow as Christmas.



Assuming all is well with the trucks , I think you hit the nail on the head ! Thanks again , Thomas