Broke down again away from home. P0336 crank sensor code.

[big bird]

Engine died while running down the road. Thought it was front tank out of gas again, back tank not transferring. It has gas, added 5 gallons to be sure. Have bled Schrader valve and it sprays gas everywhere on prime.

O2 sensor change fixed my other sensor issue. Was planning to post updates to my other threads on this truck this evening, but here we are stuck again.

Will not hit a lick, P0336 comes back after clearing code. We were going about 70 in fifth gear and the engine died.

Coasted to a stop on an off ramp, figured the back tank had quit and the front tank was empty. Added five gallons to the front tank. It ran for a minute and died while we were closing the back of the truck.

Has not started since. Fuel sprays out of the Schrader when pressed, prime is working.

Should have kept the loaner fuel pressure gage.

Here is what I'm thinking.

Make sure front tank is good by adding another 5 gallons.

Check fuel pressure.

If those are okay, crank position sensor?

Any advice greatly appreciated.

 

[95burban]

Year make model

 

[Road Trip]

Year make model

He's got a '98 5.7 Vortec in a 3500 dually with dual gas tanks.

I know this only because he's been in serious debug mode while trying
to use this recently acquired truck to make a long-distance move.

 

[Pinger]

The usual symptom of a failing CPS is engine stalling at idle when up to heat then restarting a few minutes later when the CPS has cooled a touch.

 

[Road Trip]

Engine died while running down the road. Thought it was front tank out of gas again, back tank not transferring. It has gas, added 5 gallons to be sure. Have bled Schrader valve and it sprays gas everywhere on prime.

Will not hit a lick, P0336 comes back after clearing code. We were going about 70 in fifth gear and the engine died.

Has not started since. Fuel sprays out of the Schrader when pressed, prime is working.

Should have kept the loaner fuel pressure gage.

Here is what I'm thinking.

Make sure front tank is good by adding another 5 gallons.

Check fuel pressure.

The spray out of the Schrader valve is promising. Of course if you have the capability of
checking the fuel pressure this is always a solid troubleshooting building block.

If those are okay, crank position sensor?

The P0336 DTC (Crank Position Sensor Performance) does point to the CKP.

Check out this page from the FSM. Notice that it only takes a 1/2 second of missing
signal to kick this code:

You must be registered for see images attach

Also, your symptoms also correlate. You see, the CKP signal is *the* signal that everything else is
built off of inside the VCM. Without the CKP pulses, the fuel injectors will not be triggered as
well as the Ignition system will not get the pulses required to generate the sparks at the coil. (!)

In other words, double dead. IF you were to check for spark (hopefully you have a spare plug
in the glove box that you can quickly hook a spark plug wire up to and ground to the block) ...and
not have any spark? For me this observation would confirm the P0336 DTC and the hypothesis.

But let's try a little common sense and see if the sensor has just moved just enough to make
it flaky. Q: Can you move the sensor either a little closer or a little further away and see if you
can get the beast to run again? While you are in there, also check to see if there is any chafing
of the signal wires between this sensor and the VCM? (I seem to remember reading where one
of the forum members had a chafe in the wire down to the CKP sensor and caused a no-start?)

I'll look around for some more info. Know that it's been reported that the CKP sensor has been
discovered to be too far away -and- also too close, as in the reluctor wheel grinding against the
base of the sensor.

Anyway, I'd give the CKP sensor a good visual inspection, and if nothing jumps out at you then
I'd double check for no spark and then I'd feel good about the probability that it's the essential
sensor causing the no joy.

Best of luck!

Any advice greatly appreciated.

 

[Road Trip]

Here's a CKP sensor that failed due to an obvious lack of clearance between reluctor wheel and itself:

You must be registered for see images attach

NOTE: The picture is from a 4.3, but IIRC GM released a shim kit after damaged CKP sensors
started cropping up on the 5.7 & 7.4 engines also.

EDIT: I just found a similar failure reported HERE in the forum by @Kevmore007. Supposedly
the desired clearance is ~.020-.030". No guarantees this is it, just another something to check off
of the troubleshooting checklist.

 

[Keeper]

I had a 99 k2500 suburban 454 that did that. It restarted a few times after cooling, but only a few. Thankfully, the last time it did it, and would not restart, I had slid into a parking lot. The code was correct, it was indeed the crank sensor. Easy swap though.

 

[big bird]

Sorry, forgot to add vehicle details earlier. Road Trip, thanks! '98 Chevy 3500 5.7 gas, dually cab and chassis, 5 speed manual.

Went to parts store after we got to hotel. Have crank position sensor, fuel pump, distributor cap, rotor, coil pack, pressure gage. Multimeter, assorted wrenches and such, spare battery, etc in truck.

Okay, I've got 55psi on prime, I've bled the line a lot, I have fuel pressure and flow. No fuel smell at tailpipe. I'm eliminating fuel pump and fuel supply from current problem.

I'm going to eat some dinner, have some whiskey, and start reading up. Thank you all very much for where to start figuring!

Road Trip- have a spare plug for my small generator and should be able to make that work to check spark.

I'll be digging into fire and crank sensor in the morning.

 

[big bird]

Instructions that came with new sensor state: "To prevent misfire detection by computer system a crankshaft variation relearn must be performed ... Diagnostic scan tool is required to perform this procedure. Failure to perform this procedure will result in a false trouble condition."

Haven't changed sensor out yet, just getting started.

Is the sensor relearn actually required?

 

[big bird]

No spark, don't think I've got injection either. Investigating ckp,