Use 750cc Trilogy Turbo primary to get rid of lean?

[HeroJr]

Hey all!

 

I am working on getting my injectors set up on my two cars, because I would like to sell my red 88. Here's the quick story - my silver 89 came with the Trilogy Turbos 650cc / 950cc Delphi injectors. I think they have around 3,000 miles on them maximum. The car always idled lean. I have a wideband AFR meter and I usually saw 15.5 to 17.6 on that at idle and partial acceleration. It did boost rich, dipping down into the 10s on AFR. Once the O2 sensor warmed up the car wanted to run at stoich, but if it cooled back off, it was back to lean.

 

I pulled the stock injectors off my red 88. The silver 89 idled at 13.0ish and did partial throttle and cruise around 14.7. Perfect! Except now I need to sell my red 88 and give it back its injectors. I had a few extra injectors that came with the silver 89. I put each of two primaries on and got the same performance : 13.0ish at idle and stoich at cruise. However, my extra primary injectors have slight leaks from their plastic. My extra secondary injector leaks like crazy! When I swap the Trilogy Turbos back on, I get the same lean numbers. When I read on this forum, it seems like LOTS of people get lean numbers with the 650/950 Trilogy pair...

 

So, I don't really have any stock injectors to use on my silver 89 and I worry that all stock injectors will eventually leak from their plastic bodies.

 

Could I get a 750cc primary from Trilogy Turbos (or somewhere that offers a 750cc Delphi/Lucas) and perhaps have a richer idle and partial acceleration? My simple math said that the 750cc has a 16% greater flow than the 650cc. When I multiply that times my low end AFR number of 15.5, I get 2.5. Would that pull my idle back down to 13.0 or at least somewhere in the vicinity until the O2 kicks in? I know you can't really know until you put the injector on, but is that a reasonable guess?

[Caliber308]

Do you have a way to adjust your A/F Ratios (Maf-T) or the like? I see your running a Stock MAS. First. you need a way to adjust your fuel pressure when using Delphis. Delphis require at least 40 to 45 psi Fuel Pressure to operate properly. So, you don't have a way to adjust your Air/Fuel ratios and you don't have a way to increase your Fuel Pressure. Correct? If this is the case, increasing your Primary Delphi Fuel Injector size from 650cc to 750cc will not help you out. From reading the modifications in your signature, you forgot about installing a Maf-Translator (or the like) for Air/Fuel adjustments and a Adjustable Fuel Pressure Regulator to increase the FP for the Delphis.

 

Bill

Edited October 28, 2013 by Caliber308

[HeroJr]

Bill, Thanks for your thoughts. The car had a GM MAF and MAF-T on it when I got it. As I grew dissatisfied with how lean it ran (and how that caused it to buck at part throttle), I decided to take the car back to a more stock like configuration. There were other issues too, but basically I put the stock MAS back on, put a stock cam back on plus mechanical rockers.

 

The car does have a Walbro 255 lph fuel pump. In your opinion, could I install an adjustable fuel pressure regulator, bring the pressure up to 43.5 pounds (or perhaps up to 50 pounds) and then receive good AFRs from the Delphis? I am leery of going with another MAF-T - for now I'd like to keep the stock ECU and stock MAS because my car runs so nice on stock injectors (they just leak a tiny bit).

[scott87star]

The ugly truth is you need to either stick with totally stock bits that are working correctly or make the jump to totally adjustable bits and make it run the way you want. Your math is linear, tuning is not so telling you to go buy another injector is wrong as it may work but likely not. Turning up the fuel pressure again isn't linear, meaning adding 5% or 15% fuel pressure will not give you 5% or 15% more fuel. You either need to be able to fully adjust things based on solid AFR numbers or go back to totally stock parts that you know are working correctly, and that is getting harder and harder as our cars and electronics age.

[importwarrior]

another possibility is that your injectors are pushing so much fuel that not all of it is

burning and the fuel is getting to the wideband and cooling it down causing a false lean

condition you see on the gauge.

 

i know it is a long shot but has happened before.

also MAFT is tuned impropery.

[HeroJr]

importwarrior - Thanks for the idea. I don't have a MAF-T on the car; it's a stock MAS.

