Different Injectors, Does it matter?

[eulogious]

Howdy all!

 

So when my 1990 Legacy LS Wagon with a 4EAT starting running like crap the other day, I diagnosed it to be the cylinder number 4 injector was bad. So off to the junk yard I went looking for some injectors. The only ones that I could find in the yard were off a 1990 with a manual trans. So I grabbed the injectors, fuel rail, and all off of it. I have credit at this yard, so even if I have to take them back, no harm no foul as it didn't cost me anything. What I didn't know at the time was that there is a distinct difference between the two... One of them has nipples, the other one does not. Hmmm... After making a few phone calls inquiring about this, I said "Forget it, they are going in anyways, it can't run any worse than it is off of 3 cylinders!" and I slapped those bad boys in fuel rail and all (so I replaced the entire rail on the drivers side and the 2 injectors) and attempted to fire him up!

 

So what do you all think happened?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

It runs just fine. No missing, no funny sounds, just a light ticking of the injectors firing away and a super smooth idle. Took him on a test drive and all is well. Nice power all the way through 70mph and idles like a champ.

 

So after doing all of this and talking with some people, I came on here tonight and did a little research to see what others have done in the same situation, and here is what I found:

 

http://www.ultimatesubaru.org/forum/showthread.php?t=115585&highlight=fuel*+injector*

 

http://www.ultimatesubaru.org/forum/showthread.php?t=88653&highlight=auto+fuel+injector+manual

 

http://www.ultimatesubaru.org/forum/showthread.php?t=89080&highlight=auto+fuel+injector+manual

 

Heres some pics of the two different injectors:

 

Auto:

 

Manual:

 

So what everyone has said is a resounding "NO, DON'T DO THAT!" to swapping the auto and manual injectors and some even went so far as to say that the ECU and all the wiring would need to be swapped, but no reason/facts as to why the need to do that, and nobody seemed to have actually tried it, and if they did, they didn't post back about it and now here I am.

 

So my question now is this. What the hell is the difference between the two injectors besides the obvious, and what, if anything, will happen to my car by using the manual injectors instead of the auto ones over an extended period of time? I know the injectors work since they are running great in my car now, so why would I swap them out yet again for "auto" injectors when the ones in there run just fine? I just really want to know the reasons why they would be different.

 

So if anyone has flow rates of the injectors and any other specs on the two injectors, that would be awesome! Thanks all!

Edited November 19, 2010 by eulogious

[WRX2FFU]

Thats a good question...

 

A couple years ago a mechanic friend of mine called me and he needed 1 injector for a 91 auto leg.

 

 

All I had was manual inj. He just wanted one and would not buy the whole setup from me.

 

I told him that they would work but like you he would have to swap some other stuff over like you did. He did not want to mess with it and ended up getting a new one for big $.

 

His customer was not happy about the bill, but hey.... I honestly don't think you'll run into problems and honestly I can't understand why they used 2 different kinds...

[eulogious]

If I could have removed the actual injector from my fuel rail, the manual injector would have fit. I just swapped the whole rail because I got tired of trying to remove the injector, so I just took the simple way out and swapped the whole thing. So I don't think anything actually HAS to be swapped to make it work the manual injector looks to be the same size as the auto injector so it should just fit right in. I just took the lazy way out

 

Another question... What's with all the different colors of the injectors? What do they all mean? I mean there's grey (N/A Auto 90-91), black (N/A manual 90-91), red (N/A? 92-94?), pink (EJ22T?), yellow (STI?), and they all apparently go to different cars. So what color goes with what? I am really confused on the whole color thing with the injectors...

[GeneralDisorder]

Yes - the pink tops are 22T injectors. They *for sure* flow significantly more than the other's. That much I know for certain but I don't know the differences in the black vs. grey.

 

GD

[wtdash]

Hi,

In your pics, the bottom pink ones are EJ22 Turbo injectors and avl. only on the '91-94 SS and '92-94 TW - 5-speed and Automatics - flow ~370cc. The NA versions flow about 250 (I think).

 

So, did you use those as you listed a '90 Manual injector as your replacment? Very surprised your car ran so well, if so.

