I'm trying to update some information on the 3.4 F Body engine conversion for the Fiero. So, I would like to talk with someone who has an original conversion done by Ed Parks.
There has been much discussion of the selection of the fuel injectors for the 3.4. What seems to work for one person doesn't work for another. I've been recommending Bosch injector number 0 280 150 415 injector that I and few others I know are using. The only problem we've found with them is that they run a little lean at wide open throttle, with the BLM being maxed out. This is all with a stock ECM and stock fuel pressure regulator. These were recommended by a fuel injector rebuilding service.
There are other aftermarket injectors that are reported to work well, like some of the Accel injectors. What I'm attempting to accomplish is to find an injector that will work for us, is widely available, and is reasonably priced.
I have been researching and found some information regarding the Rochester injectors that are stock for the 93-95 3.4 iron head engine. It seems that some had 17# injectors and some had 19# injectors, depending upon optional equipment. So, just keeping the stock Rochester injectors from your 3.4 conversion might give you a set of 19's. Randomly replacing one or two might give you a mix of 17's and 19's. Unless part numbers were carefully compared, you wouldn't know the difference by sight. Technical articles also stated that the Rochester disk injectors are prone to failure because of the wet coil design. They eventually fail to seal and the lb/hr increases, sometimes dramatically.
fgt1988 and I have been delving into injectors in the quest to resolve some issues with his car. While searching for the same Bosch injectors, we found that the injector in it's original form is no longer available. It has been redesigned to incorporate a 4 pintle metering system. Various rebuilder sites show this injector to flow anywhere from 16 lb/hr all the way up to 20 lb/hr. This is at an indicated pressure of 3 Bar, or according to their conversion, 42.5 psi. There are some conversion charts that says 3 Bar equals 43.5 psi, so I don't know.
Anyway, I've been told that for our application, the new design green Bosch 0 280 150 415 injectors is the way to go, but the pressure needs to be upped to 48-50 psi. The stock ECM will efficiently operate these injectors and at the increased pressure will provide the fuel needed, even for a slightly modified 3.4. They are the only OEM pintle injector with the correct dimensions for the Fiero.
So, to better evaluate the proper injector for the 3.4 conversion, I'd like to know what injectors Ed used. How are your injectors performing? Running rich or lean? Have you had to have them replaced and if so, for what reason?
I got my 3.4 through Ed, even though I installed it myself. Jeremy recommended the stock 2.8 injectors for break-in. Said that I should then install the 19 lb Bosch injectors, even though the 3.4 was essentially "stock". He said he'd rather tune for those than anything else that I might use. (Apparently it's easier to "remove" fuel than to "add".) I forget what injectors I used when I had it smogged, but it was a stock chip. Once I had the EGR working, it passed just fine.
To directly answer the spirit of the question... As I remember, what he was recommending, was upping the fuel pressure, and retaining the stock injectors. But I think it depended upon the phase of the moon, and maybe which way the wind was blowing. Seems like it was never an exact science.
FWIW... After I built up my 3.4, the 19s were very close to "right", even with an essentially stock chip, and a stock FPR. Close enough that I was in no real hurry to optimize it. (The ECM removed a bit of fuel, but by a much smaller margin that it has to add, to run the "first" BMW injectors. If that makes sense.) I still have two of the 19s around here, someplace (they came as a set of eight.) If I can find them, I'll post the part number.
[This message has been edited by Raydar (edited 12-05-2017).]
I have a turbo 3.4 engine with Ford 19 pound injectors. It ran very rich when it was first installed and performance did not improve until custom fuel tables were provided after Jeremy had the car for a couple of weeks and did some experimenting. The 17 pound injectors are likely to work OK for a stock 3.4.
According to Fuel Injector Connection, whom I spoke with this morning, the new style injectors are rated at just over 16#. They suggested just bumping up the pressure to 48-50 psi to achieve a full 17# flow with those injectors. That's well and good if you have a relatively new fuel pump. Increasing fuel pressure can put a deadly strain on an older pump, possibly leaving one stranded by the roadside. Probably doing a tune on the chip would be the easiest way to go. FIC wasn't familiar with our ECM's and didn't know if they could be reprogrammed for this particular purpose.
I'm trying to find something that the average Joe can pop in, plug up and go and play without retuning or modifications. For that reason, I was wondering if TFF had found the solution.
Raydar, I like that solution of being able to reduce the fuel as opposed to having to add it.
I have a 3.4L crate engine conversion (not Ed Parks). I originally did it with the stock 14.5lb injectors. I was having trouble where sometimes the car would stall at a stop/red light. I read about how this could be due to this stock injectors as the 3.4l was designed to use 17# injectors. I went with Accel 17# injectors from summit racing. This was approx 15 yrs ago. I have an adjustable fuel pressure regulator and set it for 45-50psi at idle. If I remember right a set of injectors back then was approx $175.
