Another hesitation problem.

[tmacc]

Ok, I've read most of the other hesitation threads, but I think mine is different. Most of the other problems seem to be w/ a fueling box of some sort. Mine hesitates (or surges, bucks, stumbles, whatever you want to call it) at 1700 rpm in OD, which is at 55 mph. Usually on a slight grade at low thottle. I think I can get it to do it in 3 gear locked up at 1700 rpm. Hard to tell. It also will do it at 2200 rpm, which is at 72 mph. This w/o a fueling box. The window of hesitation is pretty narrow. About 50 rpm. I first noticed this after I got the TSB 18-024-01 reflash. I took it back in and they did the same reflash again. They gave me some BS about "The reflash didn't take the first time. Yeah, right. It may have been doing this before the reflash and I didn't notice it. It seems to be getting more pronouced. So, this has been going on for about 6 months and I'd like to figure out what the deal is. Any help would be appreciated.

TIA

Tom

 

[Diese1nut]

Hesitation

Your problem is not much unlike the others. Most people think it's the fueling boxes. With the people I have talked to about the problem, it still exsist even with out enhancements however most only notice it when towing.

The fueling boxes and or injectors will enhance the condition, making you beleive they are the cause.

I beleive there is a serious DC problem that they are ignoring. The members here have tried to resolve it themselves with new lift pumps, additional pusher pumps, map and IAT sensors, new injectors and reflashes, but to no avail.

I haven't seen anyone try a new TPS for this problem, which solved my freinds simialar problem on his Cat. He said the stumble was so fast it would not show up on the scanner.

The problem doesn't seem to matter if it's an ETH, ETC, auto or stick.

The guys at Bully Dog tell me this has exsisted since 1998, and they still don't know the answer.

I would think that if there was a fix for this it would be found on this board.

Hopefully someone will solve there problem and share it with us.

 

[J. REUTER]

engine bucking

Awhile back I posted regarding this problem with my truck. At the time I thought it was my EZ box so I sent it in to have it checked out. Been driving without the box for about a month and still have the same bucking just not as noticable as with the EZ connected. Its always most noticable when the torque converter is locked up in fourth gear and does'nt matter if Im towing or not. I need to get the truck in to the dealer just haven't had the time.

 

[tmacc]

J. Reuter

I know what you mean. No time either. Specialy when you know from past experience that it's a waste of time. I was talking to a Cummins tech a couple of weeks ago and he said that they can hook up their computer to the truck an 'map' the fuel curve of the injector pump. Looks like that's where I'll be going to get it check. My only concern is what else that 'puter's going to

show.

Tom

 

[Diese1nut]

I have had my truck to four different dealers. They have checked everything (supposedly) and replaced the lift pump, done two reflashes,and say nothing is wrong. I guess I just like to hang out at dealerships to see how useless they are.

I even had the truck dynoed at Cummins and they said it sounded ok but didn't have the connectors to hook it up to there computor. Doesn't make sense to me. I just want my truck fixed.

 

[tmacc]

Dieselnut, I seemed to have missed your first reply. Duh. Anyway, your experience w/ the dealers confirms mine. They can be worthless at times. The Mason Dixon TDR chapter attend an open house at Cummins Powerstore in Glen Burnie Md. I had a conversation w/ one of their techs and he said that they could hook up a laptop to the truck and take it for a test drive and look at it real time and save to a disk. I guess this is the route that I will take. I did read in the latest issue of TDR page 46, where a member had what would appear to be the same problem that we are having and wound up finally replacing the injection pump. Hope we don't have to go this route.

Tom

 

[700rmk]

what if?

I have had this stumble on two different trucks with the same EZ. However it really only shows up or is noticable to me when the temperature outside falls below 40 degrees, and the fuel at the stations is the winter blend.

I have noticed that at the local corner station it runs much worse than if I fill up at flying j. I wonder if this somehow doesnt have to do with the winter blend and cold weather, could we be extinguishing the fire with this mix of fuel, is the BTU rating that much different as well as the cetain. I wonder if its like running a very low grade gasoline in a high performance car, you get the ping sensation, it this the same thing for the diesel, somehow enhanced by the EZ and the pump?



my . 02 worth.

