RedHot85Vette

Will 1986 Fuel Injectors Work on a 1985?

I've been searching... here and there.. unless I missed something, I'd also like to know...

What is the "Pounds" rating of the stock 1985 injectors?

What is the "Pounds" rating of the stock 1986 injectors?

Also, forgive my ignorance but, what is a "BLM", and what is a "DD"?

confab

Autozone shows the same part # for 85 through 88? But you probably don't want to do that.

They're a type that doesn't work well with ethanol and fail frequently. Even if they do work now, they're 30 some years old.

The best solution, and an upgrade, is to call John at Fuel Injector Connection and get a nice set of Bosh III's..

He's a great guy, and he can hook you up with what you need if you've modded it or not, or whatever..

KyleF

Yes, 22lb.

Beware of Bosch III's. They will work, but a lot of TPI guys on the Camaro boards have had to get a custom PROM with the injector constant changed for them to truely work properly. Also, there is some height difference. I haven't installed a set, but my understanding is they require a doubled up O-Ring to seal and set properly with the fuel rail.

Oddly enough, my L98 IROC has Bosch III's and it DOES NOT RUN RIGHT at low RPMs. I haven't dug too deeply into this as its a project car with other more pressing issues. I will say this, it runs well over 1500 RPMs, but that initial off idle is rough. I expect that I will need a custom PROM in my future, but I can't confirm that yet.

Tom400CFI

Heck yeah, they'll work! I put late '90's Buick 3800 V6 injectors in my '89 Corvette...they work great and cost $6 each (u-pull-it yard).

Joe C

FWIW, I've installed bosch3's in both my 90's corvettes without issues. height difference, really not an issue. the double O-ring at the intake side acts like a double seal, with the upper of the two sealing against the chamfer of the injector port opening in the intake. this helps keep dirt and other debris away from the lower seal. FIC supplies the double O-ring configuration with their injectors. also, never had to get any custom PROM tuning with either 90's as well as my 85 and 96 corvettes. IMO, no reason to beware of bosch3's.

KyleF

Do your research, I am not saying don't buy them. Lots of TPI's out there running them.

Just out of curiousity Joe C, what is your BLM value? Have you looked at your O2 cross counts? Anything... or just the butt dyno?

Good info here on fitment, installation and appearance.
Some more info here and another nod to FIC for fixing problems.
Some info from a tuner here

Here is a quote from this board:

From this thread that has some really good info.

Here is another thread here discussing the need to change constants.



Read up, often this is not a plug an play. As I said, they will work. Just like any other modification, there is other things to consider. Just make sure you are working with a good supplier and the rest of the system is good an healthy as well. Long term wise, you will at a minimum probably need to dial your fuel pressure in to help with the BLMs.

confab

I got a set of Bosch III from FIC in my 85 and I couldn't be happier with them.

Auto. Stock PROM.

Joe C

butt dyno - I have no idea of the BLM value or O2 counts, and at this point, nor do I care. my 85 starts quickly, has exceptionally smooth idle and overall, no noticeable issues. performance wise, i'm perfectly happy. I don't track the car, and I don't care about getting 110% of the performance value out of my DD. fuel economy and mileage good are in-line with pre-bosch3's, in fact, from what I can tell by the SOTP, it runs strong, and everything is pretty much in line with pre-bosch3's. I really don't want to put too much thought into over analyzing this stuff. if, down the road, i'm having problems, then i'll address the issues. at this point in my life, butt dyno is good enough for me. peace....

RedHot85Vette

That was a good idea looking up the AutoZone part. I usually use RockAuto but for some very bizarre reason, I can't access their website. Every other web site on the web I can access, but RockAuto, no luck. It's happened before, then it mysteriously returned, then it disappeared again. Computer geeks far and wide are stumped. Of course all the usual steps have been taken. Anyway, back to injectors. No, I certainly don't want to just replace my 33 year old stock technology injectors with the same. Seems most sets out there are of the Bosch III Design. The difference seems to be in the "Pounds", What are the original? I'm thinking 22 Lbs. I like the idea of simple mods. The same Poundage but with the Bosch III Design, better flow, spray pattern, direct fit, etc.

There are many out there to chose from. The first thing I noticed of course is the Pounds thing, starting at 22 and, I believe there was one at about 56-57, and several in between. Then there are used, refurbished, new... different warranties... prices all over the place...and every seller claims to have the best of the best, and a list of procedures done to ensure theirs really are the best of the best. I decided that the design should be Bosch III, since everybody seems to rant and rave about it. Then I thought I should get the Pounds right. I asked a couple of sellers and one said 22 Lbs. was Ok. Another was adamant they had to be 24 Lbs. I thought, "Uh-O, Here we go".

I want a better than stock injector. I have a good chance of getting one, but I thought if I also match the Pounds specification, I'll have less chance of something weird developing.I don't want to do any other major mods or special tuning or whatever after I replace these injectors. The car runs Ok. There's a lot I can and will do, without ripping the engine to pieces, to get it to run much better than Ok. All dirty hands agree that a must have upgrade/update should be replacing the stock injectors.

