Thread: JWT ECU: Pulsing Idle Issues Solved

The cold start and hesitation problem come from Nissan warm up procedure. It's engine temperature base, when the engine is below 149F/65C, it gets additional fuel and reduce timing to help warm up the engine. The timing stays static at 15 degree below 3k rpm.

The hunting/pulsing result from the transition period between warm up and the normal map that you see with maptrace. Right around 149F the engine jump back and forth between the two map. The engine hunts because the timing goes from 15 to what ever the timing is in the main map and back again.

My solution was to lower the temperature of the off warm up temperature to 95F and reduce the cold start enrichment. Since our ecu is DE based for 259cc injectors, we have to reduce the cold start enrichment otherwise there is overfueling, and that result in a sluggish running cold engine.

Thanks for taking the time to do this. Which table(s) are you working with? I cannot find a table with values that look like these -- maybe I have an XDF issue.

Bill

I use nistune not tuner pro. Its the cold timing advance. I also looked at cold start enrichment and yours was also higher than mine. My bin is from the calum base ve bin so that might be the diff right there. I just tweeked the timing and it got rid of that cold drive problem all together.

I'm having a hard time getting zoned in on this one. I have the following tables that might be involved:

- 0980-Timing Retard Cold Start -- this is TP vs. some function of timing
- 0990-Timing Retard Mulitplier -- this is RPM vs. some functionof timing
- 04F0-Timing 2? -- Temperature vs. Timing -- the values run 0,0,2,4,6,8,10,10,10,10,10,10,10,10,10,10 sa temps run from -40 to 110*C, leveling off at 10 at 20*C.

So, the only one that involves timing and temperature is the last one, and the values are different than the ones in your graph.

Can you help me make sense out of this?

Thanks.

I can't see what the address are that are on the nistune screen. See if this helps any.

i got a couple bins from bluerb240 a few days ago and i adjusted those maps and my hunting and decreased a bunch. thanks man.

where on tunerpro would i adjust the off warm up temp?

This is outstanding info guys. I've been having idle issues since installing my jwt ecu and other small mods and now I'm a bit more prepared when I go to attack the problem.

Thanks

OK, BlueRB240 was nice enough to mod my bin and send it back to me so I could find the change in TunerPro and work from there. The field that we are talking about here for a B13 bin is in address 04A0 which is labeled Timing Advance Normal in my xdr file. It's a table of timing advance against *C. I'm not sure how it relates to base timing -- probably adds these values to the base (15*) for the respective coolant temps? But it's definitely the data in the chart in Post #10 of this thread. The original tune (that pulses) has the gradual decrease, the BlueRB240 tune is more of a step function.

I will test and report back.

Bill

thanks bill and blue i'm gonna add this change too.

very good info .. Resurrection