 

scott87star - Thank you for your input. You have confirmed what I have been thinking - that doing a really strong stock build is getting harder and harder because essential bits like injectors are NLA from dealers or Mitsubishi. I think I am going to have to figure out how to keep my stock injectors with my silver car and figure out something else with my red car. This has also got me thinking that I might need to research MPI for down the road.

[BC_99]

Bobby are you certain that they are NLA? I can check the site I told you about that sells parts from Japan and see if they are available there. Looks like its about $400 for the pair from them, if they are available.

 

BC_99

[HeroJr]

BC_99 - So, I guess I spoke too soon when I said they were NLA. I do see them on that site you told me about. I also found them on oemmitsubishiparts.com - for $825.95!!! Now that I am Googling a bit harder, I am finding them on a few different Chrysler and Mitsu places for about $800 for the pair. That's too steep for me!

[Caliber308]

BC_99 - So, I guess I spoke too soon when I said they were NLA. I do see them on that site you told me about. I also found them on oemmitsubishiparts.com - for $825.95!!! That's too steep for me!

 

Me too This is why I suggested that using Delphis require at least 40 to 45 psi Fuel Pressure. Your not going to get that from the Stock Fuel Pressure Regulator (34 to 38 psi) or a Aftermarket Fuel Pump. Also, when using Delphis, in order to adjust the Air/Fuel ratios and achieve the proper Fuel Pressure Regulation with the Delphi Fuel Injectors you will need Fuel Management and Fuel Pressure Regulation, in other words, something that will allow you to adjust your Air/Fuel ratios and Fuel Pressure Regulation. Seeings how you already have a Wideband gauge and Delphi Fuel Injectors, the next step is to install something that will allow you to adjust your Fuel Pressure Regulation and Air/Fuel Ratios.You can't do this with the Stock MAS. That is why I suggested that you install a Maf-Translator with a GM MAF and a good Adjustable Fuel Pressure Regulator. This is the most inexpensive way I know of to enable you to get your car running properly

 

I have gone from Stock to Light Mods to Heavy Mods over the past 11 years. I'm giving you the knowledge I have gained over the years in modifying these cars so you can accomplish your goals.

 

You can not adjust your Air/Fuel Ratios with either the Stock MAS or the 1st Gen MAS or run Delphi Fuel Injectors on the Stock Fuel Pressure Regulator max. psi of 38. Believe me, I know.

 

Been there, done that.

 

 

Bill

Edited October 30, 2013 by Caliber308

[HeroJr]

Bill,

 

I appreciate your coming back to the thread and adding your ideas. I think I will eventually get to some mods, but my time is very chopped up due to my job and having a young child. I don't mind the challenge of figuring out tuning issues, but I usually only have a few hours a week maximum to work on the car. So, complex tuning stuff can mean my car gets stranded in my driveway for months.

 

I have already gotten a 2G Mitsu MAS from the pullapart off of a low mileage Galant, that is the same MAS that was on the Eclipse. I think I will eventually get a MAF-T Gen II and use my 2G MAS similar to what Frenchi did in his 89 that was wrecked. It may just have to wait a year or two to make that situation work. For now, I think I can figure out something with the one pair of stock injectors I have that seem okay.

[HeroJr]

I should clarify - I have one pair of stock injectors that does not leak and one pair that does leak, especially from the secondary. My problem is that I also have two Conquests and would like to sell one to focus on the one in my signature. Anyway, everyone's ideas and thoughts have been very helpful in helping me think through what I can attempt.

[scott87star]

Also, when using Delphis, in order to adjust the Air/Fuel ratios and achieve the proper Fuel Pressure Regulation with the Delphi Fuel Injectors you will need Fuel Management and Fuel Pressure Regulation, in other words, something that will allow you to adjust your Air/Fuel ratios and Fuel Pressure Regulation.

 

Also known as totally adjustable bits.

[Jody1]

I have read on this forum that the injectors being marketed by Mitsubishi are not stock, although they are marketed as such.

 

The "new" stock injectors are purportedly ~850 Not staggered as the stock ones were. This is indicated by the # etched on the injector.

[BC_99]

Bobby, weren't you on Maft when you got the car initially? if you were and still have that stuff you may look into the stock replacement adjustable FPR in the GP section so when you do decide to start modding and tuning, you will have all the stuff you need.