 

Also, pretty sure the rails are different in the '89-91 AT vs. '89-91 5-speeds. But if your '90 Manual injectors looked the same as the EJ22T injectors, that would mean the '89-91 5-speed rails match the turbos....which isn't in line w/what I've seen online....check out the Legacy Central BBS.

 

Always been curious about WHY Subaru used all these different injectors?

 

Thanks,

Td

Edited November 19, 2010 by wtdash

[GeneralDisorder]

Also, pretty sure the rails are different in the '90-91 AT vs. '90-91 5-speeds.

 

The rails and injectors will swap between the 90/91 auto/man as well as the 91 to 94 22T.... In fact the rails on the '92 to '94 will swap also but I beleive the injectors will not fit the older/turbo rail. People very often swap the 22T rails for 92 to 94 N/A rails in order to fit the newer WRX injectors, etc.

 

GD

[wtdash]

The rails and injectors will swap between the 90/91 auto/man as well as the 91 to 94 22T.... In fact the rails on the '92 to '94 will swap also but I beleive the injectors will not fit the older/turbo rail. People very often swap the 22T rails for 92 to 94 N/A rails in order to fit the newer WRX injectors, etc.

 

GD

 

 

Should've clarified...the AT injectors are likely not compatible w/Manual rails (and vice versa) on the '89-91, but, Yes, the rails will interchange/fit the intake manifold mounts.

 

Thanks

[GeneralDisorder]

Should've clarified...the AT injectors are likely not compatible w/Manual rails (and vice versa) on the '89-91

 

They are compatible. eulogious's car had one rail with a grey and a black in it (and seems to run fine that way). That's how we know. They also have the same resistance on the driver coil and through threads that I've read the claim is that the flow rate is the same also - thus the question - what the heck is the difference??

 

GD

[eulogious]

Hi,

In your pics, the bottom pink ones are EJ22 Turbo injectors and avl. only on the '91-94 SS and '92-94 TW - 5-speed and Automatics - flow ~370cc. The NA versions flow about 250 (I think).

 

So, did you use those as you listed a '90 Manual injector as your replacment? Very surprised your car ran so well, if so.

 

Also, pretty sure the rails are different in the '89-91 AT vs. '89-91 5-speeds. But if your '90 Manual injectors looked the same as the EJ22T injectors, that would mean the '89-91 5-speed rails match the turbos....which isn't in line w/what I've seen online....check out the Legacy Central BBS.

 

Always been curious about WHY Subaru used all these different injectors?

 

Thanks,

Td

 

Should've clarified...the AT injectors are likely not compatible w/Manual rails (and vice versa) on the '89-91, but, Yes, the rails will interchange/fit the intake manifold mounts.

 

Thanks

 

They are compatible. eulogious's car had one rail with a grey and a black in it (and seems to run fine that way). That's how we know. They also have the same resistance on the driver coil and through threads that I've read the claim is that the flow rate is the same also - thus the question - what the heck is the difference??

 

GD

 

Yup, I got 3 "black top" injectors now and one gray top. The black top one was in my car when I bought it. Never noticed it running funny.

 

The injectors that I pulled came off of a 1990 legacy with a manual transmission. Here is the passenger side fuel "rail", this is the actual one I pulled:

 

 

 

 

And here are the ones that I pulled from the drivers side of my car:

 

 

Here is a shot of the "manual" injectors installed on my drivers side:

 

 

And here is the passenger side, keep in mind I did not touch this side at all:

 

 

All I did to install the injectors is remove 6 bolts, pop out the old injectors, pop in the new injectors, and then re-insert the 6 bolts. That's it.

 

So this is why I am curious as to why the different injectors, and what is really different between the two. Because right now my car runs fine with a mix of manual and auto injectors, and the ECU isn't complaining at all.

 

To quote Gloyale from another thread:

 

 

You can swap the whole intake (or just the rails) from 92-94. With those fuel rails, you can use any red top injector from a 2.2 or a 2.5 up to 99(phase I)

 

This is what I recommend to people with 90-91s that begin having repeat injector problems.

 

They all flow the same, and have the same resistance. There is some variation in the nozzle design, but it makes no real difference in running.

 

and this statement is backed up by my recent adventures. So I still wonder why the different type of injectors? There must be a difference, but apparently it really doesn't matter when it comes to the car running, but I would still like to know...

