I have the SERT and everything works great except for an occasional decel pop I get when I am running around 2700 rpms and drop down towards 2000 at either a down shift or when I roll off the throttle. The tuner has added fuel into the zero throttle positions in both the front and real cylinder and from what I understand has maxed out these values within the 1750 - 4000 range. He slowly incremented to the point of max and it has helped about 60 percent but it still occurs. Usually I am running right around 49 mph, downshift, roll off throttle and 'pop'. This also only appears to occur when the engine is hot and the weather is warm. Anyone have a suggestion to get rid of this last bit of annoyance?



Running Big Sucker, Rhinehart true duals - no other mods

 

You are not alone...

 

I'm guessing you should look for an exhaust leak, when you say maxed out, you mean he raised ve's in the zero throttle position all the way to 127.5?, never heard of anyone having to go that far. Has he worked on the Decel enleanment tables?, or ignition timing perhaps?

 

No exhaust leaks that I can find. He has not adjusted any other tables other than ve tables during the last few times I brought it back in.

 

You might want to mention the decel enleanment table to your tuner. It's main purpose is to eliminate decel popping.

 

What should I recommend him try?

 

You would decrement the enleanment to make it richer. The table is temperature based, so change it in the range where you're having the problem...probably 96-128*C.

 

Here is a dumb question but
If I got a set of cables, can I pull off what is on the SERT currently - make adjustments to the enleanment tables and put it back on the ECM without having to keep going back to the tuner?

 

No, you can't upload the map that's in the ECM. You're going to have to get a copy of the map that's in your ECM from your tuner,modify it and reprogram the ECM. Good idea to get the cables and copy of the map, though. Very easy to do stuff like this yourself.
FWIW, I've had a very minor pop on mine when it's warmed up. Last night I decremented the decel enleanment 2 units from 96-160*C and on the ride to work this morning it seems to have fixed it.
Make small changes until you see which way you're headed. Make too big a change and you could go from too lean to too rich and have the same symptoms. I made that mistake with cranking fuel. I had hard starting when warmed up and assumed it needed more fuel because the manual says that's almost always the case. I added too much and still had hard starting, but now with black smoke. I'm backing it down now and starting to home in on it.
BTW, decel popping can be caused by too rich also so you may have to increment the enleanment. I'd try decrementing first, though.

 

I believe I have the map before the 0 throttle position was maxed. Wondering if it would be good to just start with that and work with the enleanment tables only and see if that helps.