Hi
Timing in my car is retarded way too much in light throttle conditions when the engine is still cold.
This was also a long time before I installed Nistune.
I believe many people have that issue with Nissan cars and I wonder if somebody knows a reason for this.
There are separate tables for timing/fuelling etc. when the engine is cold AFAIK, but I don't really think this is related to bad mapping from Nissan. A car that does this when new will be given to a mechanic for inspection.
I attached a log, notice how timing gets normal once engine temp reaches 65°C. From there the car runs fine.
Euro CA18DET by the way
Cheers
Christian
Bogging when engine is cold
Moderator: Matt
Bogging when engine is cold
- Attachments
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- NIStune_2009-04-26_1854_16.csv
- (212.1 KiB) Downloaded 252 times
this is known issue of MEC D0007 ECU and is described over here....
what I did found is that timing retard is certain amount from idle timing. If you have standard 15deg idle timing, it will retard it to about 5deg, what is almost impossible to drive...but try to raise idle timing to let say 25deg and you will find that cold retard will go to more reasonable values, let say around 15deg...
another possibility is to use different base image than MEC D0007...
what I did found is that timing retard is certain amount from idle timing. If you have standard 15deg idle timing, it will retard it to about 5deg, what is almost impossible to drive...but try to raise idle timing to let say 25deg and you will find that cold retard will go to more reasonable values, let say around 15deg...
another possibility is to use different base image than MEC D0007...
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Legionnaire
- Posts: 125
- Joined: Fri Oct 03, 2008 5:45 am
- Location: Moscow, CFD, Russia
As far as i know, retarded timing during engine warm up cycle is not a "bad example of engine mapping", it is used as a common practice by auto manufacturers.
Retarded timing (as well as really enriched fuelling) on cold start achieves two main goals:
1)Less heat is trapped in combustion chambers, more heat leaves with exhaust (for the same cam phasing). Hotter exhaust gases have more intensive heat exchange with engine water jacket, reducing the time required to warm up.
2)Less timing produces less torque, preventing your attempts to go all out on the throttle when engine is not warm enough
More modern cars with more sophisticated engine management systems even change cam phasing, adjust rev limiters and limit boost on warm up cycles. They also achieve additional goal - hotter EGTs help warming up catalytic converters, improving cold start emissions, that allows to reach Euro4 and higher ecology standards.
Examples of the above are audi RS4, BMW M3 E92, M5 E60, 335i and a lot of other cars. With M5 you can easily hear how its unique V10 exhaust note changes while engine is brought up to operating temperature - when I first heard it starting cold, I thought it was something wrong with the engine. 10 minutes later though it was normal silent BMW.
Cheers, Petros
Retarded timing (as well as really enriched fuelling) on cold start achieves two main goals:
1)Less heat is trapped in combustion chambers, more heat leaves with exhaust (for the same cam phasing). Hotter exhaust gases have more intensive heat exchange with engine water jacket, reducing the time required to warm up.
2)Less timing produces less torque, preventing your attempts to go all out on the throttle when engine is not warm enough
More modern cars with more sophisticated engine management systems even change cam phasing, adjust rev limiters and limit boost on warm up cycles. They also achieve additional goal - hotter EGTs help warming up catalytic converters, improving cold start emissions, that allows to reach Euro4 and higher ecology standards.
Examples of the above are audi RS4, BMW M3 E92, M5 E60, 335i and a lot of other cars. With M5 you can easily hear how its unique V10 exhaust note changes while engine is brought up to operating temperature - when I first heard it starting cold, I thought it was something wrong with the engine. 10 minutes later though it was normal silent BMW.
Cheers, Petros
Cheers,
Petros Katunian
Petros Katunian
raddy (I think we have had contact over sxoc.com a few years back??)
So you think this really is a bug in the Nissan firmware?!?
I can't remember the car doing this when I got it 11 years ago. But my memory could be a bit diluted after this time...
Maybe engine breathing mods (eg. exhaust, intake, CA16DE cam) have made the ECU reach columns where it doesn't go from stock...
legionnaire
True. Retarded timing leads to higher exhaust temp.
But the car should stay driveable IMHO. Mine starts hesitating and "jumping" a bit on light throttle. When pressing the pedal harder the hesitation goes away.
It would be cool if warmup tables could be implemented into Nistune so this can be resolved
Cheers
Christian
So you think this really is a bug in the Nissan firmware?!?
I can't remember the car doing this when I got it 11 years ago. But my memory could be a bit diluted after this time...
Maybe engine breathing mods (eg. exhaust, intake, CA16DE cam) have made the ECU reach columns where it doesn't go from stock...
legionnaire
True. Retarded timing leads to higher exhaust temp.
But the car should stay driveable IMHO. Mine starts hesitating and "jumping" a bit on light throttle. When pressing the pedal harder the hesitation goes away.
It would be cool if warmup tables could be implemented into Nistune so this can be resolved
Cheers
Christian
Warmup tables have been implemented and documented in the mapping guide ... but not for all engines at this time
HCR32 was the test case since Speedlab here had pulled apart the code and I did a test run through it with a logic analyser on the bench. BNR32 was the next and I think might have done Z32 also
The warmup timing table is dependent on RPM, TP and of course temperature. I'm sure there is a simlar table in S13 CA18, Z31 VG30 and others which have reported this issue. I can look into that this week and see if I can update the address files for these
HCR32 was the test case since Speedlab here had pulled apart the code and I did a test run through it with a logic analyser on the bench. BNR32 was the next and I think might have done Z32 also
The warmup timing table is dependent on RPM, TP and of course temperature. I'm sure there is a simlar table in S13 CA18, Z31 VG30 and others which have reported this issue. I can look into that this week and see if I can update the address files for these
Christian, as was mentioned, this is not a bug, but normal feature, but most probably becouse of engine mods it become more visible compared with standard car, Matts idea with larger injectors sounds very possible also...