Edited November 19, 2010 by eulogious

[eulogious]

Alrighty,

 

After spending some hours reading up on injectors, I think I might have a clue as to the differences in the injectors. Not really why subaru used 2 different types (I do have some ideas), but at least the main differences between the 2.

 

I came across this site that showed the different type of injectors, but didn't really lead me to anything conclusive:

 

http://www.sdsefi.com/injectors.htm

 

Then I found this...

 

To qoute http://importnut.net/ignitionfuel.htm :

 

Fuel Injectors

There are two common types of fuel injectors, pintle and disc (Lucas style). Pintle injectors have a superior spray pattern to disc actuated injectors, but disc injectors are less expensive and generally flow large amounts of fuel easily. If possible, always choose high flow pintle style injectors, as fuel atomization at anything other than full throttle (high velocity port flow) is superior, leading to better drivability and economy. Below is a picture illustrating what I mean about the spray patterns…

 

 

I highlighted the important part...

 

So that at least told me about the different type of injectors, pintle (auto) and lucas (manual). Now I was getting somewhere.

 

After some more searching I found this:

 

From http://www.pistonheads.com/gassing/topic.asp?h=0&t=703652 :

 

Over the years I have done a great deal of research into this matter, in the form of reading and experimentation. I am also privileged to have access to very thorough research on this subject done by major motor manufacturers and component suppliers (e.g. Bosch, Land Rover, etc). Although I cannot pass it on directly, I can at least give you the distilled essence.

 

The standard RV8 pump is indeed rated at 3.0 Bar, although it is only operated at 2.5 Bar so there is a useful margin available. There are a number of effects of increasing the fuel pressure which must be considered, and the results for the pump and injectors are quite different.

 

Firstly, increasing the fuel pressure will obviously put more strain on the pump. The flow of fuel through the pump provides it's cooling, and flow drops generally in a non-linear manner with increasing pressure (usually logarithmic).

 

In general, increasing pressure will improve the atomisation of the injectors for pintle and type II/III designs but not for the Lucas disc type. All fuel injectors are for a specific operating pressure, or pressure range. The effects of increasing the pressure are heavily dependant on the design.

 

For the Lucas disc design, increasing pressure will increase the flow up to a point. The injector has an upper and lower disc. The lower disc has a hole in the centre (the metering orifice), and the upper disc is lifted by the electro-magnetic solenoid to allow fuel to flow.

 

It is quite obvious that the higher the pressure, the harder it is to lift the upper disc to allow fuel to flow. This results in a much longer and more unstable opening time for the injector. After 3.3 Bar the fuel flow will actually start to decrease and become more unstable as the electro-magnet struggles to overcome the force of the fuel pressure closing it.

 

This also requires that the battery voltage compensations in the ECU are adjusted accordingly, since they are dependant on operating pressure.

 

Additionally the Lucas injector does not produce an atomised spray through the metering orifice. This function is provided by the plastic diffuser underneath, which is supposed to break up the jet into droplets. Quite often there is no atomisation at all.

 

To show you what really happens I have a couple of pictures for you. Here is a picture of Bosch (left) and Lucas spray patterns side-by-side in the injector cleaning machine at TVR Power:

 

 

Now here's another shot done with a faster exposure, using the machine at Shropshire Auto Service. You can clearly see the large droplets in the stream from both the Lucas injectors on the left.

 

 

In the simplest terms, fuel droplets burn from the outside in. It follows that the smaller they are the quicker they burn, hence releasing more of the energy contained in the fuel. Ultimately this gives the most efficient use of the fuel, and the cleanest exhaust emissions. There is a minimum size for fuel droplets, but it is not seen outside of Formula One where no engineering effort is spared.

 

Ever more stringent emissions legislation has driven advances in fuel injector design. Improvements in manufacturing technology have produced some far more effective fuel injectors, with the aim of producing more efficient combustion. Some of the best designs are the Bosch Type II and Type III versions.

 

Fuel enters the combustion process by two methods for this type of manifold injection system. Firstly there is fuel which is pulled from the manifold walls by the air stream entering the combustion chamber when the inlet valve is open. This fuel is deposited on the manifold walls by the injectors when air is not flowing in the inlet tract. During this time the fuel deposited will evaporate in a warm engine, so the smaller the droplets are the better and faster they evaporate. Some fuel droplets remain in suspension in the air in the inlet tract, and again the smaller they are the better.

