Hey guys,
I have 2000 EC Silverado 5.3L w/ ProCharger.
Have any of you experienced occasional surging that seems to be only when on an uphill grade? I have experienced it when low on gas and when full, before and after fuel filter replacement...
Don't know if this is related, but I have been getting an occasional 0420 SES code as well, however, I have been experiencing the surging for quite some time.
Any help would be greatly appreciated.
Thanks,
Al

 

Mine only does it if the toque converter is unlocked.
Have you moved your crusie control wire? I have heard if the cable is mis adjusted it will make it surge with the crusie on.

 

Haven't messed w/ the cruise, and this does it w/o using cruise.

 

Have you ever logged your AFR's? Mine surges under boost/low RPM's when it's way too rich.

 

0420 - Catalytic Converter Efficiency, Bank 1 (TWC)

Maybe your cats are plugged? Or if your AFR is way off your rear O2's might be out of range....have you had a custom tune done?

 

I believe the surging comes from the maf and the amount of air taken in with FI applications. Put it in SD, get a 2bar map and tune it will go away.

 

Thunder...No, haven't checked AFR's, just wondering why cat or A/F issues would only surge in that particular scenario and not consistently either?

02Sierra...explain please

Thanks guys

 

It may be that your VE tables are only off in one particular area. Can you rev the motor all the way up? How does it do when you do a WOT run from a dead-stop? Is the surging at low RPM? High RPM? Both? It's only doing it when loaded up and if you're cruising uphill I'm guessing it's at low RPM under boost. If your truck thinks it is pulling in more air than it really is (problem with VE tables, MAF, etc etc) then it will surge if it is running too rich. If it is running lean you will get a lot of KR.

Do you have a custom tune? Has it always done this? Anything else change right around the time it started? How much boost are you seeing when it starts to surge? There are a lot of things it could be, the more info you give us the easier it will be to track down the problem. Try to give as much detail as you can remember.

02sierra - are you thinking that he might be maxing out the MAF? I can't see that happening under low RPM high load scenario, maybe at high RPM.

 

I'll watch for those things that you mentioned and post asap

thanks guys

 

As luck has it, the surging hasn't happened since posting this thread. I can say that it is usually at low rpm's, cruise not on. From watching vac/boost gauge this morning on the way to work, I would say that it happens right after vac drops from a level of around 20-22 inHg to 10, as I begin uphill. As uphill grade is being made it drops another 5-7 inHg, all of this involves no surging this morning however. Does not enter boost as long as I don't increase acceleration. When I do experience the surging though, as soon as I depress the accelerator, it jumps into boost and accels as hard as I want it to. I do have a tune from Willie @ DiabloSport using my Predator.

Thanks