waveoff

iTrader: (11)

I installed some 75# RC injectors today. The actual install went pretty smoothly except for a couple of injectors. I used some motor oil on the o-rings as lube but they were still a little hard to push into the intake manifold. After installing, I scaled the IFR table accordingly with EFILive using the injector spreadsheet for my IFR numbers. On the first start the car ran rough for maybe 10 seconds but then smoothed out and started idling like stock. The AFR's were right around 14.7 and everything seemed peachy. I shut her down and went in for dinner. About an hour later I went back out to my car and decided to reload some different numbers into the IFR table. The numbers I originally loaded were for 60 psi...my actual rail pressure is 63 psi. I ran some new numbers in the spreadsheet for 63 psi and plugged those into the IFR table and re-flashed. I started my car back up and it started running rough and then I saw smoke coming out from under the car. I shut it down and looked under the hood to find an injector had popped out from the rail. Dummy me forgot to tighten down the bolts on the passenger side of the fuel rail and properly seat the #2 injector clip. I re-secured everything back up and re-flashed my ECM to reset everything. I started the car back up and it was idling really rough and the AFR was super lean (18:1-20:1 AFR). I looked under the hood and no fuel was leaking anywhere but I could hear rushing air. WTF? I sprayed some carb/choke cleaner around each injector and around the intake manifold but I couldn't seem to find a vacuum leak anywhere. This makes me so mad...it was running fine until the injector popped off. I'll probably just take everything off and put everything back on tomorrow and see what happens. Anyone have any ideas as to what I can check or what might be going on?

ZL1Killa

iTrader: (17)

Where are you reading your fuel rail pressure from? and what fuel pump and fuel accessories do you have? you would be fine with using 61~62psi as thats what it may fall to during WOT. But I would like to know your fuel details.

How long did you let it run for once you had tuned it?

Rushing air... usually means a vacuum leak somewhere. brake booster? something...


No you didn't.... you didn't spray carb/choke cleaner on your intake and on the injectors and the O-rings... WHY?
RE-lube them and make sure you aren't eating away at any plastic.

Ok. Apparently you know how to scale your IFR table and you can do that fine, so i'm going to assume so. Check all of your vacuum lines and such , THEN check all your fuel rail/intake bolts to make sure they are all tightened.

RE-TUNE your car with the right IFR table, say 62psi. crank it and let it run.
THEN and only then post back.

waveoff

iTrader: (11)

Thanks for the tips! I've been following your STS built for quite some time while preparing for my own STS install. I'm sure I'll have some other questions for you about stuff if I ever get this injector situation resolved.

To answer your questions about my fuel system... I have a walbro GSS-340 in-tank pump, fuel pressure gauge installed on the end of the fuel rail and 75# RC injectors.

I checked every vacuum source I could think of but I'll go over it again and check. I pulled my PCV line and plugged the TB nipple thinking it might have been the culprit but it wasn't. I felt behind the intake manfold and all connections were intact. The rushing air sounds like it's coming from around the intake manifold but I can't quite pin it down. I sprayed the carb cleaner while the engine was hot and running. It pretty much evaporated right away. I've done this on my other cars before with no ill effects but just to be on the safe side I'll wipe everything down and re-lube everything as you suggested.

My car was running for several minutes and I have logs if anyone is interested. I'll report back after I pull everything and re-install.

Old Geezer

iTrader: (3)

Is that a "mini gauge" on the rail? IE; the small face, like 1 1/2" dia?
If so, there may be a discrepancy w/ the psi readings you are getting.
I've checked many of those gauges against the calibrated gauge on my inj bench.. Some good, many waaaay off. Some as much as 7 # off.
Some were not found to be linear, either.
I didn't see where you have an adj FPR. Is this a stock unit w/ the bigger pump?

waveoff

iTrader: (11)

Yes, stock unit with a bigger pump right now. I do have a cartech rising rate FMU off of my old SC'd Honda Civic that I may be using later but for now it's just the stock regulator. The gauge is indeed one of those small 1 1/2" gauges from B&M. I forgot to mention that I also have an electronic fuel gauge tapped in with the mini gauge. That's interesting that you mentioned how those mini guages can be off by as much as 7 psi because the difference between the B&M and the electronic gauge is 7-8 psi. I've had both of these items for several years now and they have always had a 7-8 psi split. They were used on my '97 Civic and then on my '03 WRX and now on my Camaro. I was always under the assumption that the mechanical gauge was more accurate than the electronic one. Mainly because I initially went through THREE sending units when I first got the electronic gauge.

