Megasquirt Can't Rev Past 6000rpm Under Load
08-02-15, 12:01 AM
#1
Can't Rev Past 6000rpm Under Load
Hi,
After upgrading injectors and turbo, I am finally getting into tuning the higher kpa portion of the map.
I can seem to get the car to rev past 6000 rpm under load, no matter how much fuel I pull from that area of the map. It seems like a misfire or soft rev limiter, but I'm not getting any sync loss or cutout on the tach.
I just put in brand new colder NGK plugs with a much tighter gap hoping that would help. I've also turned my water meth on and off and saw zero difference. Wastegate spring is ~180kpa
Here is a brief run down of my setup:
MS2v3, 3.3.3 firmware.
FFE single VR trigger wheel kit
S5 TII block, stock port, 9.7:1 rotors.
1150cc/1600cc injectors, Walbro 400, Aeromotive FPR.
GT4088R turbo, Tial 46mm WG.
AEM progressive water meth ~ 500cc/min
NGK BR10EG plugs, brand new, 0.024" gap
Stock coils.
After upgrading injectors and turbo, I am finally getting into tuning the higher kpa portion of the map.
I can seem to get the car to rev past 6000 rpm under load, no matter how much fuel I pull from that area of the map. It seems like a misfire or soft rev limiter, but I'm not getting any sync loss or cutout on the tach.
I just put in brand new colder NGK plugs with a much tighter gap hoping that would help. I've also turned my water meth on and off and saw zero difference. Wastegate spring is ~180kpa
Here is a brief run down of my setup:
MS2v3, 3.3.3 firmware.
FFE single VR trigger wheel kit
S5 TII block, stock port, 9.7:1 rotors.
1150cc/1600cc injectors, Walbro 400, Aeromotive FPR.
GT4088R turbo, Tial 46mm WG.
AEM progressive water meth ~ 500cc/min
NGK BR10EG plugs, brand new, 0.024" gap
Stock coils.
08-02-15, 09:52 AM
#2
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
Can't see much wrong other than the TPS AE is too sensitive.
In the datalog you rev to 7000 RPM several times.
But I also see it hung up at around 6100 RPM. No evidence of misfire and AFRs were around 11:1.
Did the car work before the injector/turbo change?
In the datalog you rev to 7000 RPM several times.
But I also see it hung up at around 6100 RPM. No evidence of misfire and AFRs were around 11:1.
Did the car work before the injector/turbo change?
08-02-15, 12:38 PM
#3
Aaron,
I forgot to mention it, but the revs to 7000 were with the clutch disengaged to show that I can do so without a load. I had no problems revving past 6k before.
My current setup has the same intercooler, exhaust, and fuel system, minus the primary injectors. I switched from stock 550ccs to new Bosch 1150ccs.
I feel like I shouldn't have an almost 10VE drop in 500rpm at the same boost levels.
Here is a data log and tune from the car last fall with the old setup.
I forgot to mention it, but the revs to 7000 were with the clutch disengaged to show that I can do so without a load. I had no problems revving past 6k before.
My current setup has the same intercooler, exhaust, and fuel system, minus the primary injectors. I switched from stock 550ccs to new Bosch 1150ccs.
I feel like I shouldn't have an almost 10VE drop in 500rpm at the same boost levels.
Here is a data log and tune from the car last fall with the old setup.
08-03-15, 09:46 AM
#4
Engine, Not Motor
iTrader: (1)
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,789
Likes: 0
Received 108 Likes
on
91 Posts
So it's only under load that this happens.
About the only time I've seen such a thing is with an ignition failure (assuming not a tune issue, which it doesn't seem to be). The result was banging and popping at a certain RPM but only under load. Coil replaced, problem went away.
I also recall a similar problem in a friend's FD (w/FC coils) a few years ago. Leading wasn't firing so he was running trailings only. Ran nice around town, but into boost it hit a wall after a certain RPM.
About the only time I've seen such a thing is with an ignition failure (assuming not a tune issue, which it doesn't seem to be). The result was banging and popping at a certain RPM but only under load. Coil replaced, problem went away.
