No spark, No fuel, No run
09-13-10, 08:04 AM
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No spark, No fuel, No run
93 LS400 has quit again. Had no/poor run problems a year ago and sent ECU off to ATE, car has run great for over a year....
until it just stopped running at a stop light after a 5 mile ride. Cranks over fast but nothing. No spark from plug wires or coil wires. No fuel pump unless jumped at diagnostic port. (FP ECU has power. You can hear pressure at fuel rails only when jumped.) Going to send ECU back for a check-up. Any other ideas ?
until it just stopped running at a stop light after a 5 mile ride. Cranks over fast but nothing. No spark from plug wires or coil wires. No fuel pump unless jumped at diagnostic port. (FP ECU has power. You can hear pressure at fuel rails only when jumped.) Going to send ECU back for a check-up. Any other ideas ?
09-13-10, 12:35 PM
#5
compression test isnt needed. if he lost compression in all cylinders he should still have fuel and spark if the ecu is good. make sure the coils have +12 when the key is on. if so given the circumstances and previous ecu rebuild, id say your right, the ecu is toast.
09-13-10, 02:51 PM
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if i remember correctly their is no key up power for the fuel pump,the pump should not run until their is a crank signal or the key is in the start position check for power in the trunk at the fuel pump connector while actually cranking the vehicle. if then you have power,the next step would be to unhook the harness starting at the crank sensor all the way up to the valve cover,i just ran into a very similar issue where the harness had a tear in the front where the coils and crank sensor meet. this is very likely on the vehicle for the mileage
09-13-10, 02:57 PM
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If I lost compression in all 8 cyls. in 3 mins. at a traffic light, you could see the smoke from Fla. because I would have set it on fire by now ! I did check the top coil and it's getting juice. Didn't have time to check the other one because it's burried. This car runs and idles like new. when I went to take off and nothing, I was slightly surprised. I figured it had blow a fuse or a main electrical connector had come undone. There are 2 below the battery and 1 has a white latch that holds it together. It was loose and dirty. After I cleaned it and snapped it back together I did my crank tests again and nothing. There isn't another ECU fuse that I missed is there ?
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09-14-10, 09:50 AM
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I'll check that ASAP (if I can find it) There is a wire / connector that clips on to the r-coil (center of motor) by any chance does that run down to the crank sensor ? Does the crank sensor have to be done from underneath, or can you get to it from above. p.s. I used to live in Portsmouth.
09-14-10, 11:16 AM
#12
if 1 coil is unplugged it will still try to fire. i know this for a fact. saturday i changed the coolant temp sensor. well, when it was all back together it ran fine. later, on the way to the store it died. would try to catch and die every time i tried restarting. got out and checked connectors. the coil plug was a lil loose. pushed it on the rest the way and it started right up.
as for the cam signals, there is a sensor on each head. these signals go to the ecu. then the ecu sends a signal to the 2 ignitors to fire the 2 coils. its like 2 separate ignition systems to be honest. but it wont run if either is disabled. if one coil is unplugged you will hear it fire like it wants to run but it wont sound right.
if you have verified all voltages to the ecu are good and still nada. it does sound like a doa ecu. have you checked to see if the ecu is giving 5v at the tps plug when the key is on? if its missing thats a dead giveaway to a bad ecu. though having 5v there doesnt mean it is ok.
as for the cam signals, there is a sensor on each head. these signals go to the ecu. then the ecu sends a signal to the 2 ignitors to fire the 2 coils. its like 2 separate ignition systems to be honest. but it wont run if either is disabled. if one coil is unplugged you will hear it fire like it wants to run but it wont sound right.
if you have verified all voltages to the ecu are good and still nada. it does sound like a doa ecu. have you checked to see if the ecu is giving 5v at the tps plug when the key is on? if its missing thats a dead giveaway to a bad ecu. though having 5v there doesnt mean it is ok.
09-14-10, 03:22 PM
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rainbow;;;;;;Unhook the crank sensor lower drivers side of balancer and trace the harness all the way back to the coils,it runs up behind the ac and along the side of the block,as it gets to the top you will see where toyota split the signal,ive repaired more than one this way including one i just bought from a "shop" I called their customer and sold it back to them the next day. Feel free to call me if you would like me to walk you through it 7573909481
big ups