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I have already looked and cleaned the negative cable and it looks fine. If it were a bad cable I dont think it would turn over when I jumper it. Would it? I also pulled the starter relay out of my FJ and tried that and it didnt fix it. Actually swapped every relay that was the same to see if it fixed it and it didnt.
I had a customers vehicle do this, it wasnt a Lexus, but this may help. 1st intermittent problems are hard to diag. The vehicle had no codes, everything tested in spec and how it was supposed to. When it sat overnight it would start right up. I then got it to act up when it was at operating temperature. It would cut off sometimes after a few blocks around driving, or sometimes would be a while before it cut off, then no crank no start. Make a long story short, it turned out the fuse holder developed a hot spot where I could see on the back side signs of arcing or jumping. Electricity always takes the easiest path. Sounds a lot of like what your issue is. I changed the fuse block, problem solved.
Last edited by DiabloX22; 06-25-17 at 01:26 PM.
Reason: add
I have already looked and cleaned the negative cable and it looks fine. If it were a bad cable I dont think it would turn over when I jumper it. Would it? I also pulled the starter relay out of my FJ and tried that and it didnt fix it. Actually swapped every relay that was the same to see if it fixed it and it didnt.
Just cleaning it will do no good! did you look down at the other end of the cable where it attaches to the block, even so it can get deteriorated where you cannot see, I would really consider replacing the Neg cable at least, maybe even the positive---like I said before my friends truck did the exact thing started fine when cold and nothing when hot, changed out the neg cable and no more issues.....
I agree witk Booyah, start with simple basic principles. Then If that doesnt work, you will have to start the process of elimination. Again, intermittent problems are the hardest to diag. Something is making connection, then not. Is the fuel pump getting power? I would invest into a power probe if you dont have 1 and have someone turn the key, start testing the components that should be getting power.
did you look down at the other end of the cable where it attaches to the block, even so it can get deteriorated where you cannot see
Right - Start at the connectors, check them for cleanliness and tightness. But then run your hand along the insulation to see if there's any internal corrosion that you can't see.
The underside of the fuse box would also be a good thing to look at. Ultimately, you'll probably need to follow the current everywhere it goes, from the battery to the starter. For both the positive and negative side.
Im still stumped. Ive looked at all the grounds and I,dont see how replacing them is even viable seeing as how its part of the harness. Besides how would i get it to turn over by simply jumpering the start relay if it was the grounds. Could bo power at the fuel pump cause a now crank issue.
Could a failing alternator cause these no crank symptoms. The GX had been making a very faint whirling noise coming from the front right of the truck that would slightly get loyder with the rpms.
You can test that with a voltmeter. With the engine not running it should be about 12.6v. With it running it ought to be about 13.8v (or a little more).
Just checked it and it was 14.22 when running. So I just went out and started it probably 4 times and let it run a total of 15 sec probably. Then all the sudden im having the no crank issue. So this seems to not necessarily have anything to do with the car warming up. The only thing i did was remove the starter relay a few times to check voltage at pin 1 and 2 with the car off. Then I would check the switch power there when i tried to turn it over. I just get weird milli voltages. You would think the switch power there would be 12v but maybe not since it comes from the neutral safety switch and the ECM.
When i test with a meter the positive post on the battery to #1 pin where the relay goes I get 12v which is expected. Is what is weird is i fet the same at the number 1 pin.
You would also think that with this no crank issue that when I jumper pin number 3 and 5 it would start at least. But nope it just cranks and cranks and cranks...
Not surprised - the computer also has to direct the injector to start squirting fuel in there before it'll run.
I think you said you replaced the starter relay already. With millivolts being measured at 1 & 2, I would start looking for an open wire upstream. Pull the relay when this happens, then measure the resistance from pin 1 to the battery negative (should be very low). Then measure the resistance from pin 2 to Junction 17/C and then Junction 26/D. Use an ohmmeter, not a test light (test lights pull too much current). Sorry, I don't know the physical location of those junctions.
I also just got done jumpering pin 9 and pin 6 on the nuetral saftey switch plug and tried to start it to no avail. Not sure if thats correct but its seems like it would work via the wiring diagram.
Went out this morninng fired right up. Let it run for 40 min then shut off on its own. All the wires im tracing are ohming out and have good voltage. 13.7 volts when running as well.
Could a bad crank sensor or cam sensor cause a no crank issue without throwing a code? I was reading yesterday that certain model toyotas with the 2uz motor have a warranty TSB regarding those sensors going bad that they call an intermittent heat soak issue.
06-25-17, 12:15 PM
