Ms2 and 800cc injectors
 

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?

are they low ohm injectors? had a few people run 690cc injectors and maybe one on 750s on MS-I without issues.

Req fuel at 8 sounds a bit large for 800cc injectors.
Are you running batch or sequential injection? I think you're going to want to look for closer to 13:1 at idle.

I have my 880s at 7.3 ms, minimum turn in time at 1.13 ms. my afrs are at 11.8-12.5 at idle, I can't get it leaner or it will be rough through the whole rev range

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.

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

Interesting...

http://img40.imagefra.me/img/img40/2...am_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 shits, 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.

Gianic, have you verified that all 4 injectors are firing?

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).

One of the injectors was stucked so I cleaned it on a ultra sonic machine. Since then it works fine. Can I somehow verify that all injectors are working via tunerstudio?

There are a few cells that will overflow (>255) if this is done. That may or may not be an issue.

Jean

Haha...those cells are at 300kPa too...I know your build is serious Gianic, but have you really seen 30psi yet?

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.

I tried many different combinations but nothing. It runs like shit. The weird thing is that I have wide open the idle screw and the idle is below 800rpm.
I am getting crazy with this shit. Sometimes I feel pretty nostalgic about my emb with the 8 injectors setup.

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. :eek:
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.

Of course not. That was the reason I got rid of emb and bought an ms2 with big injectors :jerkit: (this is me)

With a 5.9 Req_fuel my VE map is in the 35% are on 460s at idle...

Now you guys have me looking at my own stuff...

Here's my VE table:

http://img40.imagefra.me/img/img40/2...am_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.

you're running out of headroom at 230kPa, since you cant go over 255%. But it looks like that's untuned anyways.

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?

didn't Joe suggest a 4.0 Req_feul and no changes to your fuel map?

if you halved your Req_fuel and doubled your map, you resulted in no change.

Yes, the 230 row itself is the headroom. My normal maximum MAP is about 190 kPa, and I get onset spikes to 195-200 kPa. Overboost protection happens at something like 210 or so.

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?