I also recall a similar problem in a friend's FD (w/FC coils) a few years ago. Leading wasn't firing so he was running trailings only. Ran nice around town, but into boost it hit a wall after a certain RPM.
08-03-15, 09:52 AM
#5
I swapped both leading and trailing coils with known working coils yesterday and the problem persists.
One thing I considered was the secondary staging. I am using tabled staging, but I'm a bit confused how it actually blends. Is the percentage value a split of the total req fuel between primary and secondary or a percentage of the secondary injector duty cycle relative to the primary? I had a pretty seamless transition for the secondaries before I changed my primaries injectors. Is this something that needs readdressed with a new primary injector size?
One thing I considered was the secondary staging. I am using tabled staging, but I'm a bit confused how it actually blends. Is the percentage value a split of the total req fuel between primary and secondary or a percentage of the secondary injector duty cycle relative to the primary? I had a pretty seamless transition for the secondaries before I changed my primaries injectors. Is this something that needs readdressed with a new primary injector size?
08-05-15, 06:02 PM
#6
I have a few more things I've tried, but nothing that worked.
I created a new tune from scratch. I did import tabels for VE, timing, ect from my most recent tune. I staered with a new project, not based on an older one. This made no difference.
Second thing I tried was reflashing firmware. Still no improvements.
I'm running out of ideas. This really seems like a rev limit at 6krpm. It feels like it pulls massive timing and falls on its face.
My rev limit is set at 8k and I don't have anything that should interfere at 6k. Could injector staging cause any of this? My secondaries come up to 100% at 5k, but 5-6k runs well.
I created a new tune from scratch. I did import tabels for VE, timing, ect from my most recent tune. I staered with a new project, not based on an older one. This made no difference.
Second thing I tried was reflashing firmware. Still no improvements.
I'm running out of ideas. This really seems like a rev limit at 6krpm. It feels like it pulls massive timing and falls on its face.
My rev limit is set at 8k and I don't have anything that should interfere at 6k. Could injector staging cause any of this? My secondaries come up to 100% at 5k, but 5-6k runs well.
Trending Topics
08-06-15, 06:27 AM
#8
I am using BR10EGs at the moment, gapped to ~.024".
I have tried a couple different sets of BUR9EQ stock trailing plugs.
I have tried Autolite AR3933X also.
I also tried a set of OEM plug wires instead of my Accel 8.5mm wires. Nothing seems to make it better.
It stick right at 6krpm
This is seeming less and less like a hardware issue. I just can't figure out which setting is causing the problem.
I have tried a couple different sets of BUR9EQ stock trailing plugs.
I have tried Autolite AR3933X also.
I also tried a set of OEM plug wires instead of my Accel 8.5mm wires. Nothing seems to make it better.
It stick right at 6krpm
This is seeming less and less like a hardware issue. I just can't figure out which setting is causing the problem.
08-06-15, 07:34 AM
#9
MegaSquirt Mod
Aaron, I forgot to mention it, but the revs to 7000 were with the clutch disengaged to show that I can do so without a load. I had no problems revving past 6k before. My current setup has the same intercooler, exhaust, and fuel system, minus the primary injectors. I switched from stock 550ccs to new Bosch 1150ccs. I feel like I shouldn't have an almost 10VE drop in 500rpm at the same boost levels. Here is a data log and tune from the car last fall with the old setup.
08-07-15, 11:59 AM
#12
At the advice of someone on msextra.com, I added dwell to both coils and it didn't seem to make any difference (3.5ms vs 3.0ms).
I did capture a composite log of 2 high rpm pulls to see if anything looks fishy. Frankly, I have no idea how to read composite logs, so any feedback would be greatly appreciated.
I've also attached my most recent tune and a datalog (logged during the composite log).
I also uploaded my VE and timing tables to an old known good map along with the proper req fuel numbers. Still no better.
Any input would be greatly appreciated
I did capture a composite log of 2 high rpm pulls to see if anything looks fishy. Frankly, I have no idea how to read composite logs, so any feedback would be greatly appreciated.