Frans96SS

iTrader: (15)

Is there a reason your running such big injectors? From the mods in your sig you should be perfectly fine with a 60#

waveoff

iTrader: (11)

I was planning on running E85 with my STS setup.

ZL1Killa

iTrader: (17)

He doesn't even need those, but hey if they run.

these 75# will be PLENTy, LOL. your car might also be running rough due to you not editing the stock OTHER injector tables that control the pulsewidth along with a bunch of other items. I would set your fuel pressure to 60psi (when tuning the IFR) and see what happens, as thats the typical.

you may have to talk to gametech/frost/ others with 60# injectors... I'm waiting to get a table together from several of them of what exactly they did to get the 60#ers to idle NON-rich on a pretty much stock car

waveoff

iTrader: (11)

Hey, I was looking for 60# injectors for weeks but no one was selling any. Then someone had this set of flowmatched RC's for a good price so I jumped on it. I heard RC's were easier to tune as well so we'll see... If they don't work out then I'll just sell them or trade them for some 60's.

I'll try re-scaling for 60 psi and see how that goes.

waveoff

iTrader: (11)

Well I re-scaled the injectors for 60 psi and it's still idling a little lean and a little rough. When it transitions from open loop to closed loop it hiccups and continues to idle rough and lean with hiccups here and there. LTFT is pegged at +25.

I pulled the fuel rails and made sure the injectors were seated in the rail properly with all clips in place. Everything looks good there. I checked all of the o-rings on the bottoms of the injectors and none are nicked or torn. However, they seem to be a tad loose and are easy to rotate on the injector. Is that bad or do they get "squished" down when inserted into the manifold to create a tight seal? I guess I'll re-lube the o-rings and push them back into the manifold and see what happens. This time I'll use propane to look for any vacuum leaks if I have to. What effect would re-scaling my injectors for 55 psi have on AFR's?

waveoff

iTrader: (11)

Alright, I just re-installed everything, re-scaled for 55 psi and it's running a tad better but still lean and a little rough. I could still hear what sounded like rushing air so I went all over the engine bay shooting propane. I shot propane around each injector, around the perimeter of the manifold and around every vacuum connection...nothing. I'm thinking that maybe it's just an engine sound or maybe just the sound of the new injectors cycling? If it's not a vacuum leak then I guess it has something to do with the tuning.

As I mentioned, I re-scaled the injectors for 55 psi. I logged my idle and a short drive. The AFR's are kind of erratic when making any throttle changes. When cruising, the AFR's are steady at 14.7 for the most part with a few lean hiccups to 15.5. On a WOT run, AFR is a bit lean as well. 11.7 is commanded but actual AFR is around 13.1. I also noticed that the LTFT's are pegged at +25 anytime the throttle is steady. The only time they change are during throttle changes. Also, instead of zeroing out at WOT they lock at +1.6.

My next step I guess would be to swap the stock injectors back in and load the stock injector tune back up. If it still runs like crap, I guess I'll know that something got messed up during the install. Maybe these RC's aren't as "easy" to tune as thought? Perhaps a swap for some 60# Mototron's is in order...

ZL1Killa

iTrader: (17)

re-scale back to 60. thats why it should be if you are running on a stock fuel setup.

Go into the injector tables and mess with the pulsewidths and other injector tuning associated tables. LEAVE THE IFR ALONE AT 60psi calculation.

talk to gametech up here or someone that has tuned 60lb injectors. what I think you need is your OTHER injector tables tuned.

also, what kind of tune are you running right now? SD? OL? CL? regular off the showroom floor tune that you have just modified?

waveoff

iTrader: (11)

I'll re-scale back to 60 and try playing with some other injector tables.

Right now it's just an off the showroom floor tune that I modified. If I'm going to spend the time to dial in these injectors perhaps I should go ahead and ditch the MAF and try an SD tune at the same time?

Old Geezer

iTrader: (3)

NE part numbers on those RC's??

spaz1

iTrader: (9)

did you get this sorted out?

waveoff

iTrader: (11)

No, still not sorted out. Haven't gone and played with any other tables yet. I'm searching for info here and at the EFILive forums to better understand what needs done before I start monkeying with tables. I think I'm just going to sell/trade them for some 60# mototron's...might as well go with a proven injector. I appreciate all of the help and input everyone!