J tube on fuel injected type 4

[john72bay]

Put j tubes on a type 4. Take off its spits and back fires then smoothed out. Any thoughts on what may be my issue.

[wwebner]

I doubt that it has anything to do with the J pipes. Go back thru tune up. Timing.dwell.

[TRL]

Or maybe the new exhaust parts aren't sealing correctly and leaking which can cause popping too.

[Kooper271]

Or maybe the new exhaust parts aren't sealing correctly and leaking which can cause popping too.

I wonder how you know this...

[wwebner]

Or maybe the new exhaust parts aren't sealing correctly and leaking which can cause popping too.

Rick has a good point. the 72 thru 78 type 4 exhaust gaskets (oval port) do not have holes that go over the studs. They are basically a copper oval ring that sits in a slight recess in the head.
Trying to install a heat exchanger or J tube (exhaust manifold) from the bottom can be tricky and the gasket can move while you are installing. That may be what happened. with the bottom tin (beneath the pr tubes) removed and the engine running (e brake on and wheels chucked in front of and behind a tire) you can get under there and should be able to tell if this is what has happened.

[john72bay]

checked the gaskets everything seems to be fine. There seems to be popping in the exhaust manifold. This is a fuel injected engine and I replace the injector which seemed to help a bit but its still doing, and only in the Number 1 exhaust.

[john72bay]

sounds very similar to this video.

https://www.youtube.com/watch?v=RI3po5rGpWQ

[wwebner]

How did you determine that it is #1? The noise in the vid does not sound like exhaust. How did it run prior to replacing the heater boxes with pipes?

[john72bay]

We recently replaced the heads. It was running great for a few days we pulled into my driveway half hour later we went back out to leave and it was losing power when going down the road in sputtering. When you open the Deck lidn you can hear it popping in the manifold the manifold coming off the number one cylinder is hotter than the rest

[wwebner]

OK. I think there hes been some confusion in terminology here. Some on my part. J-tubes is the term normally used for
heater box eliminator pipes. While the "intake manifolds" on type 4 engines are J shaped, I had not heard of them referred to as J-tubes.

Now that we are on the correct side of the engine , It sounds a bit more like a tight intake valve and back fire thru that intake. Check your valve adjustment.

Could be timing,but not likely,as that would effect all 4 cylinders.

Dripping injector? dripping on the back side of the intake valve and ignited by combustion chamber heat?
You replaced the injector. With another used one?
You replaced the heads. With used ones?

Another possibility is a poor seal between the cylinder and the head.