Until Matt add these tables to address file, just try my way, increase idle timing and you should be ok than during warmup, as timing will be retarded to more reasonable value, it works for me....
Until Matt add these tables to address file, just try my way, increase idle timing and you should be ok than during warmup, as timing will be retarded to more reasonable value, it works for me....
Same thing for my ecu: I have a 70J10 ecu in my P10
Some time ago i emailed with Pete about this issue.
Ive tried a new updated address file he gave me, it gave me access to some new maps.
The "Idle/Decel RPM Gear Timing" map seems to be the problem. At default it says 10 deg from 1400 till 3000 rpm (3000 is the last column)
If I change those values to for example 20 deg the engine reacts accordingly, consult then shows 20 deg fixed/stuck timing till 3K rpm.
@ 70'C it still switches over to the regular timing maps. It just completely ignores main timing map IF coolant temp is below 70 AND rpm is below 3000.
I have no clue what "Idle/Decel RPM Gear Timing" map normally does, cause I changed all values above 1400 rpm to 20deg to make the car driveable again at low temps.
Some time ago i emailed with Pete about this issue.
Ive tried a new updated address file he gave me, it gave me access to some new maps.
The "Idle/Decel RPM Gear Timing" map seems to be the problem. At default it says 10 deg from 1400 till 3000 rpm (3000 is the last column)
If I change those values to for example 20 deg the engine reacts accordingly, consult then shows 20 deg fixed/stuck timing till 3K rpm.
@ 70'C it still switches over to the regular timing maps. It just completely ignores main timing map IF coolant temp is below 70 AND rpm is below 3000.
I have no clue what "Idle/Decel RPM Gear Timing" map normally does, cause I changed all values above 1400 rpm to 20deg to make the car driveable again at low temps.
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Mr.sentra_specv
- Posts: 9
- Joined: Wed Jun 17, 2009 12:37 pm
if you look at most non us model sr20 powerd cars they all run low timing up untill 2000 rpms in those maps and then ramp it up from there. i have changed mine in my 20ve to run from 20-30deg and it eliminated my car from pulling timing to 5deg on cold running and does not affect the warm running of the car at all.
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Nissanclubman
- Posts: 27
- Joined: Sat Jun 20, 2009 11:40 pm
- Location: Gold Coast
I also have the exact same symptoms with my CA18DET and have been chasing the solution for over 6 months. I have confirmed it is temp related by fudging the input signal of the engine temp sensor and the 10 deg retarding immediately disappeared. However the elusive address where the cold start map is stored has been difficult to track down.
I am a Newbe to the NisTune products but love what you have done. I have however been tuning the CA ECU for many years. Unfortunately I haven’t yet taken the “Nistune” plunge but in light of what I have seen with your products my time of burning EPROM’s is soon coming to an abrupt end…thankfully.
In my travels while chasing other threads to solve this issue, there appears to be a lot of people who have given up and are just putting up with the issue. They seem to be both CA and SR owners and from what I can gather have modified their engine setup in some way. So the engine setup is no longer factory standard yet some ECU’s are and some aren’t. My guess is that those that aren’t and still have the issue haven’t correctly adjusted the cold start ignition timing map. The common issue however is the affect of the engine mods during cold starting on a factory ECU.
This all seems to fit nicely with what you have discovered and I’d like to try adjusting the “Idle/Decel RPM Gear Timing" map. Is there an address file for the CA18DET JDM that has the address details for the map? If not can anyone direct me to the ECU address location?
I am a Newbe to the NisTune products but love what you have done. I have however been tuning the CA ECU for many years. Unfortunately I haven’t yet taken the “Nistune” plunge but in light of what I have seen with your products my time of burning EPROM’s is soon coming to an abrupt end…thankfully.
In my travels while chasing other threads to solve this issue, there appears to be a lot of people who have given up and are just putting up with the issue. They seem to be both CA and SR owners and from what I can gather have modified their engine setup in some way. So the engine setup is no longer factory standard yet some ECU’s are and some aren’t. My guess is that those that aren’t and still have the issue haven’t correctly adjusted the cold start ignition timing map. The common issue however is the affect of the engine mods during cold starting on a factory ECU.
This all seems to fit nicely with what you have discovered and I’d like to try adjusting the “Idle/Decel RPM Gear Timing" map. Is there an address file for the CA18DET JDM that has the address details for the map? If not can anyone direct me to the ECU address location?
I've started investigating the issue with the R32 RB20 and have got the maps and constants together so we have this one sorted (and documented in our mapping guide)
Its on my investigate list (added recently) for other ECUs so I'm going to have a look into it for CA18, SR20 etc when I get time. I have a few days up my sleve to investigate so see what I can find
Its on my investigate list (added recently) for other ECUs so I'm going to have a look into it for CA18, SR20 etc when I get time. I have a few days up my sleve to investigate so see what I can find