Tuning 87 4Runner Turbo with CT26 tips (2 Viewers)

[thetoyotaman]

Just filled up and the 4Runner got 9mpg. Granted she's SAS with 35's but looking for tips as previous owner had the distributor off a tooth, timing mark so far advanced the mark was basically pointing at the passenger frame and the AFR messed with. I've never heard it knock so I'm guessing I'm going deaf or the computer is retarding. But for those with this setup, what was your sweet spot on the AFR wheel? My understanding is timing should be set at 5% degrees with the jumper wire. I have a standard timing light and vacuum gauge. I've replaced plugs, air, and fuel filters. Thanks in advance!

 

[nab856]

I am running two of these turbo engines. One has a Garrett, the other has an original CT20 with a CT26 compressor. I use an independent wide band O2 sensor with a digital read out in the cab to get AFRs. With these ratios you can turn the AFR wheel. The numbers @EngEngr posted are good.

 

[thetoyotaman]

Thanks for the info. I have a new problem. It stalled the other day and will barely start. If you feather the throttle you can get it above 3000 rpm but anything below that it runs real rough and dies.

 

[nab856]

You have spark. Air Fuel Ratio?

 

[thetoyotaman]

We need an AFR for sure it looks like. Also plan to check codes.

 

[thetoyotaman]

One of the problems I was aware of prior to it stalling is that if you turn the key to on without starting the fuel pump runs continually. I thought they were supposed to prime for several seconds and turn off.

Ok, tried to check codes but it doesn't seem to matter if the diagnostic connector is jumped or not with the key on (engine not running) check engine light just stays on. There's no blinking. Wondering if the ECU failed.

 

[nab856]

No telling what the previous owners installed or changed. The truck is nearly 40 years old and some parts may be broken. Get the Factory Service Manual out and follow the repair instructions. My procedure for "project vehicles" is pull the engine and transmission, rebuild both with quality parts, test wiring and sensors, replace what's broken, reinstall all parts according to the FSM, and break in the engine. This is how I've found success with "project vehicles."