On my way home today I pulled up to the stop light to turn into my apartment complex and I noticed that my truck was shaking and making a ticking sound on the drivers side. Hasn't done this before. I get home and call Bob to get his opinion and he said to look at the plugs and coils. So I start the truck and start unplugging coils. The two front coils on the drivers side made no difference in the way the engine ran when I unplugged them. All of the rest made a noticeable difference when I unplugged them. So I pull those two plugs and they are black and smell like fuel. So I think bad coils... I test both those coils for resistance with my multimeter and they both check out fine. So I throw two new plugs in and put the coils back on and start the engine. Same thing... So I remove the two coils and put two of my stockers on there. Same thing... So I disconnect my battery for 10 minutes, reconnect it and reload my tune with the XCal2. Same thing... So I check to make sure the coils are getting power. Both are getting 12.5 volts. Then I crank the engine and watch the Wideband. I'm seeing 13.1-13.3:1 at idle. I go to the engine and unplug those two fuel injectors and the A/F comes back up to 14.7:1. Then I plug them back in and it drops back down to 13.X:1. So I'm getting fuel, I'm getting voltage, the COP's aren't bad and there's two new plugs in there. What could this be???

My next step is to do a compression check on those two cylinders...

 

i had a similar problem, trying to remember but I think I was getting voltage at the coil pacs and they were still bad. Take the 2 coil pacs and put them on different cylinders and unplug them and see if it makes the engine change. If no change then you know it is the coil pacs.

 

I already swapped out the coil packs. I put two of my spare stockers on and it still did the same thing.

 

HI!... Try swapping injectors around. You might have two bad injectors. Possibly partialy stuck open. I had the same problem with #5 on my built 5.4. It ended up being a broken compression ring. Only 25PSI in #5 on a brand new built 5.4 with only 1800KMS on it. Still ran a 13.6E.T on 7 cylinders (N/A)

I'd do the compression test as soon as you can. Do a dry then wet test.

 

You have spark, you have fuel…. The only thing that’s left is compression, and timing.
If it was timing, Bad rocker arms (intake or exhaust) on both cylinders (odd) maybe the ticking noise!
Is it backfiring at all? If not maybe you’re valves are not opening…
A compression test would test good if the valves where inoperative, however you’re plugs would be wet with fuel, but no Air…
Just a guess…… Good luck!!!

 

my guess would be you have two bad injectors..

 

Spencer, I agree with the above-spark, fuel, air, if the cylinders are drowning in fuel, I'd go the coil pack/plug route then start moving the injectors around.

 

That was it, I knew i was not remembering correctly(it was several years ago and 1 Lightning ago!).,
Mine was timing. I shot a plug and when the dealer replaced the cylinder head they screwed up the timing chain. 2 teeth off on one side and 1 tooth off on the other. Sal @ PSP fixed me up quick!

 

Both cylinders read 150 PSI. I'm leaning more toward the ECM as the culprit right now. I'm gonna swap injectors around tomorrow and see what happens.

 

Good Luck

 

Wouldn't the ECM affect all the injectors?? Another possiability is that you hung up some valves?? That would support the clatter sound you heard as well.

 

I agree that it is not the ECM! lets see, you have new plugs, the cops are good, swapping the injectors will only verify that you will have fuel, you had stated that you had already “plugs saturated with fuel” so by swapping injectors, will only let you know that you are injecting fuel in to the cylinder, in addition you also have good compression.

So the question is what is missing in this equation to make it go BOOM!!!

How about oxygen, you can have fuel, compression & spark, but with out the oxygen no BOOM… I suspect it is in the head, probably the rocker arms, (valves closed, good compression) also ticking noise, camshaft noise…

Regardless, fill us in on how you solve the mystery!!!

 

Thinking some more; If it is the valves, it must be the intake valve, the reason behind this is that “the injector is injecting fuel in to the chamber”, now wouldn’t the fuel start to pool inside the cylinder, eventually the cylinder would fill up with fuel and since liquids are not compressible, you would eventually bend a rod, or at the least crack a ring.

That would cause the fuel to blow in to you’re crank case, contaminating the engine oil.

So, look at the oil, inspect it for fuel mixture???

Furthermore; if you’re exhaust valve is still working, then the un-burnt fuel would be blown out the exhaust pipe, I wonder if that would pop a Check engine light????

I bet with the exhaust heat and the un-burnt fuel that would crate a good backfire pop!!!

 

Sooooooooooo many possibilities and some are def not good, but lets hope it's something simple T

It could be in the tune/ecm, we've heard of Injector "Driver Problems" in the past. Glad to hear you have good and equal compression in the cylinders T, and it does seem you've eliminated the coils, BUT just as a remote possibility DO NOT rule out a harness problem or wiring issue to that/those coils (been there done that )@#$)@$%)@$%@)($%)@$)

GOOD LUCK

 

Update:

I swapped the injectors around and it didn't make any difference. Both front cylinders are still dead. So the injectors are good.

I pulled the COPs, stuck a new plug in them and plugged them into the harness to check for spark. Both cylinders are getting spark. So the COP's are good.

I went and bought a noid light kit and used it on the injector harnesses. The light pulses on both of those cylinders the exact same way it pulses on all the other cylinders. So it's not the ECU or the harness.

I just got done pulling the cam cover and there's nothing out of the ordinary under there. All of the followers, lifters, bolts and chains are where they're suppose to be. So the follower coming off and taking out another one theory is out the window.

Next I'm going to go back out and manually spin the engine and watch all the valves. I'll be looking for anything out of the ordinary. If that all checks out I'll be re-installing the cam cover and doing a leak-down test tomorrow.

At this point I just want to find out what the hell is going on. If the leak-down test shows that something is wrong, good, at least I know I found the problem. If the leak-down test is good, I don't know what else to do....

BTW, I priced a new computer and it's $450 before core. $350 after and you get no warranty on it.