 

During recent testing on standard TVR 5.0 Litre engines, the injectors picked up 8 lb/ft of torque everywhere over a hand picked flow-matched set of brand new Lucas originals. This has been accurately and scientifically tested dozens of times, and is always the case.

 

Interestingly the improved torque required 2-3 Degrees less ignition advance, denoting improved combustion speed and efficiency. If you simply put in an injector with better atomisation, you will indeed see a drop in power because the ignition timing is now too far advanced for the reasons given above.

 

When mapping a car and selecting injector sizes, the injectors should run no more than an 80% duty cycle at any point in the map. Obviously the time available for injection decreases with rising RPM. This limit is necessary in order to allow for transient fuelling (sudden throttle opening), and proper response when the engine is cold amongst other factors.

 

Whilst it is true that the standard Lucas injectors can be operated on motors producing 350BHP, it takes them to 100% opening at pressures well outside the operating envelope. I have asked this before and have never been given an answer - can anyone please tell me what the duty cycle was THEY MEASURED on one of these 350BHP cars? I think not.

 

A slight protrusion into the inlet air stream is permissible and can help mixture whilst air is flowing in the inlet tract, although injection during this time is undesirable since it can produce a non-homogeneous mixture. However the depth of protrusion can be adjusted, since the legs of the fuel rail are rather bendy!

 

I highlighted in red the important part about the lucas injectors.

 

Then I came across this tidbit from nabisco http://forums.nasioc.com/forums/showthread.php?t=96571 :

 

Keeping the mixture atomized in the cylinder is one thing, but conditioning the mixture prior to delivery is another story. Our experience has been that as the velocity of the air traveling through the port increases, the spray pattern should become more confined.

Fan-type spray patterns (pintle) are best suited for low rpm operation, therefore giving excellent mileage and emissions, but the fan pattern can get lost in a hurry as port velocity increases.

While I'm not all that keen on the laser-beam style pattern provided by the Lucas (RCE style) injectors for low speed applications, they do work pretty well with these high rpm engines, as their stream penetrates and mixes with the high velocity flow with ease.

 

--

.....The Old One....

 

I highlighted the important info here as well...

 

So putting this all together, this is what I came up with regarding the differences in the injectors, and why subaru might have used the two different types, instead of just sticking with one type. So feel free to correct me if I am wrong on this Here it goes...

 

So with the pintle type of injector (auto), you get a good spray pattern going into the cylinder at all times, and this is important in the lower RPM range for better fuel economy and what not. This is important on automatic's because the car spends most of it's time in the lower RPM range under normal driving. I know in my car I barely go over 4000 RPM on my way to work, so having a good spray pattern makes sense in an automatic car, since it's normal RPM range is lower than that of the manual cars because the computer keeps it that way. So in order to make up for some of the loss in MPG, Subaru must have used the pintle injectors to try to offset the MPG loss that comes naturally with the design of the auto. I should also note that the pintle type of injector is more costly to make as well when compared to the lucas disc type of injector. So due to the pintle injectors being more money and not as efficient in the upper RPM range, they only put them into the auto's.

 

Now the lucas injectors (manual) apparently perform better in the higher RPM range, which is great for a manual car since it will spend more time above 4000 RPM than an auto would, so it would make sense to use the injector that works better with more airflow (higher RPM), hence why that type of injector was only used on the manual cars.

 

This is my theory anyways, so please correct me if my logic/thought process is off

 

Another thing I noted was that both type of injectors flow the same, and that changes with the turbo models of course, but other than that, both type of injectors do flow the same.

 

So at the end of the day, it looks like the only difference between the two injectors has nothing to do with the computer used or different sensors that are used, but has more to do with cost and MPG, go figure

 

One thing that I will keep track of is my gas mileage to see if it changes at all. Of course since my trans is refusing to lockup the torque converter, I don't get very good gas mileage as it is, but I will keep an eye out and see if it changes any.

 

It's good to know that there really isn't a difference in the injectors, just the implantation of the injectors themselves, that is unless my mileage changes drastically, then I will look more into, but until then it doesn't look like there is much of a difference between the two. It's also good to know that the ECU can compensate for either type of injectors as well No need to replace anything besides the injectors themselves

 

As to the colors, I found nothing that really helps me out there...

