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surge at take offs
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=60623		 Page 1 of 2
Author:  camo [ Tue May 10, 2011 7:42 pm ]
Post subject:  surge at take offs
Hi, Ive been experiencing power surges when taking off from a dead stop like when at a traffic light. it feels as if someone kinda hit you from behind but else my libbie runs good under all other cicumstances. also, it only happens some 60% of the times.
ideas? suggestions where or what to check? thnx :roll:
Author:  Roostre [ Tue May 10, 2011 11:25 pm ]
Post subject:  Re: surge at take offs
Possibly a fuel feed issue??

Changed your fuel filter lately? Maybe the CP3 needs a lift pump?? I dunno.

My older diesels would surge when the pump was starving for fuel- it has the effect of advancing the timing, but I'm not sure if this holds true for a high pressure common rail system. Whenever it would surge I knew it was time to switch tanks or get fuel.
Author:  JL Rockies [ Tue May 10, 2011 11:28 pm ]
Post subject:  Re: surge at take offs
Some people pay extra for that.
Author:  camo [ Wed May 11, 2011 9:03 am ]
Post subject:  Re: surge at take offs
well, I did replace the fuel filter 500miles ago, so I dont thik it is the problem. About the pick up pump..... I not sure about it, will it cause other systems to have troubles? like too much pressure on the crd system or something?
thnx in advance for the replys.
Author:  sidebrake [ Wed May 11, 2011 9:48 am ]
Post subject:  Re: surge at take offs
I would try and pay attention to what other common factors exist when it happens... Is the transmission shifting from 1st to 2nd? Are you moving the throttle at all (accidentally or on purpose)? Is it happening when you cross a specific RPM? Is the Jeep modified at all?

My completely unprofessional opinion is that it's not a problem (unless it comes on violently and you're concerned about loosing control of the vehicle). Although the CRD is my first turbo diesel, I've owned 2 gasoline turbocharged vehicles and I can say that sometimes power can come on at "strange times" due to turbo lag (which the CRD has almost none), boost set points, and fuel maps. Again, I would try and pay attention to other common factors when it happens to draw a connection. :2cents:
Author:  papaindigo [ Wed May 11, 2011 11:17 am ]
Post subject:  Re: surge at take offs
I've owned 2 Liberty CRDs and driven stoutdog's CRD. They all have/had a slight bit of turbo lag. Just enough that if you use a light foot leaving a traffic light the turbo won't kick in hence no surge but if you use a heavy foot the vehicle will move forward just fine but after a very brief interval the turbo will kick in and away you go. Try light foot departures vs. heavier foot (not floorboarded) departures and see if your surge is linked to the latter. If so it may be normal or there may be some adjustments needed. I will say with the GDE EcoTune the lag is much less noticable.

Never mind this comment as the issue occurs with foot off throttle.
Author:  camo [ Wed May 11, 2011 5:43 pm ]
Post subject:  Re: surge at take offs
I'll try some different takeoffs to see if I can spot a difference!!!, for right now I can say that it happens only at take off and not when shifting or cruising or any other circumstance. e.g.: I get to a stop sign, brake gradually until dead stop, wait 3 sec then release the brake and before I even hit the gas again I fell the surge as if someone bump my rear. It is less noticeable when I give it more gas instead of less but still you can tell the difference.
thnx for your replays
:JEEPIN:
Author:  GreenDieselEngineering [ Wed May 11, 2011 5:58 pm ]
Post subject:  Re: surge at take offs
It could also be a partially clogged EGR system. You can test by unplugging the MAF sensor on the air box lid, this will shut off the EGR. You will get a CEL, but that will go away after 3 drive cycles when the MAF is plugged back in.
Author:  camo [ Sat May 14, 2011 7:37 pm ]
Post subject:  Re: surge at take offs
ok, I was able to narrow down the surges to normal operating temperature, but today the car just felt like it had no power, the engine would rev up but no power to the wheels, the transmission shifts smoothly and it came back to normal after letting the car in the garage for a couple of hours, could it be the TC??? HELP PLZ.
Author:  uham [ Sun May 15, 2011 10:06 pm ]
Post subject:  Re: surge at take offs
This problem sounds like a transmission with low fluid. I am assuming you already checked your fluid level but have you changed your transmission filter and fluid recently? I wonder if a valve in the transmission is sticking?

