Thread: JWT ECU: Pulsing Idle Issues Solved

I've been running a JWT ECU on my SR20VE since 2005 -- it was the best option for me to get running at the time. One issue that I have not been able to resolve until now is described as follows:

1. Intermittently, and often on warm start up, the idle will cycle up to 1200 RPM, then down to 900, and up to 1200 again, maybe as many as 6 times before settling down. This is great stuff in a crowded parking lot or at anm emissions testing station.
2. At a stop, turning the steering wheel a little will cause the idle to increase to 1200 RPM.
   

Annoying stuff, but nothing that you can't live with. I asked JWT about it but never got it resolved.

Recently I was poking through some bin files in Tuner Pro and found that the JWT file has the following table set at all zeros: Idle Stabilization Timing Retard (B13 address: 04C8). The stock DE bin, as well as Calum's bins for B13s have the following data entered: 0, 2, 4, 6, 8, 10, 12, 12, instead of zeros.

I am now running a Calum ECU with a modified version of my original JWT bin, so I was able to change the data in the JWT bin to the stock DE values.

Making this change resolved the problem. Every once in a while even a blind squirrel finds a nut.

I fixed mine a while ago. I can't rem what I did tho, I think it was the cold idle timing. After I fudged with that it went away. Then I just did the same for my friends, I think I looked at a stock DE bin and put in the same values.

As Murphy's Law would have it, after testing the change that I described above for several days with no idle pulse problem, when I drove my car this morning for the first time after posting my "solution," the pulsing idle on start occurred again. The power steering part is still good, but I have NOT found a complete solution to the problem.

I will investigate other possibilities as suggested by BlueRB240. Thanks for the tip -- BTW do you have an address for "cold idle timing"? I do not see it in the xdr file I am using.

Bill - Have you tried messing with these tables?

0460 - Base idle timing in neutral
0470 - Base idle timing in gear
0500 - Timing when TPS = Closed

0500 is the temp modifier table. So take the timing in 0460 + the value depending on temp in 0500 to give you the total timing output. 0470 works the same way with 0500. May be worth messing around with, this was how I worked around my cold start hesitation.

I see some differences in these tables between my JWT-based tune and Calum's VE tune. The Calum-based tune does not do the idle-pulse, so I will investigate to see if I can accomplish anything by working with these tables.

Thank you for the suggestion.

Bill

great to see when ppl post that there issues have been resolved.... closure is a must when it comes forums like these.....confirmation is key

I was doing a few hours road tunning yesty/today tidying up my timing maps and load points, i took this into advice and halved all the values so 1,2,3,4,6,8,8 or similar and it has helped alot with the hunting in two days it has only done the hunt thing once and it was no where near as agressive as it used to be!

Well done i will keep reducing them until it subsides!

MY CAR DOES THE SAME. WHEN I START IT EVERY MORNING. IT IDLES RUFF LIKE 2000RPM AND IT STAYS THERE TILL SHE GETS WARM. ONCE SHE WARMS UP A LITTLE. THE IDLE GOES DOWN.BUT THEN SHE LIKES TO IDLE UP & DOWN., JUST LIKE U SAID. I HAVE A JWT ECU. BUT I HEARD ITS NORMAL WITH A JWT ECU.

I MAY USE A CALUM ECU IN NEAR FUTURE. TO SEE IF THE CAR CAN RUN BETTER.

Hey billc can you email me your bin and I'll take a look at the cold start vs the cold start on my bin. [email]Yellow4g63@yahoo.com[/email]

ok bill I compared yours to mine. The cold timing advance on mine was different take a look. I don't think it's soo much the number advanced just the duration of the timing might get rid of it.


purple is mine red is yours.