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Thread: odd start issue..

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Posts: 1-10 of 22
2015-02-05 06:10:18
#1
odd start issue..
I had a look around and found thread with a similar issue regarding a start issue, but not the same.
The start issue is odd, first start of the day it starts perfect , however when it starts next time , hot or cold , I have to give it a touch of throttle maybe only 5%. 1 in 10 it does start fine. I am sure its a setting in Nismotronic as swapped to old ecu and all is fine. here is tcd
2015-02-05 15:30:18
#2
Sounds like a coolant temp sensor.

It could also be a bit of a boost leak or you need to work on cranking fuel trims and injector battery offsets in the lower voltages when your car is cranking.
2015-02-05 17:48:09
#3
Save a log from a cold start, and a log from a warm start (5% throttle). Upload them here.
2015-02-05 19:31:12
#4
Originally Posted by D-Unit121
Sounds like a coolant temp sensor.

It could also be a bit of a boost leak or you need to work on cranking fuel trims and injector battery offsets in the lower voltages when your car is cranking.


I think you are spot on with the temp sensor. But man, the cranking fuel trims and battery offset are so crucial to proper start up. It took me so long getting mine right when I switched to E85.
2015-02-05 22:54:08
#5
I don't think it's the sensor because when I swap back to old ecu, all starts fine. I will try to get the logs today.
2015-02-06 15:47:32
#6
Try resetting the "Cranking Injector Pulsewidth" table back to the stock values from the base tune TCD.
Last edited by OnTheChip on 2015-02-07 at 12-40-01.
2015-02-07 12:14:56
#7
Your cranking ignition table is 10 deg across the board.



Smaller engines with faster cranking speeds need a greater ignition advance (up to 20 degrees), while slower cranking speeds of a high compression engine will require less advance (down to 10 degrees). The compression ratio of the engine will also determine the likelihood of kickback on starting. Engines with a low static compression ratio of 8:1 will accept an ignition advance of anything from 0-20 degrees without kick-back. A 10:1 compression ratio will reduce this to 15 degrees, 11:1 to around 10-12 degrees, while race engines using very high compression ratios of 12-13:1 can sometimes tolerate no cranking ignition advance at all.


Maybe it will help to adjust this table to 15deg for a warm start (ECT above 40*C) if you're running a 10:1 compression ratio
2015-02-07 14:31:02
#8
only trouble is Dala that i don't think that its a temp issue, it does start on the very odd occasion hot also its a ve. what is your cranking ign set at?
I tried to log today but after fresh software install i forgot to set a log save path so I didn't get it. I will try again tomorrow and post them up. I think Its fuel /injector related , maybe too much?, as I could smell it when attempting the logs. looking into the other suggestions , thanks.
2015-02-08 14:00:52
#9
OK, ok, ok. I had this problem before. It actually gave me issues with off throttle decel too. This is a problem with the ecu not being able to see the throttle is closed>open. Take a look at your sensors setup section and click on tps. You will see a box that syas closed to open delta.

CLOSED TO OPEN DELTA - If the throttle is currently closed, the difference between the current TPS voltage (TPS Voltage on Data Screen) and the minimum_TPS_voltage must be greater than this to consider the throttle open.
These values determine the TPS voltage hysteresis between throttle open and throttle closed, to keep the ECU from switching rapidly back and forth between the two.

Now in my case, it was a mechanical issue that worn linkages, old parts.... cause the closed throttle voltage to change ever so slightly now and then. And as you can see with the delta range, it is a very small amount of voltage which relates to the tiniest amount of movement in the throttle.
2015-02-09 07:08:28
#10
OK ebinkerd,I will Look into that also.
I tried to get logs again today( haven't been able to check them yet) and it started 3 times successfully where normally it wouldn't. When I was attempting starting( I had the windows up this time, I could smell fuel. It wasn't chronic , but it was there.
I will post start logs soon.
Last edited by pedro666 on 2015-02-09 at 07-09-35.
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