 

[Big P]

I'm glad I read this thread, my truck does the same thing. It only showed up though when I installed my BD PNP2. It only does it when 700rmk said, when it's below 40 degrees and the motor is cold. I'll have to try again with the BD unplugged.

 

[Diese1nut]

Hesitation/APPS

Bad fuel is definitely a concern, and so is winter blend. However I have been following the sun with my fiver for over a year so winter fuel would be a remote problem in my case. Also with my truck, outside temp. doesn't matter.

I just read on a similar thread (APPS) that Evan B. has had only seen one instance with a bad TPS. That thread has the same symptoms as ours.

Weather it's APPS or the injection pump I don't care at this point I just want to know for sure.

This is all great input and I think these two threads should be put together. The more minds the better.

 

[Runaway]

Me too...

Like MPagnucco, I only notice this symtom when temps get down near 40ish or colder. Always in 6th gear, 55 - 60 mph, 1600 up to about 1800 rpms. Put 200 miles on truck this afternoon, temps in the mid 50s (warm for WI this time of year)and not a hiccup. Guess as it gets colder I will have to take EZ off and run to see if symtoms still exist. But weather isn't suppose to get colder for another week yet. Someone posted they replaced an APPS sensor and cured problem. Said they bought from Cummins for $40. 00. Thought the APPS sensor was one of then $200 - $300 items Maybe in the next few weeks we will get this figured out.

 

[C1B1DIESEL]

Here is some possibilitys.



ISB Hiccup/Power Loss Troubleshooting

There have been some questions about how to troubleshoot a quick hiccup that feels like a key off, or a fuel shut off on ISB engines.



This is usually caused by power interruptions to the VP44.



Check the following items:



Keyswitch - check for increasing key counts with INSITE™.

VP44 relay mounting - excessive vibration of the VP44 relay can cause the relay to intermittently open.

VP44 amp connector loose and/or pins damaged- check the VP44 amp connector for a tight fit, check pins for moisture, debris, damage, etc.

Harness damage at the VP44 relay and amp connector - check the wires for signs of fretting, etc.

Loss of throttle signal - monitor throttle signal with INSITE™.

Voltage to VP44 relay from pin 36 of ecm connector - if voltage is lost check the following:

Keyswitch

Overspeed faults

Noise or faults from other devices on the J1939 datalink (can test by unplugging datalink).



Hope this might help,

 

[tmacc]

Well guys, in my case, I don't think that it's temp. related. When this cropped up late winter, early spring, I thought it was something that only happened in cool weather, but it's now happening in warm weather, too. I've got to agree w/ Dieselnut on that. I think that it's gotten worst over the last 15-20k miles. Well not think, I know it's gotten worst. When I tested a EZ it definately exacerbated the problem. I talked to another TDR member that recommended a friendly dealer near him (werstern MD) that I may give a try. He's going to give the tech a call this week. This dealer isn't the most convenient for me, so I'm not sure I'll get there this week. We see.

Keep the input coming.



C1B1DIESEL,

Good things to check out. The TDR member I referenced above had his truck die and he thought it was the lift pump. Turns out that it was a loose wire in the relay connector. But, w/ all the folks that are having a very similar problem, it would have to be some kind of bad batch of wiring harnesses. Never the less, next weekend I'll start checking this out.



Tom

 

[GTX]

I had the same problems as Diese1nut desrcibed with my 99 and the dealer could not find the trouble until the vp44 died. They reflashed the ECM 2 times with no help and told me the lift pump pressure was low but not low enough to replace it. After driving about 8k with it stumbling and puking a grayish smoke the vp44 quit.



So do any of you guys notice any smoke out the pipe while it is stumbling?

 

[tmacc]

GTX,

I don't know. I'll have to check tomorrow. I have the perfect road for sustained stumbling.

Tom