Ms2 and 800cc injectors
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Hello,
I've changed my injectors to 800cc and was hoping that ms could manage them well. But I have some problems.
My req fuel is at 8ms and pw at idling is 2.1ms. My afr there is 14.7.
The idle is pretty rough and so does the free revving at neutral. The car is undrivable.
I tried to run it richer at higher pw's but the same "roughness" occurs.
Any thoughts?
I've changed my injectors to 800cc and was hoping that ms could manage them well. But I have some problems.
My req fuel is at 8ms and pw at idling is 2.1ms. My afr there is 14.7.
The idle is pretty rough and so does the free revving at neutral. The car is undrivable.
I tried to run it richer at higher pw's but the same "roughness" occurs.
Any thoughts?
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A bit large? No kidding. I'm running 3.5ms with 456cc injectors.
Granted, I am cheating a little on the VE table. I chose 3.5 because the native HR resolution is 35 µs (1/100th of 3.5ms), so this way every increment of 1 in the VE table causes an increment of exactly 1 in the final calculation (no rounding), but still, 8ms sounds way high.
Let's have a copy of your .MSQ, gianic. I want to look at your VE table.
Granted, I am cheating a little on the VE table. I chose 3.5 because the native HR resolution is 35 µs (1/100th of 3.5ms), so this way every increment of 1 in the VE table causes an increment of exactly 1 in the final calculation (no rounding), but still, 8ms sounds way high.
Let's have a copy of your .MSQ, gianic. I want to look at your VE table.
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Yes I'm running sequential. The injectors are high ohm.
Also here are some specs of them:
Flow Rate: 800cc/min at 43.5 PSI (3 BAR)
Flow Rate: 850cc/min at 49 PSI (3-1/2 BAR)
Flow Rate: 925cc/min at 58 PSI (4 BAR)
Resistance: 12-16 Ohms
Voltage: 8-15 Volts, Nominal 13.5 Volts
Amperage: 1.0 Amps
Pressure: Min. 36 PSI (2.5 bar), Max. 95 PSI (6.5 BAR)
Fuel Nozzle: 6-hole for multi-valve engine
Excellent fuel atomization
Low end pulse width excellent compensation to within 2% down to 2ms.
My fuel pressure is the stock one at 60 psi. (returnless system)
Here is my msq: MEGAUPLOAD - The leading online storage and file delivery service
Also here are some specs of them:
Flow Rate: 800cc/min at 43.5 PSI (3 BAR)
Flow Rate: 850cc/min at 49 PSI (3-1/2 BAR)
Flow Rate: 925cc/min at 58 PSI (4 BAR)
Resistance: 12-16 Ohms
Voltage: 8-15 Volts, Nominal 13.5 Volts
Amperage: 1.0 Amps
Pressure: Min. 36 PSI (2.5 bar), Max. 95 PSI (6.5 BAR)
Fuel Nozzle: 6-hole for multi-valve engine
Excellent fuel atomization
Low end pulse width excellent compensation to within 2% down to 2ms.
My fuel pressure is the stock one at 60 psi. (returnless system)
Here is my msq: MEGAUPLOAD - The leading online storage and file delivery service
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Interesting...
![](http://img40.imagefra.me/img/img40/2/3/25/thraddax/f_wam_ddad8d5.gif)
The numbers in your VE table are about half what I'd expect, except that I'd expect it to be that way given that your Req_Fuel number is slightly more than double what I'd expect.
Clear as mud?
For one thing, it means that every step that gEGO takes is going to have twice the effect it normally would.
Just for *****, try reducing your Req_Fuel to 4, and multiplying your whole VE table by a factor of 2. (Hit the * button at the top, and enter 2 into the dialog.) See if that has any effect at all on driveability and idle quality.
And yeah, you should probably have your AFR target set a little richer in idle. Try 13 for the moment. 800cc injectors are big even for an MS2, and more so since they're hi-z.
![](http://img40.imagefra.me/img/img40/2/3/25/thraddax/f_wam_ddad8d5.gif)
The numbers in your VE table are about half what I'd expect, except that I'd expect it to be that way given that your Req_Fuel number is slightly more than double what I'd expect.
Clear as mud?
For one thing, it means that every step that gEGO takes is going to have twice the effect it normally would.
