leaky4runner

my 85 4runner was fine all day(morning to about 1pm)... went to start it 6 hrs later, wouldn't start. thought fuel pump or filter due to just topping off gas and putting entire bottle of seafoam in gas.

for some reason checked the ecu codes(newest trick in my book)
code #6 showed followed with #7

its been throwing #7 for a while, so, not concerned with that.

code 6 in book is "RPM Signal". page FI25 in FSM. in table says to go to pg. FI73. Instead of checking coil, igniter etc. I go straight for the computer and check resistance on Ne and E1.

book specs .14-.18, not sure what this means exactly. but when I tested on the 200k Ohm setting I got "04.3", on the 20K ohm setting i got 1.(which I think means ______ infinite, overload, basically know that it is not taking a reading at that setting.
"04.3", even if i move decimals to the right place is still doesnt seem to be in spec????


long story short, plugged computer back in, reset efi fuse, and it started...
unplugged computer, took Ne and E1 and got the same 04.3 reading at the 200K ohm setting on DMM.

as of right now, its running fine(like it was).

whats going on here? im trying to figure this out but my head is boggled

IVrunner

you checked resistance and you need to check voltage. put your meter on the VAC setting.

IVrunner

i'm actually having a similar problem on my 87 runner, but the FSM i have says that the RPM signal system is code 12 and actually blinks the check engine light 3 times. Mine runs, but i have an erratic tach reading which makes the engine backfire sometimes???? keep us informed of what you find out...if anything it may put me in the right direction.

aquaprice

My code 6 was a bad coil wire.

fulk112

I know this thread has been dormant for a while but I have the same issue, my truck blinks a code 12, 21, and 25... in the service manual I have it says that code 12 is a "no rpm signal" ( no rpm signal to the ECU after 2 seconds of cranking). 21 being the O2sensor, and the 25 being a a/f ratio lean malfunction... Now last winter the truck just wouldnt start one day, after going through checking all the ignition components everything was good so I thought.. turns out I had a bad distributor, I think it was the pickup coil inside. I replace it with a used unit from the salvage yard and it has ran great until recentley, it has developed the same hesitation and lack of power unless under full throttle. But the code 12 never went away, and neither has my code 25 (I reaplaced the MAF bc it tested faulty) but I'm thinking that its probably just the O2 sensor causing both codes 21 and 25... Any thoughts? P.S. Changed the O2 sensor when I first bought the truck a couple of years ago and the code never went away so it must be the circuit for the sensor, correct?