Thank you. I think that with these injectors, the fuel pressure increase will be the answer. And they're a little more affordable to most than Accels or other aftermarket brands. I haven't looked at Nipondenso, so I don't know if there's anything similar in those, but I think most Japanese injectors are disk style.
Raydar, I like that solution of being able to reduce the fuel as opposed to having to add it.
I was working on that when I sold my 3.4. I actually had gotten the "steady state" fueling pretty close. Had a stumble that required some tweaks to the TPS settings. Since it was my "daily' at the time, and I didn't have a lot of time to mess with it, I just swapped the stock-ish chip back in, and drove it that way. (As I posted before, it ran a bit rich, but it still ran well.)
quote
Originally posted by fierofool: ... I think most Japanese injectors are disk style.
I think most injectors are disk style, period. Although I'm not sure about the newest "4-hole" designs that are being sold. (Bosch Type 3, etc.) I think they have a response similar to disk type, however. I think...
Pintle type injectors were an old design. (Dare I say "1st" design?) I think the disk style keep themselves clean more easily, than the pintle type. (Just a guess.)
If I have mis-spoken, I hope that someone will jump in.
[This message has been edited by Raydar (edited 12-06-2017).]
I talked with f85gtron tonight to see what he used. He's currently running 302 Mustang 19# injectors, but he's pretty modified and also running a 7730. Prior to the build of the engine, in it's stock form, he ran the stock Fiero 2.8 injectors, with a caveat. He sent them off to Fuel Injector Connection and had them resized to flow 17#. For anyone doing a base 3.4 swap, maintaining the stock ECM, this is probably the way to go.
He said FIC took the information on his setup, resized the injectors and sent all the data for flow, medium used, etc when they returned them. But I would still like to know what injectors someone might have in their original TFF 3.4 swap.
The "Fiero Factory" in Toney Alabama was a pioneer of the 3.4 swap into the Fiero. They started ~15 years ago. The swap has evolved a great deal since then. Charlie was looking for info regarding some of the first swapped cars.
When I did mine, Ed recommended the 19# Mustang injectors to me (they were yellow) and Jeremy programmed a chip to fuel them properly. Ran great. I'd call Jeremy and talk to him if I were you. We was prob the lead tech back then and he knows his stuff - esp with the 3.4 pushrod swap.
I was hoping to get some thoughts from some of the owners as to how their engines ran and if they know what injectors were in the engine even if they no longer have the car. I would expect the owner to have a better knowledge of their performance than someone who might not have occasion to drive the car or even to see it again once it left the shop. Jeremy will be the next one I contact if no one else comes forth. Thanks Nelson and Smartaxel for that suggestion.
I'm still hoping to find something that will work on an otherwise stock setup.
I was hoping to get some thoughts from some of the owners as to how their engines ran and if they know what injectors were in the engine even if they no longer have the car. I would expect the owner to have a better knowledge of their performance than someone who might not have occasion to drive the car or even to see it again once it left the shop. Jeremy will be the next one I contact if no one else comes forth. Thanks Nelson and Smartaxel for that suggestion.
I'm still hoping to find something that will work on an otherwise stock setup.
Charlie,
IMO you are best off with a 17 pound injector for a stock 3.4 using a Fiero ECU. My 3.4 has a 272 cam and a turbo with the Ford 19 pound injectors and it initially ran much too rich to even be even a marginally drivable car. I got Jeremy to do some testing and then burn a custom chip that I still use in this car (gray Mera) and am satisfied with this conservatively tuned vehicle performance.
I have 17# in mine..pintle style spray.. I'm not sure the number though.. I may be able to get it but the injectors are installed ... I recommend injector cleaning by RC .... https://www.rceng.com
My combo is--- 260 comp cam. 1.6 rollers... .030 over.. 9.25:1 compression.. I also have the Holly adjustable fuel regulator.. ----- With the vacuum line attached, I run it at 30psi with no issues... slight gurgle in the exhaust sound.. no popping of unburned fuel when shifting.. no terrible fuel smell... I have a narrowband air/fuel ratio gauge and stays in the clear... the wideband gauge is soon, though, so I can see numbers.. looking forward to it and have prepped for the install already.. I just need a stainless bung to weld.. just FYI.. the wideband doesn't communicate with our OBDI so I have to run (2) o2 sensors ... one for the computer and one for the new gauge.
------ and as long as you stay away from the Walbro 255 fuel pumps... I've had 2 go out on me already.-- less than 2000 miles.. now I have a AcDelco 375 ready for install... stock for an 88 corvette 5.7L.. I figured stock instead of aftermarket is alway best from all the R&R testing they do on production cars.... and if it can feed the corvette, it's good enough for me
I wasn't sure if the stock fuel pump would keep up... especial if I decide to turbo or SC
[This message has been edited by unboundmo (edited 12-08-2017).]
Thanks, Mo. Can you describe the injectors? Color or anything? Sometimes they can be identified if you have a couple of things to go by. Color and 17# might help.
