Running Rich?

[ADrewzki]

An eprom is a chip designed to have data written to it. In this case, fuel maps, timing, etc for your dsm. There are different instances when you would need an EPROM.

The EPROM+keydriver is basically a small ROM chip that has had data flashed onto it. You would swap the EPROM out each time you wanted to load a different set of data.

The EPROM+dsmlink is a small ROM chip that can have it's data values rewritten by dsmlink via laptop thus allowing you to change your fuel maps or timing on the fly.

The SAFC is what's known as a piggy back computer. It ties into the signals sent to your ecu and modifies them slightly to achieve a desired effect.

You will always keep your stock mas. Running without one or a modified one will give you problems unless you switch to a MAFT setup (that is a little beyond what you need now though).

And might I add, this thread has been one of the most informative and well written ones I have ever read.

 

[BoostedTalonTS]

Just to ad to the post above... You basically have two basic routes:

1) EPROM ECU + new EPROM flash program (including getting the ECU socketed for a new chip), an AFC (1 or 2, whatever), a logger, and other mods (like the POT mod that I linked to earlier, MAS hacking, changing base fuel pressure, etc, etc...). -Generally the CHEAPER alternative, depending on the number of DSM buddies that you have to help you out!

-OR-

2) EPROM ECU (Also having to get it socketed) + DSMLink (functions as both a logger and a way of adjusting the raw data fields allowing the user to adjust for different variables, like larger injectors and MAS air meter upgrades/swaps, timing advance, "No-Limit" mods, etc,etc..


Me personally, I went with the first option as funding became available... I can still always go and get a DSMLink anytime, but for now, I can't justify spending the $$$ on it when I can get EPROM chips flashed for next to nothing (THANKS to RON & KYLE!!!!)



The choice is yours... I would just confirm the following prior to doing anything:

A) Find out what injectors you have. I wouldn't trust the color thing, as I also have blue topped injectors that are Denso 660cc's.. Go off of the numbers stamped into the sides of the head of the injector itself... It should have a number like INP-015 B510L (that number was for my old set of 510cc injectors).

B) Get/borrow a logger and see what the car is doing and go from there.


Generally, option #1 is limited to getting setup for a specific setup, where as option #2 can be configured for just about any possible setup with minimal adjustments and does not require actual replacement of an EPROM chip, unlike option #1 (say if you get larger injectors down the road, you SHOULD get another EPROM chip that has the data to correct for them, thus replacing the chip entirely with another, and/or sending the initial one out to be reflashed and returned... With the DSMLink, you just need to make some changes in the data and go from there, without having to purchase any additional hardware.

Hopes this helps

 

[avw0516]

EPROM ECU + new EPROM flash program (including getting the ECU socketed for a new chip),

So I need the ecu socketed for eprom to change the fuel mapping? Can't just do that with an safc? I understand the use of a logger now and how an safc works, I am just confused (to say the least) about the EPROM stuff. Also with the eprom flash, how do you program that. Do you use a laptop to do the mapping, then flash it to the chip and then plug it into the ECU or is there a cable that comes with the EPROM stuff that you can hook some device into. Is the whole EPROM thing user friendly or could I really mess my car up?
Thanks
-Andrew

 

[andymoraitis]

Andrew,

I used to tune mostly V8's for a while in the mid 90's, but my GSX is my first turbo car and I bought that in January. Believe me when I tell you that I know nothing compared to some of the wisemen here, but research and trial and error have taught me enough to hurt the motor! Thanks for the props, but you should really talk to some of our real experts and be blown away by what they know.

The explanations above on EPROMS were right on. As an example, mine is all I have for fuel control. It handles my injectors, max timing, and air/fuel ratios as well as eliminates fuel cut (I'll explain that in a little bit) and shows me knock values on the stock boost gauge.

