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-   -   Help--Surge at 30 MPH in 05WK 5.7-- Help (http://www.jeepgarage.org/f5/help-surge-at-30-mph-in-05wk-5-7-help-11131.html)

Juanvaldz 07-17-2010 11:08 AM

Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Picked up my WK used last fall with 62K miles.

I noticed recently that at about 30mph I can feel it surge and slow.

If I lock in the cruise control, I can watch the tach swing up and down about 200RPM.
I was thinking a dead spot in the throtle position sensor, but that would just drop the rpm, not make it go up...

Other than that, she is a dream.
Any ideas??
:confused:

XXX007 07-17-2010 11:19 AM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
my 3.7 does the same thing

maxst2 07-17-2010 12:52 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
I could of sworn there is a TSB fix for this...

robpp 07-17-2010 02:09 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
max i think you mean this one which is 4.7 only

http://www.wkjeeps.com/tsb/tsb_wk_1801810.pdf


but OP, there are numerous TSBs for the 05 5.7

I would go thru these and see if something makes sense. bad part is no warranty = you will have to pay for the tsb......

here is transmission but there rest are on this same page too.

http://www.wkjeeps.com/wk_tsb.htm#TRANSMISSION

maxst2 07-17-2010 02:19 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Well.. i was kinda right XD

jeepgcoman 07-17-2010 02:53 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
I'll bet it's the EGR valve. My 5.7 did the same exact thing, but I soon got a light with the EGR malfunction code. I reset the code and drove it another day or so and it came on again. I then started monitoring EGR operation with my DashHawk and found that the Commanded EGR and EGR error %ages were fluctuating wildly. This causes the PCM to try and respond by changing fuel mixture and timing. It can't keep up and you start getting the surge. You'll find that the EGR problems usually start between 40-60K on the Hemi's. Mine had 54K when it went out.

The change is relatively easy, with one exception. There are numerous threads on the various jeep forums, some with pictures showing/telling you how to do it. I paid $54 for a new valve from Auto Zone. The only problem is the lower mount bolt. It hits the alternator just about when it comes free from the cylinder head. I got mine off without messing with the alternator, or cutting the bolt off, like some have done. I cut the new bolt off about 3/16 in., put a good chamfer on it, and ground lip off the top of the bolt. Next time it will be a simple 30 minute job.

Walt 07-17-2010 08:32 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Quote:

Originally Posted by jeepgcoman (Post 236933)
I'll bet it's the EGR valve. My 5.7 did the same exact thing, but I soon got a light with the EGR malfunction code. I reset the code and drove it another day or so and it came on again. I then started monitoring EGR operation with my DashHawk and found that the Commanded EGR and EGR error %ages were fluctuating wildly. This causes the PCM to try and respond by changing fuel mixture and timing. It can't keep up and you start getting the surge. You'll find that the EGR problems usually start between 40-60K on the Hemi's. Mine had 54K when it went out.

The change is relatively easy, with one exception. There are numerous threads on the various jeep forums, some with pictures showing/telling you how to do it. I paid $54 for a new valve from Auto Zone. The only problem is the lower mount bolt. It hits the alternator just about when it comes free from the cylinder head. I got mine off without messing with the alternator, or cutting the bolt off, like some have done. I cut the new bolt off about 3/16 in., put a good chamfer on it, and ground lip off the top of the bolt. Next time it will be a simple 30 minute job.

What jeepcoman said. Start with the EGR valve, because it's an under-rated PITA for HEMI performance issues. It should be listed as a 40K-50K miles required replacement item, but it's actually not listed anywhere in the '08 service schedule. If yours has never been done, it will need it anyway.

If that fails to fully cure it, go to this new TSB: http://www.wkjeeps.com/tsb/tsb_wk_1800610b.pdf for 5.7L MDS driveability.

Juanvaldz 07-21-2010 07:48 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Thanks for the input!!!
I picked upa EGR this evening and will be installing it this weekend.
$39 including the gasket, small prive to pay if I get my performance and MPG back.

jeepgcoman 07-21-2010 10:55 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Let us know if that fixes it.

Joe in PA 07-21-2010 11:01 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Just replaced the egr on my 07' WK tonight and let me tell you it is a PITA!

The bolts for the tube that feeds the gas into the intake are no problems. The upper bolt that attaches the egr valve to the manifold is no problem either even if it can be a tight squeeze to reach it with a ratchet. The lower bolt is a royal pain, needs to be taken out with a 10mm wrench and the bolt will hit the alternator before it is all the way out. If you remove the serpentine belt and top bolt from the altenator, loosen the bottom bolt, slide the alternator down and to the left, you can make just enough room to get the bolt out.

Took me nearly an hr and a half but it was freakin 95deg out, humid and I had to hold a flashlight to see what I was doing once the sun went down! :D

jeepgcoman 07-22-2010 09:24 AM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
Joe, I hope you cut the new bolt off a little before putting in the lower mount hole. That's what I did on mine. Next time it'll only take about a half hour to change. Also, did it solve your problem? Did you have surging, and poor economy too?

Joe in PA 07-22-2010 04:20 PM

Re: Help--Surge at 30 MPH in 05WK 5.7-- Help
 
I've been battling a drop in fuel economy the last couple months and figured the egr valve was worth a shot. I have a dashhawk in the 07' and the egr readings were all over the place. The upstream O2 sensor mV readings also seemed a bit out of whack. Replacing the egr valve seems to have settle down the egr readings and the O2 as well. Might still replace the two upstream O2 sensors depending on the mileage I get the next couple weeks.


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