Injector misfire with forced induction kits..

voodoo50

voodoo50

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Anyone with a forced induction system installed on their car have injector induced misfiring issues on your car? I am having a frustrating time trying to smooth out injector misfire issues with my Kraftwerks 9th gen kit installed on my Si. Apparently this is a HARDWARE ISSUE and not a software issue. This kit comes with Grams 1000 cc injectors. I have also upgraded the fuel pump to a 265 lph unit as well. The car is currently being tuned, however these injectors are pissing me off. I didn't expect to dish out the cash for this kit only to be told the injectors may be an inferior product when compared to other brands... Anyone have the same issue with this kit or otherwise? Any help, recommendations greatly welcome and appreciated. Thanks.
 
voodoo50

voodoo50

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I spoke with Scott at Kraftwerks earlier today. I explained to him that I was working with Vit to tune the vehicle. I ask Scott if he had anyone else complain of the Grams injectors and the issue I am having with them. He said that some customers have sent the injectors in to have them flow tested but that none of the injectors that have been sent back for flow testing have failed. He said I could send them in for flow testing but if they are found to flow within spec, that the injectors would just be sent back to me. So Vit tells me that the Grams injectors are some of the worst performing injectors out in the marketplace. I did a HELL of a lot of research and I could NOT find anyone who has this kit say that the INJECTORS were a headache. So NOW that I am searching HIGH and LOW to find out about this issue... Seems like the answer is going to be to PURCHASE the Deatschwerks injectors. WTF!!??? We shall see.... I haven't yet finished tuning with Vit yet though. That guy is one cool cat.... I just don't want to hear that my Grams injectors are junk. So effin pissed. But I will keep you informed @webby . Thanks boss...
 
webby

webby

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vit's post on the 8th gen forum regarding injectors -

=======

Injector matching and what it really means to YOU
Several injector manufacturers have a process they follow to test and flow injectors and sell them as "matched" sets. Why do they do this? Injector Dynamics has a good article on why this matters:

Does Dynamic Matching Really Matter? - Injector Dynamics

But what does this actually mean to YOU and YOUR car? Everyone and their mom is trying to sell a "Bosch" injector to you. From my experience all their marketing hype isn't what it's cracked out to be. Most simply do not do this kind of dynamic matching and it shows in the logs and on the cars I work on.

Basically, in simple terms, the idea behind dynamic matching is to package a set of injectors that flow the same (or damn near close) across the workable "pulsewidth" range of the injector, 2ms to 10ms (we actually run them to 15-16ms, but that's such a large pulsewidth that if you're already matched at 10ms you're fine beyond that). The better matched the set of injectors, the smoother your car will run. This is notable as the injectors get larger and larger in size (a 10% deviation on a 400cc injector isn't nearly as much as 10% on a 1000cc or larger injector).

Why is this the case? Well, let's take your typical 1000cc injector and apply it to your standard stock motor K20 or K24 Civic. At idle you will be around 1.8ms pulsewidth. At normal "light" driving and cruising you will be around 2.0-4.0ms. It is very important for idle quality and light throttle/cruise drivability that the injectors be perfectly matched as a large enough deviation and you start feeling light "jerks" or "stutters" at cruise or light throttle acceleration, all the way to full blow misfires (on a single cylinder usually). Your idle also sounds very "poppy", and it is, because the motor is basically misfiring every few cycles.

But why does this happen? Well first of all at light throttle and idle the motor runs at "stoic" fuel targets, 1.0 lambda (14.7 afr or so), this is essentially your "economy" mode under normal driving conditions. If you have a 12-15% deviation between injectors, at idle you could essentially be seeing something like this on the 4 cylinders:

- 14.5 afr, 15.2 afr, 13.8 afr, 16.3 afr

Not very well balanced, and in all likelihood the 16 afr will cause a slight miss, or at the very least a "stumble" in the engine (basically a hesitation).

What if we only have a 5% deviation? We might see something like

- 14.5 afr, 14.8 afr, 13.9 afr, 15.3 afr

Better right? But still not very smooth and we might get the occasional stumble.