The benefit to an EPROM ECU over an AFC lies in how each of them work. The EPROM has custom maps in it, as I mentioned above, which are pretty much 3-dimensional. You can have the programmer change the air/fuel ratio, timing and adjust for larger injectors to make them trigger like stock. The AFC works on a different principle. What it does is allow you to subtract fuel by subtracting airflow. This "lies" to the computer and tells it that there's less air coming into the motor and that less fuel is required. As an example, if you had 550cc injectors as opposed to 450's, you would subtract something like 18% on the AFC (AFC tuners let me know if that's off). What this will do is show the ECU 18% less airflow and lean the car out. The downside to this is that when you subtract airflow, you add timing and too much timing can lead to knock, which is excessive heat in the combustion chanmber caused by detonation. As a single tuning device, the AFC is not the best option, especially as you move to larger injectors, which subtracts more airflow and adds more timing. It leads to a condition that leaves you chasing your tail between timing, airflow and knock.

Another thing to understand is that although we have an MAS on our cars, our system is really referred to as VAF (Volume Air Flow). This means that as we increase airflow into the motor, we have a tendency to run into fuel cut. Fuel cut is NOT caused by having insufficient fuel supply (pump and injectors) but by the MAS sensing too much air coming through it. When this occurs, it triggers fuel cut as a safety mechanism to keep the motor from hurting itself. I would compare it to feeling like you literally hit a brick wall and it's pretty scary the first time it happens. This is another area where an EPROM ECU and a Keydiver Chip can help. By bypassing the airflow limits of the MAS, the chip code allows you to run past the point of fuel cut. This is only dangerous if you're running too much boost on a stock fuel system, but if you had upgraded the pump and injectors, you'd be fine. The pain about our VAF system is that it isn't plug and play. You can't add a bigger pump and bigger injectors and simply have the car "learn" what's in there. That's why some form of fuel control is required.

As far as what to upgrade first, you're right (see you're learning). The pump is what I'd install first (a 190 will be fine) and then you can move on to injectors. When I bought my GSX, it was configured like this on a Big 16G

Stock fuel system and injectors: 15 psi
190 pump and stock injectors: 17 psi
190 pump, 550cc injectors and stock intercooler: 19 psi
190 pump, 550cc injectors and upgraded sidemount: 22 psi

So, definitely upgrade the pump first and then work forward to the injectors. Once the injectors go in, you'll be able to up the boost a bit and still run safely. If it were up to me, I'd tell you to by an EPROM ECU and Keydiver chip from the first go around since you can have custom maps for timing and air/fuel done for it. It's marinally more expensive than an AFC and less expensive than DSM Link, but the great part is that you can upgrade to DSM Link in the future and you'll already have the ECU. Once you decide which route you want to go, I'll help you with the chip maps and get you in touch with Jeff from DSM Chips so that he can answer any additional questions you may have. He would sell you the complete setup (ECU and chip already installed so all you'd have to do is plug it in).

Finally, let's talk about your stuttering at high RPM. Usually, this is referred to as high RPM misfire and is most likely caused by spark issues. Make sure that you install a set of NGK BPR7ES gapped to .028. You may also want to change your plug wires if you don't know how old they are. Avoid platinum plugs like the plague as these are garbage and make sure that plug gap is correct since too wide of a gap will blow out your spark and cause some of the issues you're experiencing.

Whatever you do, keep reading and researching. I'm no expert on this, but I spend plenty of time trying to learn. There will be times when the lightbulb will click and it will all start to make sense and that's when it feels rewarding.

Hang in there and don't be afraid to ask more questions.

Andy

P.S. Once we know what injectors you have, that'll tell us which way to go.

 

[avw0516]

Well, I just pulled the fuel rail and injectors. You were right, its not hard at all to do. Anyway the news is that their 450's. I do think that I have had fuel cuts before because my car had felt like how you described it. What is causing those, too much boost? Also what is the next step now knowing that they are 450's.
Thanks for all the help, turns out that the previous owner didn't know what he was talking about or he just lied to me.

Just an update: While doing this I "un-hacked" my mas.

