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intermittent no start/losing spark, ignition timing signal

posted Jun 22, 2016 04:50:15 by AllanBriones
Hello everyone, I'm looking for some direction, my brain is getting fried....
- 2010 toyota tacoma 2.7L w/68,000kms intermittent no start/extended crank time.
- It Usually acts up when it's at normal operating temp. Lately it's been happening when the outside temp is warm (25c).
- When the vehicles does starts, it runs great with no misfire.
- I have Checked for DTC-none. Check fuel pressure-41 PSI- during cranking.
Pressure also remains when sitting.
- Check for spark -intermittent. Check powers and grounds on all coils-ok.
Check IGT(ignition timing) signals on the coils and from the ecu, it goes from no signal to intermittent signal during intial cranking.
- When it's cool outside or the truck is cold soaked it will give IGT signal instantly and will start. I have check the cam and crank sensor signals and matched up the cam and crank correlation with signals from a known good vehicle.
- The timing chain was also checked just to make sure timing was dead on.
- Data PiD shows RPM while cranking/ no start.
- I have check the immobilizer input and output signals, also matching it up to the known good vehicle, just for kicks I programmed a new key.
- Checked ecu powers and grounds during the cranking no start. Power show good voltage, ground are less than 100mv.
- Checked 5 ref during cranking no start.
- Did a ecu pin out. Pin out was within spec.
- I've tried disconnecting sensors and cleaning all ecu grounds with no luck.
- Checked for any aftermarket security or remote start-none. I have done a relative compression test.
Measure voltages for coolant temp, iat,maf,tps, they all seem to be good during the no start.
- All tests and checks have been done during the no start and starting conditions.
- Some history on the vehicle the the dealer did, was change the battery, starter, crank sensor, engine ecu all with no luck...
- I can't figure out why the ecu is not outputing the IGT signal when the ecu is getting the proper inputs.
Am I missing something??? Any help will be greatly appreciated. Thx
[Last edited Jun 23, 2016 11:36:17]
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2 replies
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MattWhite said Jun 22, 2016 15:23:53
Just to clarify, you've checked the cam and crank signal while the fault has been occurring? Being effected by temperature like that I'd definitely jump straight into the cam/crank signals.
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AllanBriones said Jun 22, 2016 16:05:41
Yes I have checked the cam and crank signals during the no start
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