Bama99z

iTrader: (7)

Ok so here is the problem. Finally got my new motor in this week ( 2 1/2 year project ) and had my Tuning buddy come down today to tume it ( HP Tuners ). Low and behold it appears that I have some issues that we need some help with please. Once he installed the base tune in it so that we could get it running and fine tune it below is what we found.

First of all I've built a 408, it has got a Lunati crank and rods Fast 102 Intake, NW 102 TB, Texas Speed 100 MAF and Deks 60 lb injectors.Below is a list of the issues that arose today while trying to tume it.

Got a P0335 and a P0336 ( which is a Crankshaft Position Sensor codes ). However the CPS sensor is a brand new ( GM ) sensor. Looked to be ok after messing with it for a while trying different things without any luck we decided to install the old one it idled somewhat better until it seams to get to operating temperature, then it goes to crap.

Through out our trouble shooting process we found out that cylinders # 1,7,4, and 6 are not firing at all ( checked with a temp gun as well as removing the plug wire and installing another plug to sheck and see if it was firing). Thought that there may of been something going on with the valves. However we checked compression on # 1 cylinder to make sure that the valves were operating and closing properly. All is well with this as the cylinder has a touch over 200 pounds of compression it leaked down to roughly 195 pounds but held that.

Once we determined that everything with the valves were operating properly, we revisited the CPS again and checked all of the wiring, still no blazing gun.

So after everything checked out we removed the CPS once again and inspected the crankshaft reluctor ring to verify that I did indeed have the 24 tooth and it is. From what we could tell the reluctor ring looked to be in good shape with no issues.

I will send my tuner guy a link to this thread because he is well versed in these LS engines and checked other items as well while he had HP Tuner hooked up.

Sorry for such a long post but I am just very frustrated and I wanted to give everyone as much information as possible.

Any suggestions as to further checks would be greatly apprecieated.
Thanks,
Eric

JakeFusion

iTrader: (7)

Couple of easy questions: 408 so iron block? Gen III or IV? If IV are you using the Gen IV timing cover and CPS?

Are you sure all your grounds are connected and that you're getting juice to your passenger side bank if those cylinders aren't firing?

Chevy406

iTrader: (12)

It is a Gen III iron block with the cam sensor in the rear of the block. He is using the GenIII 24 tooth CKP sensor that is black in color.
The cylinders that aren't firing are #1 and #7 on the driver's side and #4 & #6 on the passenger side. A savvy reader will recognize that these 4 cylinders are ever other cylinder in the LS1 firing order. Another common point on these cylinders is their injectors are supplied 12 volts from the same fuse.

Let me list the symptoms and then the testing that we did today:
Symptoms:
1. Quickly throws P0336 "Crankshaft Position Sensor A Performance"
2. Tach does not work but momentarily will work when I reset the SES light
3. Cylinders 1, 4, 6, and 7 do not run (might run for a short while but do not stay running - possibly when ECM goes into closed loop)
4. Tested for spark on cylinder #1 & #7 (inconsistent spark at best)

Troubleshooting / Observations:
1. Cranking compression test cylinder #1 (200 psi)
2. Confirmed 12 volts on cylinder #4 injector and 12 volts on cylinder #4 coil
3. Pulled crank position sensor (2 times). Ohm'd wiring back to a extension splice with no problem noted. Swapped brand new sensor with a used CKP sensor.
4. Used borescope to verify 24 reluctor wheel.
5. Measured header tube skin temp (with wet finger and with temp gun).

Tuning:
Using HP Tuners I made a startup tune and progressivly added more startup airflow and RAF. I feel like it's a close enough tune that it will run fairly well once all 8 cylinders are firing. I did verify that the following sensors are reporting:
IAT, IAC, TPS, ECT, MAP, MAF, Bank1&2 Sensor 1, RPM, CPS

So the big question is - what triggers a P0336 engine code. What is the cause for every other cylinder not firing (1, 4, 6, 7). Is the tach not working a typical symptom of the P0336 code?

Question #2 - from my reading the crank relearn (CASE) procedure is only used to calibrate the ECM for reporting misfire. However I've also seen a couple people report that a CASE relearn fixed a misfire condition. Can anyone comment with authority whether a CASE relearn is needed, or can even be performed on an engine that is misfiring?

JakeFusion

iTrader: (7)

Sorry I saw 1,7 and didn't notice it wasn't 3 and 5.

You spliced an extension in there? These ECMs are finicky as hell about changes to the ohms they expect and when you add wire length and resistance, it can do some whacko ****. One test I would do is this:

If you test the reference on the wiring with the key on and sensor unplugged and its not over 11.5v, you have a short to ground in the harness....if its higher than that, bad ecu.