Today I found a 17# pintle injector at 43.5 psi, stock Fiero pressure. The only thing I can't find is if they have the same dimensions as the stock Fiero injectors. I've got a couple of people in the business and one PFF member that I plan to contact to get more information.
Thanks, Mo. Can you describe the injectors? Color or anything? Sometimes they can be identified if you have a couple of things to go by. Color and 17# might help.
Today I found a 17# pintle injector at 43.5 psi, stock Fiero pressure. The only thing I can't find is if they have the same dimensions as the stock Fiero injectors. I've got a couple of people in the business and one PFF member that I plan to contact to get more information.
I think if you have the stock fiero fuel regulator plus programming, you will always run rich with any lb higher than the 15's.... but then I don't think the 15's are enough for the 3.4.. better to have more fuel than not enough... and 43 psi with 17-19 lbs will practically foul my plugs... even if at 35 you can tell the engine is running a little rich by smell and sound. To me anyway.. that's why I bought the holly regulator.... stock tune but lowering the spray flow/pressure.. seems to work well for me
----- > I want to say that they are these Rochesters.. remanufactured for a GM 3.1-3.4L OEM... 17lb.. model# 17109826... same color as the link below
Yes, the stock Rochesters like that were what was in the 2nd 3.4. Couldn't stand to drive behind it.
What I'm looking to do is find an injector that requires no modifications to the ECM or fuel pressure and that will operate properly in a stock 3.4. I appreciate all the information. If I can't find the perfect injector, this will help me find the next best.
Yes, the stock Rochesters like that were what was in the 2nd 3.4. Couldn't stand to drive behind it.
What I'm looking to do is find an injector that requires no modifications to the ECM or fuel pressure and that will operate properly in a stock 3.4. I appreciate all the information. If I can't find the perfect injector, this will help me find the next best.
I think this would be a perfect 🌎 above --- the right injector.. ..
.. but honestly, my ride runs bomb and with plenty of goodies there after.. I love it😜... Just an ever so slight rich but not smelly.. my wife didn't complain.. which is a definite 🅰️Okay!. Idles at a 1000 and gets when you want it too
..but back to the injectors...it's like it's inevitable.. the same regulator, the amount of cylinder bore difference of what the computer "thinks" it sees and dumping (the same) tons amount of fuel working those little (what the ecm thinks) 15lbders for the 2.8L (because of prior programming from factory) is really the problem.. then due to having to install bigger injectors that is required for the 3.4 cylinder size, really allows them to flow causing the rich scenario...(same programmed chip).
I wonder why the computer doesn't see the richness from the O2sensor and adjust the flow rate of the injector? Or Is it because the computer only knows how to adjust a 15lb down, percentage wise, verses having the 17... or 19lbs?
I've never seen a 16lb......that would be cool! but honestly, I never looked for one.. word was, back then, to go with 17..so I did..
a 16 maybe the answer ?.. is there one?
But hey!... if you don't find what your looking for.. the fuel adjustable regulator is your friend.. $100bucks and some change------done. And easy to install!..... go with the 17's, that's just my opinion..
----- I wish I had an OBD1 tune shop /chip burner over here.. testing the exhaust as they go.. that would be my perfect world! Dyno run this bad b****
[This message has been edited by unboundmo (edited 12-08-2017).]
I'm not sure that the ECM needs to know the physical size of the injector. The same physical size injector can flow at different rates at the same pressure. Based on input from the engine sensors, the ECM adjusts the pulse width to correct A/F ratio. f85gtron solved his problem by having the stock 15# Fiero injectors resized to 17#. He does have a scanner that can do a real time scan, and he said everything's working as it should. But of course, if trhe ECM 'sees' the injector, it recognizes it as stock.
Bosch injector 0280150415 fills the bill for a 16# injector and falls within the correct resistance range, however, I don't know if the injector is the correct physical size for our needs. https://www.injectorrx.com/bosch-fuel-injectors/
Note injector number 0280415778. That's what I'm looking at and am awaiting some replies about it's specs.
Something I've found on every injector calculator chart is that they are rated at a base pressure of 43.5 psi and a duty cycle of 85%. The duty cycle can be pushed upward but overtaxes the injector if it's a constant. Injectors actually flow less than the lb/hr they are rated at for this reason. Our 15# injectors only flow 14 something. One number I remember is that 17# injectors flow 16.66 lb/hr.
The ECM doesnt know what injector it's trying to operate. It only changes pulse width based on info from other engine sensors. It can't adjust the nozzle size. It will send a signal even if the injector is unplugged.
So in a 3.4, it would theoretically increase the pulse width of a 15# injector to provide the correct air/fuel ratio or decrease a 24# injector's pulse width to cut fuel. That's within rhe range of its programmig, of course.
Fuel flow can be increased with the regulator as you indicate, so if I can't finf the perfect injectot, and the fuel rail is already exposed during a swap, that would be the way to go but it may require flow bench testing to determine the correct pressure. All this adds to a Frugal Fierologist's expenses.
Seems like it was never an exact science.