Now how does this translate to part throttle in the 2.0-4.0 range? Well when you're in the 2.0-3.0 range the motor will be very touchy to having a deviation between injectors, and you also have to take into consideration a few other variables like how the injectors are flowed, their spray pattern, etc. I've seen injectors that have been matched pretty well still have some slight issues in the 2.0-3.0 range, but if that deviation is high in that area, you essentially can run into a situation where the motor runs something like

- 14.7 afr, 14.6 afr, 14.3 afr, 15.5 afr

Now you won't get a full blown misfire, but the motor will sort of "stumble" (and doesn't necessarily happen every cycle) and you'll feel a very very light hesitation at cruise or as you try to lightly accelerate. In this situation you'll add throttle and once you're in the 3.5ms+ pulsewidth area things smooth out.

Keep in mind this is just a very short explanation for something that I have seen a lot of over the years. I'm in no way an "injector expert", so my explanation may have holes, but it's a good idea of what's going on when you experience this drivability nuance. And no, a "tune" technically can't fix this behavior, as it is a mechanical issue related to the combination of parts on the car.

=====
 
voodoo50

voodoo50

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Thanks @webby both articles cleared things up for me to better understand what I'm dealing with. I appreciate it.
 
webby

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voodoo50 said:
Thanks @webby both articles cleared things up for me to better understand what I'm dealing with. I appreciate it.
Click to expand...
No problem. Honestly, I didn't find much in the way of bad reviews specific to your injectors. Quite a few threads on honda-tech and other forums saying they're running them without a problem. I'd wait to see what happens with your tuning & see if vit is able to fix your issues.
 
323

323

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Just read through the thread now... Have you upgraded your spark plugs? I had issues when I went with a ct-e kit, having misfires because the spark plugs were getting too hot.
They might be the culprit instead of your injectors.
 
voodoo50

voodoo50

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@323 yes I did upgrade the spark plugs. They are the NGK 1422 plugs. I believe they were gapped at .032. I was thinking about that as well. I might pull them out and gap them at .028 to see if it alleviates the symptoms. Thanks BTW.
 
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Christian12

Christian12

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Injector Sticking Issues.png funny enough I'm having the same problem getting KW to send me new injectors not sure if I'm gonna be putting them in or buying some DW
 
JonnyRotten

JonnyRotten

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voodoo50 said:
Anyone with a forced induction system installed on their car have injector induced misfiring issues on your car? I am having a frustrating time trying to smooth out injector misfire issues with my Kraftwerks 9th gen kit installed on my Si. Apparently this is a HARDWARE ISSUE and not a software issue. This kit comes with Grams 1000 cc injectors. I have also upgraded the fuel pump to a 265 lph unit as well. The car is currently being tuned, however these injectors are pissing me off. I didn't expect to dish out the cash for this kit only to be told the injectors may be an inferior product when compared to other brands... Anyone have the same issue with this kit or otherwise? Any help, recommendations greatly welcome and appreciated. Thanks.
Click to expand...

voodoo50 said:
I spoke with Scott at Kraftwerks earlier today. I explained to him that I was working with Vit to tune the vehicle. I ask Scott if he had anyone else complain of the Grams injectors and the issue I am having with them. He said that some customers have sent the injectors in to have them flow tested but that none of the injectors that have been sent back for flow testing have failed. He said I could send them in for flow testing but if they are found to flow within spec, that the injectors would just be sent back to me. So Vit tells me that the Grams injectors are some of the worst performing injectors out in the marketplace. I did a HELL of a lot of research and I could NOT find anyone who has this kit say that the INJECTORS were a headache. So NOW that I am searching HIGH and LOW to find out about this issue... Seems like the answer is going to be to PURCHASE the Deatschwerks injectors. WTF!!??? We shall see.... I haven't yet finished tuning with Vit yet though. That guy is one cool cat.... I just don't want to hear that my Grams injectors are junk. So effin pissed. But I will keep you informed @webby . Thanks boss...
Click to expand...
Sorry to hear about all of your frustration @voodoo50. I hope it all gets resolved shortly so you can have a little bit of fun with your car.
Thanks for bringing this up. I know you are looking for some help from the forum but at the same time you are making the rest of us more knowledgeable on the potential problems that we might encounter should we decide to upgrade to forced induction or be looking at injector upgrades.
 
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