Fires then dies. HELP

[XfireZ51]

R u sure its the cam angle and not the crack sensor?

[Ozruss90]

Originally Posted by XfireZ51

R u sure its the cam angle and not the crack sensor?

I?m assuming a typo and you meant CRANK sensor. No, I don?t know. The only reason why I have referenced the CAM angle sensor is that this, fire up and die straight away, situation started when I went to re start the car after pulling the cam angle sensor out to replace the O ring due to an oil leak
Should I pull the CRANK angle sensor out to check, and test (if possible) ?

Cheers, Russell 🇦🇺

[RSLyrick]

I think that you would get no spark at all if the crankshaft position sensor was faulty, as the ignition module selects which coil packs to energize based on the sensor output. Your engine is starting and holding for a while and you checked that you had sparks, that already sounds good to me.

If this sensor is working fine, you should logically get RPM readings as well.

If you want to test it (we never know), there's a nice method provided in the FSM which allows you to test without removing the crankshaft position sensor from the engine and make it easy to test (see 6E3-A-32) :

1- Get yourself an engine coolant temperature harness from a 1985-1989 C4 (PN : 12046623)
2- Unplug the actual sensor harness from the sensor and plug the floating engine coolant temperature one in with the two floating leads.
3- Measure the resistance between the leads
4- Should be a value between 965 and 1075 Ohm at 25?C (77?F) for a working sensor.

In any cases, try to give a quick call to Marc. Please, give us a feedback about it, I'm interested!

[Ozruss90]

Well it looks like the problem has been solved. I rang and spoke to Marc Haibeck yesterday and described my situation. He said start with the basics, has it got fuel pressure ? Yes confirmed by pressure gauge. When I told him it happened straight after removing the cam angle sensor, he suggested that I unclip the harness from the sensor to the ECM. I hadn?t done this as I had checked codes at the ALD port and no faults detected. I had also read in the FSM that the engine will still run without Cam sensor input, so assumed problem had to be elsewhere. Looks like the cam sensor is faulty and while connected to the ECM was causing an issue with the ECM. Once I unclippped that harness the engine fired up and idled as per normal. Very relieved to know what the problem was. Thank you Marc. 👍

NOW I have to source another sensor if anyone on here can help me out with one or steer me in the right direction to get one 🤞 would be much appreciated.

Cheers,
Russell. 🇦🇺

[RSLyrick]

Hey Russel,

Very nice ! It's weird that the ECM didn't throw you a DTC31...must have been so confused by the non-working sensor that it didn't know how to react (the failure was probably not landing into the "missing pulses" category or "extra pulses" one...interesting.

So, if I'm not wrong, you will face the second issue. The camshaft sensor lands into the "hard to find parts" section. No longer manufactured or stored.

Original PNs were : 10137658 / 10137658 / 213-141

I came across the following threads about modifying an aftermarket one.

https://zr1.net/forum/showthread.php?t=28584

Phil (Jagdpanzer) seems to be able to make some based on aftermaket parts : he provided his email in the above thread : pwasinger@aol.com

Latest requests were done in June this year, so it should be feasible to get one I guess.

[Ozruss90]

Originally Posted by RSLyrick

Hey Russel,

Very nice ! It's weird that the ECM didn't throw you a DTC31...must have been so confused by the non-working sensor that it didn't know how to react (the failure was probably not landing into the "missing pulses" category or "extra pulses" one...interesting.

So, if I'm not wrong, you will face the second issue. The camshaft sensor lands into the "hard to find parts" section. No longer manufactured or stored.

Original PNs were : 10137658 / 10137658 / 213-141

I came across the following threads about modifying an aftermarket one.

https://zr1.net/forum/showthread.php?t=28584

Phil (Jagdpanzer) seems to be able to make some based on aftermaket parts : he provided his email in the above thread : pwasinger@aol.com

Latest requests were done in June this year, so it should be feasible to get one I guess.

Thanks for your input. Much appreciated
Question. Do all year models of the LT5 take the same sensor ??
I have the opportunity to borrow one from an acquaintance who purchased an LT5 engine out of a pre production test car here in Australia. I was going to borrow that until I can get hold of another one.
To what extent does the engine run with the cam sensor disconnected? Can the car be driven and if so are there any restrictions on how it?s driven ??
Cheers, Russell 🇦🇺

[RSLyrick]

When I got my new sensor it was listed for 1990 to 1995. I do not think that there are differences but I have no certified proofs at hand. Maybe other members can comment on that.

Without a proper working sensor, optimal SFI cannot happen as the ECM doesn't have the info about the intake valve opening state. I'm not sure but additionnaly to the engine running poorly, you may get RPM limitations as well.

I'd like to add a bit more thoughts to this topic.

I'm still thinking that the ECM being faulty is a valid hypothesis. By that I mean, that the interface with the sensor is damaged or has failed. You didn't get a DTC31 that's the reason why I keep the hypothesis alive.

This is (probably) what happened to the Autofunk guys (https://www.youtube.com/watch?v=_-By...bqpGO&index=11).

Similar issues as yours but they managed to get a DTC 31 (camshaft sensor issues). Their ECM was faulty, not the sensor.

Did you get a DTC 31 when running the car with the sensor harness disconnected ? Just to be sure that the sensor interface is actually capable of computing what's happening at this specific pin.

Also have you probed the camshaft sensor output when ignition is ON ? should be at 0V when the slot of the camshaft reluctor wheel is in front of the sensor, 12V otherwise.

And the supply wire to the sensor when ignition is ON (12V) ?

[Ozruss90]

UPDATE:
After a phone call with Marc Haibeck, he suggested that I disconnect the harness from the cam sensor to the ECU. I didn?t think this would achieve anything due to, knowing that the engine would/should run without the cam sensor functioning. BUT, with the harness connected, and the sensor faulty, I can only assume that it was sending a bad signal to the ECU. Once I DISCONNECTED the harness, it fired up and ran as per normal. BINGO. I took it for run yesterday, to a car show approximately 30km away and it ran perfectly with the harness disconnected.
I borrowed a cam sensor off a friend and fitted that in today, and with the harness CONNECTED as it should be, it started up and ran perfectly again.
I can only conclude that the cam sensor was faulty and caused my initial problem.
All the car show & shine events are starting back up, now that our weather here in OZ is nice and getting better. So good timing. I?m happy as??.😁

Cheers,
Russell 🇦🇺

[RSLyrick]

Thanks for the update. It is interesting to see that we can run the ZR-1 without cam sensor on long distance...

Still surprising that you didn't notice any driveability issues, did you try high RPM driving ?. Not even increased fuel consumption ? Sounds like the ECU manages to perform good SFI only based on the crankshaft sensor then...

Do we have a useless sensor in our cars ?

[Ozruss90]

Originally Posted by RSLyrick

Thanks for the update. It is interesting to see that we can run the ZR-1 without cam sensor on long distance...

Still surprising that you didn't notice any driveability issues, did you try high RPM driving ?. Not even increased fuel consumption ? Sounds like the ECU manages to perform good SFI only based on the crankshaft sensor then...

Do we have a useless sensor in our cars ?

Hi RSLyrick,
My secondary key switch not working consistently at the moment but did rev past 5000 and run it up to 180kmh on the road s that I had available at the time. Seemed to run great even without the cam sensor connected. Go figure.
Marc did mention that the cam sensor was there just for fine tuning and making sure the engine met emission requirements.

Cheers,
Russell