Cam sensor signal missing

Holden/Delco Tuning. ALDL, OBD 1.5. Circa 1989 to 2004.
User avatar
Posts: 179
Joined: Sun Oct 28, 2012 12:57 pm

Re: Cam sensor signal missing

Postby 'quipt4it » Thu Dec 24, 2020 6:55 pm

I replaced mine well before 100k's.
You do know with these things it's a lottery...
Was going to say check connectors, but it's already been done...

User avatar
Posts: 6798
Joined: Mon Oct 08, 2012 6:41 pm
Location: Kyneton, Vic

Re: Cam sensor signal missing

Postby vlad01 » Thu Dec 24, 2020 7:00 pm

I have had several cars, many which were 300K +. No CASs have died. I think the biggest factor is heat, if you are stuck in traffic all the time the senors and wiring gets cooked, on the freeway there is plenty of air to keep things cool. Heat is the enemy of electronics.

I live in the country so I mostly do highway and its also not that hot in Vic for majority of the year.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

User avatar
Posts: 179
Joined: Sun Oct 28, 2012 12:57 pm

Re: Cam sensor signal missing

Postby 'quipt4it » Thu Dec 24, 2020 7:03 pm

agree, however the later ones have a 'dust shield', that would keep the thing nice and toasty :lol:

User avatar
Posts: 179
Joined: Sun Oct 28, 2012 12:57 pm

Re: Cam sensor signal missing

Postby 'quipt4it » Thu Dec 24, 2020 7:55 pm

Thought this was interesting
Pay note to what the guy says at 1:37
https://www.youtube.com/watch?app=desktop&v=dYbRcPkUQsw
This is probably better than a lot of to and fro-ing on the keyboard lol
Check that screw is tight from harness plug to DFI module

Posts: 10
Joined: Thu Dec 24, 2020 12:09 pm

Re: Cam sensor signal missing

Postby wrx884 » Thu Dec 24, 2020 10:25 pm

'quipt4it wrote:Hi wrx884,
Running OK then running slightly off then nothing at all points to one of those sensors.
CAS have been problematic for these since they were new. I wouldn't trust 'off brands', especially with even genuine items having problems.
Intermittents are the hardest to track (fwiw).
Did it run after you replaced the CAS?
If not, you may have inadvertently 'wiped' it without properly 'gapping' it in the interrupter rings.


Yeah it ran good for like a week b4 the issues came back, the only reason i haven't tried to replace this again yet is the tech 2 was showing ok voltages at the time so thought id explore other issues that could be causing the cam signal to go missing? From what i understand too u cant adjust these CAS's they pretty much lock into position unlike others ive seen so im sure that gapping it should be fine? I tried the water trick on it but it didnt make any changes when the car was at OP temp so i thought again it might be something else. I have heard the after market CAS's can be pretty bad unfortunately its all i could get hold of at the time but if this is the cause i'll try find a genuine one.

The connections at the DFI seem clean as and go on fairly tight, ive swapped that DFI around many times with the spare thinking ive surely missed something but im certain its fine. can i test the wires for the cam signal at that DFI plug? ur saying it should still run with out the cam sensor tho so that might be pointless to check?

User avatar
Posts: 179
Joined: Sun Oct 28, 2012 12:57 pm

Re: Cam sensor signal missing

Postby 'quipt4it » Thu Dec 24, 2020 11:04 pm

I only have a VN service manual, it shows the CAS is earthed through the DFI module which goes to the Crankshaft Reference Earth at the ECM (VN model). VT should be same. The DFI is secure?
Not only are the connections important, all the earths are as well.
Here is Cam sensor check:
This also checks PCM and DFI etc...
Attachments
CPS.jpg

Posts: 10
Joined: Thu Dec 24, 2020 12:09 pm

Re: Cam sensor signal missing

Postby wrx884 » Fri Dec 25, 2020 11:52 am

cheers mate i'll give this a shot after all the xmas shin-digs today if not tomorrow and hopefully have more info for u then. much appreciated and merry xmas everyone :)

Posts: 10
Joined: Thu Dec 24, 2020 12:09 pm

Re: Cam sensor signal missing

Postby wrx884 » Mon Jan 11, 2021 1:01 am

sorry for the lack of reply guys ive finally got around to doing some more tests mainly i couldn't get hold of the bolts needed for the harmonic balancer removal tool over the xmas break, everything was shut but have now and have installed a new genuine CAS and still no go. As it sits now ive checked for spark and have notice it doesn't spark but will sometimes after cranking for a while but its random and no where near sparking enough to fire the car. I checked for spark by watching it jump between each coil pack and all 3 coil packs do the same thing. Ive replaced again with my known working standard ecotec DFI and coil packs even that shows same symptoms.

Tested the cam signal plug A-B shows 6.1V B-C shows 10.6V
Measured 5V at terminal D3 with ignition on

I obviously couldn't run the engine to see if the voltage fluctuates so couldn't run the tests with the test light

last thing i haven't checked is the magnet pick up, will this stop my spark? can this magnet be seen if i take out the cam sensor out and rotate the motor by hand? i dont even know what it looks like im assuming it should stand out pretty obvious tho?

Been told to clean the under side of the DFI and mounting plate to ensure good earths and as fare as i can tell its good.

User avatar
Posts: 6798
Joined: Mon Oct 08, 2012 6:41 pm
Location: Kyneton, Vic

Re: Cam sensor signal missing

Postby vlad01 » Mon Jan 11, 2021 8:54 am

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.
I'm the director of VSH (Vlad's Spec Holden), because HSV were doing it ass about.

User avatar
Posts: 179
Joined: Sun Oct 28, 2012 12:57 pm

Re: Cam sensor signal missing

Postby 'quipt4it » Mon Jan 11, 2021 9:11 am

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'
Attachments
1sensor.jpg
1sensor.jpg (345.51 KiB) Viewed 83 times

PreviousNext

Return to Holden ALDL ECUs

Who is online

Users browsing this forum: No registered users and 5 guests