R.A.R.E.

Hello,
I'm working on a dual sport off road car with a 3.4 out of a 98 Tacoma. The computer is a M.T. 4x4 supposedly from the same truck as the engine. Trans is now a 4 speed VW. The vehicle runs ok , but the fuel pump is wired through a relay triggered off of key power. I wanted to hook it up to the ecu so it will shut off if the engine dies. I located E8 pin 18, but it only goes to ground when the engine is rotating. when "key power" is turned on I get a split second continuity to ground.When a dmm is connected between pin 18 and 12v it rests at 3 volts and goes to batt voltage while cranking. The engine seems to have all of the basic sensors hooked up, however there is a small bundle of wires that were not used. Is there a switched power or ground missing ???
HELP!!!!!

Thanks!

wyoming9

iTrader: (1)

Might help to give the Toyota part # on the ECM In case you got a different one.

Then what your looking at

Are you sure your looking at the correct pin ??

The color of the wires also helps

R.A.R.E.

Thank you for responding!!!

If I am looking at the wrong pin that would be awesome!!!

The label has:
TOYOTA
89661-04410

Below that is:
TN175000-9681

next to that is:
5VZ
4x4
M/T

The wire I am testing is E7 pin 18 (22 pin plug) green/ yellow tracer.
I am using the Creative Commons 1998 Tacoma 5V-FE 4x4 ECM automatic vs manual reference chart.
Thank you.

cr@ves4wheelin

You have the right wire according to my '98 T100 EWD.

As far as I'm concerned, in my own experience anyways, is that the older ECUs like ours won't prime the pump when the key is just turned to the on position, like the newer ECUs do. Our year motors use the old style COR for the fuel pump and will only run it while cranking, or when the motor is running, kinda like the older 89-95 trucks with 3.0 motors. Just the way the ECU was made I guess.

If anybody wants something to support theory, find an online parts store and compare a '98 T100 COR to a...2002 Tacoma COR maybe.

If you're concerned, I would disconnect the starter real quick, try to crank it and hear if the fuel pump runs while cranking. If the motor is running already, sounds like you did something right. Sorry for the late reply.

R.A.R.E.

I'm surprised any manufacturers would leave a function like that out. I primarily work with domestic EFI and I can't recall anything I have come across that doesn't prime the system. I built a timer circuit that grounds for 5 seconds and shuts off until reset. I diode isolated this along with the factory fuel pump trigger at the fuel pump relay I installed to attain the desired results. Now when the "ignition" switch is turned on the pump will prime and shut off after 5 seconds and when the start button is pressed the computer triggers the relay once it detects the engine rotating. The most important function retained is that the pump will shutoff if the engine stalls should he stuff this thing or put it top side down.

Thanks for the responses.

cr@ves4wheelin

Who knows, probably because it was something that worked and didn't need to be changed. Fuel pumps have check valves in them to prevent reverse flow of fuel back into the tank, but if they don't work right (like almost every aftermarket pump nowadays), then it gets annoying.

Glad you got it workin how you wanted it though, good idea too.

slacker

iTrader: (1)

I agree ..
love to see your design on paper .. do you have a draft you could post or email to me ?


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