Oh, and as said before in this thread, the 450's are a blue top injector.
-Andrew

 

[andymoraitis]

Andrew,

Well that's good news. At least you know where you stand. With the 450's, you're seeing black smoke because of the very rich stock air/fuel ratios that are programmed into the ECU. Your next step would be to add a 190 fuel pump so that you can bump the boost by 2-3 psi while still on the stock injectors.

Once you have the pump installed, then you can go with a larger set of injectors (550's will be fine on the 14B turbo). At that point, I'd recommend the EPROM ECU with the Keydiver chip. Also, if you don't have an aftermarket boost gauge and a manual boost controller, now would be a great time to buy those so you can reliably see and adjust what your boost levels are. A logger would also be a great idea so that you can see if you're running lean and getting into the danger zone.

When and only when those are installed should you turn up the boost and keep logging to see what's going on. At the current moment, I know you're strapped for funds, so leave everything alone and just maintain it until you can do things properly.

A good move at this point would be to pull the spark plugs and check the gap on them. Even a gap that's too wide by .002-.004 can cause some of the high RPM miss you're feeling. If the spark is being blown out, you'll get a stutter, especially under boost in the high RPM's.

Let me know if that works,

Andy

 

[avw0516]

Ok, I will get my spark plugs changed with my clutch. Right now the car is in the shop so I won't have it for like a week
Hopefully after I pay my way out of the clutch repair I will be able to get a new pump, eprom and keydriver chip.
Thank you so much for all of the information and advice it has really helped me a lot. I'm sure that I will find myself looking at this thread many times for information .

 

[BoostedTalonTS]

So I need the ecu socketed for eprom to change the fuel mapping? Can't just do that with an safc? I understand the use of a logger now and how an safc works, I am just confused (to say the least) about the EPROM stuff. Also with the eprom flash, how do you program that. Do you use a laptop to do the mapping, then flash it to the chip and then plug it into the ECU or is there a cable that comes with the EPROM stuff that you can hook some device into. Is the whole EPROM thing user friendly or could I really mess my car up?
Thanks
-Andrew

In either case, you will need an EPROMed ECU, then you will need to have it socketed (either to have a new EPROM chip installed into the new socket, or you plug in the DSMLink's EPROM "emulator" to that same location). Since you have OE 450cc injectors, you don't really have a need to start modding the ECU at this time, but if I were you, I'd first verify wether or not the ECU that you have in the car is an EPROMed ECU or not. -I got lucky, mine had one so I just socketed it myself and got a new EPROM chip with a better program that was more suited towards my specific setup at the time. By findin out if your car came with an EPROMed ECU or not now, you can better plan your future upgrades accordingly.

Generally speaking, any decent PC (with a hex edit program)+ a specific type of EPROM burner is what is needed to begin burning EPROMs... The only problem with that is once you are setup to make them, you still need to find the correct values to change in the OE program in order to better utilize your engine components (injectors, MAS, "No-Limit" mode, etc, etc...) -You generally get this data from taking logs from your current setup and finding out what is going on, and what you would like to change. For me, I ended up getting another EPROM chip every time I upgraded my injectors. Larger injectors have a different rise time (or dead time) and the program must be changed to accommodate for the additional fuel as well.

A LOT of good reading on specific EPROM "how-to's" can be found here:
http://www.fullthrottletech.com/forumdisplay.php?f=5
-Just be sure to modify the thread time parameters... I think that the default setting is like 30 days back or something like that... There's a lot of good stuff here

 

[avw0516]

My ecu is stock, not epromed. So really I need to get a logger to see what is going on in my engine. I will try to get one asap. Thanks for the link, thats a great site. I really have appreciated all the help that everyone had given me.
-Andrew

 

[kanderson111]

When you decide to get a data logger this is the place http://www.dsmloggers.com/ I got mine from these guys for basically $110 I don't think they even charge anything for shipping. This item is valuable to diagnose problems and help you tune. I wish I would of had one of these for every car I've ever owned.


Hope this helps
Keith