Edited November 20, 2010 by eulogious

[GeneralDisorder]

Cool! The more you know......

 

Now I'm wondering which style the red-tops are? They seem to be pretty much the most reliable of the 90 to 94 injectors.....

 

They have 4 holes in the business end (which is metal)..... so they seem more like a disc injector - maybe with an improved spray pattern?

 

It would seem that the best approach is to just swap out the grey-top injectors for the red-top's and associated rails since those are drastically cheaper injectors and were used on auto and manual.

 

GD

Edited November 20, 2010 by GeneralDisorder

[Gloyale]

Cool! The more you know......

 

Now I'm wondering which style the red-tops are? They seem to be pretty much the most reliable of the 90 to 94 injectors.....

 

They have 4 holes in the business end (which is metal)..... so they seem more like a disc injector - maybe with an improved spray pattern?

 

It would seem that the best approach is to just swap out the grey-top injectors for the red-top's and associated rails since those are drastically cheaper injectors and were used on auto and manual.

 

GD

 

Yeah,the red ones you can find easy. They are on all 92+ 2.2s and I believeall the Phase I 2.5s

[wtdash]

eulogious,

Nice write-up and thanks for taking the time to look into it.

 

Maybe Sticky material?

 

Td

[eulogious]

Cool! The more you know......

 

Now I'm wondering which style the red-tops are? They seem to be pretty much the most reliable of the 90 to 94 injectors.....

 

They have 4 holes in the business end (which is metal)..... so they seem more like a disc injector - maybe with an improved spray pattern?

 

I believe you are correct on this. I saw those injectors in my research but really didn't go any farther than glancing at the pic of them. They seemed like the disc type with an improved spray pattern, probably subaru trying to get the best of both worlds. But this is just an assumption on my part, since I didn't really look into the red top (later year) injectors while researching I just glanced and the pic, but it would make sense that they would do that.

 

It would seem that the best approach is to just swap out the grey-top injectors for the red-top's and associated rails since those are drastically cheaper injectors and were used on auto and manual.

 

GD

 

Yup yup, and this would tie into possibly why the red top injectors have different holes than the earlier injectors, to save on cost by only needing to stock and make one type of injector. I guess that's what I get for buying a car that was produced in 1/90 It was probably literally one of the first few to roll from the factory. So it only makes sense that they would find a good compromise at some point in the future, since it is kinda silly to have 2 type of injectors when it really isn't needed.

 

Now when I go to a yard, I am going to be on the lookout for the different injectors and the rails (red top) to just have on hand, since I still have one grey top injector. So it will probably be a good idea to have a backup set on hand.

 

eulogious,

Nice write-up and thanks for taking the time to look into it.

 

Maybe Sticky material?

 

Td

 

Thanks man!

 

I just don't like not understanding what I am doing or changing in my car. If I change something like an injector that looks and seems completely different than the one I am replacing, I want to know the most I can about what just happened. I am just anal that way That's why it took me 4 months to do my paddle shifters, I wanted to understand assembly language, which I had to teach myself… Good times, but speaking of paddle shifters and gas mileage…

 

So earlier today I decided to install my paddle shifter TCU into my car to see if it even worked, since the chip I got that has the firmware on it was "damaged" by USPS, so I plugged it in, and then I got no powerlight flashes!! I took it on a test drive and I finally have torque converter lockup as well! YAY!! :banana: Paddle shifters for the win! Who woulda thunk that 10 months ago my paddle shifter project was going to solve my transmission duty b problem? I love it when a sweet mod actually FIXES your car instead of messing it up

 

So I guess I won't really be able to test my gas mileage since I fixed my trans problem and my gas mileage should get ALOT better now that I have torque converter lockup. Oh well, I don't think that the different injector is really going to make a big difference in the overall picture when it comes to gas mileage. Whatever. At least I know my car isn't going to blow up now! I am on a subaru fixing roll here! Now time to remove my loyale's disk brakes :-\

 

Thanks for all the help everyone!