Just for *****, try reducing your Req_Fuel to 4, and multiplying your whole VE table by a factor of 2. (Hit the * button at the top, and enter 2 into the dialog.) See if that has any effect at all on driveability and idle quality.
And yeah, you should probably have your AFR target set a little richer in idle. Try 13 for the moment. 800cc injectors are big even for an MS2, and more so since they're hi-z.
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Just for *****, try reducing your Req_Fuel to 4, and multiplying your whole VE table by a factor of 2. (Hit the * button at the top, and enter 2 into the dialog.) See if that has any effect at all on driveability and idle quality.
And yeah, you should probably have your AFR target set a little richer in idle. Try 13 for the moment. 800cc injectors are big even for an MS2, and more so since they're hi-z.
And yeah, you should probably have your AFR target set a little richer in idle. Try 13 for the moment. 800cc injectors are big even for an MS2, and more so since they're hi-z.
I would expect the values in those VE bins to be roughly appropriate with a Req_Fuel of 3.8 (which would be proper for injectors at that flow rate and pressure).
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The cells that overflow actually "wrap around" throwing in really low numbers, making them easy to spot and you can manually plop in 255. If datalogs keep bumping them up then the ReqFuel will have to be upped, but if not they will lean down properly.
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I tried many different combinations but nothing. It runs like ****. The weird thing is that I have wide open the idle screw and the idle is below 800rpm.
I am getting crazy with this ****. Sometimes I feel pretty nostalgic about my emb with the 8 injectors setup.
I am getting crazy with this ****. Sometimes I feel pretty nostalgic about my emb with the 8 injectors setup.
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Try the injector test mode to see if each injector has a connection to the ECU.
Those injectors are also huge... We're talking 90lbs/hr at operating fuel pressure... That's 600+ whp worth of fuel on gas.![](https://www.miataturbo.net/images/smilies/eek.gif)
Not to mention they're high Z...
Your Req_Fuel needs to be around 3.8, and you need to get your basic settings nailed in. From there, the wideband will help you get it tuned.
Those injectors are also huge... We're talking 90lbs/hr at operating fuel pressure... That's 600+ whp worth of fuel on gas.
![](https://www.miataturbo.net/images/smilies/eek.gif)
Not to mention they're high Z...
Your Req_Fuel needs to be around 3.8, and you need to get your basic settings nailed in. From there, the wideband will help you get it tuned.
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Now you guys have me looking at my own stuff...
Here's my VE table:
![](http://img40.imagefra.me/img/img40/2/3/25/thraddax/f_wam_d3f7fce.gif)
This is for Req_Fuel = 3.5 on 465cc injectors. As I mentioned before, this is a bit of cheat, but we're all capable of doing basic math so I trust nobody will get too confused.
If I were to double my injector flowrate (and gianic's injectors should, in fact, be flowing about 2x mine given his fuel system) then I'd halve my VE values for 3.5 ms, and slightly more than halve them again if I were running 8ms.
IOW, if gianic sets his Req_Fuel to about 4 (or 3.8, or whatever) then yeah, it looks like the table he's got might actually be close to accurate as Ben said.
Here's my VE table:
![](http://img40.imagefra.me/img/img40/2/3/25/thraddax/f_wam_d3f7fce.gif)
This is for Req_Fuel = 3.5 on 465cc injectors. As I mentioned before, this is a bit of cheat, but we're all capable of doing basic math so I trust nobody will get too confused.
If I were to double my injector flowrate (and gianic's injectors should, in fact, be flowing about 2x mine given his fuel system) then I'd halve my VE values for 3.5 ms, and slightly more than halve them again if I were running 8ms.
IOW, if gianic sets his Req_Fuel to about 4 (or 3.8, or whatever) then yeah, it looks like the table he's got might actually be close to accurate as Ben said.
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I tried what Joe said, the 4ms req fuel with the new ve table(x2) but nothing changed.
Free revving in neutral is like running on 3 cylinders , very roough.
Should I try lowering my fuel pressure?
Free revving in neutral is like running on 3 cylinders , very roough.
Should I try lowering my fuel pressure?
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That was my first suggestion, but after careful consideration (and reading Ben's posts) I changed my suggestion halving Req_Fuel and leaving VE alone.
gianic, isn't your gEGO just having to go nuts trying to make your original map work?