Diablo tuner

**Sas** · 09-21-2015, 05:39 AM

I've been having nothing but problems ever since I installed long tubes on the Firehawk, so a friend told me to get a Diablo tuner and re-tune it so that I stop burning out catalytic converters. I called them this morning to find out that not only do I pay for the tool, I'll also need to pay for a custom tune. I just ended up canceling the order for the tuner and am thinking of just buying a new PCM and sending it to Frost to have it done. Has anyone else had this problem, with melting cats out within an hour of putting them in off a stock tune for long tube headers? I've got emission coming up in a couple months and hope to have my car ready to pass them.

**0rion** · 09-21-2015, 08:21 AM

never heard of it......any codes? What exactly is going on with more detail? I would also recommend skipping the tuner in favor of a frost tune so you're on the right track. I was first try to figure out if you have something mechanical going on before getting a tune. Your post is a little vague and I would like to hear more details about exactly what's going on.

**35th-ANV-SS** · 09-21-2015, 08:39 AM

Usually, when installing headers, since you're allowing more air to exit the exhaust side quicker, the motor will tend to run a little rich (more fuel compensation from the PCM), but not to the tune of destroying catalytic converters. Especially that quickly. Sounds like perhaps something else is occuring. Like Tim said, post up any other details you can. Many install headers and never even get a retune, even though that would give you the most out of them.

**Sas** · 09-21-2015, 08:51 AM

The only codes I get are related to catalytic converters, enough to trigger a check engine light, I don't remember the exact code right now (in my office at work) but it only started happening after I switched from stock manifolds to the long tubes. I've had a couple full time mechanic friends of mine look it over and all they can think of is it needs a tune for the headers. Every other year when emissions come around I generally got to the muffler shop and have them put new cats in, then straight to the emissions testing center, and last year the light came on halfway through the test and it barely passed. I'm trying to get to the bottom of this to get things running proper up here in our thin air. I'll get the codes when I get back home, but the last 2 sets of cats I've pulled out have been completely hollow.

**Sas** · 09-21-2015, 10:00 AM

Codes P0420 and P0430 have been on for awhile now. I also see that I have 2 new codes that popped up and I'm guessing it's my rear o2 sensors (replaced them last year) P1153 and P1133

**silverWS6** · 09-22-2015, 07:39 AM

Definitely steer away from a handheld tuner, Frost is a good bet. What o2's are you running? What headers? I'm assuming no leaks either? Air leaks could cause those codes to come up also. I'm confused as to how it's hollowing out the cats.

**0rion** · 09-22-2015, 07:54 AM

where are you getting the cats from? That would be the first time ever I've heard of hollow cats. I've had cats fail but they plug up with the ceramic material. Something isn't right with the whole cats thing. 420 and 430 would be consistent with either cats failing or rear O2's failing. The 1133 and 1153 are switching codes for the front O2's which are common with headers. Frost can maybe tune around that but don't quote me on that. I, along with others, have had luck with switching and heater codes by going to bosch 13111 sensors in the front. What I would probably do is put the bosch sensors in the front and move your front sensors to the rear since those sound like they're new. Those sensors will work in the front or rear.

**Sas** · 09-22-2015, 05:23 PM

Bosch o2's, magnaflow cats, just checked the gaskets and no leaks up top. My tablet deleted my last post somehow.

**0rion** · 09-22-2015, 07:41 PM

bosch makes more than one O2. 13111 sensors are actually vette rears and will have a longer harness than the stock fronts. Did you have to use O2 extensions when you went with headers? That's the quickest way to tell if you have 13111 sensors because they don't require the extensions since the harness is longer.

**RONS98TA** · 09-23-2015, 04:36 AM

Hollow cats??!!!! You my friend have been getting ripped off. Someone is selling you a shell and not a cat. Catalytic converters have a honey comb beehive look to them on the inside. They are NOT hollow.

**RONS98TA** · 09-23-2015, 04:46 AM

Attachment 26395 This is before modification.

**RONS98TA** · 09-23-2015, 04:56 AM

cat after.jpgThis is BEFORE modification. If your cats are not coming off the car like this, then they have been hollowed out. I have never seen a cat get that way by itself. I dont even see how its possible. and this has happened more than once?

**Sas** · 09-23-2015, 05:44 AM

I know how the cats are supposed to look, and they looked fine when they went on, however when they came off they were empty both times. I have the Bosch 13111 o2 sensors on it. As far as the cats hollowing out, I was told if they get put on with a hammer it will happen every time, so I'm guessing the shop I had do it got a little carried away with a hammer. When I get the new cats in I'll be doing them myself with clamps, rather then having them welded on like I had in the past.

**35th-ANV-SS** · 09-23-2015, 06:35 AM

Agree...the material inside the cat just doesn't disappear. It doesn't melt away either. It breaks down and collapses clogging it up. If they are hollow on the inside, that is not a catalytic converter...that is a metal shell you're buying that represents a real one to pass visual inspection.

**Sas** · 09-23-2015, 07:32 PM

Texas Speed is where I've been getting them through, listed as high flow cats. They had material in them both times before install, and none after.

**speedyWS6** · 09-23-2015, 10:45 PM

Not sure if you have had ceramic or metallic compounds inside your cats but I always
go for the metallic internals as they are more durable.

As far as using a hammer to fit them... never should have to if the slip fit is ok and there
is ALWAYS a way to not use the BFH method if you do it right!

In the past I have tracked down a place to open the dia. up slightly with a tubing expander.

**Firebirdjones** · 09-25-2015, 07:05 AM

I've never experienced this myself but I have heard and seen some cats with pieces of the honeycomb broken off and missing. I was told the car was blowing pieces out of the tailpipes. I did see the cats removed and there was a small section of honeycomb missing.
I have no clue how that could happen however, and I don't think a tune would have anything to do with it. I kind of wondered if that car had bottomed out over something and broke the honeycomb that way. Just a guess.

I tend to believe when it comes to this aftermarket stuff, it has more to do with a cheaply made cat. They use cheaper materials making these aftermarket cats, that's how they are able to sell them so cheaply. By design, I've read they usually don't go more than 2-3 years before they need replaced. Which is why the aftermarket stuff generally doesn't have much of a warranty with them. The OEM cats are the only ones I've seen that last in most cases the life of the vehicle and are usually warrantied for 100k miles or so. Shucks the little 89 5.0 mustang I have still had all four of it's original cats in place and functioning properly after 220,000 miles, ran perfect and passed the sniffer.

I hate to say it but in my opinion, with long tube headers you are stuck using aftermarket cats, and with that said you might be stuck replacing the darn things more frequently.

**RONS98TA** · 09-26-2015, 04:09 AM

So the moral of the story is cheap aftermarket cats = junk. I would get a frost tune to delete the rear o2's, so the cats will no longer be needed. Keep the hollow shells there just so it appears it has cats on it. Then, the car will then always pass emissions. (as far as the cats are concerned anyway) While you're at it, also have frost tune out the A.I.R. and EGR systems. You can then remove all that stuff to clean up the engine compartment a little, and lose a few lbs of weight off the car.

**Sas** · 09-26-2015, 06:22 AM

Thanks for the input, if this last set of cats doesn't hold up, I'll probably just put everything back to factory, because I'm sick of fighting the danged things. I plan on sending the pcm to Frost before I slap the new cats on. Might be awhile though before I have the funds for it. Cross your fingers for me on this last set.