 

Bill, I have the GM Maf/Maft on my car and the Maft is zero'd out and I am tuning with the apexi SAFC which piggybacks into the stock ecu. It has a much finer adjustment range than the Maft alone. My question is, could you not tune with the apexi and a 1g or 2g maf or even a stock maf to overcome some of these issues? Just a thought...

 

BC_99

[HeroJr]

Britt - I don't have the MAF-T itself anymore. It was the first gen one. The person I sold it to told me that he had an electrician friend look over it and that it was "all out of whack" and put some bits back together correctly. In any case, if you look at Frenchi's 89 build, he installed the MAF-T Gen II and it had settings such that you could use a 1G MAS and he did that with his stock MAS initially. So, I might do that next Summer and run Delphi or Lucas injectors. The MAF-T Gen II like the apexi unit has much finer grades of fuel adjustment.

[Caliber308]

Bill, I have the GM Maf/Maft on my car and the Maft is zero'd out and I am tuning with the apexi SAFC which piggybacks into the stock ecu. It has a much finer adjustment range than the Maft alone. My question is, could you not tune with the apexi and a 1g or 2g maf or even a stock maf to overcome some of these issues? Just a thought...

 

BC_99

 

I have never had to use a SAFC in conjunction with the 1st Gen MAF-Translator (w/ the GM MAF) to enable me to adjust the A/F Ratios correctly. In my case, I'm using:

 

1st Gen MAF-T.

3" GM MAF.

Aeromotive Adjustable Fuel Pressure Regulator.

950 Primary/1150 Secondary Delphi Fuel Injectors.

 

My A/F Wideband ratios:

 

12.50 afr at Idle.

14.50 afr at Midrange.

11.50 afr at Wide Open Throttle.

 

Why use a Stock, 1st or 2nd Gen MAS??

 

You will get better airflow with a GM MAF. Cost for a good used one.......$75.00. Cost for a 1st gen MAF-Translator...$199.00. Cost for a Air Filter.....$25.00. How much is a Apexi SAFC? perhaps $250.00.

 

So. The way I see it is this. Your adding $250.00 for a Apexi SAFC that is not really needed. The poster just needs to get away from the mindset of using a Stock, 1st Gen or 2nd Gen MAS.

 

I am trying to tell the poster the most inexpensive way to enable him to adjust his A/F Ratios. After all, his car is mostly Stock. I already addressed what is needed to run the Delphi Fuel Injectors (40 to 45 psi regulated Fuel Pressure. As far as adjusting his Air/Fuel Ratios, I addressed that too, with suggesting that he install a 1st Gen MAF-Translator, GM MAF, a good Air Filter and a Adjustable Rising Rate Fuel Pressure Regulator.Total cost: around $550.00. With the money he saved by not installing a Apexi SAFC, he should be able to afford these upgrades. Modifying these cars is not cheap. Changing the Stock Fuel Injectors to Delphis......You will need increased Fuel Pressure Regulation. Need a way to be able to set your Air/Fuel Ratios according to acceptable limits? Install a MAF-Translator (1st Gen) GM MAF,and a Air Filter that allows you a way to adjust them at a reasonable cost.

 

You can make a Starquest run richer by installing a larger Delphi Primary. But if it is too rich, how are you going to make it run leaner at a Idle? I know how. And have explained it in the above post the best I can.

 

Good Luck,

Bill

Edited November 4, 2013 by Caliber308

[BC_99]

Good info Bill. I got my apexi unit used for $125ish but I wasn't aware the fpr needed to be upgraded for delphis until you mentioned it earlier. However I still want to know if the apexi piggybacked into the ecu with a 1g or 2g mas could work. Regardless of which is cheaper.

 

BC_99

[Caliber308]

Good info Bill. However I still want to know if the apexi piggybacked into the ecu with a 1g or 2g mas could work. Regardless of which is cheaper.

 

BC_99

 

To me, it is a waste of time and money, especially for a 1st or 2nd Gen MAS. I already stated that a GM MAF gives you better airflow.. You also need to clarify on which ECU your talking about: 1987 or 1988/89.

 

1987 ECU:

MD084852, MDO71084,MD111820, MD106394.

