[Sam's IDI]

Ok I am Starting a new thread for my issues due to not being related to my old post. The truck I bought wasn't what I thought it was so now throwing parts at it with no success (Rebuilt IP and new injectors). So I changed the normal stuff when buying a used vehicle (Oil, filter, Fuel Filter, Air filter). Then I changed out the IP and injectors, still not running right. I tried several different timings with the IP and still the same result. I have a pop sound in the exhaust and too much blue smoke coming out the tail pipe. I removed the valve covers and everything looks great. I pulled off the rockers and valve springs, checked the push rods, nothing bent or broken. I am at a loss right now. I am considering pulling the whole motor just so if the bottom end has issues I can get it rebuilt as well. If anyone else has had this "Popping" sound with a miss out of the exhaust let me know what it was. I am hoping its just a valve job. If I have to take it further I will.

 

[madpogue]

Have you actually _timed_ it (with a timing meter)?

Have you done a compression test?

 

[oldrebuiltdodge]

Popping out the exhaust most times indicates a burned/broken exhaust valve. Popping through the intake usually indicates a burned/broken intake valve. either way you will hear the miss in the exhaust. Run a compression test to find the dead cylinder. If it started all at once, then it might just be a stuck valve, especially if the truck sat still for any length of time. Could be something as simple as a piece of carbon under the valve. I'd sure try to clean it up before I pulled a head, or engine.

 

[junkrider]

I had a pop out the intake a couple years back, it sounded like a firecracker in a coffee can. LOUD LOUD LOUD.

Turned out to be collapsed exhaust lifter on cyl 7, if I recall correctly.

I put new lifters, push rods, and rockers at all cylinders.

 

[oldrebuiltdodge]

I had a pop out the intake a couple years back, it sounded like a firecracker in a coffee can. LOUD LOUD LOUD.

Turned out to be collapsed exhaust lifter on cyl 7, if I recall correctly.

I put new lifters, push rods, and rockers at all cylinders.

Yes very loud, because the exhaust valve wasn't opening, and the compression had to be released somewhere. The OP said that there wasn't anything apparently wrong under the valve cover, so I left that scenario out.

 

[Sam's IDI]

well here is the update the inside of the valve covers clean as a whistle, not 1 thing out of place. I took off all the rocker arms and pulled all but 3 push rods because of clearance issues but they all looked good. the wear on everything looks really even. I have played with the timing a little bit and gonna advance it to the max tomorrow. Just an FYI the previous owner was afraid of any work. The valve cover gasket on the passenger side was never changed. I had trouble with the 2 passenger side injectors when I removed them. like they had never been changed. It came up with 3 different types of injectors. So here is the video of what it sounds like I will upload another video of advanced timing tomorrow weather permitting.

https://www.youtube.com/watch?v=7viYjawggEo

 

[junkrider]

Excellent video.

Have you done a compression test?

You may be able to isolate the offending cylinder by loosening the injection line at each cylinder, one at a time, and listen for a change.

My thoughts are possibly a weak injector, or a valve issue. I notice there appears to be a change in exhaust appearance, possibly synchronized with the pop.

But there's people here with more experience than me. That's just the stuff I would check first.

 

[oldrebuiltdodge]

There may be one injector hanging up and causing it to fire late. It might also be late IP timing. The pop IMO is too soft for it to be a burned or broken valve. It sounds like there is still too much flame when the exhaust valve opens. If it was staying open, there would be more of a hiss. How tight is the exhaust system? Holes in the muffler, or the pipe can sound just like that. Just like the old gassers when cool oxygen hits the hot exhaust fumes, the unburned stuff pops

 

[Sam's IDI]

So I found the problem! I was cracking the lines when the engine was cold every time I was trying to locate the problem. I let the engine Idle for about 15 minutes to get that pop to come back and the fuel coming out the exhaust very little. Then I ran it up to about 1300 rpm where it was shaking really bad and smoking and started cracking injectors. As soon as I got to #5 smoke stopped completely and still had the miss. I found one of the old injectors that looked to be in the best shape and swapped it out. Point of the story even if you replace all the injectors with new ones, You can have a bad New injector. On another note the #5 injector was covered in fuel and looked about 1/2 the needle wasn't seating and could see past the seat.

If the weather is on my side tomorrow I will upload another video showing the change in the truck from replacing the 1 seriously messed up injector.

 

[oldrebuiltdodge]

Just because it's new doesn't mean it's any good.