Running Rich, Low Power: Tuning Advice

[Xyster101]

Short story. I took the car to the dyno last Saturday and got some ugly numbers for each pull:

1. 15psi at 169 hp and 8.7 AFR
   
2. 18psi at 202 hp and 10 AFR
   
3. 11psi at 156 hp and 9.5 AFR
   

 

The car is a Toyota '91 MR2 Turbo with a 2.0 engine (3SGTE) with the following simple bolt ons:

• 3" ATS DP
  
• 2.75" ATS B-pipe
  
• Upgraded Inter Cooler
  
• Aftermarket Air Filter
  
• Manual Boost Controller
  

 

Still running stock injectors, stock ECU, stock fuel pump, and stock turbo (CT26). Since the dyno day I have done a compression check (~135psi on all 4), check plugs (little black, but it is rich), checked Air Flow Meter (it is not a MAS) according to the Toyota Service Manual, it is ok. Did a leak test on my turbo hoses (held 20psi for an hour). Checked timing, it was ~12.5 (stock is 10). It has a new cap and rotor. The OEM plug wires are a year old ( <5,000 miles). It pulls -19psi for a vacuum while cruising on the high way.

 

My question is:

What is the best way to fix this for around $500? I don't plan on getting a bigger turbo. I like the power the car has now. I do a lot of track days and I want it reliable. I don't drive the street much.

 

Possible solutions people have mentioned from hours of searching here:

getting an APEXi S-AFC.

Someone said they would sell me a Greddy E-manage Blue Box for $300 with a MAP sensor

Opening the AFM and adjusting the tension on the spring while on the dyno to fool the stock ECU

Getting a stand alone ecu, but really out of my budget.

 

Could there be other reasons why I have low numbers? Maybe engine knock? I know I have a strange car here, and not many people are familiar with this engine. I was hoping for some ideas on what to do next since I have never tuned an engine. I will take it somewhere to be done, I just want to know what it needs so I can understand what I need to have done. Also if someone knows a place to do this, offer it up. I have been to Performance Theory Motorsports off Cleveland Ave for other things, Nate is good there. Brian at Dyno Tune said he could do it, but he needed something to tune (like a ECU, fuel pressure regulator, or piggy back system). My stock ECU can't be reprogrammed.

Is there engine knock in this dyno chart? Does it look ok except for the crazy rich fuel reading? Can a dirty injector cause it to run rich because the gas does not atomize as much?

 

Dyno:

http://www.adamdaley.com/max/mr2/dyno/dyno.jpg

[Farkas]

As long as you're running the stock ECU, you're going to be running stupid rich, and very conservative timing.. Toyota is known for doing such, especially on their turbo'd vehicles.

 

The problem with piggy-back units is again, the stock ECU. They'll hold a tune for maybe 500 miles and then it will re-learn the specifications and override the piggy-back, another common issue with Toyotas.

 

I strongly suggest not opening the AFM. This is an oldschool trick people did back in the day to richen and lean out a fuel mixture, however it has been concluded it's more harmful than anything in the long run. I did extensive research on this myself, when I was tinkering with my old 16v 4AG.

 

You would really be best off with a standalone if you're really looking for the best numbers, even if it's not in your price range.

[budfreak]

It seems the fuel is the problem obviously. Maybe a bad/misreading O2 sensor making the system run rich? Bad MAF? Injector (or 2) gone bad and stuck open? Have you checked the ohms on your injectors? How is the idle and everything else?

[Ef8sirJunkie]

Could put a honda ecu in it and tune it that way

im not lying either its been done several times

http://www.homemadeturbo.com/f10/honda-ecu-toyota-108114/

looks to be some work though but i figure someone on some MR2 forums have full write ups that might make it easier.

 

o and here is another link and pic for a corrolla and honda dizzy

http://i159.photobucket.com/albums/t150/tomdata57/DSCF0001.jpg

 

http://forum.pgmfi.org/viewtopic.php?t=13414&highlight=toyota&sid=810f64c268f817f513054b3def5ead94

[okami]

Just for reference, take a look at this kit.

 

http://www.turbo-kits.com/mr2_turbo_kits.html

 

The turbo is different, but otherwise it only has a tuned ROM, lower temp thermostat, and a fuel pressure regulator. I wonder if you can just get a tuned rom from a place like this. I also think a fuel pressure regulator might help because at WOT the car should be open loop. Otherwise, in closed loop mode, the ecu should be able to adjust fuel delivery even if you alter the fuel pressure.

 

+1 for checking injectors.

 

What about checking the O2 sensor or water temp sensor too?

[Dave1647545494]

S-afc is probably the easiest way to do it

[Ef8sirJunkie]

actually i remember this company from a long time ago seems there website is still up and have daughter boards for toyota ecu's

 

http://www.technosquareinc.com/rom.htm

check out the tech tom stuff

[Xyster101]

Thanks for the advice guys. Some areas to read over. Good information.