JSPulliam21

I just bought the truck in my sig today. On the way home I was getting on it a little to pass a truck on the interstate and the truck bucked a little. It was like the fuel was shut off and then came back on. Any ideas? It is pretty random, and it does not occur evey time.

JSPulliam21

Anyone think the injector nozzles could have something to do with it?

JSPulliam21

Truck also has a boost elbow. With no chip to do boost fooling, could the computer see an overboost condition and cut fuel? Awaiting your knowledgeable responses.

starkey

Kinda sounds like its de-fueling. I think your on the right track thinking about the overboost condition. I plugged the gate on mine last week and she threw an overboost and would de-fuel at around 2500 rpm. opened it back up and its workin fine now.

can17

Starkey, when you say your truck would defuel at 2500, was it like the fuel just quickly stopped/started and very jerky or would the truck just keep pulling until it got to 2500 and then no power?

starkey

Well, it kinda varied somewhat. Sometimes it would pull up to 2500 and then de-fuel, but sometimes it would jerk untill i shifted. After i unplugged the gate, it still de-fueled untill the overboost code cleared, now its smooth.

kycatpower

If you can find an answer to this one PLEASE PM ME!!! I know EXACTLY what you mean and I have tried unsuccesfully to answer this question for about 3 years and 90,000 miles. I have a TST PM3 and boost elbow - no difference. I will sometimes drive for 8 to 10 weeks and never have a problem, other times I may feel this "hiccup" two or three times in a day. No consistancy as to speed or load, just a random event.

It feels like the key is turned off for about a half-second. Will definately get your attention. Occasionally it will even kick my cruise control off.

I have seen some posts on this subject suggest lift pumps, but my full FASS 150 GPH didn't cure it. I have seen the famous "you're about to lose your VP" posts, I now have almost 170k on the original pump (the pump was tapped in 2002). I believe there was even a recall for a similiar problem on some of the CTD's, but according to Dodge mine is not one of them.

I guess I will just keep hoping that this is an annoying quirk. You would think if something were going to break it would have done it by now.

Copenhagenjunkie

I am going to say it's lack of available fuel for the VP. I went from stock sticks to DD2's and have hesitations under load when towing and slight hesitations when empty. Since doing big line and lp relocate last weekend hesitations are gone when empty all the way to 3,500 rpms, have not tried towing yet.

It's not all about fuel pressure, you have to have volume.

Just a thought..........

JSPulliam21

That is exactly what it feels like. Where could I find more info on this possible recall? I ordered gauges yesterday, so they should be here next week. After that I will probably order a FASS HPFP. The truck has bigger lines than stock, but the lift pump is a stock unit mounted on the engine.

Z

I had this problem a long time ago. When I ran across this TSB I went straight to the dealer, had the ECM reflashed and it never happened again.

JSPulliam21

I have a similar thread going over at cumminsforum.com. There has been more discussion on it there, and some ideas abot the root of the problem have come up. I have installed a FASS HPP, 3/8" line, 1/2" Vulcan line from fuel filter to IP, Vulcan Draw Straw, and DiPricol pyro, boost, and fuel pressure gauges. Here is the link to the other thread: http://www.cumminsforum.com/forum/98...nder-load.html
Does anyone have any ideas? Maybe the nozzles are the problem.

JSPulliam21

My truck is a 98.5. Could it still have a build date in 99?

JSPulliam21

Here is a video of my truck a couple of weeks ago at a truck pull. You can hear the bucking/missing/flubbering several times. It started doing it around 2800 - 3000 rpms, and I had to keep it just below 2800. Maybe this will help you see my problem.
http://video.competitiondiesel.com/v...6201761a26.htm
(the vid may not be up right now, but it should be soon)

JSPulliam21

Two serious diesel mechanics that I have been dealing with say that the pump is slipping timing. Today we hooked up a code scanner and drove the truck to check sensors while the "event" was happening, and everything checked out. We put an APPS on it, and that did not solve it. The only thing that is left is the pump. I guess I will just keep running it until it throws a code or dies. Thanks for all of the help guys!

JSPulliam21

The other day I took the electrical connector off of the VP to check the wiring and pins. The pins and connector looked clean and straight, and the wiring looked unmolested and solid. So, I put some dielectric grease in the pin sockets, like I do with any electrical connector, and plugged it back up. Today, I decided to see if it would buck and carry on. I could not induce the bucking and flubbering at all, and I reamed it hard past redline in every gear or about 10 miles. It revved clean and smooth all the way to 3500 rpm's where it defueled smoothly, like it should, and stayed there. I wonder, if one of the pin sockets in the plug is loose, and a certain rpm's the pin or connector vibrates and breaks the connection intermittently. If so, then the dielectric grease took up the slack. Any thoughts on this diagnosis? Good and bad are welcome, as always! I will continue testing, and update you guys as I learn new things.