Hi,
At risk of sounding completely ignorant on the subject, from what i understand with the feature pack the TIM should be the main (if not only) value that should change for a resize injector operation.
I've got a 1986 300zx Z31 Turbo (VG30ET) and I'm going from the stock 260cc injectors to 650cc injectors. After downloading the maps from the ECU i do a resize injector operation. Leaving the options default i enter 260 as the current size and enter 650 as the new size, it changes the TIM to 411. I adjust the injector latency to 868us as per the specifications, burn the maps to the ECU, and when i turn the engine over it sputters for at most 3 seconds. In that time a tremendous amount of unburnt fuel is passed through the exhaust to the point that there is a puddle forming underneath the car.
This is the kind of behavior that i would expect if no changes were actually being applied to the ECU, however i have every indication that my changes are indeed being stored correctly. I can connect to the ECU, download the maps and confirm that the changes have been applied. After each change Nistune confirms each memory address that is updated successfully.
Changing the injector latency higher or lower seems has no effect, and setting the TIM to lower values seems to have no effect.
My question is; have i missed something obvious, and what other area should i be looking into to adjust for this resize operation.
N00b question about resizing injectors
Moderator: Matt
Re: N00b question about resizing injectors
Resizing the injectors changes a few things
For 260 to 650 it would do the calculation TIM (default) = 512 * 260/650 = 204. So this is double what I would expect, unless MAF was also changed (are you using the stock MAF)
Change your TIM to 204
Also check your Crank Enrich table and see what 'ms' this is set to. About 3-4ms is expected above 60degC (top half of the table)
Only resize injectors once, otherwise it will keep adjusting those tables
For 260 to 650 it would do the calculation TIM (default) = 512 * 260/650 = 204. So this is double what I would expect, unless MAF was also changed (are you using the stock MAF)
Change your TIM to 204
Also check your Crank Enrich table and see what 'ms' this is set to. About 3-4ms is expected above 60degC (top half of the table)
Only resize injectors once, otherwise it will keep adjusting those tables
Re: N00b question about resizing injectors
Hi Matt,
Thank you for your help. For some reason the TIM value before resizing was 1024 but using a value of 204 looks pretty spot on.
The main issue it turns out i was having was that i had plugged the wire harness in incorrectly. On the Z31 there are 7 parts that use the jetronic connector type, 6 are the injectors and 1 is a throttle body bypass valve thing to assist with cold starting or whatever. What was happening is that 5 of the injectors were working fine, which is why the engine would run at all, but 1 injector was basically stuck open which explains the massive rush of unburnt fuel. After realising my mistake and plugging everything in correctly the engine is now working just fine.
Thank you for your help. For some reason the TIM value before resizing was 1024 but using a value of 204 looks pretty spot on.
The main issue it turns out i was having was that i had plugged the wire harness in incorrectly. On the Z31 there are 7 parts that use the jetronic connector type, 6 are the injectors and 1 is a throttle body bypass valve thing to assist with cold starting or whatever. What was happening is that 5 of the injectors were working fine, which is why the engine would run at all, but 1 injector was basically stuck open which explains the massive rush of unburnt fuel. After realising my mistake and plugging everything in correctly the engine is now working just fine.