Idle Droop

[Bdubbz]

Anyone know of where to maybe start for fixing idle droop on a manual?

I have an 03 that will actually stall sometimes after coming off the exhaust brake.

Normal operation it droops to about 450-500 rpm before catching itself. So like coming to a stop sign for instance, push in the clutch and it almost stalls. If using the exh brake it will stall.

This started to happen after pulling back on the Inj PW to eliminate smoke off the line and after each shift on a manual. I'd hate to start adding more fuel because its still not that clean.

Anyone play with the no throttle fuel for like friction say? Or some other setting?

Thanks,

[sasdakota]

I would set pulse back to stock (assuming still factory injectors). And limit fuel by boost tables. also look at timing for that range (pilot and main or combo of both)

[Bdubbz]

Thanks for the tips. Injectors are 60 HP that's why I was cutting pw.

I've continued to play with the boost limiter, seems like that and the pw is the best way to reduce my smoke off line and after each shift.

I've changed the main timing quite a bit, but have not touched the pilot. What would I be looking for? Too much or too little? Would adding a little timing to the pilot help in this area?

[sasdakota]

Are they full injector sets or nozzles on your stock injectors?

Is the "smoke" thick and dark or more like a light grey haze?

Post up your tune I'll see if some points stick out to look for.

Either way, 60hp isn't a huge jump so pulse shouldn't need too much changes. Use qty limiters, run higher rail which uses less pulse width if low rpm/idle hazes, adjust timing to keep EGTs down at cruise slope off for low rpm high load to get the turbo spinning and ramp timing back up following your boost for power.

On your signature it says 351ve arduino. Does that mean you are controlling the vanes in 351ve? What does that map look like?

[Bdubbz]

Thanks again for the tips and help. Great info about the pressure and pw down low. I had really good results mid/high end with egts and cutting pw for my towing tune. I'm using the 04.5+ fuel pressure table smoothed over. Should probably start getting a little more aggressive down low with that, but if I remember correctly it starts getting a bit rattly.

60hp dragon fly nozzles.

Just got back from a 1200 mile trip with the camper. Runs great, 1250 max egt, not much coolant temp rise (maybe 5-10 degrees), good power but not the greatest fuel mileage. Seems like I'm about 14 mpg unloaded and 10-14 loaded. Not too bad for being loaded and going 75-80, but it could be a little better especially unloaded.

Yes controlling the vanes on the vgt. Map is the same as the hx super 40. Code is using rpm as a feedback.

The smoke is more of a grey haze. The black smoke down low has been mostly mitigated by modifying the boost table. After this trip it seems I could work on that a bit more. Obviously less smoke overall when closer to sea level.

[sasdakota]

Thanks again for the tips and help. Great info about the pressure and pw down low. I had really good results mid/high end with egts and cutting pw for my towing tune. I'm using the 04.5+ fuel pressure table smoothed over. Should probably start getting a little more aggressive down low with that, but if I remember correctly it starts getting a bit rattly.

60hp dragon fly nozzles.

Just got back from a 1200 mile trip with the camper. Runs great, 1250 max egt, not much coolant temp rise (maybe 5-10 degrees), good power but not the greatest fuel mileage. Seems like I'm about 14 mpg unloaded and 10-14 loaded. Not too bad for being loaded and going 75-80, but it could be a little better especially unloaded.

Yes controlling the vanes on the vgt. Map is the same as the hx super 40. Code is using rpm as a feedback.

The smoke is more of a grey haze. The black smoke down low has been mostly mitigated by modifying the boost table. After this trip it seems I could work on that a bit more. Obviously less smoke overall when closer to sea level.

I didn't pack my gear with me today I'll take a look later.

What boost are you seeing flat ground cruising at 60mph? Both towing and empty. And what is peak boost?

Is the arduino/code able to ask the actuator for current position? What I meant by map was the calibration's commanded vane position. The 351ve is not nearly as powerful up top as the 351cw brethren. All gases have to pass the turbine vs wastegate diverting the extra pressure. I know, I've got a 67/67 modified VGT on my 2010 and it does well but exhaust back pressure is CRAZY on the top end 3k+ with 0 vane.

Also, I just tuned an 03' cummins drivetrain with dragonfly 60hp injectors. I'll see if I can find some notes on that when I review yours'.

[Bdubbz]

Thank you very much, no rush.


Not 100% on your question though. So the arduino is a node on the canbus and I'm constantly linearly interpolating vein position based on RPM. So always slightly changing positions. I'm also monitoring the bus for the actuators commanded position, actual position and a few other irrelevant things. So, I know what I'm commanding and also that its getting there.

Flat ground boost is tough because I live at 7000 ft, so it is a bit different than sea level. On this recent trip in Oregon (~3000ft) was about 20-25 psig at 70mph and 1700rpm, 2000lb truck bed camper. And if I remember right maybe 10-15 same conditions unloaded, but at 7000ft. Max boost I see is around 35 psig and my back pressure from a gauge and a pressure sensor are just above that at around 40 psi at 7000 ft. I saw 40psig boost on this last trip at lower elevations and my back presssure at those rpms (around 125000) is always just above my boost. Looking at an arduino log from a little while ago, I see boost at 28, bp at 35, turbo rpm at 121258 and my command and actual position is at 465 or between 14 and 15 cm^2 and 7000ft.

Now, I can and sometimes do, open up the turbo more, but my egts will sky rocket and I puke the soot. Doesn't seem as though I can really open this turbo up without maybe making some bigger changes in the engine tune. If I manually run the turbo with my potentiometer mounted on the shifter and I try to open the turbo slowly manually my boost and back pressure will drop and egts will rise very quickly.

You mention crazy back pressure above 3k rpms and 0 position commanded.... whoa, there's your displacement difference. My lowest code command is 40, same as 0 really, at 25 cm^2 and I never get there, just not enough energy. I idle at 480 and quickly snap closed to between 760 and 815, depending if I'm towing or not, then slowly open it up and rarely will open more than 450. In fact, towing this last trip at 450 (~15cm^2) my max boost was ~30-35 along with my backpressure (uphill loaded here) and that will make the egts climb from 1250 to 1350 and there I put it back to 'auto' mode and boost goes up, back pressure goes up, egts come back to 1200. My backpressure is never higher than around 45 psi unless I'm using the exh brake function and then I manage it to 60psi and under, sometimes a quick spike to 80 then back down to 60 and less.