DRIVER456

I did some work on the car,Had the heads off,new lifters,pushrods,shaft mount roller rockers,Honed the cylinders,new rings,rod bearings,Put everything back together and cylinders # 7 & #8 not firing,Swapped coils,plugs,wires,injectors still nothing,Its getting spark,The injector has the same ohm's as all the other injectors,Also the same voltage with the key on.Changed out the ECM still the same,Changed crank sensor.Checked compression,All 150psi,A little low have to break in the new rings.I turned the motor over with the valve cover off,Everything looked good.I don't know what else to check,Am I missing something Any idea's?

stevieturbo

So you've confirmed without doubt there is a spark on both at all ( relevant ) times ?

You're confirming fuel is being injected ? Or just you believe the injector is getting a signal ?

Try swapping injector wires so cyl 5 is feeding 7 and 6 feeding 8 etc and see of the non-fire moves to 5/6 ?

Are those plugs wet, dry, other ?

How much lifter pre-load did you hit prior to rebuild ? Can you loosen it easily for a test ?

DRIVER456

Yes spark on both,I swapped injectors,still the same.I'm going to put in another set of injectors in on my day off from work just to make sure its not the inj.#8 inj.wire won't reach #6 to short.Plug was dry.I checked the lifter preload 3 to 4 times,I have about .042" preload,The lifters I put in called for .040" to .050" preload.I do have code P1336 crank relearn,But it never gave me a problem before,I tried to do a relearn with EFILive but it wouldn't take.It sounds like something is wired wrong,I had it running today but it was spitting and back firing out of the exhaust.I checked the ECM for a boken wire,nothing,Gound wires are on the back of the heads,Is it possible the crank or cam broke or would it not run? I ohmed out the inj. plugs to the ECM and all the numbers were the same.Now that I think about it,Maybe it is the injectors

stevieturbo

Then add a short piece of wire for the test.

Repeatedly swapping injectors isnt going to give you a different result if you've already done that.

And whilst you havent directly said it...this engine has not run correctly at all since you put it back together ?

BLOWNBLUEZ06@RKT Performance

I'm a bigger fan of isolating the problem over throwing parts at it until the problem goes away. I would recommend putting a stethoscope on the injectors and listening for their opening and closing action. It's something you'll be able to hear. If the injectors are clicking, move on to the coils. I have a number of things to test the coils for function. One of them is an old timing light where I clip on the inductive clamp and verify that the light flashes. I also have an oscilloscope with an inductive clamp that can be used on both the power and/or ground inputs of the coils and injectors. It is possible to analyze the signals and tell if the injector pintle is actually moving. It's also possible to tell if the coil is firing through the spark plug with some experience. You can compare the neighboring cylinder signals to get an idea of what they should look like. It's not the cam signal. If the cam signal is lost, the PCM transitions to an alternate mode but continues to function and the engine continues to run properly.

DRIVER456

OK I will try that.Correct the engine is not running right since I put it back together.I worked on the motor dozens of times and put it back together and fired up on the 1st shot,Never had a problem........But I guess there is always a 1st time Like I said I do have P1336 crank learn code,I've had it before and it never gave me a problem,I would do a crank relearn with EFILive and all was good.I looked that code up on EFILive website and some guy's say they had the same symptoms I'm having.I'm off tomorrow so I will give it another shot.

DRIVER456

I do have a stethoscope and yes the inj. was ticking,I will try some other stuff tomorrow.Thanks! I use to have a timing light,But I think I threw it away,had no use for it at the time.

stevieturbo

Given the symptoms, and the fact it is a new build so to speak, the chances of those cylinders being off for anything wiring, coil or injector related are probably fairly slim.

But all the tests mentioned above are fairly easy to do to rule them out. But given it has never run correctly since rebuild....a trigger problem of some sort is possible which could be causing those cylinder not to receive any fuel....but as a cause of the trigger problem, not a fault with the outgoing circuits.

As for crank/cam etc....are you sure the cam/gear is installed correctly ? Could the crank trigger wheel have been damaged in any way when things were apart ?
Crank sensor wiring etc all ok ?

http://www.ls2.com/boggs/dtcs/DTC%20P1336.htm

DRIVER456

Didn't touch the cam or cam gear.Hmmmm I did have alittle rough time getting the header in and out on the passenger side and the crank sensor wires are there,maybe I caught one of the crank sensor wires with the header,I will check that tomorrow!

DRIVER456

OK I got it,I tried my other PCM just for the hell of it and it worked,No more P1336 code,Revs up no popping spittin out of the exhaust.I don't know why it worked this time.My other PCM is a Roadrunner from Moates with real time tuning,I had that in there since 2008 so I can't complain.Those 2 back cylinders are still colder then the rest,But it idles fine.So I either have to look at other after market computers or solder the RR guts to this PCM.Thanks for the replies/help guy's.

C5 Pete

Roadrunner?? Bah! HPTuners FTW


PS. Glad you got it running.

DRIVER456

Whats up Pete! With the Roadrunner and EFILive you can tune and make changes while the car is running

C5 Pete

I've read about Roadrunner. I've never tried it though.

stevieturbo

Same tune in each or different ?

Was anything done that might have corrupted the tune in one of them ?

Welding with ecu plugged in, maybe jump starting or something ? What about loading the tune from the working one back into the other to see what happens ?

DRIVER456

I forgot one thing,I put the ohm meter on the 2 crank sensor's I had,Came up with 2 different readings,So I ran to autozone,Bought a crank sensor,put that in and thats when I tried the other PCM,So it had to be a combination of both ,the sensor and the RR pcm.Stevie I think what screwed it up was I hit the positive wire on the alternator and arced for a split second.Yea I read on efilive website about the P1336 code,You can read another good PCM,save the case data and flash it into the RR pcm the do a calibration flash only.I did try that but nothing,I will try again today now that I it working.