The latest random issue and what I hope is the last with the 3FE was very perplexing.
I've had two exhaust leaks from each of the manifold flanges. I figured I would just replace the gasket and be done. When we swapped the pedal bucket I was feeling like I was on a roll, so I got under the truck and snugged the 4 nuts down for the downpipe flanges. They were extremely loose.
I started the truck back up and the exhaust leak stopped, I couldn't feel the obvious leak but now the truck would barely run. The flow out of the tail pipe greatly increased but it felt like half the pulses were weak. The idle would lope with the batch fire sequence of the 3FE. Driving it around, the floor panel was nuclear recently. The cat looked fine, but the heatshield was completely gone and the floor has been greatly discolored. You cant put your hand on the floor panel with the engine running.
My expert intuition told me that the catalytic converter (outside of the frame rail) was completely plugged. After 20 mins of trying to get it to run, I finally relented and loosened the exhaust manifold bolts. The massive misfire stopped.
I recently got the EGR misfire sorted. I cleaned the valve out, the idle became much more stable and closer to the 650rpm target. Between the TPS replacement and calibration, the EGR cleaning and function check and the catalytic converters getting replaced, I feel that is all I can do to make this engine run at peak performance. The truck is at almost 300,000 miles and all of the smog equipment has been intact. The cold start injector was completely clogged, the intake was caked in carbon and the throttle body was partially blocked off. In my mind, if that's all that got gunky in 300,000 miles, the smog stuff isn't a big deal and I'll keep it all. Well, I'll keep it all except for the smog pump. The truck will likely get another 100,000 miles before the world runs out of gas or the 3FE explodes. I have very modest expectations from it.
This is my wifes truck, not mine. We want max efficiency, improved drivability and zero smell from it. I went on rock auto and ordered two catalytic converters for it. I measured both catalytic converters and they are both 12.5 inches long. This means they are identical side to side. The Toyota EPC says they are both the same size, so this conflicted what I read on rockauto. They list two locations and one has a slightly different length.
I went with two of the Davico 16288 units. A bit over $300 to my door. Currently waiting for them to ship.
I thought long and hard about just making up test pipes, but to get the correct flanges was a pain. I was going to be easily $50 into each test pipe and it would likely smell like my 60 does with no converter. That wouldn't do. My hopes for the replacement of the converters is to balance the flow between both manifolds, reduce heat on the floor board since they have their own heatshield built in and keep the smell down.
Cats will be installed next week, and then I'll be starting the 5 speed swap.
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