lj78 turbo and engine lights

[flyfishbc]

hello, first post, been here awhile but now i need to ask a couple questions. i recently picked up a 1990 prado, lj78 with 91k on it. got it for a grand because it didn't run properly. it would only do about 60kmph, and had no power. i started researching this and other forums and came to conclusion the turbo was pooched. good news is, with the new turbo it will easily do the speed limit. now for the questions. it takes about 10 minutes from cold start ,and then the check engine light comes on. during that 10 minutes the green turbo light seems to work correctly and seems to run properly. once the check engine light comes on the green turbo light does not work anymore. im not sure but it seems to loose some power too. also, how do you set the tps. i think it is out of whack too, because it seems to slow to shift down and pedal beyond half way does nothing. i understand it is a 2lte, and has issues but i have never driven one before, that was in normal working order, so i don't quite know what i should expect. i know it should be guttless but i think this is more than that. any help would be much appreciated.

 

[Radd Cruisers]

Trans shifts are controlled by the TPS and the pressure by the kickdown cable. Both have to be set within parameters to get good shifting. TPS should be set with a start voltage of about 0.6V.

CEL - sounds like you're getting a fault code. Retrieve the blink codes and go from there. Don't just randomly think/guess things are wrong until you've done the proper diagnostics.

~John

 

[flyfishbc]

cool, thanks. but how do you get the check engine light to flash the codes. newer fords and chevs are no problem, my friends have diagnostic tools. old toyota however is a whole new learning curve for me.

 

[Radd Cruisers]

cool, thanks. but how do you get the check engine light to flash the codes. newer fords and chevs are no problem, my friends have diagnostic tools. old toyota however is a whole new learning curve for me.

Older Toyotas all use the same procedure - google it to save me time explaining it here.

~John

 

[flyfishbc]

code 12, now what

thanks for your help john. did as you said, and had code 9,and code 12. code 9 was due to a dry speedo cable, squeaky. lubed it and reset codes and only code 12 now. it would seem that that means there could be a couple reasons for it. what would you say is most likley the reason.

 

[Radd Cruisers]

The 1KZ manual says that DTC 12 is for an open or shorted engine speed (crank position) sensor. Found in the lower part of the block, left side - almost behind the inj pump if I remember correctly.

Check the wiring and the plug on that one, it's quite important for timing the inj pump.

The other part of this is in the injection pump - basically the RPM sensor (feeds the tach) and coordinates the timing of the injection cycle with the TDC signal from the CKP sensor.


~John

 

[flyfishbc]

crank position sensor

checked wiring, looks good. unplugged it and cleaned connections and plugged back in. still code 12. the guy i bought the truck from had the local toyota dealer change the injector pump last thing before he parked it. he thought that might be his problem , but it was the turbo. my neighbor is a gm mechanic and is wondering if the dealer didn't set the pump timing correctly. do you think this could be the case, if so , how do you set the pump timing on one of these things. if i can learn how he will bring required tools and give me a hand to check it and adjust if needed. thanks for your help, i appreciate it. im also going to change the fuel filter.

 

[Radd Cruisers]

Pump timing is set by lining up the mark on the case with the mark on the injection pump, the rest of it is taken care of by the computer and the sensor in the block (crank sensor). There is no actual timing to be done as with other non-electronic inj pumps.

As for the sensor, a lab scope hooked up to the sensor output will tell you if it's giving you a signal. If it's good at the sensor, then test the wiring near the computer to see if there's a wiring fault somewhere between the two points.

Was the injection pump brand new?

~John

 

[flyfishbc]

pump looks brand new. maybe a rebiuld. found reciept for 1500.