Seeking injector help
 

Hello all,

I have a 1997 Miata I'm in the process of turning.
My plan is to do it in steps. Today I installed my intercooler, and my 700cc dw injectors.

The car will no longer run. It'll idle for maybe 7 seconds, then lean out and die. The rpm go down as the AFR go up....

I've gone into my ms2 and switched the req fuel to calculate for 700cc. All vacuum hoses checked. All fuel lines checked...

I'm at a loss.

There's a lot more to update than just req fuel

I thought req fuel would scale everything...
any input as to where to start?

I don't remember if it was MS2e or MS3 that they incorporated all those changes. (req fuel global applies to many of the others,etc.)

But you still need to update dead times, battery voltage offset, and injection timing if your unit/car is set up for that.


....to name a few.

And then there's the whole "large dw injectors suck on Miata's" thing so you'll probably need to re-shape your VE map too

As an FYI, I'm running a ms2e from reverent

Adjusted the deadline to 1.3ms.
still runs rough, but at least it idles.

Only thing is if I apply load, ie, lights and blower to 4, the idle dips to almost stalling the car, goes lean to 17, and 5 seconds later the idle stabilizes along with the AFR...

So confused.
I have attached a datalog where I'm idling and start rolling on the throttle. The car goes lean, and has a hard time idling up.

Is 1.3ms correct for those injectors or did you just guess? You will most likely need to retune the car even after changing your req fuel, as that recalculation is just to get you in the ballpark. New injectors are probably gonna have totally different characteristics than 20 year old injectors. I know when I switched mine over to FF640 my idle improved drastically after I retuned the car.

The deatschwerks website states 0.76 at 43psi and 13v.

Megasquirt assumes 13.2v on the deadtime screen.

The car will not even start at 0.76, so I brought the value up until it was able to idle at 14.5-14.7afr.

Even at 1.3ms, it'll still bump up to 15afr from time to time.

Use the measured dead time. And tune the car. Different injectors have different characteristics. Req_fuel is just to get you in the ballpark. I wouldn't use dead time to tune your idle. Instead tune the ve table.

New injectors will require using auto tune for the ve map once all the correct parameters are entered in most cases I have encountered.

Problem is that with the supplied data inputted into tunerstudio, the car will not start at all.

So after working on it most of the morning, I got it running at 0.76 deadtime as per deatschwerks website.
This meant I had to adjust injector sizing to 450cc instead of 700cc, which made a req'fuel of 6.9

The car will not catch or start with an injector size of 700cc, It can start with throttle on, but will run at 20afr..... I shut it off immediately once I saw those AFR.

Had to fatten my fuel map everywhere in order for the car to run, worked in my idle cells first.
Having a hard time getting it to run smoothly....

Here is a log file of it idling, in case some of you have input and would like a look.

thank you all in advance for any input you may have.

.

Thank you,
ive read the manual, even though my ms2e came premapped. I've learnt a lot over the past year when the car was na with stock Injectors and ms.

I think I've found my issue. There was a similiar thread where a deatschwerks employee cited to use 1.4ms deadtime at 700cc. It would therefore make sense that is currently working at .76 at 400cc.

I just need to retune my fuel maps accordingly.
That being, something still feels off with my startup and idle. That's the main reason I posted. As much knowledge as I may have acquired, I know there are some here that have vastly more know-how then I do.

.

So I have gotten it running normally, I've been fine tuning the fuel map all week still a few issues I didn't have before.

Upon startup, it won't keep running unless I give some gas, idle drops to 300-400 and afrs go up.

It won't follow my AFR targets, it's always above the 14.7, closer to 15.0-15.5 on accel until a few moments then it'll go back to 14.5-14.8.

When I let go of the gas, it'll go straight to 11 AFR, then overrun kicks in.

When I get on the gas, it'll go to 15/16 AFR for a half a second before cuing in to give gas.

I'm assuming the last error is due to an enrichment issue, or throttle tip in.

But I can't seem to identify the other problems...