And here is what the service manual says (quick Google search):

DTC P0336

CIRCUIT DESCRIPTION
The crankshaft position (CKP) sensor signal indicates the crankshaft speed and position. The CKP sensor circuits are connected directly to the engine control module (ECM) and consists of the following circuits:


The 12-volt reference circuit
The low reference circuit
The CKP sensor signal circuit
If the ECM detects that the CKP sensor signal is inconsistent, DTC P0336 sets.

DTC DESCRIPTOR
This diagnostic procedure supports the following DTC:
DTC P0336 Crankshaft Position (CKP) Sensor Circuit

CONDITIONS FOR RUNNING THE DTC


The engine is cranking or running.
DTC P0336 runs continuously when the above conditions are met.
CONDITIONS FOR SETTING THE DTC
The ECM detects that the CKP sensor signal is inconsistent for 10 seconds

JakeFusion

iTrader: (7)

Also here is this from Paul at EFIlive:


"When you perform a CASE (Crank Angle Sensor Error) learn the PCM records the *exact* relationship between the crank teeth and the crank angle sensor - for the current crank/sensor configuration.
It uses that information to detect the small acceleration of the crankshaft at the instant of each firing event. If a firing event does not occur the PCM will not detect the small crank acceleration and will log a misfire.
Note: large cams, rough roads and rough idle can cause false misfire detection.

When the PCM "learns" the crank position sensor error, it writes the learned information to non-volatile memory.
In a new PCM, that memory is blank and it will throw a code immediately indicating that a crank relearn is required.

If you swap your PCM for a PCM that is not new, i.e. one that has already had a relearn done - probably for a different engine, then the PCM does not "know" that the learned information is incorrect for the current engine. Hence it will not log a code to indicate that a relearn is needed.

If you change any part of your engine that effects the relative positioning of the crank to the crank sensor then the learned information will probably no longer be correct. And still the PCM will not know that a relearn is needed.

If the learned information is not correct, the PCM may not be able to detect valid misfires and/or may detect false misfires. P0300 codes"

gMAG

iTrader: (1)

Have you checked the short driver's & pass harnesses at the heads...that they are on the correct sides, and are oriented correctly, front to rear?
The cylinders which appear to have not fired, may be firing at the incorrect times, after the gas has been expelled, leading to a cold cylinder.

Chevy406

iTrader: (12)

Thanks for the research JakeFushion. I had pulled up the EFI text about CASE learn on my phone yesterday, but it's always hard for me to absorb information on a tiny screen. Since we aren't seeing a P1336 code at this time I feel comfortable ruling out CASE learn. I'll likely try it at some point after we get the engine running on all 8 cylinders so we have the misfire detection capability.

If the ECM detects that the CKP sensor signal is inconsistent, DTC P0336 sets.
So this root cause is yet to be determined - why is the CKP sensor signal inconsistent.

gMAG - I don't know which harnesses you are talking about. Possibly the coil harnesses? The coil harnesses are attached to the coil brackets so one would have to really make an effort to alter their orientation. The injector connectors are only long enough to reach the proper cylinder. I'm sorry - just not following your idea here.

Bama99z

iTrader: (7)

Good morning all, first of all I'd like to thank Chevy406 a ton for coming down and tuning what he could, I appreciate it very much.

Jake, Chevy406 is spot on all of the checks that we done yesterday. I'm glad that he chimed in on this thread as he knows everything that was checked.

gmac, please chime in more about which wiring harness it is that you are speaking about.

Now lets get those thinking caps on and get her figured out.

Happy Fathers Day to all as well!!!

Drj8787

He would have been talking about the to the coil part of the harness but if u never removed it completely and still had it attached to brackets it is very unlikely that got messed up

gMAG

iTrader: (1)

^^^This is true.
It is also possible that after the valvecovers were removed (with harnesses intact) that the valvecovers for pass & driver's were swapped. (most unlikely!)
However, if you did remove the two small harnesses, verify that the correct color codes for #1 coil pack, and also for cyl #2, are going to their respective cylinders. If they are, there is no need to verify anything else.
I had a situation where not only were the two small harnesses flopped (pass & driver's), but in addition, were backward. The engine ran, but sounded like a locomotive, chugging uphill (with some cold cylinders).

