2g GSX fuel injector tuning / trouble shooting

[Jovie]

Hello, I have a stock fuel pressure regulator, switched to 950cc injectors before upgrading my fpr and now need to move my car up an incline, and suggestions on how I could increase my fuel pressure with the stock regulator in a pinch so I can get the car running ? I have adjusted the tune for the 950s apready. Would a clamp work? If not why not?

 

[curt-s]

Why do you want to increase your fuel pressure after putting bigger injectors in, just to get the car running?
You want to reduce the amount of fuel the injectors will spray in a single injection event, not increase it.

With larger injectors you need to either reduce your MAF signal, telling the ECU to shorten the pulse width in response, which is why some people pair 2G MAFs with 550s on a stock 1g ECU, or you need an ECU capable of being tuned for injector pulse width. The former is right out of possibility because you're now over double the size of stock injectors.

Even an AFPR won't save you from installing injectors that big (or any size). You need to adjust the injector pulse width.

*edit* ok so you've now stated you have a tune for the 950s. As @dwb asks, what pump are you using? You have no profile.

 

[dwb]

What fuel pump are you running? The FPR has more to do with the pump than injectors.

 

[curt-s]

The FPR uses a diaphragm and return restriction (ball/seat) to modulate fuel pressure based on vacuum/boost. The more vacuum, the less fuel pressure as it bypasses more fuel back into the tank. The opposite for boost.

A clamp in place of an FPR to raise the fuel pressure from an unregulated open return only would work if your vacuum level remains constant.
Every time you touch the throttle, your vacuum changes due to engine speed and throttle butterfly position, and thus your vacuum will be all over the place trying to get a car to move. Your fuel pressure, however, will remain constant with just a clamp. That will mean you'll be spraying in way too much fuel when you shouldn't, and way less when you should. The car may even be uncontrollable at that point and could create a dangerous situation, if you could get to it to run at all, because cranking gives a different vacuum than idle run.

 

[Jovie]

The FPR uses a diaphragm and return restriction (ball/seat) to modulate fuel pressure based on vacuum/boost. The more vacuum, the less fuel pressure as it bypasses more fuel back into the tank. The opposite for boost.

A clamp in place of an FPR to raise the fuel pressure from an unregulated open return only would work if your vacuum level remains constant.
Every time you touch the throttle, your vacuum changes due to engine speed and throttle butterfly position, and thus your vacuum will be all over the place trying to get a car to move. Your fuel pressure, however, will remain constant with just a clamp. That will mean you'll be spraying in way too much fuel when you shouldn't, and way less when you should. The car may even be uncontrollable at that point and could create a dangerous situation, if you could get to it to run at all, because cranking gives a different vacuum than idle run.

Sorry for the late response, I was told that the car did have an upgraded fuel pump when I purchased it, what it is I am not sure and have yet to take a look. I just removed the spark plugs ( changed less than 200 miles ago ) and cleaned and recapped those, those were not issues for this. I made sure all connections were secure to and from the sparkplug etc, next, I made sure all connections were good for the fuel injectors aswell, they seemed fine. When I was logging the data the injector duty never got above 2% while cranking. I know that for high z injectors, you must solder the one box together to bypass the register but not for low correct?

I also looked at the MAF Comp area but didn't know what a good point to start is, -Is 53% the same as the global fuel %?

I am currently using the numbers off of the ECM Link web page where it tells me to put in --53 % for the Global Fuel and 330 for the deadtime.

Below I have attached a log of when I was first able to get it to start, after this my car has cranked a few separate times but has yet to fire up, I believe the injectors are not delivering fuel, potentially.

I am currently looking at this thread and have been following this advice (LINK)

 

[curt-s]

Low Z injectors need the resistor pack.
High Z you can use a pre-made plug or just deal with the wiring yourself -- there's guides for it.

If it's got an upgraded pump, it's probably the Walbro 190 or 255, just speaking statistically, although it could be anything.
IF it's the 190, your stock FPR should deal with it fine at vacuum. It will struggle a bit with a 255 but it's better than a clamp. A 255 high pressure, probably not.
Anything larger and, no, a clamp won't solve your problem. You need an aftermarket FPR.

 

[Jovie]

Low Z injectors need the resistor pack.
High Z you can use a pre-made plug or just deal with the wiring yourself -- there's guides for it.

If it's got an upgraded pump, it's probably the Walbro 190 or 255, just speaking statistically, although it could be anything.
IF it's the 190, your stock FPR should deal with it fine at vacuum. It will struggle a bit with a 255 but it's better than a clamp. A 255 high pressure, probably not.
Anything larger and, no, a clamp won't solve your problem. You need an aftermarket FPR.''

Sorry for all the questions but since my previous ( stock 450cc ) injectors were low z there should be no issue correct?
I also plan to install an FPR latter on, I currently am waiting on parts from STM and then I will install that, hoping to have that done by this coming Monday.