Oh, and I almost forgot to mention, I'm working with a fixed income and don't have hundreds of dollars to spare on upgrading my car. I'm going to try my best to accomplish my goals without having to share bowls with the dogs for a month or so. John

RedHot85Vette

Oh, and Confab, Thanks for the reference, those are always great to have.

confab

If I remember right, 85 injectors lbs rating is misleading because it is measured at a different pressure..

John mentioned this..

But, regardless, you want a modern injector that ethanol will not break down..

I used FIC and I am totally happy.. Have been for years.

But others may have options for you also.

confab

PS: They have a video comparing various injectors, including your stock ones, on the FIC website..

RedHot85Vette

KyleF, Good Tip! If I have to double up the o-rings, are they the same size o-rings? ...or is one larger to create something of a tapered fit?

RedHot85Vette

Tom400CFI, Guys with great know how are fun to hang out with... I have a fantastic "Gary's-u-pull-it" yard very close by. Super dirt cheap prices. Always great specials. You can get an entire engine for $149 dollars. I love to just walk around auto salvage yards just for the thrill of it... the smell is intoxicating. Unfortunately due to health reasons I'm not able to do that anymore. But I can dream, can't I ?! John

Tom400CFI

Heck yeah! I love strolling the yards too...looking, thinking, bargain hunting. .

RedHot85Vette

Thanks! I'll check out the videos. i'm not ruling out any seller right now, just collecting data. I'd like to hear from the guys who bought the less expensive, no name, refurbished, etc... type injectors and see what kind of experiences they have had. I'm going to see what kind of verifiable data I can find about ethanol corrosion. I guess one can assume there's ethanol threat throughout the entire fuel system, and or wherever gasoline comes into contact with anything aluminum, or other metals in general. I bet there's a pretty good fuel system additive, like Lucas, to help prevent such corrosion. It would be interesting to see a cross section of 2 injectors after a year of usage in the same vehicle to see what's inside. Maybe just giving each one a good cleaning to see what comes out of them will do.

BlowerWorks

Oh I so love getting old and remembering 'worthless' **** !!! Anyhow "back in the day" we all used '85 Vette injectors after seeing LPE do so. Why ? They were like 30 pounders (huge right ? - lol) when run at '86 & newer Vette fuel pressure of 42 or whatever. That's because the 1985 Vette ran a very low fuel pressure - stock was like 28 or something !
Point here is the 1985 Vette, with newer injectors, will run LEAN: 22 pounders vs. 30 or so for stock. So if you are going to install 22's or so into an '85 Vette with stock FPR the BLM's will run very high to compensate. Don't remember if you can easily upgrade the '85 FPR, but that's what I would do first. Otherwise you'll need a 30 pounder injector all other things being equal. greg

KyleF

Well, I am an engineer in the OEM automotive world. So, I care a lot.

As BlowerWorks stated, there are differences you need to know about. In this instance, the Fuel Pressure would cause a major issue. I didn't know that about 85's since I have never worked on one. This is why I am telling the OP to read up and do research to be prepared. The injectors are a major component to how the engine runs and shouldn't just be swapped without taking other aspects into consideration.

Joe C

I understand what blowerworks posted, but in stock applications, there is enough latitude within the ECM's operating parameters to account for minor variations within the injectors. now I understand that you can't put 60 pound injectors in a system that was designed for 19, 22 or 24 pounders without affecting something, so as long as you don't mix apples and oranges, things should be fine. BTW, i'm also an engineer - university of dayton (go flyers) - 40 years (jet) engine development, flight simulation and aircraft maintenance training systems. as far as my 85 goes, its stock - quick starts, smooth idle, it runs just fine, so, I really don't care. as I said, i'm not going to over think or over analyze this stuff.

blowerworks - BTW, 85 injectors are 24# and should run around 32 psi fuel pressure at the rails. I seem to recall, my last 90 was running about 37 psi (w/ 22# injectors). i'm sure there is a correlation between 22 or 24# injectors and the fuel pressure. now whether the ECM can compensate for 22 or 24 pound injectors, and there is enough latitude in the operating system, that I cannot answer. most components will have an operating tolerance - fuel pump, pressure regulator, injectors, even the pressure drop across the filter will have a +/- operating window. remember, these are production units and there will be variances in the individual pieces-parts. GM would have to allow for these variances across large production runs or they would have to install adjustable FPR's and/or custom ECM proms for individual cars to balance the numbers. I would venture to guess that stock FPR probably have a minor +/- psi tolerance window of maybe a couple psi. as I said, for stock applications, keep apples to apples and oranges to oranges.

confab

It has been a while, but that sounds exactly right..

Come to think of it, I believe he did sell me different rated injectors and said it would effectively be the same because of the pressures they were rated at.

It's been a while, but it was the difference between 19lbs and 22 or 24?