Slow Down, and Noise

Gents,

I had the Slow Down light come on and had to drive another 10 miles. I have always had a noisey exhaust but not sure this is the exhaust. Replacing with Fab Speed. Added one quart of oil.

Race the engine, noise goes away. At idle, it is noisey. Trying to add an audio but too large (3 meg). So my question:

1. How to add an audio file or link to a file.
2. Going to turn the Slow Down light off and see if it returns.

I was planning the 30K service later, but may need to do it sooner.

Bob

 

Try putting it on You Tube with a link here.

What kind of cats do you have on the car?

 

Hi John K.

Factory everything. Had Cat error codes forever. I thought as you did. It is louder over the engine compartment than the exhausts, which worries me. I think the cats are shot.

Here is the link. Thanks and let me know your thoughts.

Boaf

 

It sounds a bit like exhaust rattle? Maybe cats. They are easy to pull and look inside, or even pull the muffler and look inside. This is what mine look like, notice nice clean honeycomb. If the cats are bad it will be VERY apparent and you can probably shake them and hear as well.

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Yep. I can still drive it 50 miles or so to my tech. I usually do this stuff myself, but just moved, had to leave my lift in my house (SH&^%$&). Shouldn't damage the motor, should it?

Boaf.

 

Hard to tell from the sound on my lap top speakers, but if it cats no it wont damage the motor. It its something else like valve-train or belt tensioners or what not then that's a different story.

Pull the rear bumper and pull the muffler, you can do that with the car on all 4 wheels no lift needed for that kind of stuff. Check the cats get peace of mind before going anywhere is what I would do.

 

Good point Ferrarium. I have a rubber hammer if I can get to the Cats, will give them a hit. I am feeling more and more confident that is it, but like you say, better safe than sorry. Looking at Evoflow cats. any experience with them?

Boaf

 

@ernie, Con I replace the factory cats with Evoflow flat on my back without my 4 post lift?

 

Well good and bad:

Found broken clamp on Drivers side exhaust. That was a nice rattle.
Hit the passenger side exhaust with a rubber hammer and heard the exhaust debris in the Cat.
Took a stethoscope to the engine, smooth (Yeah)! To the exhaust passenger side, marbles. Gonna replace both cats. Had engine codes for them anyhow so, it's time. Oh well.

Thank you gents for the help. Still wondering if I can replace the cats on my back. I think so but hate to do it in an apartment complex without jacks. Why did I move and not bring my lift with me? AARGHHH !

 

Dud you don't need a lift. Remove the bumper, drop the exhaust its right there. There is no "on your back" for that task.

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Like Eric said, you don't need a lift. I have done it with the bimper off and with it on. You don’t really need to remove the bumper unless you want ample space. I have replaced them by removing the rear wheels, wheel well liner/splash guard, I also remove the airbox, and muffler heat shielding for easier access from the top. It can be done either way, but you don’t need a lift to replace the cats.

 

Have you thought about re-coring your old cats (for originality)? I was thinking of doing that, but bought some Larini high flow cats in the meantime. They are relatively inexpensive comparted to OEM and well made.

 

If you're getting new cats consider new O2 sensors and thermocouples as well. Neither are designed to last forever.

Here are the thermocouples that I replaced recently. Notice the frayed shielding and exposed wiring.


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I agree I'd do thermo-couples and O2 and cats at the same time, wipe the slate clean and avoid other issues.

 

They look pretty good actually. That's how they are made, the two TC wires have to be exposed near the connector so that they can go into it. What looks "frayed" is a very thin plastic wrap over the two wires to protect their insulation under the metal shield and has no function over the exposed section of the wires. It is usually left loose there as it is difficult to trim back to the end of the shield. Otherwise, the individual insulation of the TC wires is a very tough type and will not fray or disintegrate easily.

 

Good to know. Thanks. My criteria is based on too many years of inspecting and fixing F-15s...

I was having random CELs but was mostly 1211 and 1212. So far so good with the new O2 sensors and TCs.

 

Having just pulled and gutted both cats in our car, it can be done from the top, too - just have to pull airboxes and the cat bypass pipe. Muffler and rear bumper can stay in place.

It's probably easier to get them from the bottom, but it's pretty simple from the top also.

 

Me too, replaced those items and whole fuel system, coolant temp sensors, coils, ignition, thermostat etc unrelated to any code. Then I got a 1212! It was MAF (or rebuild but I had new ones) it was the only thing not new. ta da fixed. 1212 can be lots of things or combo of things so fingers crossed for you! Coolant temp sensors are cheap and easy next step if it persists.

 

My cats wre shot, cracked honeycomb. I changed them with the bumper on, but I needed to jack up, jack down as the clamp bolts were on the top and bottom, and I couldn't reach the top if jacked up to reach the bottom. Quite doable though.

 

I was going to post the same thing earlier. I had 1212, 1211 codes periodically. Each tine I change the O2 sensor and it would go away for a while. Eventually it would come back. The 3rd time the car started running poorly at idle and would not take gas quickly. After dicking around with it in the garage I got it to throw an MAF code. Replaced the MAF and haven't had a problem since. I suspect what happens is that as the MAF starts to die it looses calibration and tells the ECU the wrong air volume. This, in my case, appeared to make the car run lean. As a result I suspect the LT fuel trim was bouncing off full rich and the O2 sensor had reached full scale and could correct any further. I also notice that my tail pipes have a little more carbon build up, like all my other cars.

 

I have hyperflow cats and Big daddy O2 simulators. They seem to work well, but I dont put very many miles on my car.

 

Ernie, Eric, thanks. I will order Evoflow cats and replace the originals. My jacks are also back in PA. I will get a new low profile jack. You don't appreciate a lift until you don't have it. Have you used EvoFlow's? $5400 for original Cats is not good.

Boaf

 

Thanks, I don't want to remove the bumper as I had it repaired from the Previous owner crack.

 

You might want to check out Nouvalari. Very similar 200 cell cats. When I bought mine that were about $500 less than the Evoflow cats. Good quality. No emission problems (sniff test). My car is a 95 so no cell issues to worry about.

 

I will thank you John, I appreciate it. I don't like to over pay for stuff, Like a $90 muffler clamp!