92 Lexus, LS400, V8 NO SPARK.

Tiny
PEARLHICKORY
  • 1992 LEXUS LS 400
  • 277,000 MILES

Hi Guys, 1992 Lexus, v8, no spark any ideas, not very familiar with the Lexus, not getting spark, any help greatly appreciated, thanks.

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Wednesday, October 10th, 2012 AT 1:42 PM

18 Replies

Tiny
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Scan for codes first. Then go to teh site here under tune up it will explain how to diagnose your system.

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Wednesday, October 10th, 2012 AT 1:54 PM
Tiny
KHLOW2008
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First thing you need to check would be power supply to the ignition coil.

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Wednesday, October 10th, 2012 AT 2:56 PM
Tiny
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Ive checked relays and fuses, all seem ok, no voltage at coil packs, power supply to ignition? Does it have separate component to power coil packs? I was about to look at the crank position sensor, the car starts at times and wont other times, .

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Wednesday, October 10th, 2012 AT 3:55 PM
Tiny
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If either the carnk or cam sensor is bad the car wont' start so check both or actually all as you have two cam sensors.

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Wednesday, October 10th, 2012 AT 4:36 PM
Tiny
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I got the crank sensor out, any particular steps to test the sensor? I hooked up my meter, im getting 1100 ohms, I looked up the average reading should be 2200 to 5000 ohms, correct me if im wrong, what about the cam sensors? Any readings I should be looking for thanks.

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Wednesday, October 10th, 2012 AT 4:44 PM
Tiny
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It may be the cranks sensor as the ohms are low but if it's cold that may be why. We havn't any specs for those. But they should have ohms as well.

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Wednesday, October 10th, 2012 AT 4:50 PM
Tiny
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If you don't have battery voltage to the coil packs, you are not going to start the engine. Sine problem is intermittent, you caould have a faulty ignition switch or an intermittent break in the circuit due to a loose connection somewhere.

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Wednesday, October 10th, 2012 AT 5:18 PM
Tiny
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I got the part about lack of voltage to coil packs ive looked over most wiring looks ok, im fixing to pull cam sensors out and test them, I found a source telling me I should have between 800 to 1400 ohms on the sensor and to do a voltage test also, with sensor connected and motor spinning.

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Wednesday, October 10th, 2012 AT 6:43 PM
Tiny
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Did you check for trouble codes?
The cam sensor should be 950 to 1250 ohms for your model.

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Wednesday, October 10th, 2012 AT 6:50 PM
Tiny
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No codes, im trying to locate the cam sensors, cant see them.

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Wednesday, October 10th, 2012 AT 7:31 PM
Tiny
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They are in distributors. Also check the ignition relay it may have a bad ground goind to it and not allowing power to the coils.

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Wednesday, October 10th, 2012 AT 7:32 PM
Tiny
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Cool, I thought I was missing something here, so behind the distributor, last check I did was for voltage output on the crank, had around 600 milliamps, looks like a good reading, so off I go to distributors and check for bad ground on relay, thanks.

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Wednesday, October 10th, 2012 AT 7:48 PM
Tiny
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Could be inside the dist too.

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Wednesday, October 10th, 2012 AT 7:50 PM
Tiny
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Ok, I was able to see the driver side sensor, it read 1125 ohms, the passenger side was open circuit, fluctuated a bit then back, to open, and its the one thats worse to get to, havent checked anything else yet, should he be condemned, [ replaced yet or keep looking ] will it start with only one cam sensor working?

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Wednesday, October 10th, 2012 AT 8:36 PM
Tiny
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It might but would require excessive cranking time. The fluctuation of readings could be due to the probes not getting correct contact and you should reconfirm the testing again.

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Wednesday, October 10th, 2012 AT 8:49 PM
Tiny
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I found one issue for sure, the passenger side cam sensor lead is split, only one lead is attached, other is cut and looks been like that a while, could it have still been making conductive circuit being very close, the car started sometimes then wouldnt, I had probes in there good, ive worked meters long time, finally wouldnt start anymore, I imagine could also have other issues.

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Wednesday, October 10th, 2012 AT 9:06 PM
Tiny
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Splice back the wire and test if it works. If you had checked for trouble codes, the cam sensor should have come up.

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Wednesday, October 10th, 2012 AT 9:44 PM
Tiny
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Will do, im calling it a day, ill splice it up, and repost in morning, thanks a lot for all the help, maybe tomorrow get it running, have a good evening.

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Wednesday, October 10th, 2012 AT 11:05 PM

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