ECMlink MAF or SD

[srebos]

Quick question for ya'll, I'm running the stock maf on my 98 gs-t. My setup I'm running is stock evo 8 pistons, rods and 750cc injectors in a 7 bolt. Fp green turbo, greddy type s bov, ecm link ecu, tubular exhaust manifold and s90 throttle body. My question, would the stock maf be fine with this setup, or should I go speed density to handle all that's on it?

 

[steve]

Either will work, MAF may be easier/quicker to get running and tune, Speed Density might give you more control. In many cases it's a personal preference decision and not some actual limit of a MAF setup. Which are you most comfortable with?

 

[srebos]

Either will work, MAF may be easier/quicker to get running and tune, Speed Density might give you more control. In many cases it's a personal preference decision and not some actual limit of a MAF setup. Which are you most comfortable with?

I appreciate the info, I personally don't have a preference as I don't know how to tune and will have someone else tune it. I'd love to know how since I have the capabilities on my laptop now, but also don't want to screw it up with the money I've put into it.

 

[steve]

If you don't know how to tune I suggest sticking with the MAF for now. You can just plug in your injector data and be pretty safe.

 

[srebos]

The vehicle has been running pretty rough and rich (afr shows idling at around 10-11) even after I did adjust the injector scaling to 750cc, I was showed how to do that at the very least. I just was told that I may need to upgrade from the stock maf too, which is good to know I don't need to worry about another thing.

 

[steve]

#include standard DSMLink answer
Please post a log file. You use the Add Photos button.
From it we can see how your ECU is configured and some of what's going on.

You don't need to replace the 2G MAF until you start overrunning it and then you could swap in an EVO 8 MAF or consider converting to SD.

There are several advantages to learning how to use DSMLink on your own but two key reasons are knowing what's going on and saving money.

 

[srebos]

I'll have to save a file tomorrow to upload. I setup my afr into the ecu, but it does not read the same as my gauge.

That sounds good.

For sure, are there any good videos posted that walk through dsmlink?

 

[Spleen8urLSX]

Steve just gave the best break down that could be given and I’m glad he got to this post before the crowd came along that jumps straight to “speed density is way better!!” without any factual knowledge of it except they assume it’s better because it’s more common.

Despite what anyone says using a maf has its definite advantages, and while I like speed density too there’s things I like about using a maf sensor. One very common misconception you’ll see when the topic is being discussed is for whatever reason people think speed density magically makes more power which is simply not true, if a set up isn’t at the limit of what a maf sensor can do (and even then there’s “maf clamping” capabilities and such but that’s a whole different discussion) then it’s not going to magically make less power than what speed density can do. With that being said a set up can go as far as what that particular maf that’s being used can do, and even then if you max out a 2g maf an evo 8 maf can go further, if you max out an evo 8 maf a GM maf can flow even more than that, etc.

With that being said, your issues at idle are a tuning issue, nothing to do with the maf you’re using. You could bolt on the biggest turbo you can come up with that’s practical to bolt on to a dsm and airflow at idle wouldn’t change much over anything else you can bolt on it, in other words any amount of air you could move through the maf at idle or out of boost conditions is not going to max it out.

As far as references for tuning Scott Laird and a few others have good videos in regards to tuning ECMlink on YouTube, I’m pretty sure some of Scott’s videos are in direct regards to tuning with a maf but I haven’t referenced them for quite some time as I no longer use ECMlink. I believe he also has some posts on here in regards to so (his username is V8sareslow or something along those lines) so it’s worth searching. Steve who posted above is also a guru and been at understanding our ECU’s since long before ECMlink was thought of so take in all he is willing to tell.

As far as tuning yourself those references are great for dialing in your idle and drivability but I highly recommend you let a tuner do your WOT work until you get a better understanding of it. That’s not to be discouraging by any means but when you have someone else work with it and you get a good understanding of how other things work it’s even easier to make sense of it and you can apply what you learn to see how they came up with what they did, plus you avoid making an error that ends up costing you a lot in the long run.

 

[steve]

Steve who posted above is also a guru and been at understanding our ECU’s since long before ECMlink was thought of so take in all he is willing to tell.

I wish that was all true but Todd Day, Tom and Dave were all there before the rest of us got started reverse engineering and disassembling the ECU code. I wish I knew half as much and I'm thankful for them answering my questions in the past along with all the people on the DSMECU group. Each of us moved the ball forward at one time or another.

 

[Spleen8urLSX]

I wish that was all true but Todd Day, Tom and Dave were all there before the rest of us got started reverse engineering and disassembling the ECU code. I wish I knew half as much and I'm thankful for them answering my questions in the past along with all the people on the DSMECU group. Each of us moved the ball forward at one time or another.

Oh not doubting that, I just remember reading of you working with the ECU’s before ECMlink hit the market, I figured they had been in the game too long before their product came about haha.

 

[srebos]

Thank you for the direction of tuning, I appreciate it. It helps substantially having guys who have been into dsm's for so long. I'm new to doing most of these things as before all I really did was maintenance type things but want to continue learning as I build this eclipse up.

@steve
As for the data on my ecu I have it attached now to give an idea of what I have going on. My AFR gauge the whole while I ran the log was reading between 10.7ish to 11.5. I still have to figure out why they are reading differently from the gauge to the ecu since I have it soldered into the rear o2 sensor wires. But it's a work in progress.

 

[1990TSIAWDTALON]

Ground your gauge to the same point that the ECU is grounded to and re-check the readings. My tuner had me do that to make the gauge and ECU read the same. Just a suggestion.

 

[srebos]

Ground your gauge to the same point that the ECU is grounded to and re-check the readings. My tuner had me do that to make the gauge and ECU read the same. Just a suggestion.

I ended up soldering my gauge to a ground wire in the ecu with the same results, which is why I'm a bit stumped by it. Unless I'm just not getting a good enough connection now due to my soldering job.

 

[steve]

The ECU thinks your battery voltage is 5v. I'm surprised the car runs at all because the ECU usually shuts down below 7v. You also have a FR fault on the alternator. I wonder if they are related. It's pretty unusual for the ECU to report battery voltage that low making me wonder if the ECU is damaged.

I don't see any additional deadtime comp for your 750cc injectors and your fuel global is set for 985cc injectors. What fuel are you running, I assume gasoline since 750cc are usually too small for E85.

The ISC position is 0 and your idle is much higher that the 1000rpm setting you have. That suggests a vacuum leak and possibly a dead ISC. Your Coasting FC Offset shouldn't be 1000 rpm it's usually only increased a few hundred rpm over the default to work with a higher idle.

It looks like your IPS is working so there is no need to simulate it or disable while moving. Some might suggest targeting 0.63v for the TPS adjustment but as long as your IPS is switching pretty much as the throttle butterfly starts to open your TPS voltage will work.

Is this a new DSMLink or a used one? Who's been adjusting it, some settings don't make much sense to me?

 

[srebos]

The ECU thinks your battery voltage is 5v. I'm surprised the car runs at all because the ECU usually shuts down below 7v. You also have a FR fault on the alternator. I wonder if they are related. It's pretty unusual for the ECU to report battery voltage that low making me wonder if the ECU is damaged.

I don't see any additional deadtime comp for your 750cc injectors and your fuel global is set for 985cc injectors. What fuel are you running, I assume gasoline since 750cc are usually too small for E85.

The ISC position is 0 and your idle is much higher that the 1000rpm setting you have. That suggests a vacuum leak and possibly a dead ISC. Your Coasting FC Offset shouldn't be 1000 rpm it's usually only increased a few hundred rpm over the default to work with a higher idle.

It looks like your IPS is working so there is no need to simulate it or disable while moving. Some might suggest targeting 0.63v for the TPS adjustment but as long as your IPS is switching pretty much as the throttle butterfly starts to open your TPS voltage will work.

Is this a new DSMLink or a used one? Who's been adjusting it, some settings don't make much sense to me?

The battery is junk, I have to use a jump box everytime to start it, so that may explain that.

Yes I am running 93 in it, the ecu resets after the battery dies on occasion so the settings seem to be changing back to what they were set to before as it's a used ecu that must have run 985cc injectors. I bought it from Jason Roach who had a few.

