Here's the cranking trace with no cmp. Shows #1 coil output. The trace doesn't always look like that, the first half varies from start to start. But what is apparent is that the ECM settles on a pattern. If the engine hasn't started by then it's 50/50 whether it will or not from what I can see.
Jim
Kur4o, that was good information about sensor alignment. To restate, chevrons on the wheel to the rear (D shaped hole to the front) sensor connector facing forwards in line with the crank, aligned to the crank centerline (not off axis, note the tab is at an angle) wheel edge at the center of the sensor side to side, and in line with the index hole with #1 piston at TDC. Is this all correct, and have I missed anything?
Now on the CMP sensor, In-Tech I see that you show an LS1 sensor at 12v and an LS3 sensor at 5v. So my question is, what happens if you put 12v on the 5v sensor? That could possibly account for my failures. And since RockAuto doesn't list the sensors by LS1 or LS3 engine it would be easy to get the wrong one if you aren't ordering for a specific vehicle. I suspect I ordered the first two for the Silverado. LS3 right? The last one that I just ordered was for the Corvette, so LS1? To further confuse the question, both the Camaro and the Silverado use the same pin (C2-39) to feed the CMP sensor, but the 0411 with the Camaro OS feeds 12v to the sensor. Did they offer both the LS3 and the LS1 in the Camaro? Don't know if the Corvette is different or not. So the voltage change could be in hardware or software.
I will try the ones I have on 5v to see if it works.
Well, that does fit with my general methodology: Try every wrong way first, but a little more consistency would have been helpful.
Jim
Edit: My 2001 Silverado ECM also outputs 12v on pin 39 of C2. Just to further confuse things. Oh, but that used the rear sensor so that probably makes sense.
Last edited by Jim Blackwood; 03-03-2020 at 09:43 PM.
LS1 5.7L (car)
LS3 6.0L (car)
LM7 5.3L (truck)
I can get you the cam connector pin locations for the 0411 truck if needed.
89 K1500 Scottsdale 5.7L 5spd 3:42 RamJet cam Dart iron TBI heads 427 PCM swap
95 C2500 Cheyenne 6.5L turbo diesel 4L80e 4:10 DB2-4911 Manual pump conversion 0411 PCM trans control 2Bar COS
05 Outback XT 2.5L turbo gas auto
The voltage of the sensor depends by the pcm used. If you put 12v to a 5v sensor it will be fried.
The ls1 style PCMs are 12v, 2005 corvette ls2 and all ls3 and 6.2l engine use the 5 volts sensor. SO anything pre 05 will work for you, later depends on the engine type and pcm used.
The info for the sensor position seems correct. I am planning to take some shaddy pics and measure the gap between sensor and wheel too.
Hi Jim, I'm not sure my terminology is correct using "open collector" but the GM sensors(and the honeywell ones I have used) don't care if they are fed 5v or 12v. Sometimes, it appears the 5v sensor only outputs 5v so you have to use a pullup 1k resistor on the power and signal line to "boost" the signal output. I should have checked that deeper when I did it using a Mefi controller that will do 24x or 58x(flag settings and some other stuff) and whenever we used that controller on an LS3 we always had to use a pullup on the crank sensor.
I call LS1 cam any that are in the rear of the block(truck or car). I call LS3 cam any that are in the timing cover(truck or car). The early LS2 had the cam sensor in the timing cover and that's the only one I am not sure of as I think they are unique but have little experience with them and think those were all E40 computers, so again, not sure on those. I posted those voltages as that was what was on my notes so don't get too excited about that, lol.
-Carl
p.s. the cars and trucks use all the same sensors meaning if I need a crank or cam sensor for an LS1(24x, 1x, I order one for a 2001 truck and it is the same sensor as used in that year camaro/firebird/vette. When I want LS3(58x 60-2, 4x, stuff I just order for a 2011 Truck and it is the same sensors as Camaro/Vette etc
Hope that helps
Last edited by In-Tech; 03-03-2020 at 10:58 PM.
-Carl
OK, thanks for the clarification. The Corvette sensor I ordered matched the reference number in Matt's EFI book for the front sensor so I'll check it out when it arrives. The one I have on the simulator also checks bad with 5v. I did not expect 12v would hurt a 5v automotive device. Most solid state devices I've dealt with seem to have a breakdown voltage at least 2 or 3 times the operating voltage. But it's the current that kills them.
Anyway, got the 2nd Perytech scope add-on for the laptop today (DSO U2200) but so far haven't been able to get the 3rd and 4th trace so I'm working on that. Hope to upgrade the drive on the sensor wheel to get a cmp flag tomorrow too. I've got a 4 tooth geneva wheel that I'm thinking about using. That'd be pretty sci-fi-ish but should work. I'd like to increase the speed range also but probably don't have too many options for that. Once it all works I may clean up a few rough edges, maybe add some more sensors too. Maybe the cmp sensor will get here tomorrow.
Jim
This is too much even for coincidence.
The new sensor came in today. Immediately I set up to test it on the 5v source for EGR (C1-48) from the ECM (pin C), ground (C1-61)(pin B) and signal (C1-73) (pin A). No voltage change on pin A with the flag using a pair of medium sized unplated channellock pliers as the target. Changed to the 12v lead from the ECM (C2-39). Flag gives change from 3.31 to 3.23V out. With the signal line disconnected it is 341 and 3.33.
Three different sensors ordered at three different times from 2 sources and they all test bad in the same way? I'm at a loss here. Anybody got any idea?
It's the tan sensor for the timing cover. Controller is 12200411, OS is Camaro.
