running a little rich on my 86 MR2 4AGE

[yellow86MR2]

I just did the Wiseco pistons, port and polish head,... and my car is running a bit rich. I adjusted the diaghram under the throttle body because the stop screw wasen't returning to the vacuum valve. Since then it a bit better. I notice when I stand next to the engine and rev the living sh*t out of, I see black smoke. The engine has about 2,500 km's on it now. If there was a problem with the coolant tepm sensor wireing or the o2 sensor wireing, would the check engine light come on? I went to Yoshio the get the ecu reprogramed, but he told be to come back when he gets his dyno in. (2 weeks)


Martin

[bondobondo]

i would check the afm and anything along the intake tract.

look for vacuume leaks too.

the spark plugs are totally soaked if you were to take them out?

[yellow86MR2]

I have the HKS intake on the car. The afm is working. I didn't check for vacuum leaks. I notices that when idling some times the rmp's go to 800. It idles perfect at 1000-1100 rpm. This only happens when I have all my lights and accesories on at one time and in hot weather. What whould happen if I remove the EGR system. My friends 85 MR2 has a J-spec motor with no EGR system. I do have a vacuum guage, so I will go through my Repair Manual and check all vacuum hoses. The plugs are clean and dry. A little bit of carbon on the edges of the threads. I'm using the Denso Irridium plugs now. Big difference over the NGK laser platinums.


Martin

<font size=-1>[ This Message was edited by: yellow86MR2 on 2002-05-14 00:02 ]</font>

[neil85AE86]

which injectors are you running? even with the slightest mods you will need to upgrade your injectors to get any benefit whatsoever.. since your running rich you've either got an AFM that has been opened and adjusted or your injectors are probably too big or a faulty sensor. If your injectors are oversized you will have to open the AFM and play with it until you establish a good idle.

Vaccuum leaks would cause the engine to be lean if anything.

NEil

[yellow86MR2]

I'am using the stock injectors. Yoshio at Japanesse Automotive said that The injectors will flow more than enough gas. I did play with the AFM gears by 4 points. That didn't do anything so I put it back to stock. The thing that might cause the problem could be one of the sensors like cold start injector, start injector time switch or fuel pressure regulator. I have to figre out a way to test them all or just buy all 3 new. It has a new O2 sensor aleady.


Martin

[yellow86MR2]

Finally solved the problem. Went to Yoshio and go my ECU custom programed. Now there is more power, better milage and no more black smoke when I floor it. Also It got me an extra 11 hp at the rear wheels on the dyno!!!

So if your car is running rich and there is no check engine light on, then this would be a good idea if you intend to keep that engine for some time.

[Rolla GT-S]

you could have also done the afm mod trick. You open it up and adjust the ticks/spring. Don't remember how, but you can adjust it to make it leaner or richer.