Bama99z

iTrader: (7)

I indeed did remove the coil brackets, harness, and valve covers. I had everything painted ( sold horse gought ss ) which might I add looks great. However it dont make it run lol. I did have to replace the coil harness on the passanger side, but this morning I checked and verified that the harness is hooked up correctly so that therory is out the window

luigiandme

iTrader: (2)

Me and a friend of mine were chasing this down for ever. Same deal, youd fire up the car and the rpms would go up to 100 then drop down immediately. Throw a code for crankshaft position sensor. Pulled the sensor out and spun the motor over, the reluctor was bent!
Pulled the pan off, straightened it out and now its all good.

gMAG

iTrader: (1)

Eric,

I want to make sure that the cylinders really AREN'T sparking. While the temp gun & changing plugs/wires are a way to eliminate components, it doesn't verify that the cylinder isn't firing.
For example, if there is not enough fuel in cyl #4, but there is spark, the heat gun will only indicate no heat, rather than to tell you there is no spark.
Perhaps there IS no spark, but I only want to make this distinction.
Do you smell raw gas leaving the exhaust? With 4 cylinders not combusting, there should be some raw gas.
Is there an injector pulse to those affected cylinders?
If no smell, is it possible that those injectors are plugged? I can't remember whether your build included new injectors.
Hope you don't mind me "picking"...sometimes a nuance will send the troubleshooter in a different direction.

Bama99z

iTrader: (7)

gMAG, Here is what I did today.

1. Removed the ( 2 ) connections to the PCM just to verify that there were no damaged pin connectors. All were straight and looked as they should.

2. PS Grounds. The ones that I and remembered are as follows. There is one that runs down with the hot cable to the starter. And another short one that comes directly off of the ground cable and hooks up to the chassis right behind the battery On the 5.7 it is bolted to the engine in the vacinity above the Crankshaft Position Sensor. however the 6.0 does not have the provision at the same location so I re-located it to the front of the engine below the engine mount. its tight. on the rear of the PS cylinder head there is a ground as well ( it appears that this one comes from the PCM ). From all indications it is all good.

3. DS Grounds. The ones that I and remembered are as follows. There are ( 2 ) that runs down with the O2 senor ( 1 short about 2" long ) that hooks up to the engine ( 1 long about 8~10" long ) that hooks up to the body almost under the fuse box with another ground I'm calling this one a chassis/body ground. On the rear of the DS cylinder head there appears to be ( 2 ) grounds as well ( it appears that these come from inside of the wiring harness loom ). From all indications it is all good.

I' am going to borrow a bore scope/ fiber scope from work tomorrow so that I can visually inspect the grounds closer. The ones that we have at work have a 4" lead that will rotate and it also has a extremely brite light on the end as well as takes video.

Heck while I've got it I'm gonna drop the starter and the CPS sensor AGAIN and spin the motor over and video to see if I see anything going on with it. Lord I hope that there is nothing wrong with it. I don't wanna have to drop the engine.

As far as checking for spark they way that I checked it was remove the plug wire from the plug and installed another plug and spun the engine over to verify spark. Do you know of another way? If so please let me know.

RonSSNova

iTrader: (3)

Is this an engine swap? Or replacement in a car that was orig LS car.
I'm wondering why the CPK was extended.

The coils are grounded at one location normally. At the rear of the drivers side head. A busted wire there causes all sorts of issues. Like 4 dead cylinders.

Ron

jbruder

iTrader: (1)

You said that there are only two grounds on the back of the ds head, shouldn't there be three? I just put my engine back in last week and I'm pretty sure there are 3 ground wires on the back of the head.

RonSSNova

iTrader: (3)

2 lugs but 3 wires.
Also, you need to make sure the head is clean, no paint etc around that bolt.

Might not be the issue at all, but something to check.

And I'm sure Clyde knows these harnesses. :-)

gMAG

iTrader: (1)

Spark is good.
Grounds are all there? Did one of them fall behind the pass head?
Do you have injector pulse? Rent yourself a noid light from AutoZone, or any other parts place, and verify that the injectors are being told to fire. Is fuel getting through the affected injector(s)?

I would check all of the easy items before digging deeper.

Bama99z

iTrader: (7)

Ron, this was just a engine swap 5.7 to 6.0 2001 Camaro.

jbruder, As Ron mentioned below IIRC there was just 1 on the PS head and 2 on the DS head, however I think that 1 of them had 2 wires in the smae eyelet. Not 100% sure but I will take a look when I get the fiberscope from work.

Ron yeah the head is clean they are brand new TFS heads.
And Clyde is the man around here, so to have him stumped, I have a real problem!!! Anyone that can do what he has done knows their stuff. He's always wrenching and tuning on the Vette's.

gMAG, I'm gonna verify all grounds are hooked up with a fiberscope hopefully tomorrow evening. As for injector pulse to be honest I'm not sure I dont think that we checked that. Well maybe we did Clyde checked to make sure that we had power to them. I'll have to check on the noid light. I'm not sure if the affected cylinders are getting fuel or not.
You had asked in another post if the injectors were new. They are not However I purchased them from Chevy406 from a demod that he did for one of his friends Vette with very low miles. He actully put them in new and removed withing a month or 2.

RonSSNova

iTrader: (3)

Ha!

Clyde and I both have C5's and turbo LS Novas.

We are kindred spirits.

Good luck!