Bf Zf - holding 1st

[BeerTurbo]

Ok Team, time to pick your brains.

I cannot for the life of me get my bf/zf/r31 to change out of 1st gear in D or P mode before 2k. This is lowest load possible it will always be above 2k before it shifts into second. then usually straight into 3 and maybe 4th.

In manual mode everything is fine.

ive done stupid stuff like change all the oss in 1st gear to 1, still stays in 1st.

 

I cant understand why it refuses to change as per the shift maps, is there some setting im overlooking, something that keeps it holding a gear?

[BeerTurbo]

did some data log and you can see it knows the oss to shift at, but goes way past it for first gear only.

it has up-shift prevention on.

is there a way to find out what :upshiftprevention its using to ask it why its active?

upshift prevention.teclog

[yoda598]

I had this issue in a converted gu patrol, I'll see if I still have the zf file so you can compare if you like. I don't remember how I sorted it as it was afew years back 😅

[Bill]

Has it always had the problem in the conversion? Have you tried returning the ZF to stock to see if it has the issue?

[BeerTurbo]

2 hours ago, yoda598 said:

I had this issue in a converted gu patrol, I'll see if I still have the zf file so you can compare if you like. I don't remember how I sorted it as it was afew years back 😅

if you dont mind, id like to see it yes

[BeerTurbo]

1 hour ago, Bill said:

Has it always had the problem in the conversion? Have you tried returning the ZF to stock to see if it has the issue?

Hi Bill,

the zf config is stock in the data log I posted.

i ran the conversion without a canbarra and it would drive in limp mode, with the canbarra its not in limp mode - but has allways held 1st.

I can zeros out 1st in the shift map and it will takeoff in second and shift like normally into other gears.

 

 

[Bill]

On 8/28/2021 at 9:27 AM, BeerTurbo said:

i ran the conversion without a canbarra and it would drive in limp mode, with the canbarra its not in limp mode - but has allways held 1st.

I can zeros out 1st in the shift map and it will takeoff in second and shift like normally into other gears.

When it was in limp mode, (without the CANBarra module), would it upshift to second at low RPM or shift straight from first to third?

Trans temps are only 43-44 degrees. Have you had it up to full operating temp to see if it's not being inhibited due to operating temp?

Also looking at another of your posts, you have changed speed/pulse out settings. Could this be causing your shift inhibit & changing from first to third?

[BeerTurbo]

11 minutes ago, Bill said:

When it was in limp mode, (without the CANBarra module), would it upshift to second at low RPM or shift straight from first to third?

Trans temps are only 43-44 degrees. Have you had it up to full operating temp to see if it's not being inhibited due to operating temp?

Also looking at another of your posts, you have changed speed/pulse out settings. Could this be causing your shift inhibit & changing from first to third?

hi bill this latest stuff is all with the zf config as stock.

limp mode was locked 3rd/or 4th its hard to tell with the 3.9 rear gear the car just moves even in the high gears... but it was locked to one of the higher gears.

log shows 1-3 shift but it does hit 2 its just not logging fast enough.

 

yeah temps been everywhere, still same.  its been running in car for last 8 months and im only now getting around to trying to fix it, because i could ignore it before but now its kinda annoying me.

Edited August 29, 2021 by BeerTurbo

[Bill]

20 minutes ago, BeerTurbo said:

limp mode was locked 3rd/or 4th its hard to tell with the 3.9 rear gear the car just moves even in the high gears... but it was locked to one of the higher gears.

log shows 1-3 shift but it does hit 2 its just not logging fast enough.

Yeah, I can see where the logged "torque source" changes from "driver demand" to "transmission shift" just after you back off in first & before the change to third.

I assume you have adjusted all the locations for axle ratio in the pcm tune to 3.9. There's another hidden in the ZF tune to try as well "ZF03985 Ratio of differential"

[BeerTurbo]

30 minutes ago, Bill said:

Yeah, I can see where the logged "torque source" changes from "driver demand" to "transmission shift" just after you back off in first & before the change to third.

I assume you have adjusted all the locations for axle ratio in the pcm tune to 3.9. There's another hidden in the ZF tune to try as well "ZF03985 Ratio of differential"

yes sir. got that one.

[Bill]

Whilst the log shows that in between the shift inhibit & change to third the torque source changes to transmission shift, it shows the gear commanded is never second gear.

Have you logged while sports shift is selected to see if the "shift inhibit" shows in the same place? Does it show second gear as commanded with manual upshift?

[BeerTurbo]

Allright that was a bit of a rollercoaster, but a big shoutout to everyone trying to help me in PM (Bill, Yoda, Nigel). Played with a lot of ZF settings that basically had no affect on the issue. 

 

The logs show the shift prevention active and eventually found the brake flag was doing the same thing as the ESP flag.

Originally tried to do silly things like reduce the max esp time and so such, but it didn't change anything. 

The car had no brake switch connected and it was turned off in the PCM. In forscacan the brake log actually shows as off... but the ZF seems to do its own thing, possibly in a brake light failure mode?

 

I stupidly tried to test the brake light, by turning it on and grounding out the wire and feeding it power - forscan just allways showed it on. Infact when the brake switch was turned on in the pcm forscan would allways show brake ON. that sorta wasted some time.

 

Nigel basically told me to wire up the brake switch correctly, as it will do sanity checks and expect Ground and +12 inputs. 

So after wiring in the nissan brake switch, forscan was still showing BOO:ON but the ZF log would mimic the brake pedal with the brake flag.

its worth noting here you cannot use the cruse control brake and brake switches tied together as they get reversed inputs and the cruse has a small dead zone - so you need to change to a falcon brake switch.

 

With the ZF seeing brake, the holding 1st gear issue was gone and it changed gears as expected.

 

 

 

 

 

[yoda598]

Good stuff. I'll have to remember this for future reference. 

[BeerTurbo]

Just now, yoda598 said:

Good stuff. I'll have to remember this for future reference. 

another good point for ZF conversions is the reverse lights, if you dont have them connected the trans selector will flash on the dash and presumably be in error mode, as it produces a TCM error code. 

P1910 or p1911 or p1912

 

trans has two wires for reverse lights, both connect to the activation point on the relay.
if your like me and were in a  rush, you can simply wire in a resistor and it will think its connected.

 

 

 

 

[Bill]

Thanks for updating us all. The info you’ve provided is very thorough & will no doubt save a few headaches for others 👍🏼