Hey guys,

I have ran into a pretty big problem on my truck. What started out as a misfire, has now turned into a completely dead cylinder. I tried switching plug wires still had the misfire (at the time it was still a misfire). Well last night I moved the coil around to make sure it was not a coil, same thing the number 5 cylinder was still dead. We checked for 12v it had 12v, we then checked for the 5v trigger and we could not get anything out it, but we are not really sure you would test that?

I think it is something in the wiring and I really don't want to start ripping wiring out blindly.

Has anybody else ever had this happen? And does anybody have a clue what it could be?

Thanks
Kody

 

How are you testing the voltage, i.e., key on/engine on, cylinder 5 coil connector disconnected and checking the male terminals?

 

Yeah we tested for 12v with key on and a testing on the female side (plug). And we tried doing the same thing for the trigger but we turned the motor over.

 

Before you dig too deep into something, let's break this down first. Each cylinder needs air, spark, and fuel to fire.

It's probably safe to assume that it's getting air.

So let's try spark. Either get a new plug, or find a plug that is known to be good, plug it into the number 5 coil, but not into the head, and see if it sparks while the engine is running (keep it away from anything the spark could damage, wiring etc.). If not, then you're looking in the right direction, if you do get spark, change the plug out and see if the misfire clears, if it doesn't, then you should probably start looking at a fueling issue. Bad injector, or something along those lines.

G'luck. Electrical gremlins are never fun.

 

It could be several things. You mentioned it was missfiring before but now its completely dead.

Do you have compression in this cylinder??? is it Equall to the other cylinders

If not then you need to open it up and see why. It could be a broken valve spring. damaged valves or so on down the line.

If you do have good compression, then you need to check the spark plug and make sure it's firing. If it is, then you should move to the fuel injectors. Swap them out and see if the missfire follows.

If all the parts check out good, then you need to put a noid light on the injector plug and see if it flashes when the truck is idleing. The Flashes indicate the signal is being sent. Although rare I have seen a few injector drivers go bad in the ECU. When this happens you either have a solid light or no light at all.

 

im not sure if you said you checked it or not.. but inspect the spark plug very closely.. I had one awhile back that the porcelin(spelling??) around the plug had cracked and that cylinder wouldnt fire at all.

 

I have not checked for compression yet. I should have stated earlier but I put a timing light on number 5 back when it was a misfire and the light was very intermittent. Now it does not light at all on number 5.

Would the pcm knock off the spark to that cylinder if it does see fuel?

 

Oh and yes I checked all the plugs I thought maybe one was not sealing very well so I pulled them to put never seize on them, and they all looked good.

 

I would pull the connector off injector #5 and put 1.5v to it from an AA battery to see if its working. You'll be able to hear a click, loud and clear. If it doesn't, that's your problem. If it does I would do like 1FastBrick said and move two injectors, like 3 and 5. If the misfire moves, you've found it.

 

Well as it's not a misfire anymore... it's a no fire now.


Would a injector cause there to be no spark?