I'm running the 17lb injectors in my 3.4L. Unfortunately I'm running way to rich. Who has gone back to the 2.8L 15lb'ers? How does it run now? If you kept the 17's, did you just add a adjustable fuel pressure regulator?

P.S. It's a 88 GT Auto Trans.. Normal highway driving at 65 to 70mph, I'm only getting 135 miles per tank.

Thanks for your help.
-Haze

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ClassicFiero.com

I read on here someone had that same problem. there fix was the stock 15lbs injecters with more pressure thru the regulator. Hope this helps.

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JOEJOE Aol:SSFiero
Two 88FORMULAS Red & Yellow and a Black 86GT
SSFiero@Aol.com

I don't think you problem is the injectors, but you should be able to be sure by installing a pressure regulator.

Phil

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GTDude
25 years GM experience

im running 15lbs/hr injectors at about 50psi and it runs very well.

really if i was you id just get the adjustable regulator, because youll never know when you want the larger injectors.

I ran into the same problem with my 3.4 haze. I tell everyone on this forum that is doing a 3.4 swap to use the stock injectors with slightly increased fuel pressure but they never listen. In fact I might have even told you.

You need to go back to your stock injectors and turn the fuel pressure up a little (3-5-lbs. max). If you have a scan tool you want to try and get the BLM at 128 or as close as possible to that. You'll have to play around with it but the 2.8 injectors will work much better on your 3.4 than the bigger injectors will with the fiero ECM. I had my 2.8 injectors blueprinted at www.injector.com . You don’t want dirty clogged injectors running your new engine!

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Just so everyone knows, 3.1L injectors are disc type and will not get dirty or clogged as easily as the 2.8L injectors. They are also 15 lbs/hr. The also have a better spray pattern than the 2.8L injectors.

I used my stock (blueprinted) 2.8 injectors at stock fuel presure for over a year without any lean problem in my 3.4. I installed 3.3 ones becasue they are the new design and soon I will tune them for the car (using 1FST gizmo).
Regarding the FPR, you may or may not need it. I would put the 2.8s and measure if it gets lean before investing the $60-$90 bucks. In my case anything above 43psi just slowed my car or painted the tailpipes black.

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Alex4mulas :-)
N2O! 3.4!

quote Originally posted by Oreif: Just so everyone knows, 3.1L injectors are disc type and will not get dirty or clogged as easily as the 2.8L injectors. They are also 15 lbs/hr. The also have a better spray pattern than the 2.8L injectors.

Yes, but the fact that they are disc type is a problem in itself, and is THE "problem" with using 3.4L Camaro injectors. The Fiero ECM is set up for using pintle style injectors, and as such the opening and closing time (which is much slower on pintle injectors) built into the ECM is much different. The Fiero ECM can't reliably control disc style injectors below about 1.7ms pulse width, and at higher RPM's tend to dump a bunch of extra fuel with the same commanded pulse width compared to pintle style.
That being said, the 3.1L injectors likely would work fine, since your idle PW will probably be higher than 1.7ms anyway.

2.8L injectors do flow enough to work, though getting the pressure "just right" to not be rich at idle and still not lean out on the top end is tricky. But, for good all around drivability and decent performance (the 3.4 just doesn't breathe enough thru the Fiero plenum for good high RPM power anyway) they work very well.

FMS 19lb injectors work great out of the box, with stock fuel pressure. They are still pintle type, and idle fine. Your BLM will be on the low side, since the ECM will have to pull some fuel out, and top end will be a little rich. I've done a few chips for 3.4's running the FMS injectors, and can honestly say with some tweaks to the fuel tables, it's the best combo I've driven (and I've driven all of them, except the 3.1L injectors mentioned above. Theoretically, they should work well, as long as the BPW at idle doesn't drop too low. Those of you who've run 3.4L injectors in your 3.4 and have a "hunting" idle, that's probably what caused it.)

HTH's...

Jeremy B.

quote Originally posted by Fierotech: Yes, but the fact that they are disc type is a problem in itself, and is THE "problem" with using 3.4L Camaro injectors. The Fiero ECM is set up for using pintle style injectors, and as such the opening and closing time (which is much slower on pintle injectors) built into the ECM is much different. The Fiero ECM can't reliably control disc style injectors below about 1.7ms pulse width, and at higher RPM's tend to dump a bunch of extra fuel with the same commanded pulse width compared to pintle style. That being said, the 3.1L injectors likely would work fine, since your idle PW will probably be higher than 1.7ms anyway.

Well they work fine on a 2.8L engine. Been running them for about 4 years now without any problems. (at idle or high RPM)

When you say "disc style" do you mean Multecs? Multecs were used in the 2.8L engines.

quote Originally posted by terryk: When you say "disc style" do you mean Multecs? Multecs were used in the 2.8L engines.