If this problem is more pronounced after shifting from reverse to drive then I would start looking at the transmission.
Author:  racertracer [ Sun May 15, 2011 10:28 pm ]
Post subject:  Re: surge at take offs
I had the same problem when I first bought my CRD, it went away when I replaced the torq converter and pump.
Author:  camo [ Sun May 15, 2011 10:36 pm ]
Post subject:  Re: surge at take offs
well, a week ago took it to riveroaks jeep and they did a tranny service (flush, filter, oil) and they said it all looked ok. however, I just chek the tanny oil today and before starting the crd (cold) the fuild showed at the highest hot mark dot of the tranny dipstick, then i started it and drove it about 3 miles and recheck, this time the oil was a bit lower than the lower hot mark dot of the the tranny dipstik. Does that mean something out of the ordinary? could it be whats causing the issues?
thnx
Author:  camo [ Sun May 15, 2011 10:38 pm ]
Post subject:  Re: surge at take offs
what are the part numbers for the euro spec TC and the revised pump? thnx
Author:  irollgen4s [ Sun May 15, 2011 11:27 pm ]
Post subject:  Re: surge at take offs
occasionally i experienced what i think is surging. usually it happens when im driving at a slow speed/taking off. and ill be accelerating at maybe 30-40 percent throttle and all of a sudden the turbo kicks in and a big poof of black smoke puffs out :-)r . It happens MAYBE once every couple of weeks, so im really not worried about it. Now that i think about it, it is actually a very rare occurrence.
Author:  camo [ Sun May 15, 2011 11:30 pm ]
Post subject:  Re: surge at take offs
puffs out LOL.
fart like?? :ROTFL:
Author:  irollgen4s [ Sun May 15, 2011 11:59 pm ]
Post subject:  Re: surge at take offs
ahaha not fart like. But the only time i really get any black smoke to pour out is when the turbo kicks in, whether it be the random surging, or when im merging for an expressway.
Author:  racertracer [ Mon May 16, 2011 3:18 am ]
Post subject:  Re: surge at take offs
irollgen4s wrote:
ahaha not fart like. But the only time i really get any black smoke to pour out is when the turbo kicks in, whether it be the random surging, or when im merging for an expressway.


Sounds like you need the tune.
Author:  irollgen4s [ Mon May 16, 2011 6:07 am ]
Post subject:  Re: surge at take offs
its on my list, but i dont have the money now. and on top of that i have 152xxx miles on it and the TC is still fine, its hard to justify replacing it when its lasted that long with no issues.
Author:  racertracer [ Mon May 16, 2011 6:41 am ]
Post subject:  Re: surge at take offs
camo wrote:
well, a week ago took it to riveroaks jeep and they did a tranny service (flush, filter, oil) and they said it all looked ok. however, I just chek the tanny oil today and before starting the crd (cold) the fuild showed at the highest hot mark dot of the tranny dipstick, then i started it and drove it about 3 miles and recheck, this time the oil was a bit lower than the lower hot mark dot of the the tranny dipstik. Does that mean something out of the ordinary? could it be whats causing the issues?
thnx



Correct me if I'm wrong but I believe that the proper way to check if the transmission fluid is at the proper level is in this way:

1. Drive the vehicle for 15 minutes to get the transmission warmed up.
2. Park the Jeep on a flat level surface.
3. Place the transmission in neutral.
4. Set the parking brake.
5. Turn the engine off.
6. Wait 3 minutes.
7. Check Transmission fluid level.
Author:  Joe Romas [ Mon May 16, 2011 7:44 am ]
Post subject:  Re: surge at take offs
camo wrote:
well, a week ago took it to riveroaks jeep and they did a tranny service (flush, filter, oil) and they said it all looked ok. however, I just chek the tanny oil today and before starting the crd (cold) the fuild showed at the highest hot mark dot of the tranny dipstick, then i started it and drove it about 3 miles and recheck, this time the oil was a bit lower than the lower hot mark dot of the the tranny dipstik. Does that mean something out of the ordinary? could it be whats causing the issues?
thnx


Your jumping all over the place with your "surge" :furious:
Stop and take a deep breath. Then check your fluid properly. Start the jeep after letting it sit overnight and move the shifter between all the gears and with it running check the fluid level. It should be at the COLD level. Then drive it long enough to get it totally warmed up, maybe 5 miles or so. Then check the level. It should be in the HOT level.

Have you read Sir Sam's noob guide and downloaded the FSM :?:

Now reading one of your posts you said:

"I get to a stop sign, brake gradually until dead stop, wait 3 sec then release the brake and before I even hit the gas again I fell the surge as if someone bump my rear"

What your discribing in that situation sounds like the slip joint in the rear driveshaft binding on the splines of the transmission. It's a simple fix of removing the drive shaft and putting some grease on the splines shaft :BANANA:
It happens because when your stopping the rear end of the jeep raises up and the drive shaft moves outward from the transmssion. Then when you let off the brakes the rear settles back to normal and the drive shaft then needs to slide back into the transmission. It is at this time the driveshaft binds and you get what is best discribed as a "feeling" that something is amiss. I've owned 3 automatic XJ's (cherokees) and they have all done this untill I lubed the slip joint. This sensation can vary from being just noticable to good thump. My CRD has recently started doing it too, I suspect the proper grease or any grease was not used when the TC was replaced, and I've choosen to ignore for now :JEEPIN:
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