99 Ram: intermittent loss of power

It's your engine, transmission, driveline
kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat May 12, 2018 9:44 am

I think it is federal.
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kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat May 12, 2018 11:15 am

After beating on the cat, it ended up even worse where you could punch the throttle in park and the engine would run to about 3,500 and then slowly fall to below 3,000 and start misfiring. Ok, has to be exhaust restriction.

Drilled a hole in the cat and tried to remove as much as I could.
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Just road tested. Oh my god does it run better.

It pulls hills in 4th lockup (for the most part). Winding out 1st feels like 230hp again. Wow. And above 2800rpm at WOT, to my ear, it sounds exactly like Bob's rental Charger R/T which is hilarious. Below that it drones something fierce.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat May 12, 2018 2:44 pm

Also should mention that fuel trims were suspiciously negative, like -10% before. That's because the volumetric efficiency had gone to crap. Fuel trims after drilling a hole and the partial gutting are 0-4% in the positive now. My fuel economy is going to increase, too.

I reset the misfire codes and the light has not come back yet.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat May 26, 2018 5:14 pm

It acted up on me yesterday. Power started diminishing severely. So I finished the gut job, out of that small hole. It was quite tedious but I didn't have a band clamp so I didn't want to cut the pipe.

There was quite a bit of cat ceramic left. I think it is empty now.
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It seems even louder. Plugging the hole quiets it down significantly. Also I lost a blue shop towel in the hole at one point. Later I plugged the hole with something else (for testing) and the blue towel came out the tail pipe. So the exhaust can't be jammed up with a piece of cat if that slipped through, I figure.

I did find the circle piece from when I drilled the cat originally. I thought I lost it but I realized it was in the hole saw. Hoping to tack that back together soon.

For what it's worth I still have not seen a cat efficiency code.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sun May 27, 2018 3:50 pm

Drove to Adam's. So loud and annoying.

I didn't realize how much metal gets eaten by the hole saw so the piece I had was really not big enough to patch the hole. So he just kept welding until there were no leaks.
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So ugly. It seals though.

It is SOO much quieter. Just a little hollow cat sound but honestly it had some of that before for whatever reason.

Oddly, it threw a front O2 code while idling in Adam's driveway. So he reset it. I drove home, about 25 miles. No light (which means still no cat efficiency code). Maybe my front O2 is marginal. Drove well on the way home at least.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Mon May 28, 2018 4:59 pm

Should it ever throw a code and I still don't want to replace the cat, there is this:
https://www.magnumtuning.com/en/detail/ ... 500-pickup

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat Jun 23, 2018 4:04 pm

So it definitely needs an upstream O2. Had some issues at idle that clear up under any throttle (O2 heater not working right maybe?).

But then leaving Home Depot it started acting up even under throttle but still cleared up under more throttle, still indicating O2. Here are some bad readings I caught to help further my case:

The idle started falling off as low as like 250 rpm. Look at it pulling 33% of the fuel. Crazy. That's not right.
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I saw the same -33% under part throttle after I left Home Depot. Initially it was in open loop and driving fine. Then it went to closed loop, pulled all the fuel, and ran like shit.

So I ordered an NTK O2 sensor for $30. I wonder if the O2 sensor made the engine lean and that is what caused the cat to fail. I guess I'll never know.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat Jun 30, 2018 11:27 am

That's better.
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I was able to remove the O2 sensor without lifting the truck up. I did have to apply heat and use an open end wrench but I worked it back and forth. One of the hardest parts of the job was releasing the harness, which was on top of the transmission, with one hand. Once I did that it came out.

The new one threaded in and I tightened it with the wrench. However I just could not snap the harness plugs together with the room I had. So I drove it on ramps so I could get one hand around each side of the trans and snapped the plugs together.

The good news is the NTK 23151 appears to be the correct sensor, with the 12" harness. Per the scantool shot above, you can see the fuel trims are back to where they should be and I have not experienced the issue since replacement.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sat Sep 22, 2018 6:47 pm

Still no catalyst efficiency code despite the totally gutted cat. That's hilarious but I'll take it.

kevm14
Posts: 13936
Joined: Wed Oct 23, 2013 10:28 pm

Re: 99 Ram: intermittent loss of power

Post by kevm14 » Sun Sep 30, 2018 9:51 am

My cousins borrowed the truck all last week. The check engine light is on now. It finally set a P0420, cat efficiency. Must have been all the highway driving. Going to reset it...

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