Jim
My L31 Vortec 5.7 Liter 24x / '0411 system uses the stock 1999 K1500 5.7 liter CKP sensor and stock 1999 K1500 5.7 liter CMP sensor. For my L31 Vortec 5.7 liter 24x / '0411 conversion, I started with a stock 2002 DBC LS1 Flash and tuned from there.
dave w
GM spec for gap is .020" - .040"Originally Posted by Jim Blackwood
LS1 Cam
A=Signal
B=Ground
C=12v
LS3 Cam
A=5v
B=Ground
C=Signal
LS1 Crank
A=Signal
B=Ground
C=12v
LS3 Crank
A=Signal
B=Ground
C=5v Sometimes requires a 1k pullup
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Your wiring to THAT LS3 cam sensor is wrong, it is still wired like a LS1 cam. Easy fix and usually won't damage the sensor. Also you might grab power from pin B2 instead. Attached is a nice pinout chart for that ecm if you already don't have this one.
-Carl
OH HO! Here we go!
Connecting cmp pin A to a 5v source, in this case C1-48, pin B to sensor low C1-61, and pin C to sensor signal C1-73. I get switching at 4.45v flagged and 0.01v open. FINALLY, results. So, does the other sensor work? No it does not.
Switching to 12v gives a 10.9v signal return.
First check in the car will be to reverse pins C2-39 and C2-73 at the ECM and see if I get a return. Maybe I'll get lucky and that sensor will be OK, and just need to be aligned with the crank sensor.
Jim
Cool,looks like you are on your way. I was just reading back through a little and it's humorous how posts can be so vague and I apologize, I didn't mean to as I wasn't clear enough in what I was thinking especially on the voltage. Also I will verify my thoughts sometime. As far the 24x crank sensor, yes it is designed for a split wheel, so is the LS1 cam sensor that is used in the rear of the block. I believe I saw someone post a drawing of the internals of that sensor type compared to a standard proximity hall sensor. Its' orientation is critical as well as it being centered.
Next time I am playing with this stuff I will verify what I believe on the LS3 crank sensor. I believe if you feed it 5v or 12v it will only output 5v hence the need for a pullup resistor in that application where the signal needs to be higher than 5v. GM Mefi 4x controllers come to mind. Now, the cool LS3 cam sensor basically mimics whatever the input voltage is... 5v in, approx 5v out. 12v in, approx 12v out, as you saw.
Just noticed one other thing in your previous post, you said C2-39 and C2-73. I've never called them C1 or C2 and use Rx for Red connector and Bx for Blue connector. The cam signal input is on the blue connector B-73. The cam sensor ground is on the blue connector B-61. The cam sensor voltage is on the red connector, R-39.
It sounds as if you are not using both connectors correctly in the car. Hope this helps
-Carl
-Carl
Thanks for the correction Carl, that was a typo (or a brain fart take your pick) as pin 39 is on the red connector or C2 as you said. 73 and the ground are on C1 or the blue connector.
Bit of an oddity I noticed yesterday that might make sense to you. The new Delphi sensor PN 1P1209 from a 2005 6.0L Corvette tracked the input voltage as you said. However the one in the car returned a 5v signal. It is also the front mounted type but likely was sourced from either an '05 Silverado or Camaro, I'd have to dig far back in receipts to confirm. I'm uncertain if this will meet the voltage requirements of my ECM or not but as the sensor is very troublesome to access I expect I will just have to try it and see.
Good news on another front, I got a reply from Perytech and using multiples of their scope module is a simple matter of daisy chaining the external trigger to the square wave output with a jumper. Voila, I have a 4 trace scope. So today I plan to check all the coil trigger output signals.
Jim
Hi Jim,
The LS2 cam sensors(in timing cover) seem to be an oddity that I haven't spent much time looking at. I've seen Black LS2 cam and Tan LS2 cam, maybe that's the key. I have seen times where they required a pullup and times where they didn't. I think all of the LS2's used an E40 computer(24x 1x) and the LS3 is E38(58x 4x) and E67(58x 4x) and for sure those cam LS3 tan sensors are Voltage in = ~Voltage out. So, yeah the 2005,2006 stuff I have no definite truth. Maybe the SS trailblazer and Corvette has one and the GTO(australian) has another. Either way, sounds like you are making good progress.
I've never heard of that Perytech scope and just googled it. That thing is way cool for the money and is perfect for our BS car stuff. Really Really cool it can be daisy chained. I've got a 4 channel Rigol but I hate having to rip it out of my "lab" and drag it to the dyno. One of those Perytech's would be really cool in one of the laptop bags
-Carl
-Carl
I'm just guessing the black/pink thing may be for something else, but the first two I bought were pink and the Delphi one was tan (Vette). I'm using the 0411 ECM so I guess once I get this thing to start I'll find out if the pink ones will work or not.
Jim
Sort of a good news/bad news thing today. The good news? Testing in-car, the pink CMP sensor outputs 10v on the sensor line to pin 73. So there seems to be functionally no difference between it and the Corvette sensor.
The bad news? the line goes high at TDC on the compression stroke. My fault, that's the way I installed it. But according to the scope graph on page 1 that's backwards and it needs to go low. Not usually a big deal but I have to remove the top radiator hose to get to the oil pump drive it is mounted on. Such fun.
Last edited by Jim Blackwood; 03-05-2020 at 10:55 PM.
And here are some pics. You already figure it out, but other folks can benefit from it. Cant confirm the position of the small hole,[no piston available], but it looks like it is at the center of the sensor on #1TDC.
on 3rd pic the tab is pointing forward of engine. The line is parallel with the crank centerline. Just use the tabs on the sensor to get it right.
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