My biggest concern at the moment is just getting it running, I feel like I may be completely missing something in my tune ( maf comp ?) or some other values that would make it work?

 

[pauleyman]

You still haven't said why you want to clamp the fuel pressure regulator. You 100% do not need to do that.
It would be the opposite of what you need.
Did this car run previous to the injector install?

 

[Jovie]

You still haven't said why you want to clamp the fuel pressure regulator. You 100% do not need to do that.
It would be the opposite of what you need.
Did this car run previous to the injector install?

I was thinking wrong, I thought that because I upgraded the injectors a higher pressure would be needed.

The car ran previously with the only issues being that it ran rich, it was on around 10 psi of boost at wide open throttle.

I don't really know wear to go from here, i will check the fuel pump later and report back with the model and any info I find.

 

[pauleyman]

If it ran fine before fuel pump isn't your problem. Different injectors changes nothing on that side. Either your ecmlink settings are wrong or you don't have the injectors you think you have. Or possibly both. You may consider pulling those injectors and have them flowed so you know for sure what they are.

 

[Jovie]

I got these brand new from FIC, I belive it has to do with the ecm settings as the flows on these all seem good.

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[curt-s]

So, no, you dont need to mess with fuel pressure. Your FPR will do what it needs to and when you do your injector calculations in link you state base fuel pressure and it generates the amount of compensation (will be negative) for you

The aftermaket FPR allows you to control your pressure when the pump puts out much more than a stock one, and the stock fpr can't handle it. Anything more than a walbro 190 generally requires one but there are exceptions.

Show us what your fuel settings are in link, post a log even if you don't start your engine. It still allows us to see all the settings

 

[Jovie]

So, no, you dont need to mess with fuel pressure. Your FPR will do what it needs to and when you do your injector calculations in link you state base fuel pressure and it generates the amount of compensation (will be negative) for you

The aftermaket FPR allows you to control your pressure when the pump puts out much more than a stock one, and the stock fpr can't handle it. Anything more than a walbro 190 generally requires one but there are exceptions.

Show us what your fuel settings are in link, post a log even if you don't start your engine. It still allows us to see all the settings

I linked the first rough start that I got after I installed the injectors in post #6 this was the first time it started and it quickly sputerd out so I am guessing it was running off fumes from the carb cleaner after this start I got 2 - 3 more stutters then it died again and again until it eventually would only crank and I was getting low flow rates, I will post another log later when I am back ar my home.

 

[pauleyman]

Is this a fresh ecmlink install? You've never ran it before? If so did you switch the firing order? 2gb requires a different firing order.

 

[Jovie]

Is this a fresh ecmlink install? You've never ran it before? If so did you switch the firing order? 2gb requires a different firing order.

No, this has been installed and running the car since I got it. But it is up to date to the best of my knowledge, I followed the links on the ecm link page.

 

[curt-s]

I linked the first rough start that I got after I installed the injectors in post #6 this was the first time it started and it quickly sputerd out so I am guessing it was running off fumes from the carb cleaner after this start I got 2 - 3 more stutters then it died again and again until it eventually would only crank and I was getting low flow rates, I will post another log later when I am back ar my home.

Sorry, didnt see that on my phone.
Carb cleaner?
Nobody sprayed carb cleaner into the MAF did they

 

[Jovie]

Sorry, didnt see that on my phone.
Carb cleaner?
Nobody sprayed carb cleaner into the MAF did they

No, I sprayed carb cleaner into the fuel rail while it was detached and a small amount into each end of the afr, nothing that would hurt it.

 

[pauleyman]

Why don't you just put the stock injectors back in, change settings and move the car. THen you can diagnose what is going wrong. What is it doing? What did you take apart/replace etc? Why did you spray carb cleaner in the fuel rail? What were you trying to diagnose or cause with that?

 

[Jovie]

Why don't you just put the stock injectors back in, change settings and move the car. THen you can diagnose what is going wrong. What is it doing? What did you take apart/replace etc? Why did you spray carb cleaner in the fuel rail? What were you trying to diagnose or cause with that?

Good news, I wad able to move the car up the driveway by pushing it, bad news, one of my old injectors broke while removing them.

The old stock 450 had brittle plastic, brittle seals and in general would need to be rebuilt, I do still have them and could throw them in in a pinch if I really needed but don't think that's the best idea as one is almost completely clogged and they were very unreliable with fuel delivery.

I sprayed carb cleaner into the fuel rail as I had completely pulled it off to give it a clean and figured might aswell, no debries came out and no issues before this.

Tonight I plan on making sure I have no air trapped in the system ( dont know how i would ) and I will pull some more logs trying to start it. I also plan to pull one of the injectors and make sure i didnt do something like forget a cap or something dumb like that. Are their anything else I should try to pull logs oncinorder to get the best assistance possible?

 

[Jovie]

This is the noise aswell as a quick run-through of the car, I have also linked the log going to continue to work on this any help would be great, thank you.

 

[Jovie]

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