[eulogious]

I have some more info here regarding the use of the "redtop" injectors that was interesting and makes sense. This is qouted from Legacy777 on legacycentral:

 

http://bbs.legacycentral.org/viewtopic.php?f=5&t=45526&p=345310#p345310

 

The injectors are paired to the ECU. The 90-91 non-turbo legacies had two different ECU types, Hitachi & JECS. MT's had the Hitachi ECU and AT's had the JECS ECU. As long as you're using a 90-91 non-turbo injectors, I don't see any major issues in swapping them. They are supposed to have the same flow rate.

 

The only issue I see is the spray patterns could be different so you may get some differences in fuel atomization & mixing in the cylinder. Is it a big deal, probably not.

 

In 92, all the non-turbo legacies went to the JECS ecu for both MT & AT, and have different injectors (red tops) from the 90-91 non-turbo legacies. I swapped these into my 90 legacy and ran them on the 90 legacy ECU. From my experience the car seemed to run a little on the rich side (too rich) with the 90 ECU. Power was a little less, fuel mileage wasn't as good, and the car just wasn't as "snappy". I then switched to a 92 JECS ECU, and the power was better, fuel mileage was better, etc. That leads me to believe the 92-94 non-turbo injectors may flow a little more than the 90-91 non-turbo injectors.

 

The 92-94 JECS ecu is plug & play. The only thing I did have to do is alter the MT/AT identifier pin. For some reason on the newer JECS ecu's that pin on the ECU is wired backwards from how the 90-91 ECU's were wired and how the factory manuals indicate.

 

I'm not sure if this was unique to my 92 JECS ecu or if it is common to all the 92-94 JECS ecus. Here's a little more info from my swap page.

 

http://www.surrealmirage.com/subaru/swap/electrical.html#ecu

 

So there is some more info about swapping the injectors for the redtop ones. You should grab the ECU as well. Makes sense that they made them flow a little bit more and then changed the ROM on the ECU accordingly. But good to know! I just thought I would add this info for the good people here

[Legacy777]

Thanks for posting that over here

[1-3-2-4]

sorry late here but at least for my 95 Legacy the red injectors are NON California spec car..

 

If you have Grey fuel injectors it's for a car California.

[coldfusion21]

awesome info guys! im gonna hunt down a set of rails and swap to newer injectors for sure now!

 

Can someone take a pic of a old style rail next to a new style? I wanna make sure i got the right parts.

 

I just bumped another thread on this same topic, maybe i should post a link to this thread as well for anyone that goes looking in the future?

[eulogious]

I just did that for you, glad you found it

[heartless]

ok, so if i am reading all of this correctly, I could swap injectors/rails on my 90 auto Lego to the newer red top ones by including the ecu with pin swap?

 

that would be so sweet - have had injector problems in the past - went with rebuilts and all is good for now, but would be nice to know that it is possible to "upgrade" if needed.

[1-3-2-4]

Looking at the fuel rail pictures here can I pull the whole fuel rail out without worrying about the orings?

[Legacy777]

ok, so if i am reading all of this correctly, I could swap injectors/rails on my 90 auto Lego to the newer red top ones by including the ecu with pin swap?

 

that would be so sweet - have had injector problems in the past - went with rebuilts and all is good for now, but would be nice to know that it is possible to "upgrade" if needed.

 

To swap to the 92 red top injectors, you will need the ECU, injectors and fuel rails. The fuel rails are different as well.

[eulogious]

ok, so if i am reading all of this correctly, I could swap injectors/rails on my 90 auto Lego to the newer red top ones by including the ecu with pin swap?

 

that would be so sweet - have had injector problems in the past - went with rebuilts and all is good for now, but would be nice to know that it is possible to "upgrade" if needed.

 

Yup, that's what I plan on doing now, just make sure you include the rails like legacy777 mentioned... I am going to be on the look out for the redtop injectors and ECU at the yard...

 

Looking at the fuel rail pictures here can I pull the whole fuel rail out without worrying about the orings?

 

I didn't do anything with the O rings. I just used what was there, so I guess yes? to your question?

[heartless]

very cool - nice to know I have other options if I need them.

 

Thx guys.

[scott6058]

Legacy777

Your the man:Flame:

You saved my car from certain doom.

I easily obtained red injectors and rails with the ECU for $80.00.

My sub never ran better.

I swapped the ECU from MT to my AT and had zero volts at pin 20 so I left it alone. Is this alright? Thanks again I love your site and you guys are the best:banana: