Street tuning a MAPECU, which gear should I be in?

[Suprapowaz!(2)]

I've been street tuning this MAPECU in third gear for the most part. Right now I'm tuning the idle and cruise part. I'll be dabbling in the boost areas later once I do the non-boost section. I'm doing pretty decent tuning to Vf right now.

I've gone up to about 3000rpm. Problem is when I start getting up higher in the rpm range I'll be doing close to 100mph in top of third gear. I don't want to drive that fast on the street. Is it ok to tune in second gear in the upper rpm range? So that way I'll be around 65 mph.
BTW, I'm going to be employing a friend to help me with the rest of the tune because I don't like driving with my eyes off the road. Or do I need to finish it up in third gear?

 

[Suprapowaz!(2)]

Another question is about tuning for open loop. From what I've read somewhere TCCS will continue to tune for 14.7 even in the early stages of boost. I want to shoot for 11.0:1 so at what point do I begin fattening up the map? At 1psi on up? 5psi up? I don't want to disturb TCCS.

 

[gurley0916]

you can tune in second but to create more the load areas of the map 3rd is better. Not familiar with the TCCS but i always tuned to have it the in the 13s up until 5 psi

 

[CyFi6]

Another question is about tuning for open loop. From what I've read somewhere TCCS will continue to tune for 14.7 even in the early stages of boost. I want to shoot for 11.0:1 so at what point do I begin fattening up the map? At 1psi on up? 5psi up? I don't want to disturb TCCS.

The ECU is going to shoot for around 14.7 if you are in closed loop, any corrections you make here are going to be counteracted by the ECU, once load gets high enough it will switch to open loop and stop correcting according to the o2 sensor. The ECU doesn't know pressure only airflow/tps and input from other sensors so when it switches to open loop will depend on several things. Vf will drop to 0v in open loop so that is one way to tell whether or not you have switched into open loop.

 

[Suprapowaz!(2)]

Vf will drop to 0v in open loop so that is one way to tell whether or not you have switched into open loop.

That is what I wanted to know. For some reason I was thinking that Vf would flatline at 5v as to continuously dump fuel.

 

[Suprapowaz!(2)]

Frustrated.

Yesterday I had a rock solid idle tuned to 3.5v 15.1:1 afr. That same night it started to bounce around and showed 1v from Vf, but AFR's were leaning out between 16.8:1 to 18:0. There's a couple of cells on the table that it bounces around searching for a good spot to sit. I wondering if TCCS is trying to kick my tune out.

Everywhere else in closed loop mode is running pretty good. I've got TCCS satisfied at 2.2v throughout most of the fuel table. There are some 3.5v areas in there that I'm going to richen up a little to get close to 2.5, but 2.2 seems to be where it always lands and stays. That's where it runs smoothest, and runs good afr's cruising.

Fuel cut:

Yesterday did some tuning and datalogging. In boost mode it was showing that the car was running 12.2:1 up to 5psi of boost then starts to richen up to 10.4:1 @ 5.5psi. It slowly increases up to 10.9:1 at 9.5psi then BAM... fuel cut?! I thought running this MAP ECU eliminating the AFM would completely bypass fuel cut. Getting so close to where I want to be in closed and open loop, and satisfying TCCS... things were looking pretty good.

This morning I went out for a run. Again, idle was soul searching. I made another pull and datalogged it. Mind you, I haven't made not one single change to the fuel table since yesterday's pull. It hit fuel cut at 11.7psi at 13.7:1 afr! It ran 14:1 up to 5psi, then high1 13afr's up to fuel cut. Why such a drastic change in afr's from one day to the next?

Is it just me, or are other MAP ECU tuners having the same issues?? This thing seems to be inconsistent... or it might be me. It just seems like I'm doing everything right tuning to satisfy TCCS's Vf fuel trim and all, but I'm having issues now.

 

[gurley0916]

I know it can be fustrating, 2 things that make it hyper sensitive are the iat in the supra. Idk if your running one or not but if so do the resistor instead. Another is the hvac sensor. If you have a 89+ ecu i believe it is separated from the ecu and can be unplugged. This will steady the fluctuations as well. If you have the years where its in the ecu ur SOL. Another thing the tune will bounce around a couple cells at idle, you have to remember that it takes averages of the cells around the cell its on. So my advice is to tune in 3D map not individual cells and make the map.

Fuel cut is based on the frequency being sent to the ecu, but this also regulates fuel. So fatter you are in boost higher the freq the ecu sees and throws you to fuel cut. To postpone fuel cut you lean out the a/f. Most I could achieve on stock inj and a ct26 60 trim was 14 lbs. Also make sure you tps is calibrated as mapecu gets grumpy with that if it isnt.

What turbo and Inj do you have?

 

[Suprapowaz!(2)]

I know it can be fustrating, 2 things that make it hyper sensitive are the iat in the supra. Idk if your running one or not but if so do the resistor instead.

2.2K resistor is plugged into the afm harness plug.

Another is the hvac sensor. If you have a 89+ ecu i believe it is separated from the ecu and can be unplugged. This will steady the fluctuations as well. If you have the years where its in the ecu ur SOL.

1991. But I thought it was the pre 89 that were separated from the ECU.

Another thing the tune will bounce around a couple cells at idle, you have to remember that it takes averages of the cells around the cell its on. So my advice is to tune in 3D map not individual cells and make the map.

That makes so much more sense, and will try that next time out.

Fuel cut is based on the frequency being sent to the ecu, but this also regulates fuel. So fatter you are in boost higher the freq the ecu sees and throws you to fuel cut. To postpone fuel cut you lean out the a/f. Most I could achieve on stock inj and a ct26 60 trim was 14 lbs.

I think I'm SOL here. My head is P&P'd and this damn engine demands gobs of air. Now it makes sense cause fuel cut hits when 2200Hz is reached (11PSI).

Also make sure you tps is calibrated as mapecu gets grumpy with that if it isnt.

Did that last year, hopefully it hasn't changed.

What turbo and Inj do you have?

Garrett 60trim T4 with .70a/r hotside. 550cc injectors.



Back to the fuel cut issue. I have an HKS FCD on hand. Do you think I can install that to cap the ECU and continue to tune with MAP ECU? Or will it cap the info coming from the MAP ECU too? I think I have outgrown this MAP ECU.



EDIT: Outgrown the MAP ECU? That was a dumb thing to say. This thing can handle up to 800cc injectors I believe. I should bump up the base fuel pressure and retune. I want to say my base pressure right now is 40 or 42psi. I have to double check.
That still leaves me with why the same tune would vary so much from one day to the next. I wish I had an external hvac sensor I could plug.

 

[gurley0916]

Yes you are correct on the hvac sensor. I didnt have one either and I hated it lol. Every time a storm came through it threw my tune off. My buddy had 750s and same turbo and achieved 500hp at 22 psi on mapecu. Mapecu is great but I would suggest picking up a standalone if you want great drivability. I'm on a base tune on proefi and its lightyears ahead in drivability compared to the 7m/mapecu hiccups. Having the timing control is very helpful because on mapecu you are at the mercy of the stock timing maps based on freq and rpm. So there can be danger there. Just food for thought and If you have some other troubles keep posting and I'll try to help

 

[Suprapowaz!(2)]

Thank you for the help. Yesterday was cool and dry. This morning was cool and humid with very light mist in the air. Could that have made a differenc in why I was running 10.9:1 yesterday, and 13.9:1 this morning? That's a pretty big jump. I would look into the stand alone thing, but I have no intentions on spending that kind of money for this 7m. I want to go LSX next go round. I'm done with this 7m as far as upgrades. I should have enough in this car to put out at least 450rwhp. That was my goal.

 

[CyFi6]

Yeah like Dustin said the only way to raise fuel cut is to pull more fuel which decreases the AFM frequency, unfortunately the more fuel that you pull the more dangerous the timing gets. What kind of FPR do you have? You might want to make sure it has a good vacuum source to it and is rising with boost. You could have something restricting the fuel flow which would require you to add more fuel via the mapecu which ends up putting you in fuel cut too early.
All the FCD does is cap the AFM signal so that it cannot exceed an amount that would allow the ecu to hit fuel cut. All this means is that any extra airflow once you have reached the FCD setting results in a leaner and leaner mixture, its a pretty stupid tool if you ask me, and wont do you any good in this case.

 

[Suprapowaz!(2)]

Aeromotive AFPR (red top). Vacuum source is the same as where the stock FPR gets it.
Walbro 255lph pump. When I had the injectors cleaned and flowed they measured them at 526cc's tested at 35psi. They flowed 118ml/15sec. So they aren't true 550cc injectors, but a little fuel pressure bump will help them.

 

[Suprapowaz!(2)]

Correction, 526cc @ 43.5psi.

I wanted to see what the car could do at 20psi. In order to do that I had to crank up the fuel pressure to 65psi vacuum disconnected. I got as far as 18.8psi running 12.2 afr. I was close to 2000Hz which is the FC limit for my ECU. I'm going to need bigger injectors. Running that high of fuel pressure makes my idle quality poor. I also think that my injectors are just spitting fuel instead of atomizing like that should be doing at "normal" fuel pressure. That could be bad if it's puddling back into the intake. I didn't get the "WARNING Danger to Manifold" on my laptop though, so I should be alright.
In the meantime I'm going to back the pressure down to 44psi and tune for the most boost it will handle. Hopefully that'll be at least 15psi. I should get my good idle and cruise quality back. I think I'll be somewhere in the low to mid 300rwhp range with that set up. Sucks, but it'll have to do until bigger injectors fall in my lap.