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Working on a 2011 ram 1500. I want to find out if this truck intentionally shuts down injector firing and coil firing when misfire is detected? In my experience I've seen injectors get shut off but never ignition coils And im thinking this might be my case. Truck lost compression on one cylinder and i'm about to tear it down but don't know if I have a separate issue. The truck came to me with a new computer new spark plugs new coil and wiring repair
do you have a bi directional scantool? I know on older Chryslers you can control the coil to fire with a scanner. where itll toggle it off and on. it should be under the key on engine off tests
chris.arriazola wrote: Working on a 2011 ram 1500. I want to find out if this truck intentionally shuts down injector firing and coil firing when misfire is detected? In my experience I've seen injectors get shut off but never ignition coils And im thinking this might be my case. Truck lost compression on one cylinder and i'm about to tear it down but don't know if I have a separate issue. The truck came to me with a new computer new spark plugs new coil and wiring repair
ScannerDanner teaches that in cases of intentional shut down, the PCM will still activate the driver on startup.
If you scope the control wire while you start the engine, you'll typically see a few turn on signals, then when the PCM realizes the cylinder is missing, it will deactivate the driver.
I really like Cheryl's suggestion of using the scanner bi-directional test for the injector and the coil. Personally, I've never seen a Chrysler product intentionally shut down an injector OR a coil, but that doesn't mean they can't.
No compression on one cylinder? Unfortunately, there's plenty of different ways that could happen to ANY of the engines that came with this truck. :lol: Let us know what you find!
Yeah I have a Verus edge. The thing is that at start up everything fires correctly and injection works correctly but win heavy misfire is detected both injection pulse and coil firing shut off. I've seen injectors get shut off before in other cars but I've never seen coils shut off. Just trying to figure out if I have a separate issue other than my low compression on that cylinder
before you tear it apart I would remove a spark plug from another cylinder to duplicate the no compression. then id current ramp the injector and coil and see if the driver shuts them off. if nothing is mentioned in the service information. takes a few minutes to do
cheryl hartkorn wrote: before you tear it apart I would remove a spark plug from another cylinder to duplicate the no compression. then id current ramp the injector and coil and see if the driver shuts them off. if nothing is mentioned in the service information. takes a few minutes to do
chris.arriazola wrote: Yeah I have a Verus edge. The thing is that at start up everything fires correctly and injection works correctly but win heavy misfire is detected both injection pulse and coil firing shut off. I've seen injectors get shut off before in other cars but I've never seen coils shut off. Just trying to figure out if I have a separate issue other than my low compression on that cylinder
Interesting... Maybe they figure, if the injector is off, what's the point of firing the coil! :lol: I think you're definitely on the right track with the intentional shutdown, though.
before you tear it apart I would remove a spark plug from another cylinder to duplicate the no compression. then id current ramp the injector and coil and see if the driver shuts them off. if nothing is mentioned in the service information. takes a few minutes to do
This truck just threw me off one more time. I checked compression to see what cylinder was low and was expecting to see low compession at the cylinder 2 with the misfire but nope! My low compression is that cylinder number 6. What the heck is going on? Why would cylinder 2 shut off. Ive swapped plugs and coils around. plus scoped the coils but everything looks good. It also had injector number 2 put in as well at another shop. I think I need to scope my crank and cam sensors. I haven't worked on it much but I'm afraid need to hurry on it before the owner starts complaining
chris.arriazola wrote: This truck just threw me off one more time. I checked compression to see what cylinder was low and was expecting to see low compession at the cylinder 2 with the misfire but nope! My low compression is that cylinder number 6. What the heck is going on? Why would cylinder 2 shut off. Ive swapped plugs and coils around. plus scoped the coils but everything looks good. It also had injector number 2 put in as well at another shop. I think I need to scope my crank and cam sensors. I haven't worked on it much but I'm afraid need to hurry on it before the owner starts complaining
What tha... ? :blink: What engine, specifically?
Thinking out loud about a problem with the misfire monitor. Sometimes the PCM will flag one cylinder, when it's actually the companion. But if it's a V8, then the firing order is 1-8-4-3-6-5-7-2. That'd make #2/#3 companions, and #1/#6 companions, so that doesn't work. A V6 is 1-6-5-4-3-2, which also doesn't work.
Cylinders #6 and #2 aren't adjacent in either firing order, so that's out, too. :blink:
This is a 5.7 engine. I was going to work on it today but had other work in front. Trying to get ready mentally lol . Im thinking of doing a leak down test first to figure out what caused the low compression at #6 cylinder and attacking it. Ill worry about the number 2 miss later. I just cant put it together in my head on whats causing this.
Wanted to do an update on this Ram 1500 5.7. Turned out to have a lifter that seized and tor the cam to crap.Here is a picture of the cam. Took valve cover off and turn the truck on and noticed the number 2 cylinder intake valve didn't move . Thanks for the help on this site.
chris.arriazola wrote: Wanted to do an update on this Ram 1500 5.7. Turned out to have a lifter that seized and tor the cam to crap.Here is a picture of the cam. Took valve cover off and turn the truck on and noticed the number 2 cylinder intake valve didn't move . Thanks for the help on this site.
I'm sure it's not what the owner wanted to hear, but nice work all around. That thing looks toasted! Too bad these Hemi motors eat valve trains...
So do we have confirmation of intentional coil driver shut down?
Thanks for posting an update to this one and including that pic of the cam
Weird. :blink: Thanks for posting the update, sir!
So just to be clear, the misfiring cylinder was indeed #2? But your compression testing showed a problem with #6... No wonder we were confused. :lol: I'm trying to account for why the compression test didn't expose the lobe problem... Perhaps a running compression test would have been the way to go?
I did run compression test but it passed because the intake valve was staying closed. The lobe was so bad it wouldnt open to inject gas in the cylinder. Thats why it tricked me. The other problem with number 6 was a bent valve. It was kind of weird. If only I would of taken valve cover off at the beginning i would have seen the problem but i was focused on playing with my scope I made it a nightmare. LOL
chris.arriazola wrote: I did run compression test but it passed because the intake valve was staying closed. The lobe was so bad it wouldnt open to inject gas in the cylinder. Thats why it tricked me. The other problem with number 6 was a bent valve. It was kind of weird. If only I would of taken valve cover off at the beginning i would have seen the problem but i was focused on playing with my scope I made it a nightmare. LOL
Ahhh, so there really was a compression problem with #6, too...
I'm really not arguing with you about the compression test, but I'm still a bit confused. The last time I saw an intake valve stuck closed, it resulted in low compression, but perfect leak down testing. I theorized this was this because there was no air charge entering the cylinder, therefore there was nothing to make compression with. I talked about it in this thread:
BUT, your Ram managed to make compression despite the stuck closed valve. :blink: Again, not disputing your testing, just trying to make sense of it. :lol:
Do you think it's possible that there could have been enough vacuum in the combustion chamber on the pistons downward strokes to pull the intake valve off it's seat a bit and take in little gulps of air? Or do you think the seated tension on the spring would be too high to overcome?
If the injector was intentionally shut down by the PCM cylinder wash wouldn't be a factor
Not sure how to respond to that question. Obviously You are more advanced in this area lol. I am trying to make sense of the intentional coil shut down my self. Ive ran into injector shut down all the time but not coil drivers. Thats another reason this threw me off. A in cylinder transducer would have been the way to go. I have a snap on transducer but dont know how to use it yet. I need to start using it on good working cars to get an idea what to look for.
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