Cylinder 1 & 3 dead

[seethrough]

I have an 06 RC with Roe supercharger and Roe Racing built engine. This is the grey truck that I bought from Kyle. After chewing the front of a cam sensor off last year I ended up pulling the pan and front cover to clean up the debris and finally got around to putting everything back together. Got the new cam sensor in (correctly this time) and still getting a miss. I let the engine run for a few minutes and then measure exhaust temps and I am not getting combustion on cylinders 1 & 3. I have done the following and can't seem to figure it out so any help is appreciated. I am not getting any codes or check engine light either but truck has not been run more than 10 minutes since it was put back together.

-Swapped #1 and #5 plugs-Cylinder #5 works, cylinder #1 doesn't
-Swapped #1,3 injectors with ones off of my other truck-no change
-Ohmed injector wiring between injector and PCM on #1,#3,#5.
-Ohmed injectors #1,#3,#5
-Tested spark on cylinders #1,#3
-Leak down tested #1 cylinder
-Tested injector signal on cylinder #1,#3,#5
-Double checked firing order
-Swapped PCM with spare unit
-Reloaded tune on swapped PCM
-Replaced crank sensor with a spare unit.
-Compression test on all cylinders (last year when I initially had this problem)
-Checked wiring harness near passenger rear of the engine for burned wires.

I have the supercharger off again and not sure what I can do next since I am know the firing order is correct, the plugs are firing so wires are good; the injector is getting power and a signal from PCM. I am going to soak the injectors tonight but I'm fairly certain this is not the issue. I thought that I might contact Sean Roe to see if he can verify the tune.

 

[VENOMOUS1 RACING]

You say you tested spark, so are 1 and 3 not getting spark still? Gotta be coil or wires it seems if you've ruled all else out.

 

[Slitherbeast]

probably broken injector wiring from the PCM. pull the plug from the PCM and check(ohm) the wiring to the injectors.

 

[seethrough]

I got spark on cylinders #1,#3. That's what is confusing me - seems like I have compression, fuel and spark and firing order is correct. I ran one of those inline spark testers so the coil had to have enough juice to jump a gap (although it is not under compression). These two cylinders' exhaust are 200-300 degrees cooler than others so I'm certain this is where the miss is coming from.

 

[seethrough]

probably broken injector wiring from the PCM. pull the plug from the PCM and check(ohm) the wiring to the injectors.

Did that. Ohmed wires between PCM plug to cylinders #1, #3, #5 and they were all the same. Also attached one of those injector test lights on cylinder #1, #3 injector wiring harness and it lights.

 

[ARRESTmeRed04]

probably broken injector wiring from the PCM. pull the plug from the PCM and check(ohm) the wiring to the injectors.

Looks like 3rd on his list. What were the numbers on the compression test

 

[seethrough]

Looks like 3rd on his list. What were the numbers on the compression test

I don't recall because I did it last year when I first had this problem. I do know that there was not more than 10-12% difference between all cylinders. The leakdown test on cylinder #1 I did today was 80 psi and only a 2-3 psi loss.

 

[JTS VENOM PERFORMANCE]

you need three things, fuel, fire, air, you have those, you have ignition

sounds like you have no compression possibly

take all the plugs out,

spark plug in each wire, make sure each individual one is firing, that will rule that out

next you need fuel, easiest and most dangerous to do , but quick way to do it, pull the rail on each side, lay blue work towels under each injector, again turn it over a couple rounds, if each injector is leaving a wet spot you have rulled that out

all you need is air, could be anything from valve bad, open, misadjusted, lifter bad, rings, piston, quite a number,

air , fuel , fire boss, that will narrow it down

 

