Cam sensor signal missing

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
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Re: Cam sensor signal missing

Postby wrx884 » Mon Jan 11, 2021 10:31 pm

vlad01 wrote:I had that symptom of multiple coils firing at the same time, wasn't obvious until I filmed it with the high speed camera on the phone though. My problem was the trigger wheel had chewed up the CAS and the magnets had come out of it. But that's not your problem.


You can't remove the cam magnet unless you take the timing cover off and remove the timing sprocket. You can see it through the hole though. It would be worth trying another harmonic balancer in case there is something odd going on with the trigger wheels on it.


Mayb i worded that wrong but i didn't remove all leads when i was checking spark, only did a coil at a time but each coil acted the same way. When u say something odd might be going on with the harmonic balancer, is there anything to look out for that looks odd or could be a culprit? as far as i know it looks ok but then again i haven't seen behind that balancer b4 so im assuming everything's good behind it.



'quipt4it wrote:Engine should run w/out the sensor connected, but not in sequential mode.
Still do the chart check from 9a on up.
This is what you're looking for (see photo)
A weak or intermittent spark is considered as 'no spark'


Ok i'll have a look and try that with the test lamp from 9a onwards. cheers for the pic thats worth the weight in gold knowing what im looking for now. im almost certain i could see those other circles on the sprocket when i had the cam sensor off.

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Re: Cam sensor signal missing

Postby wrx884 » Sat Jan 16, 2021 4:52 pm

OK can confirm the pick up magnet is still there and the volts on D3 drop to 0 when i connect the test lamp so i guess that suggests there's a wiring issue on the cam sensor wiring?? where exactly would i be looking as i thought if i had wiring issues on that connector then i wouldn't be getting my readings i tested earlier?

I have swapped over another known working cam senor from the standard ecotec i have sitting here so one would assume that is fine.

i found this as a pin out guide for the DFI is there others i need to check?
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Re: Cam sensor signal missing

Postby Jaydo383 » Sat Jan 16, 2021 6:09 pm

im actually having exact same drama is yours a conversion?

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Re: Cam sensor signal missing

Postby 'quipt4it » Sat Jan 16, 2021 6:11 pm

This pic shows how the wiring is linked.
If you have swapped out PCMs I would double check none of the contact pin sockets have 'backed out'. Are the anti back out 'combs' still in the harness connectors.
It still sounds like an earth, as it's common to both spark and cam sensor
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Re: Cam sensor signal missing

Postby wrx884 » Sat Jan 16, 2021 10:25 pm

Jaydo383 wrote:im actually having exact same drama is yours a conversion?


Yeah i have 2 exact 98 VT models tho, only 2 months apart but all the L67 stuff has gone into an standard ecotec body. The only thing missing from the conversion is the fuel pump module but thats not needed.


'quipt4it wrote:This pic shows how the wiring is linked.
If you have swapped out PCMs I would double check none of the contact pin sockets have 'backed out'. Are the anti back out 'combs' still in the harness connectors.
It still sounds like an earth, as it's common to both spark and cam sensor


I have checked multiple times the connectors at the PCM as far as i can tell they are pushed in nicely including the actual wires in the connectors too. This was one of the 1st things i got told to check funny enough since we did the swap. The only thing thats not original with this car is the BCM but that came from another VT and had it linked up to the original L67 PCM for a couple years with no issues but i cant see the BCM having any relation to spark or the cam signal surely?

cheers for that image mayb i will take off the harmonic balancer again and test the wires between the cam sensor and the crank sensor, they seem to be the only wires i think i cant access properly especially the crank sensor plug and mayb with heat over the years 1 of the wires has snapped or corroded somewhere there? i was told the DFI's do have a shitty earths but i have checked the DFI plate and mount bracket is nice and clean.

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Re: Cam sensor signal missing

Postby 'quipt4it » Sun Jan 17, 2021 12:18 am

The key fob has to match the BCM.
It was running previously for a short while, then the troubles started?
If BCM related, you can have a VATS disabled memcal burned, but you won't have security features. Also other options.
The Tech 2 scan tool should have picked up any faults/ issues re the BCM.

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Re: Cam sensor signal missing

Postby Jaydo383 » Sun Jan 17, 2021 7:09 am

Have you tried bypassing the vats by leaving reds on for 45 mins then cranking?

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Re: Cam sensor signal missing

Postby 'quipt4it » Sun Jan 17, 2021 7:36 am

Jaydo383 wrote:Have you tried bypassing the vats by leaving reds on for 45 mins then cranking?

This can be a little hit and miss, sometimes will work, sometimes not. I have had mixed success with it. Some say leave ign. on for two hours.
Won't hurt to try.

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Re: Cam sensor signal missing

Postby vlad01 » Sun Jan 17, 2021 9:54 am

BCM/key fob have nothing to do with spark, only cutting the fuel injectors.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

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Re: Cam sensor signal missing

Postby wrx884 » Sun Jan 17, 2021 3:09 pm

The key fob came with that replacement BCM and was linked to the PCM using the tech 2, didn't need to disable vatts at all as i had the security pins for it and i was driving the car fine for a couple years b4 the conversion and then a month after the conversion so i dont think that could be the issue at all??

When we run diagnostics using the tech 2 i had no fault codes logged only thing that was showing up weird on the tech 2 was the cam signal was missing in the live test and thats it. Even the crank sensor was reading fine.

if its not wiring can a failing PCM cause spark issues? im able to get hold of another l67 ECU and engine harness, im thinking maybe i should get it at least i can test some wires on the harness and compare mayb?

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