Stuttering/DSMLink/FIC 750s

spooln4fun · 03-17-2008, 04:11 PM

I just installed a walbro 190, 750cc injectors, and put my eprom in with dsmlink installed and set to 750 cc injectors. and new ngk plugs(bpr6es gapped at .28)

I get a terrible stuttering problem, and hesitation during idle, and any type of throttle

at first i was getting a cylinder misfire #2 come to find out my injector was leaking, fixed that but the problem is still occuring.

Anytype of suggestions I would like to drive my car

Maybe new plug wires?

1992awdlaser · 03-17-2008, 05:15 PM

Can you post a log on dsmlink forums and give me your username? Did you tune your fuel trims? Did you do a boost leak test and fix all boost leaks?

turboglenn · 03-17-2008, 05:24 PM

DO you have a wideband? It's most likely pig rich, but you'll need a WB to know for sure as it could be really lean and missing too. I'm not sure on the amount of DSMlink customers who were able to just put their's in and drive, but most of the time in tuning what works on one car will barely start the same exact setup on a different motor. This is because each motor requires slightly different fuel and spark setting, and since you're dealing with things that are measured in milliseconds, the slightest bit of "out of adjustment" makes a big difference.

Try and borrow a ideband if you don't have one, let us know what you see

spooln4fun · 03-18-2008, 07:44 AM

1992awdlaser-I have not got on the link forums yet, I have not messed with any setting wtih dsmlink yet either. Boost leak test done checked OK.

Turboglenn- I have a wideband but its not installed.

I always though you could "plug and play" but I read both your post, then buried my head in the fuel section of the dsmlink manual to only find out i need to reset my global fuel setting. the 2-3 second log i was able to get it showd my a/f ratio of 18:1 which i know is pig rich. I will be doing the calculation and changing my global fuel setting today to see if that helps( i belive it will)

As for the wideband, since its a 2g it can just be threaded right in to the rear o2 sensors place correct?

Thank you guys for your input, and sorry for my ignorance in reading the manual

1992awdlaser · 03-18-2008, 07:58 AM

18:1 would be lean not rich. 18 parts air for each part fuel. Your deadtime should be set at 315 and global should be -40%. When you hook up dsmlink to the car and open it hit F4 and left click on air/fuel once. Then click on props and input the proper injector settings. That will bring your air/fuel estimate closer to what it should be. But don't go by that, install your wideband immediately and use that. The air/fuel estimate is going to be different then what yours actually is because it is just that, an estimate.

spooln4fun · 03-18-2008, 08:14 AM

Will do, will be heading overto the garage shortly to try and put this in where my rear o2 is.

my username for link forums is spooln4fun

1992awdlaser · 03-18-2008, 08:27 AM

I made it sound like hitting F4 and going under props is how to compensate for larger injectors. All that does is get the air/fuel estimate closer to what it actually is. To input your deadtime and global to compensate for the larger injectors Hit F6 and you will be able to input the settings on the side of a box that pops up.

spooln4fun · 03-18-2008, 03:08 PM

I did hit f4 and set my injectors to 750, then i went to the fuel tab(f6) set global to -40%, and dead time to 315. which brough my a/f ratio down to aroun 11 to 1, now that is only a estimate as i read from your previous post. the wideband is in, but i need to hook up the red, black, blue, and another color wire which i have a link to on here.

The car is still suttering under any throttle response, and i also have not messed with the fuel trims(nto sure where they are at)

1992awdlaser · 03-18-2008, 03:27 PM

Yeah, Dsmlink just shows an estimate. Take a look at this site for the fuel trims.
http://jeffgst.com/gmafcalibration2.html

The guy that runs that site is a member on here and dsmlink forums (jeffgst). He is a well known and trusted guy on Dsmlink forums.

spooln4fun · 03-18-2008, 07:27 PM

So after a small test drive today, i pulled it back in the garage, and low and behold that injector is leaking again. Going to swap back the stock injectors tomorrow to see if that cures this "stuttering".

spooln4fun · 03-19-2008, 08:06 PM

After swapping the stock injectors back, the stuttering went away, it was a completely bad seal that came with the injector, so I have to find new FIC 750 injector lower seals somewhere? anyone know where?

1992awdlaser · 03-19-2008, 08:25 PM

Here is a link where you can buy them from. Slowboy Racing, Inc. :: DSM :: Fuel :: Fuel Injectors :: Mitsu Injector Parts :: Lower Injector Seals