[seethrough]

you need three things, fuel, fire, air, you have those, you have ignition

sounds like you have no compression possibly

take all the plugs out,

spark plug in each wire, make sure each individual one is firing, that will rule that out

next you need fuel, easiest and most dangerous to do , but quick way to do it, pull the rail on each side, lay blue work towels under each injector, again turn it over a couple rounds, if each injector is leaving a wet spot you have rulled that out

all you need is air, could be anything from valve bad, open, misadjusted, lifter bad, rings, piston, quite a number,

air , fuel , fire boss, that will narrow it down

Thanks Tony. I will try pulling the fuel rail and making sure the injectors are flowing - I know that they are getting the signal from the PCM. A quick question that you will surely know - since the coils are a wasted spark design does cylinder 2/3 fire at the same time since they are directly across from each other (shared coil)? My thought is that the PCM triggers one coil for both cylinders even though only one is under compression. If so I have to assume that since cylinder #2 is fine that the coil for cylinder #3 is shared and also good. Same for cylinder #1/6.

 

[JTS VENOM PERFORMANCE]

Thanks Tony. I will try pulling the fuel rail and making sure the injectors are flowing - I know that they are getting the signal from the PCM. A quick question that you will surely know - since the coils are a wasted spark design does cylinder 2/3 fire at the same time since they are directly across from each other (shared coil)? My thought is that the PCM triggers one coil for both cylinders even though only one is under compression. If so I have to assume that since cylinder #2 is fine that the coil for cylinder #3 is shared and also good. Same for cylinder #1/6.

yessir

 

[seethrough]

OK I Ned to know how this works. How does the PCM know when to trigger spark on each cylinder. I know it is taking a signal from the crank and cam sensor but I need more details on how it works. Both sensors are magnetic pickups that sense a loss/creation in the magnetic field whenever a gap in either the crankshaft wheel or camshaft gear occurs. The crankshaft is easy because it has 10 gaps to represent each cylinder but the cam gear has a raised 180 degree profile. Does the PCM sense the beginning of this 180 degree platform and use that as a reference? What is that a reference for? The number one cylinder? I know this is deeper than I need to go for my current problem but I just need to know - I can't figure out women but I have a chance at understanding this!

 

[ZCx]

i had just one cyl. die on a shared coil.

so nothing writ in stone

 

[seethrough]

i had just one cyl. die on a shared coil.

so nothing writ in stone

Understandable - the shared coil must have an individual connections to each plug wire tower.

 

[ZCx]

i OHMed the old to the new.

no open circuits just real high ohm's on the old one

 

[seethrough]

i OHMed the old to the new.

no open circuits just real high ohm's on the old one

Thanks I will try that while the supercharger is off and I have access to the coils

 

[VPRPWRD]

you said you had this problem last year. Did you correct the problem last year or has it sat since the problem started? If you did fix it last year what was the fix?

 

[seethrough]

you said you had this problem last year. Did you correct the problem last year or has it sat since the problem started? If you did fix it last year what was the fix?

The truck sat after I chewed the tip off of the cam sensor so it has not run.

 

[Slitherbeast]

Air,spark,fuel. when the engine spins you have air. Seems you are confident there is spark. you probably have fuel problem. remove the fuel rail and all injectors and check for debris in the rail. won't take much to create havac .

 

[seethrough]

Air,spark,fuel. when the engine spins you have air. Seems you are confident there is spark. you probably have fuel problem. remove the fuel rail and all injectors and check for debris in the rail. won't take much to create havac .

Pulled the injector rails and activated one injector at a time and they are all flowing. Rechecked my firing order and ohmed out the coils and they all tested good. Installed new plugs and ran the truck for 10 minutes and then pulled the plugs. Cylinder 1/3 are clean and don't smell like fuel - all other plugs look good. Went to do a compression test and realized that when I did the leakdown test I used the compression tester's hose which has a Schrader valve in it so my leakdown test was bogus. Started doing the compression test and only got 30lbs on cylinder 1 - tested cylinider 5 and only getting 40lbs so my test hose is not sealing. Gonna deal with the compression test on Monday. I don't hear alot of valvetrain noise so I don't believe I have a broken spring or bent pushrod. I am a little concerned about flat lobes on the cam or a head gasket leaking but I didn't see any metal shavings in the oil change and I am not loosing coolant. I guess Monday's compression test will either give me the answer or at least point me in a new direction.

 

[VPRPWRD]

I don't like the direction this is going......