Helping a friend. 1999 c5 coupe stock.
He was driving and the engined shut off. No codes. Got it towed to my house.
Checked all fuses that pretian to CKP sensor, Injectors ,coil packs and map sensor.
Car cranks no start. Fuel psi 60.
Start with map sensor. A- Blk/white wire low ref ground gets 5v from C-orange 5v supply and orange to neg battery gets 5v. key on engine off B- signal wire to A- low ref ground is 1.5v when i pull vacuum volts go down to .25v at -20hg.( HPTurenes scanning shows 15kpa not 95kpa when engine off key on.
I have not checked CKP sensor valves or wires yet saving that for last since starter has to come out. But when cranking tach does not move and verified with HPT rpm stays zero so no signal from sensor when cranking.
Ignition coils main connect with 7 pins. orange gets 12v to ground but when i check supply 12v orange wire to the other wires they all get 12v but if i check each other wire to ground all get 0v. and when i check for continually from supply 12v wire to ground i get continuity. All the other wires to ground i get 1000omhs.
When i check the 4 wires to each coil i get 12v Pink supply and pink to check each of the 3 wires shows 12v from pink When i crank pin c firing signal get no volts no spark.
Fuel injectors 2 wires. Pink gets 12v to ground stripe to ground 0v
stripe wire with test light to ground when crank does not blink so no signal from PCM same as coils. When i check between pink and the stripe wire i get 7.8v This is unpluged from injector
So since i didn't physically check the CKP sensor. Can a bad CKP sensor effect all these other issues. Hope it makes sense.

One lead on the orange wire to ground 12v . And from orange to each other wire i get 12v. But each other wire to ground 0v and from each other wire to each wire but orange is 0v. This is main feed to coils

Pink wire to ground i get 12v. From pink to each other wire i get 12v but the 3 wires to ground i get 0v. Green is the signal wire when crank 0v no signal.
I searched but cant find a 1999 pcm wiring diagram. If these are related to the PCM. Have not back proded to PCM yet. Don't have diagram.

And from ground wire from coils to + battery i get 12v Wire on the back of head. Yes cleaned the grounds to car chassis.
Any ideas or any questions to verify any or all confusion.???

 

So a bad CKP sensor will not send timing pulses to the PCM which will not generate fire pulses for the ignition coil packs or pulses for the fuel injectors. My best guess.

 

In cases where you have a no-start condition, you have to crank the engine for 15 sec continuously to generate a DTC. Make sure you have a fully charged battery before you do this.

 

I guess the starter has to come out.

 

OK have not tried that. Yes battery on charger 13v and when checked all the power supplies i get the battery voltage also. When i took off MAP turned car off then back on i got code p107 checked and that was MAP code cleared code hooked back on and no MAP code. THx

 

Well i just got ***"ED. This is B.S. I went to crank for 15 sec and the ************ started right up everything is working perfect WTF WTF im so pissed.

THis is the worse motherfucking case possible WTF I'm screwed
P. ******* S. no ******* codes.
I just found this so im not going to take a chance and change the CKP sensor. I dont know what else to do.

Yes, a3-wire crankshaft position (CKP) sensor—typically a Hall effect sensor—can absolutely work intermittently (bad then good) before failing permanently. While a totally fried sensor will stop the car completely, the most common scenario for a failing sensor is that it functions properly when cold, but fails when it reaches operating temperature.

Another update, I checked everything again since its running all have the same valves. I'm confused.

 

LOL another update. I think the stars angined for my favor. Had the car running got up to temp and died. No rpm cranking, so not 100% but it seems to be the CKP sensor but that 1% I'm weary about is there is no codes. But i have to start somewhere. I'll get back once we change the CKP sensor.

 

And you cranked it for 15 seconds in the no start condition and no DTC?

 

yes i was taking ur suggestion to crank for 15 sec but it started within a second. I found that quote I copy paste from AI. So I let the car run tell it reached 200 degrees and it shut off and was back to crank no start and no tach movement. What sucks is still no codes.

 

Ok, so you are a no start situation again....did you let it crank for 15 sec?

 

Helga, if you're gonna buy a sensor, if I were you I'd buy a new GM sensor.....IF they still make them!! Not aftermarket...

 

o **** no. Good idea when I get home I'll try 15sex crank.

 

good call. Im going to tell I'm buying the senor from gm. If he wants ebay or Amazon I'll tell he to take the car elsewhere. He's going to do the work I'm going to be the back seat driver. I can't physically get up and down with my injuries. Since last time on here I sidelined my car for good because I just can't drive it without pain. I'm going in for my 4th surgery in 2 weeks. Since the past 6 month. And let's see after the cranks for 15 seconds to hopefully through a code to verify its the CKP sensor if not I have no other choice but to gamble and hope that's what it is.

 

Well i'm probably the only c5 owner that prayed and prayed that i would get a code after cranking for 15 seconds aaaaaannnnnnnnnndddddddddddd. NO CODES and the tach is not moving and no RPM's on scanning with HPTuners which should show around 150 to 200rpms but nothing. so i'm back where i started, going to take a chance and change the CKP sensor. Well i'm definitely not a person to count on luck just throwing parts but i think i did du dilagents on this issue so i'm going to test the CKP sensor before we commit to buying a new one. I really hope it test bad. If it doesn't test bad i don't even know where to start to troubleshooting this issue. So first things first is to get to the sensor, so we can test it and take i from there.
If it starts tomorrow morning ill let it get up to temp and hopefully it will stop running again when it gets up to temp and then we will proceed to check the sensor while hopefully it failed.
In the meantime if anybody has any ideas let me know. Thx.

 

This is the sensor I used to replace my failed one on my ‘02 C5 recently. It’s a Delphi. Worked perfectly. Amazon

 

Sucks that did not throw a code. It sounds like it is isolated if Hp Tuners does not show any RPM. Could be heat damaged wiring from the headers or the sensor.

 

Nothing Comes up for CKP

 

Good lord.....don't buy off Amazon.

 

Fixed it. See above. It’s from the official Delphi store, on amazon.

 

Well that's the fun part of gambling occasionally you win.

So it's the official Delphi store that's really the unofficial Delphi store because they were bought out years ago. There is no Delphi anymore. Parts are still sold under the Delphi name although any quality and association with General Motors is long gone.


So anyways, don't buy parts off Amazon