I was getting some misfires and slight idle hiccups with my stock injectors so I decided to swap to some FIC 1050s thinking that maybe I had a bad injector or seal. After installing the FICs the idle is even worse than it was with the stock injectors even though I found that one of the stock injectors had a broken tip. With the stock injectors the car would actually idle smoothly when AFRs were below 14 but the leaner it got the rougher the idle got. It would idle OK below 15, but above 15 there was some noticeable misfire. Now with the 1050s, it idles smoothly below 13 but above 14 it misfires like crazy. Any thought on what the issue could be?

Here are my current injector settings. Any other tables I might need to adjust?



Update 9/2/11

So here I am almost two weeks later basically right back where I started. Tonight I pulled out my stock fuel rail, stock FPR, and the FIC 1050s and threw in another stock rail and FPR along with some stock injectors. The end result is that I'm right back where I started. I can still hear and feel a small hiccup/msifire in the idle but it's not nearly as bad as it was with the 1050s so I'm going to stick with the stock injectors for now. After working on this issue almost every night for nearly two weeks here's what I've learned:

1. Even though one of the stock injectors had a broken tip, that was not the problem.

2. I now know how to install injectors but switching to larger injectors (FIC 1050s) made the problem worse and much more noticeable.

3. I now know how to disable and block off the EGR but that also did not fix the problem.

4. Putting in a different stock fuel rail and FPR did not fix the problem.

5. I could not find any vaccuum or boost leaks that were causing the problem.

6. Even though the idle was worse with the 1050s, in daily driving the car actually drove better with the 1050s than it did with the stock injectors. The car would go rich and nearly die when coming to a stop sometimes with the stock injectors. That problem went away after installing the 1050s. (Probably a tuning issue)

7. Tuning for larger injectors was a lot easier than I thought it would be.

I'll be sure to update the thread if and when I find a solution to the problem but at this point I'm done messing with it for at least a few days.

 

Your inj scaling looks alittle high. Try something lower 960-988 see if that helps.
I'm having issues myself, cruise at high vac 20in hg. it goes lean 18 afr for a split second followed with bucking.

 

Lowered the scaling all the way down to 914 but it's still misfiring

 

Hmm, could be that the plugs are fouled?... My plugs fouled after having misfiring issues while dialing in my injectors. New plugs helped with that untill I fouled em again from being too rich wot.

 

Possibly but the plugs are Iridiums and they've only been on the car for maybe 2K at the most. Also, I noticed this issue as soon as I started the car up the first time after the install, so it's not like the car had been sitting idling for a while and then this problem occurred. I just find it really odd that I was having basically the same problem before the swap and now after the swap the problem is even worse. It's as if the FICs have magnified it.

 

Try these scalings and latency's

FIC 1050s

Scaling: 1008

Latencies:
Volts ms
4.69 4.440
7.03 3.192
9.38 1.752
11.72 1.032
14.06 0.840
16.41 0.576
18.68 0.432

 

Thanks for the scalings. I gave them a shot but unfortunately they didn't help the problem. I also put in some fresh plugs, but again, there was no change.. still misfiring like crazy. I did notice that when the car is cold and I first start it up it runs smoothly for a few seconds. AFRs start out at 14.7ish then drop to mid 12s until the O2 shortterm feedback kicks in starts to lean it out. That's when it starts missing.

 

Is the car throwing any codes?

 

Nope. No codes. I almost wish it was. At least that way I'd have a good idea of what the problem is.

 

big injectors have big squirt. small squirts are messy and inaccurate from such.

just because injectors are well matched at 80% flow rates doesnt mean they are at low duty cycles (1-5%) . if you could put a/f on each cylinder you would be very unhappy with what you see. this problem cannot be fixed with individual cylinder trim. if you fix idle end then problem will move to WOT end. you need a better set of injectors.

this is why there is a crazy jump to new style injectors. they have tiny pintle mass and there fore control 1% openings ten times better than old technology injectors

 

I understand what you're saying but there are plenty of people running these injectors without any issues. Also, again, this is not a problem that started with FICs, I was having this problem before, the FICs have just magnified it. I'm starting to think maybe my FPR is bad or something.

 

probably nothing to do with it but have you looked at the o2 voltage? im assuming its fine since your idle afr sounds normal.

sometimes i can hear a what i think is a small miss when my car is warming up, almost sounds like tiny cam lope for a cylinder fire or two...my front o2 its only putting out like 0.05 volts.

 

No I haven't checked that but it's a possibilty because the car doesn't start running bad until the front O2 kicks in and starts trimming the fuel. Of course that's also when it starts to run leaner so it could just be coincidence.

 

There was a post last week about certain FIC injectors causing problems similar to this. I'll see if I can find it.

EDIT: Here it is:
https://www.evolutionm.net/forums/ev...rich-help.html

2nd page has info on the why the injectors were causing the problem. Might be worth looking into.

 

First, dont try to blame this on the FIC injectors. If you read the whole thing, you would see the OP was already having issues before he installed the FIC injectors.

Now OP, why did you throw parts at the car, if it had problems? Its best to fix the problems and make the car run good, then start upgrading.

Also, I run these injectors and run scaling similar to what is posted in this thread. All my trims are within -/+5.