Engine/Transmission (1998.5 - 2002) need help with surging problem I think

[MSalvatore]

Hi all,

Yesterday I was towing my jeep through poconos up 5mile hill on rt80.

When I get into the throttle about half way or so the rps jump up and down about 300 rps the truck doesn't move faster then slower just motor does boost was about 20psi temp around 800. Dealer replaced thi injection pump but it has done this with old pump also. I have a edge comp but left the wire off on this one after the 1st pump died. Dealer said transfer pump is fine but why would the injecter pump go and not the transfer?THe whole truck seems a little down on power , maby I was usedto having the wire tapped. truck has no codes I checked this morning. Any ideas would be great.



Thanks,

Marc

 

[Straight6Jeff]

Are there any codes being thrown? Mine did the same thing. audible rpm surge. Toast injection pump. No boxes, no injectors, butt stock. Both injection pumps lasted 30K. I'm on #3 in 70K.

 

[MSalvatore]

nope no codes at all.



Marc

 

[cerberusiam]

The 300 rpm surge is about right for the converter locking and unlocking.



Have you done the normal trouble shoot for APPS interference?



Reset the APPS?



Does it do it all the time or just under a certain load and/or terrain?

 

[MSalvatore]

yes I reset the APPS. Does it mostly when towing. also I get a shudder when it goes into 3rd or OD under heavy accel. What is normal troubleshoot for interference? I spoke whit DTT and they are sending me a noise filter hope it helps.





Thanks,

Marc

 

[cerberusiam]

Off hand I'd say the converter is toast. If your seeing shudder under heavy acceleration and it is doing it mostly towing the converter lockup clutch is probably trying to apply and slipping.



Since the converter clutch is obviously slipping there could be clutch material in the solenoids that are not allowing them to work correctly also.



The noise filter from DTT helps a lot if it is interference in the APPS wiring. You should also check both batteries and make sure they are good, clean and dielectric grease all the grounds, dielectric grease all the connections for the APPS and the transmission. Have even had to do PCM to clear up connection problems.



Does it do the surging when you are trying to maintain speed as opposed to accelerating?

 

[MSalvatore]

Most noticeable under accel but slightly at cruise. Hopefully the noise filter works,But after loosing 1 vp44 I want to upgrade pump but which one I was looking at fass2 .

thanks,

Marc

 

[cerberusiam]

Converter should not be unlocking/locking under acceleration unless there is a problem internally. Usually the converter lock/unlock shows up at a steady cruise under light throttle but considering the electronics involved its hard to tell for sure.



The surging could be the VP44 not working right. Have seen them do that and still work fine and not throw codes. Given you already have a shudder in the trans on lockup that could be affecting it also.



Personally I would go with the AirDog but the FASS would probably work as well. There are some failures starting to show up with the FASS and I think it is due to the small lines from the tank unit. Not sure if its only the heavily fueled ones ore just the normal drivers yet but as long as they warranty the system it doesn't matter.



Good luck.

 

[rvjohnmd]

I have the same problem under same conditions. Trans shop finds no problem, no codes, it shows up under load. Can you tell me what a "VP44" is? Also "AirDog" and "FASS"?

 

[Oil Burner]

Your VP44 is your fuel injection pump. Very expensive (rebuilt pumps go for about $1200 to $1500).



AirDog and FASS are fuel transfer pumps that replace your stock lift pump and keep the VP44 fed with plenty of fuel.



Thanks,

Jason

 

[BillH]

Mine also started surging and threw a 216 code. Dealer is installing a new I/P, 2nd one in 67000 miles.



BillH