I've also attached my most recent tune and a datalog (logged during the composite log).
I also uploaded my VE and timing tables to an old known good map along with the proper req fuel numbers. Still no better.
Any input would be greatly appreciated
08-11-15, 01:02 PM
#13
MegaSquirt Mod
That composite log looks fine. At this point the only things that seem weird to me are 1) with your settings you can't have wired the VR+ to pin 24. It must be wired backwards, and 2) the 10k resistor should not be needed.
08-11-15, 01:20 PM
#17
MegaSquirt Mod
Yeah, I went in and calculated RPM, and I can see it getting to around 6200 RPM or so and the log looks fine. With the settings you're using it would only work if you wired the VR backwards... the resistor doesn't appear to be causing any kind of drop out on the signal.. so that really only leaves a tuning issue.
08-11-15, 01:25 PM
#18
Like too much fuel?
My AFRs in the higher rpm in lower gears are okay, pretty rich in 4-5th.
If I keep pulling VE at 6krpm/180kpa, I saw no difference. I went from a reasonable AFR at 5500rpm and ~124 VE to falling on its face at 6000rpm and ~114 VE!
That dropoff seems extreme to me, but maybe I need to keep plucking at it.
My AFRs in the higher rpm in lower gears are okay, pretty rich in 4-5th.
If I keep pulling VE at 6krpm/180kpa, I saw no difference. I went from a reasonable AFR at 5500rpm and ~124 VE to falling on its face at 6000rpm and ~114 VE!
That dropoff seems extreme to me, but maybe I need to keep plucking at it.
08-11-15, 02:40 PM
#20
I do have multiply AFR on. The note in TS says use caution and 99% of users use multiply.
I consider a reasonable AFR one that shows up on the gauge and not just 10.0000 where the 0-5v is pegged lol. Obviously that is rich, but I haven't had trouble lighting off low 10s before. Before meaning before this engine/injectors, ect.
Thanks,
Alex
08-11-15, 06:06 PM
#21
I pulled some more fuel out of the 6000rpm/180kpa area and still no better. One thing I thought about that I may not have mentioned before, but I did not readjust my secondary injector staging map. My secondaries stage to 100% at 5000rpm and 105kpa. Could my bigger primary injectors be causing the staging to be weird now?
08-12-15, 07:23 AM
#22
MegaSquirt Mod
I do have multiply AFR on. The note in TS says use caution and 99% of users use multiply. I consider a reasonable AFR one that shows up on the gauge and not just 10.0000 where the 0-5v is pegged lol. Obviously that is rich, but I haven't had trouble lighting off low 10s before. Before meaning before this engine/injectors, ect. Thanks, Alex
08-12-15, 07:23 AM
#23
MegaSquirt Mod
I pulled some more fuel out of the 6000rpm/180kpa area and still no better. One thing I thought about that I may not have mentioned before, but I did not readjust my secondary injector staging map. My secondaries stage to 100% at 5000rpm and 105kpa. Could my bigger primary injectors be causing the staging to be weird now?
08-12-15, 07:38 AM
#24
Yes, injectors sizes are correct and req. fuel has been scaled back to match my primary injectors.
Also, I can't seem to find where multiply AFR is an options. I set up most of the setting in TS per Aaron's writeup, minus the FFE-specific ignition stuff.
Also, I can't seem to find where multiply AFR is an options. I set up most of the setting in TS per Aaron's writeup, minus the FFE-specific ignition stuff.
08-12-15, 09:09 PM
#25
So I was able to get the car to rev a bit higher, but it required removing a LOT of fuel. I had to drop the VE table at 180kpa 24 pits from 5500 rpm to 6000rpm. I'm not exactly sure why. VE is still rough and needs even more fuel removed.I double checked and my injector sizes are correct, so this may or may not have to do with the secondary staging.
Thanks for all the help.
Below is my most recent tune and datalog showing the steep drop off in VE and revs past 6k
Thanks for all the help.
Below is my most recent tune and datalog showing the steep drop off in VE and revs past 6k
Last edited by Shainiac; 08-13-15 at 07:28 AM.