I don't have an ISC setup to the s90 throttle body, I bought the car with it like that. I also purchased a stock throttle body from Jason that has the ISC, but I just don't have all the hoses to set it up if I went that route.

I have done bare minimum trying not to mess anything up. I've just adjusted the injector scaling from the fuel global when it reverts back, and I put the afr in the ecu following a video on how to do it. The vehicle sits and doesn't get driven because I have a few other issues going on as well (oil blowing out of the exhaust manifold, so I'm thinking piston rings). So I try not to run it long with the way it's running.

 

[danl]

You absolutely need to get a good battery in it. Without that nobody can help you.

 

[srebos]

You absolutely need to get a good battery in it. Without that nobody can help you.

I'll get a new one in it tomorrow then

 

[srebos]

Here is a new log with a new battery.

 

[steve]

There is something broken here, the battery voltage is still reading very low.

 

[DSMPT]

I'm surprised the car runs at all because the ECU usually shuts down below 7v.

Could be the same case as in the link below?

https://www.dsmtuners.com/threads/low-voltage-in-ecmlink-but-perfect-at-alt-and-batt.533014/

 

[danl]

Here is a new log with a new battery.

As mentioned above, something is very wrong here. Can you back probe pins 12 and 25 while the low voltage problem in ecm link persists? What does it read to ground?

2G ECU pinout:

http://www.dsmlink.com/images/forums/2GECUPinout.pdf

 

[srebos]

As mentioned above, something is very wrong here. Can you back probe pins 12 and 25 while the low voltage problem in ecm link persists? What does it read to ground?

2G ECU pinout:

http://www.dsmlink.com/images/forums/2GECUPinout.pdf

I wonder if this may be due to my soldering job of the afr to the ecu, I see you mentioned pins 12 and 25 which I did ground to one of those wires. So my connection may be poor enough that it could cause the issue.

 

[steve]

Could be the same case as in the link below?

https://www.dsmtuners.com/threads/low-voltage-in-ecmlink-but-perfect-at-alt-and-batt.533014/

Much like I was thinking in that thread.

I wonder if this may be due to my soldering job of the afr to the ecu, I see you mentioned pins 12 and 25 which I did ground to one of those wires. So my connection may be poor enough that it could cause the issue.

Could be but I'm thinking that if the voltage were actually that low the ECU wouldn't start the car and clearly your car starts.

Once we get past this I strongly recommend you reset the ECU back to stock baseline settings, then add in your injector comp (both global and deadtime) and fix your idle issue. Either the S90 isn't closing all the way or you have a vacuum leak.

 

[srebos]

Much like I was thinking in that thread.



Could be but I'm thinking that if the voltage were actually that low the ECU wouldn't start the car and clearly your car starts.

Once we get past this I strongly recommend you reset the ECU back to stock baseline settings, then add in your injector comp (both global and deadtime) and fix your idle issue. Either the S90 isn't closing all the way or you have a vacuum leak.

I'll check my connection first just to make sure to cover every step. Could it also be due to an incomplete circuit? My radio wiring is a complete mess and my all soldered due to the previous owner having completely messed that up. I've yet to find a good schematic to get it all wired correctly all the way back from the main harness to the radio harness. I've half a mind just to replace the entire harness to fix all the wiring issues he caused.

I'll definitely do that, would you suggest a hard reset through connecting the positive and negative terminal or doing it through ecmlink to prevent damage? I'll also double check that I don't have a vacuum leak somewhere.

 

[steve]

would you suggest a hard reset through connecting the positive and negative terminal or doing it through ecmlink to prevent damage? I'll also double check that I don't have a vacuum leak somewhere.

Disconnecting the power doesn't reset the ECU back to factory stock. ECMLink has some non-volatile memory they save setting into and you have to load the ECU with a file to get back to stock. The files are at http://www.ecmtuning.com/wiki/v3configs

You'll also need to reconfigure your AEM WB after the reset.
Do you know who's 750cc Injectors you have?

If you like you can post pictures of your ECU board and we'll look to see if there is anything visible.