Yup, that's what I mean, though I would say Multecs were used in SOME 2.8L engines. Definitely not all. Think they fall under the same little "loophole" that covers the 3.1L injectors...they never need to go below 1.7ms (that's probably an arguable number, but it's just what I've seen on a scantool and Diacom as "the point that idle gets funky", but we all know how &%*$% slow the Fiero ECM spits out info) since they supply the "correct" amount of fuel to begin with. Have to add, though, that I've seen HUNDREDS of Fiero motors come apart, and can only recall ONE car that had the Multec injectors in it. Original owner. Said it had this "funny hunting idle problem" in it since the day he got it. Dealership could never fix it. We put a 3.4 in it a year or so ago, and kept his injectors since "the dealer told him they were the better, self cleaning type, and the car has always run perfect (except for the funny idle hunting problem noone can find)". I pulled out the Multecs and swapped in a known good set of 2.8L injectors, and the "mystery idle problem" was spontaneously cured.

I KNOW I'm likely to get a ton of "I'm running multecs/discs/whatever and my car runs fine" comments. If so, GREAT! Congrats!
I'm not here to tell anyone they're wrong, or that something WON'T work, etc...just sharing what I've found during my "Fiero Repair" career. I just hope it helps someone.

Orief, like I said, I've had no experience personally with the 3.1L injectors, and I quote myself: "That being said, the 3.1L injectors likely would work fine, since your idle PW will probably be higher than 1.7ms anyway." and "the 3.1L injectors mentioned above. Theoretically, they should work well, as long as the BPW at idle doesn't drop too low." Never said you were wrong, or they wouldn't work. Matter of fact, your input on this enables me to tell people in the future "I've heard the 3.1L disc type injectors work fine..."

I would imagine there was more than a few Fieros out there with the Multec injectors in it from the factory (though not a bunch, it seems), and I would hope at least MOST of those ran well, and idled well. IF I'm right on everything I've said, than they should, because they don't need to drop to a low BPW at idle to keep from flooding the motor, they're actually calibrated correctly to begin with. Also, I have no clue if the Multec style are identical to the later (93+) disc style used in the Camaros. I would *assume* they are, but assuming isn't something I'm REAL crazy about.

Take care all...
Jer (still hoping this helps, at least some...)

Does anyone know what type of injector ACCEL sells? They are "Bosche type" injectors, but I was wondering if the are pintle or disc.

Good question. I have bought 2 sets of Ford Motorsports injectors. The 19lb were pintle and the 24lb were disk/Multec. They both are made by Bosche, so it may depend on what size you get.

Edit- More useless crap added below:
I must have been lucky with my 3.4 because it ran pretty good with the stock chip and 3.4 injectors. It ran better with a tuned chip to clean up the idle and full throttle richness, but when I gave that chip and injectors away, that guy's 3.4 ran pretty nasty with them. Since I like tempting fate, I am running the 24lb Multec injectors and at idle they are staying between .9 and 1.1ms. They don't hit 1.7ms until around 1800 rpms. Sometimes being lucky is a wonderful thing

[This message has been edited by Cooter (edited 05-13-2002).]

You guys have managed to confuse the he!! out of me.

So I guess I can keep the 17lb-ers & get a good adjustable fuel pressure regulator?

quote Originally posted by Haze_Performance: You guys have managed to confuse the he!! out of me. So I guess I can keep the 17lb-ers & get a good adjustable fuel pressure regulator?

Ummm...not trying to be rude...but reviewing the replys to your post, there was only really ONE person who advocated that idea, two if you count a "I must have been lucky" followed up by them not running in a friends car. Everyone else spoke about going to lower flow rated injectors (stock 2.8's, 3.1's) or FordMotorSports injectors. Cooter said that his car ran "pretty good with the stock chip and 3.4 injectors...better with a tuned chip/when I gave {them} away, that guy's 3.4 ran pretty nasty with them". Doesn't sound, to me at least, like shining recommendations to just throw a pressure regulator on it, unless you have Cooter's (exceptional ) luck.

Also, MOST pressure regulators I've dealt with won't lower the factory pressure much, if any...so I'm really not sure how a regulator is going to help you a lot, anyway.

Easiest/cheapest solution, based on the replys? Looks to me like going to 2.8L injectors, seeing how it runs. If it still wants a little more fuel, then go for a regulator. There's, what, 4 people who have actual experience with that setup (with or without the regulator) that responded with positive results, not "I heard that..." or "I think that...".....

88formula, I know how you feel.