 

1988/89 ECU:

MD120197.

 

Irregardless, the GM MAF supplies better airflow than either the Stock, 1st or 2nd Gen MAS does. That tells me this, whether or not a Apexi SAFC "piggybacked" into the ECU on a Stock, 1st or 2nd Gen MAS works....Is a mute point. After all, less airflow is less airflow. No matter how you try to spin it.

Bill

Edited November 4, 2013 by Caliber308

[BOHO]

The GM Maf wouldn't give you better airflow. The SAFC manipulates the signal the same way.

[Caliber308]

. Edited November 4, 2013 by Caliber308

[19cturbo]

 

 

BOZO,prove to me that the GM MAF doesn't flow more air than a 1st Gen,2nd Gen or Stock MAS does. All you have to do is look at all of them. Even a blind man can see that the GM MAF is "unrestricted" and will provide more air flow than ALL the Mitsubishi Mass Airflow Sensors ever built.

 

Bill

 

wow, thats very mature, just manipulating someones name and taking a personal stab like that, i guess with mods in your back pocket you can get away with that sort of thing but others cant even make a funny. and i was just curious, do you have the numbers to prove that the GM does in fact flow better? or is it just the visual aide enough for you without solid numbers and proof?

 

 

 

 

 

Read my posts throughout this thread. Then tell me why I need to install a SAFC "piggybacked" to my ECU, when I only have a 1st Gen MAF-Translator with a GM MAF installed on a 1989 ECU that works just fine.

 

Bill

 

Read his post, i dont recall anyone telling you that you "NEED" to install a SAFC, all he said is it manipulates the air flow signal the same way. Either way will work "just fine" bill, but just because you done it one way and someone else does it another doesnt mean one is right and one is wrong.. im pretty sure that no where in the FSM does it advies you to install a MAF-translator and a GM MAF. so technially your setup is wrong as well

[BOHO]

Not sure why your name calling for me making a simple post....HeroJr, Is your setup draw through or blow through...as this is a big difference in the setup. I'd like to understand why you believe it flows better or why it would give you better afr's vs an SAFC setup. I also didn't say you needed an SAFC.....Really confused why you are being so defensive....I would like to help Hero get his car running the best it can be.....

[Caliber308]

im pretty sure that no where in the FSM does it advies you to install a MAF-translator and a GM MAF. so technially your setup is wrong as well

 

Doing troubleshooting and repair work according to the Factory Service Manual, and doing modifications to these cars are two completely different things. I know how to do both.........Do you?

 

Funny. Not one member that I have given advice to concerning the Factory Service Manual or doing modifications to these cars has ever told me that I was wrong in providing the information to them.

 

Try it

 

Bill

Edited November 4, 2013 by Caliber308

[HeroJr]

BOHO - I think there are two different topics being talked about here -

 

1) Can you use aftermarket injectors on a mostly stock (stock MAS, stock ECU, stock fuel pressure regulator) setup? The answer seems to be no. That was pretty much all of my question.

 

2) If you ARE using aftermarket injectors, what are the best pieces to support those? Caliber308 is making some suggestions, and I think his primary concerns are price and performance. So for the least amount of money and the most amount of airflow you can use his setup. And I think that's fine. For the moment, I will be sticking with stock (stock MAS, stock ECU, stock fuel pressure regulator). I have not driven my car or worked on it that much, so I want to do stock before I dive into modifying. When I do modify mine personally, I will either go with MPI, which is a whole other can of worms, or go with a 2G Mitsu MAS and a Gen-II MAF-T because I want to have the same general setup as the 0G MAS we have, which has corrections and readings for barometric pressure and so on. From what I have read (and experienced when I first got the car), the tune will slip as the seasons change because the GM MAF does not have sensors for anything other than airflow. I will never be modifying my car for maximum power, but some combination of power, driveability, reliability and so on.

[HeroJr]

Oh, I also realize that my sig has lots of mods listed. That's how I bought the car. I bought it because it ran and the body was very, very dry. I have already returned many pieces to stock, particularly where fuel delivery are concerned. I don't see the need currently to disassemble the head or downsize the exhaust which are my two major non-stock systems remaining. I am working on lowering the boost on my 19C and will switch out the Stage 4 clutch for something much more streetable.