Cooter, yup, the 24's are disc type; as a matter of fact Ford's come out with a "new" style 19lb injector (plastic body) that, from what I've *heard*, is disc type too. I wasn't real crazy about hearing that, since the pintle ones do work so well with a little tuning. I'm going to have to get a set and check them out, I guess. Also...the 24's your running now, I'm assuming you've got a custom chip with that setup, or a motor that flows a *little* more air than stock? The one 3.4 I stuck 24 lb'ers in hit a WALL at about 3500 RPMS...flooded the engine out bad enough it would NOT pull. I pulled a BUNCH of fuel out in the chip to get them to work....
If not, ya, you ARE lucky...lol...

Take care, all...I'm going to go fix some Fieros for the next 8 hours...

Jer

Jeremy,

Excellent and well considered comments! Glad to see someone who has a handle on it.

Fierotech,
I mistakenly posted:

quote You guys have managed to confuse the he!! out of me. So I guess I can keep the 17lb-ers & get a good adjustable fuel pressure regulator?

I meant 15lb-ers & get a regulator. I have an extra set of the 2.8 stock injectors that I was going to get rid of. I don't think everyone needs to get so upset about this.

Now... What was confusing me was when Cooter mentioned 19 & 24lb-ers.

88formula,
Sorry.. I don't remember talking about this with you before. I've been completely stressed out just getting the car back. Now I had to bring it all the way back again today. (more bugs to work out) Bob said he would try to fix the fuel problem but I wanted to learn how to modify the system myself. If I get it back & it's still wrong I can try to fix it.

===

Thats why I don't tend to post in the Tech section.. If you don't understand you get jumped on...

===

Thank You for the info guys.. I plan on getting my 15lb-ers blueprinted.

-Haze

quote Originally posted by Larry: Jeremy, Excellent and well considered comments! Glad to see someone who has a handle on it.

Thanks Larry...but, a handle on something? Me? You must be kidding...

Jer

[This message has been edited by Fierotech (edited 05-13-2002).]

Haze,

Not only do I sometimes confuse others, but very often I tend to confuse myself. It seems to be happening more often!

Good luck in the learning process of how these silly little cars work. I know I have a long way to go. If only I would quit changing things, I just might catch up.

Larry

quote Originally posted by Haze_Performance: Fierotech, I mistakenly posted: I meant 15lb-ers & get a regulator. I have an extra set of the 2.8 stock injectors that I was going to get rid of. I don't think everyone needs to get so upset about this. Now... What was confusing me was when Cooter mentioned 19 & 24lb-ers. 88formula, Sorry.. I don't remember talking about this with you before. I've been completely stressed out just getting the car back. Now I had to bring it all the way back again today. (more bugs to work out) Bob said he would try to fix the fuel problem but I wanted to learn how to modify the system myself. If I get it back & it's still wrong I can try to fix it. === Thats why I don't tend to post in the Tech section.. If you don't understand you get jumped on... === Thank You for the info guys.. I plan on getting my 15lb-ers blueprinted. -Haze

Dude...I don't think anyone was jumping on you, or particularly upset. I certainly wasn't. It is a little frustrtating when myself and others post advice, and it lookes like it wasn't even read; Typo, no biggie.

If ya knew the answers to questions before you posted them to the tech area, what would be the point of posting them?

Plus, this isn't exact science. All any of us have to go on is our own, and other's, experiences. I shared mine, others shared theirs. Take that info and do what you wish and can with it, and always with the proverbial "grain of salt".

I am truly sorry if you had the impression I was jumping on you...I was just re-stating, maybe in a way that would better get your attention, what was previously stated, in case ya missed it...even prefixed it with "Ummm...not trying to be rude..." just so there'd be no hard feelings.

As far as Cooter and the 19 24lb'ers, those are the FMS injectors I mentioned, and in MY experience they work very well (at least the 19's) with a custom chip. I'd still like to talk to Cooter some about his setup; we're both in AL, so I guess I'm gonna have to look him up and try to learn his secrets!

Hate to see anyone nervous about posting a question. Heck, if you ever need/want some advice, shoot me an Email or PM, and I'll try my best to help. Not saying I'll definitely be able to, but I'll certainly try...

Take care---
Jeremy B.

Edit---odd, my quote of your post didn't include your quote of your other post. <shrug>

[This message has been edited by Fierotech (edited 05-13-2002).]

I try not to keep secrets, I just don't want to bore people with too much detail.
It took a custom chip in my friend's stock 2.8 to run the 19lb injectors. We chose them because they were cheap replacements for his leaking injectors.
Eventually, my 3.4 will get a turbo and the ecm I have was set up for a 4.3 with 30lb injectors. A 3.4 is 21% smaller than a 4.3 and 24lb injectors are 20% smaller than the 30lb injectors, so I was hoping the fuel map would be pretty close. I was not that lucky